1
|
Venugopal A, Paplikar A, Varghese FA, Thanissery N, Ballal D, Hoskeri RM, Shekar R, Bhaskarapillai B, Arshad F, Purushothaman VV, Anniappan AB, Rao GN, Alladi S. Protective effect of bilingualism on aging, MCI, and dementia: A community-based study. Alzheimers Dement 2024; 20:2620-2631. [PMID: 38376105 PMCID: PMC11032525 DOI: 10.1002/alz.13702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 12/27/2023] [Accepted: 12/29/2023] [Indexed: 02/21/2024]
Abstract
INTRODUCTION Lifelong bilingualism is associated with a delayed age at onset of dementia, but evidence from community-based studies is limited. We investigated the relationship between bilingualism and the prevalence of cognitive impairment in a linguistically diverse community. METHODS A door-to-door community study was conducted from January to December 2021 in urban Bengaluru, India. 1234 individuals aged ≥60 years participated in the study. Participants were diagnosed with no cognitive impairment (NCI), mild cognitive impairment (MCI), or dementia using established diagnostic criteria. RESULTS Dementia prevalence was higher in monolinguals (4.9%) than bilinguals (0.4%) (P = .001). The prevalence of MCI was also higher in monolinguals (8.5%) than bilinguals (5.3%) (P = .001). The study also revealed better cognitive function in bilinguals than monolinguals with NCI, after controlling for confounding variables. DISCUSSION The current study provides significant support for the protective effect of bilingualism on cognitive impairment in an urban community with extensive bilingual interactional contexts in everyday life. HIGHLIGHTS Bilingualism has been demonstrated to protect against dementia and mild cognitive impairment in a linguistically diverse community with extensive code-switching contexts. Bilingual older individuals had superior baseline cognitive performance compared to monolingual older individuals. Bilingualism was found to have an independent effect on general cognition after adjusting for major social determinants of health in the group without cognitive impairment.
Collapse
Affiliation(s)
- Aparna Venugopal
- Department of NeurologyNational Institute of Mental Health and NeurosciencesBengaluruKarnatakaIndia
- Department of Speech Pathology & AudiologyNational Institute of Mental Health and NeurosciencesBengaluruKarnatakaIndia
| | - Avanthi Paplikar
- Department of NeurologyNational Institute of Mental Health and NeurosciencesBengaluruKarnatakaIndia
- Department of Speech and Language StudiesDr. S. R. Chandrasekhar Institute of Speech and HearingBengaluruKarnatakaIndia
| | - Feba Anna Varghese
- Department of NeurologyNational Institute of Mental Health and NeurosciencesBengaluruKarnatakaIndia
| | - Nithin Thanissery
- Department of NeurologyNational Institute of Mental Health and NeurosciencesBengaluruKarnatakaIndia
| | - Divya Ballal
- Department of NeurologyNational Institute of Mental Health and NeurosciencesBengaluruKarnatakaIndia
| | | | - Revathi Shekar
- Department of NeurologyNational Institute of Mental Health and NeurosciencesBengaluruKarnatakaIndia
| | - Binukumar Bhaskarapillai
- Department of BiostatisticsNational Institute of Mental Health and NeurosciencesBengaluruKarnatakaIndia
| | - Faheem Arshad
- Department of NeurologyNational Institute of Mental Health and NeurosciencesBengaluruKarnatakaIndia
| | | | | | - Girish Nagaraja Rao
- Department of EpidemiologyNational Institute of Mental Health and NeurosciencesBengaluruKarnatakaIndia
| | - Suvarna Alladi
- Department of NeurologyNational Institute of Mental Health and NeurosciencesBengaluruKarnatakaIndia
| |
Collapse
|
2
|
Vélez-Uribe I, Rosselli M, Newman D, Gonzalez J, Gonzalez Pineiro Y, Barker WW, Marsiske M, Fiala J, Lang MK, Conniff J, Ahne E, Goytizolo A, Loewenstein DA, Curiel RE, Duara R. Cross-cultural Diagnostic Validity of the Multilingual Naming Test (MINT) in a Sample of Older Adults. Arch Clin Neuropsychol 2023:acad093. [PMID: 38123477 DOI: 10.1093/arclin/acad093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 11/06/2023] [Accepted: 11/11/2023] [Indexed: 12/23/2023] Open
Abstract
OBJECTIVE We aimed to evaluate the psychometric properties and diagnostic accuracy of the 32-item version of the Multilingual Naming Test (MINT) in participants from 2 ethnic groups (European Americans [EA; n = 106] and Hispanic Americans [HA; n = 175]) with 3 diagnostic groups (cognitively normal [CN], n = 94, mild cognitive impairment [MCI], n = 148, and dementia, n = 39). METHOD An Item Response Theory model was used to evaluate items across ethnicity and language groups (Spanish and English), resulting in a 24-item version. We analyzed the MINT discriminant and predictive validity across diagnostic groups. RESULTS A total of 8 items were differentially difficult between languages in the 32-item version of the MINT. EA scored significantly higher than HA, but the difference was not significant when removing those 8 items (controlling for Education). The Receiver Operating Characteristics showed that the MINT had poor accuracy when identifying CN participants and was acceptable in identifying dementia participants but unacceptable in classifying MCI participants. Finally, we tested the association between MINT scores and magnetic resonance imaging volumetric measures of language-related areas in the temporal and frontal lobes. The 32-item MINT in English and Spanish and the 24-item MINT in Spanish were significantly correlated with the bilateral middle temporal gyrus. The left fusiform gyrus correlated with MINT scores regardless of language and MINT version. We also found differential correlations depending on the language of administration. CONCLUSIONS Our results highlight the importance of analyzing cross-cultural samples when implementing clinical neuropsychological tests such as the MINT.
Collapse
Affiliation(s)
- Idaly Vélez-Uribe
- Florida Alzheimer's Disease Research Center, Miami Beach and Gainesville, FL, USA
- Wien Center for Alzheimer's Disease and Memory Disorders, Mount Sinai Medical Center, Miami Beach, FL, USA
| | - Mónica Rosselli
- Florida Alzheimer's Disease Research Center, Miami Beach and Gainesville, FL, USA
- Department of Psychology, Charles E. Schmidt College of Science, Florida Atlantic University, Davie, FL, USA
| | - David Newman
- Christine E. Lynn College of Nursing, Florida Atlantic University, Boca Raton, FL, USA
| | - Joanna Gonzalez
- Wien Center for Alzheimer's Disease and Memory Disorders, Mount Sinai Medical Center, Miami Beach, FL, USA
| | - Yaimara Gonzalez Pineiro
- Wien Center for Alzheimer's Disease and Memory Disorders, Mount Sinai Medical Center, Miami Beach, FL, USA
| | - Warren W Barker
- Florida Alzheimer's Disease Research Center, Miami Beach and Gainesville, FL, USA
- Wien Center for Alzheimer's Disease and Memory Disorders, Mount Sinai Medical Center, Miami Beach, FL, USA
| | - Michael Marsiske
- Florida Alzheimer's Disease Research Center, Miami Beach and Gainesville, FL, USA
- Department of Clinical and Health Psychology, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA
| | - Jacob Fiala
- Florida Alzheimer's Disease Research Center, Miami Beach and Gainesville, FL, USA
- Department of Clinical and Health Psychology, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA
| | - Merike K Lang
- Department of Psychology, Charles E. Schmidt College of Science, Florida Atlantic University, Davie, FL, USA
| | - Joshua Conniff
- Department of Psychology, Charles E. Schmidt College of Science, Florida Atlantic University, Davie, FL, USA
| | - Emily Ahne
- Department of Psychology, Charles E. Schmidt College of Science, Florida Atlantic University, Davie, FL, USA
| | - Alicia Goytizolo
- Department of Psychology, Charles E. Schmidt College of Science, Florida Atlantic University, Davie, FL, USA
| | - David A Loewenstein
- Florida Alzheimer's Disease Research Center, Miami Beach and Gainesville, FL, USA
- Department of Psychiatry and Behavioral Sciences and Center for Cognitive Neuroscience and Aging, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Rosie E Curiel
- Florida Alzheimer's Disease Research Center, Miami Beach and Gainesville, FL, USA
- Department of Psychiatry and Behavioral Sciences and Center for Cognitive Neuroscience and Aging, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Ranjan Duara
- Florida Alzheimer's Disease Research Center, Miami Beach and Gainesville, FL, USA
- Wien Center for Alzheimer's Disease and Memory Disorders, Mount Sinai Medical Center, Miami Beach, FL, USA
| |
Collapse
|
3
|
Mendez MF. Can Speaking More Than One Language Help Prevent Alzheimer's Disease? J Alzheimers Dis 2023; 95:363-377. [PMID: 37545240 DOI: 10.3233/jad-230285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Alzheimer's disease (AD) is an age-related neurocognitive disorder that is epidemic in the elderly population. Currently, there are limited pharmacological interventions, and this has heightened the urgency to identify potential preventable or modifiable risk factors that promote resilience to the neuropathological effects of AD. The regular use of two or more languages is one such factor that may increases cognitive reserve through the long-standing executive control involved in managing multiple languages in the brain. There is also evidence that bilingualism is associated with increased brain reserve or maintenance, particularly in frontal-executive structures and networks. This review examines the current, sometimes conflicting literature on bi/multilingualism and AD. These studies have confounding variations in the assessment of age of second language onset, language proficiency, language usage, and whether determining incidence of AD or age of symptom onset. Despite these limitations, most publications support the presence of increased frontal-executive reserve that compensates for the development of AD neuropathology and, thereby, delays the emergence of clinical symptoms of dementia by about 4-5 years. Although regularly speaking more than one language does not protect against AD neuropathology, the delay in its clinical expression has a potentially significant impact on the lifelong morbidity from this age-related disease. Learning other languages may be an important modifiable factor for delaying the clinical expression of AD in later life.
Collapse
Affiliation(s)
- Mario F Mendez
- Departments of Neurology and Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, and Neurology Service, Neurobehavior Unit, U.S. Department of Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| |
Collapse
|
4
|
Gallo F, DeLuca V, Prystauka Y, Voits T, Rothman J, Abutalebi J. Bilingualism and Aging: Implications for (Delaying) Neurocognitive Decline. Front Hum Neurosci 2022; 16:819105. [PMID: 35185498 PMCID: PMC8847162 DOI: 10.3389/fnhum.2022.819105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 01/11/2022] [Indexed: 12/27/2022] Open
Abstract
As a result of advances in healthcare, the worldwide average life expectancy is steadily increasing. However, this positive trend has societal and individual costs, not least because greater life expectancy is linked to higher incidence of age-related diseases, such as dementia. Over the past few decades, research has isolated various protective "healthy lifestyle" factors argued to contribute positively to cognitive aging, e.g., healthy diet, physical exercise and occupational attainment. The present article critically reviews neuroscientific evidence for another such factor, i.e., speaking multiple languages. Moreover, with multiple societal stakeholders in mind, we contextualize and stress the importance of the research program that seeks to uncover and understand potential connections between bilingual language experience and cognitive aging trajectories, inclusive of the socio-economic impact it can have. If on the right track, this is an important line of research because bilingualism has the potential to cross-over socio-economic divides to a degree other healthy lifestyle factors currently do not and likely cannot.
Collapse
Affiliation(s)
- Federico Gallo
- Centre for Cognition and Decision Making, Institute for Cognitive Neuroscience, National Research University Higher School of Economics, Moscow, Russia
- Centre for Neurolinguistics and Psycholinguistics (CNPL), Vita-Salute San Raffaele University, Milan, Italy
| | - Vincent DeLuca
- PoLaR Lab, AcqVA Aurora Centre, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Yanina Prystauka
- PoLaR Lab, AcqVA Aurora Centre, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Toms Voits
- PoLaR Lab, AcqVA Aurora Centre, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Jason Rothman
- PoLaR Lab, AcqVA Aurora Centre, UiT-The Arctic University of Norway, Tromsø, Norway
- Centro de Investigación Nebrija en Cognición (CINC), University Nebrija, Madrid, Spain
| | - Jubin Abutalebi
- Centre for Neurolinguistics and Psycholinguistics (CNPL), Vita-Salute San Raffaele University, Milan, Italy
- PoLaR Lab, AcqVA Aurora Centre, UiT-The Arctic University of Norway, Tromsø, Norway
| |
Collapse
|
5
|
Taylor C, Hall S, Manivannan S, Mundil N, Border S. The neuroanatomical consequences and pathological implications of bilingualism. J Anat 2022; 240:410-427. [PMID: 34486112 PMCID: PMC8742975 DOI: 10.1111/joa.13542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 07/26/2021] [Accepted: 08/23/2021] [Indexed: 01/17/2023] Open
Abstract
In recent years, there has been a rise in the number of people who are able to speak two or more languages. This has been paralleled by an increase in research related to bilingualism. Despite this, much of the neuroanatomical consequences and pathological implications of bilingualism are still subject to discussion. This review aims to evaluate the neuroanatomical structures related to language and to the acquisition of a second language as well as exploring how learning a second language can alter one's susceptibility to and the progression of certain cerebral pathologies. A literature search was conducted on the Medline, Embase, and Web of Science databases. A total of 137 articles regarding the neuroanatomical or pathological implications of bilingualism were included for review. Following analysis of the included papers, this review finds that bilingualism induces significant gray and white matter cerebral changes, particularly in the frontal lobes, anterior cingulate cortex, left inferior parietal lobule and subcortical areas, and that native language and acquired language largely recruit the same neuroanatomical structures with however, subtle functional and anatomical differences dependent on proficiency and age of language acquisition. There is adequate evidence to suggest that bilingualism offsets the symptoms and diagnosis of dementia, and that it is protective against both pathological and age-related cognitive decline. While many of the neuroanatomical changes are known, more remains to be elucidated and the relationship between bilingualism and other neurological pathologies remains unclear.
Collapse
Affiliation(s)
- Charles Taylor
- Centre for Learning Anatomical SciencesFaculty of MedicineUniversity of SouthamptonSouthamptonUK
| | - Samuel Hall
- Centre for Learning Anatomical SciencesFaculty of MedicineUniversity of SouthamptonSouthamptonUK
- Department of NeurosurgeryUniversity Hospitals Southampton NHS Foundation TrustSouthamptonUK
| | - Susruta Manivannan
- Department of NeurosurgeryUniversity Hospitals Southampton NHS Foundation TrustSouthamptonUK
| | - Nilesh Mundil
- Department of NeurosurgeryUniversity Hospitals Southampton NHS Foundation TrustSouthamptonUK
| | - Scott Border
- Centre for Learning Anatomical SciencesFaculty of MedicineUniversity of SouthamptonSouthamptonUK
| |
Collapse
|
6
|
Sörman DE, Stenling A, Sundström A, Rönnlund M, Vega-Mendoza M, Hansson P, Ljungberg JK. Occupational cognitive complexity and episodic memory in old age. Intelligence 2021. [DOI: 10.1016/j.intell.2021.101598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
7
|
Berkes M, Bialystok E, Craik FIM, Troyer A, Freedman M. Conversion of Mild Cognitive Impairment to Alzheimer Disease in Monolingual and Bilingual Patients. Alzheimer Dis Assoc Disord 2020; 34:225-30. [PMID: 32049674 DOI: 10.1097/WAD.0000000000000373] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Conversion rates from mild cognitive impairment (MCI) to Alzheimer disease (AD) were examined considering bilingualism as a measure of cognitive reserve. METHODS Older adult bilingual (n=75) and monolingual (n=83) patients attending a memory clinic who were diagnosed with MCI were evaluated for conversion to AD. Age of MCI and AD diagnoses and time to convert were recorded and compared across language groups. PATIENTS Patients were consecutive patients diagnosed with MCI at a hospital memory clinic. RESULTS Bilingual patients were diagnosed with MCI at a later age than monolingual patients (77.8 and 75.5 y, respectively), a difference that was significant in some analyses. However, bilingual patients converted faster from MCI to AD than monolingual patients (1.8 and 2.8 y, respectively) resulting in no language group difference in age of AD diagnosis. This relationship held after accounting for education, cognitive level, immigration status, and sex. DISCUSSION The findings suggest that greater cognitive reserve as measured by language status leads to faster conversion between MCI and AD, all else being equal.
Collapse
|
8
|
Abstract
Dementia is a global public health priority which cost global societies $818 billion in 2015 and is disproportionately impacting low and middle-income countries (LMICs). With limited availability of disease modifying drugs to treat Alzheimer's disease (AD), researchers have increasingly focused on preventative strategies which may promote healthy cognitive aging and mitigate the risk of cognitive impairment in aging. Lifelong bilingualism has been presented as both a highly debated and promising cognitive reserve factor which has been associated with better cognitive outcomes in aging. A recent metanalysis has suggested that bilingual individuals present on average 4.05 years later with the clinical features of AD than monolinguals. Bilinguals are also diagnosed with AD ~2.0 years later than monolingual counterparts. In this perspective piece we critically evaluate the findings of this metanalysis and consider the specific implications of these findings to LMICs. Furthermore, we appraise the major epidemiological studies conducted globally on bilingualism and the onset of dementia. We consider how both impactful and robust studies of bilingualism and cognition in older age may be conducted in LMICs. Given the limited expenditure and resources available in LMICs and minimal successes of clinical trials of disease modifying drugs we propose that bilingualism should be positioned as an important and specific public health strategy for maintaining healthy cognitive aging in LMICs. Finally, we reflect upon the scope of implementing bilingualism within the education systems of LMICs and the promotion of bilingualism as a healthy cognitive aging initiative within government policy.
Collapse
Affiliation(s)
| | - Vanessa Raymont
- Oxford Brain Health Clinical Trials Unit, Oxford, United Kingdom
| | - Naji Tabet
- Center for Dementia Studies, Brighton and Sussex Medical School, Brighton, United Kingdom
| |
Collapse
|
9
|
Fishman KN, Roberts AC, Orange JB, Sunderland KM, Marras C, Tan B, Steeves T, Kwan D, Lang AE, Grimes D, Levine B, Masellis M, Binns MA, Jog M, Strother SC, Investigators O, McLaughlin PM, Troyer AK. Bilingualism in Parkinson's disease: Relationship to cognition and quality of life. J Clin Exp Neuropsychol 2021; 43:199-212. [PMID: 33827353 DOI: 10.1080/13803395.2021.1902946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Some studies have found that bilingualism promotes cognitive reserve. OBJECTIVE We aimed to determine whether bilingualism, defined as regularly (i.e. daily) using at least two languages at least since early adulthood, is associated with cognitive advantages in Parkinson's disease (PD) or whether the possible benefits of bilingualism are lost in the context of PD, possibly affecting quality of life (QoL) and independence. METHOD Participants with idiopathic PD (n = 140, mean age = 67.9 [SD = 6.4], 78% men) completed standard neuropsychological tasks evaluating attention/working memory, language, executive function, memory, and visuospatial ability, as well as measures of wellbeing and functional independence. RESULTS Bilinguals with PD (n = 21) performed worse than monolinguals with PD (n = 92) on attention/working memory and language measures. The between-group differences in attention/working memory were restricted to verbally-based measures. When measured along a continuum, a higher degree of bilingualism was correlated with lower scores on measures of attention/working memory and language. There were no group differences in self- or informant-reported cognitive decline, PD health-related QoL, or functional independence. CONCLUSIONS Bilingualism in PD was not associated with better cognitive performance. Lower scores on language-based measures may reflect a distributed fund of linguistic information across more than one language, lower language proficiency in English, and/or other cultural artifacts. Furthermore, using normative data specific to the dominant language spoken or conducting neuropsychological testing in participants' self-reported most proficient language may enhance additional studies addressing this topic. Future research may also examine the roles of bilingualism over time and across other neurodegenerative diseases with and without EF impairment to illuminate further the impact of bilingualism on cognition and QoL, and shape culturally and linguistically diverse research and clinical care.
Collapse
Affiliation(s)
- Keera N Fishman
- University of Ottawa, Ottawa, Ontario, Canada.,Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Angela C Roberts
- Northwestern University, Evanston, Illinois, USA.,, Western University, London, Ontario, Canada
| | - J B Orange
- , Western University, London, Ontario, Canada
| | | | - Connie Marras
- , University of Toronto, Toronto, Ontario, Canada.,Toronto Western Hospital, Toronto, Ontario, Canada
| | - Brian Tan
- Baycrest Health Sciences, Toronto, Ontario, Canada
| | | | - Donna Kwan
- Queen's University, Toronto, Ontario, Canada
| | - Anthony E Lang
- , University of Toronto, Toronto, Ontario, Canada.,Toronto Western Hospital, Toronto, Ontario, Canada
| | - David Grimes
- University of Ottawa, Ottawa, Ontario, Canada.,The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Brian Levine
- Baycrest Health Sciences, Toronto, Ontario, Canada.,, University of Toronto, Toronto, Ontario, Canada
| | - Mario Masellis
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Malcolm A Binns
- Baycrest Health Sciences, Toronto, Ontario, Canada.,, University of Toronto, Toronto, Ontario, Canada
| | - Mandar Jog
- , Western University, London, Ontario, Canada
| | - Stephen C Strother
- Baycrest Health Sciences, Toronto, Ontario, Canada.,, University of Toronto, Toronto, Ontario, Canada
| | | | - Paula M McLaughlin
- Queen's University, Toronto, Ontario, Canada.,Nova Scotia Health Authority, Halifax, Nova Scotia, Canada
| | - Angela K Troyer
- Baycrest Health Sciences, Toronto, Ontario, Canada.,, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
10
|
Abstract
Evidence suggests that bilingualism may contribute to neuroplasticity and cognitive reserve, allowing individuals to resist cognitive decline associated with Alzheimer's disease progression, although the idea remains controversial. Here, we argue that the reason for the discrepancy stems from conflating incidence rates of dementia and the age at which the symptoms first appear, as well as statistical and methodological issues in the study designs. To clarify the issues, we conducted a comprehensive meta-analysis on the available literature regarding bilingualism and Alzheimer's disease, including both retrospective and prospective studies, as well as age of onset and incidence rates. Results revealed a moderate effect size for the protective effect of bilingualism on age of onset of symptoms of Alzheimer's disease (Cohen's d = 0.32), and weaker evidence that bilingualism prevents the occurrence of disease incidence itself (Cohen's d = 0.10). Moreover, our results cannot be explained by SES, education, or publication bias. We conclude with a discussion on how bilingualism contributes to cognitive reserve and protects against Alzheimer's disease and recommend that future studies report both age of onset as well as incidence rates when possible.
Collapse
|
11
|
Liu H, Wu L. Lifelong Bilingualism Functions as an Alternative Intervention for Cognitive Reserve Against Alzheimer's Disease. Front Psychiatry 2021; 12:696015. [PMID: 34366926 PMCID: PMC8339371 DOI: 10.3389/fpsyt.2021.696015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/04/2021] [Indexed: 11/13/2022] Open
Abstract
Bilingualism has been reported to significantly delay the onset of dementia and plays an important role in the management of Alzheimer's disease (AD), a condition inducing impairment in the brain network and cognitive decline. Cognitive reserve is associated with the adaptive maintenance of neural functions by protecting against neuropathology. Bilingualism acts as a beneficial environmental factor contributing to cognitive reserve, although some potential confounding variables still need further elucidation. In this article, the relationship between bilingualism and cognitive reserve is discussed, interpreting the advantage of bilingualism in protecting against cognitive decline. In addition, the possible brain and biochemical mechanisms, supporting the advantageous effects of bilingualism in delaying the onset of dementia, involved in bilingualism are reviewed. Effectively, bilingualism can be considered as a pharmacological intervention with no side effects. However, the investigation of the pharmacological parameters of bilingualism is still at an early stage.
Collapse
Affiliation(s)
- Haiqing Liu
- Department of Foreign Languages, School of Humanities and Social Sciences, Gannan Medical University, Ganzhou, China
| | - Longhuo Wu
- Department of Pharmacy, Gannan Medical University, Ganzhou, China
| |
Collapse
|
12
|
de Leon J, Grasso SM, Welch A, Miller Z, Shwe W, Rabinovici GD, Miller BL, Henry ML, Gorno-Tempini ML. Effects of bilingualism on age at onset in two clinical Alzheimer's disease variants. Alzheimers Dement 2020; 16:1704-1713. [PMID: 32881346 DOI: 10.1002/alz.12170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 03/26/2020] [Accepted: 07/10/2020] [Indexed: 12/11/2022]
Abstract
INTRODUCTION The effect of bilingualism on age at onset has yet to be examined within different clinical variants of Alzheimer's disease. METHODS We reviewed the research charts of 287 well-characterized participants with either amnestic Alzheimer's dementia or logopenic variant primary progressive aphasia (lvPPA) and identified bilingual speakers based on regular use of two or more languages and/or ability to communicate with native speakers in two or more languages. We evaluated whether bilingual speakers demonstrated a delay in age of symptom onset relative to monolingual speakers while controlling for other variables known to influence cognitive reserve. RESULTS A 5-year delay in age at symptom onset was observed for bilingual relative to monolingual speakers with lvPPA. This delay in onset was not observed in the amnestic Alzheimer's dementia cohort. DISCUSSION Bilingualism may serve as a unique cognitive reserve variable in lvPPA, but not in amnestic Alzheimer's dementia.
Collapse
Affiliation(s)
- Jessica de Leon
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, California, USA
| | - Stephanie M Grasso
- Department of Communication Sciences and Disorders, University of Texas At Austin, Texas, USA
| | - Ariane Welch
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, California, USA
| | - Zachary Miller
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, California, USA
| | - Wendy Shwe
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, California, USA
| | - Gil D Rabinovici
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, California, USA
| | - Bruce L Miller
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, California, USA
| | - Maya L Henry
- Department of Communication Sciences and Disorders, University of Texas At Austin, Texas, USA
| | - Maria Luisa Gorno-Tempini
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, California, USA
| |
Collapse
|
13
|
Voits T, Pliatsikas C, Robson H, Rothman J. Beyond Alzheimer's disease: Can bilingualism be a more generalized protective factor in neurodegeneration? Neuropsychologia 2020; 147:107593. [PMID: 32882240 DOI: 10.1016/j.neuropsychologia.2020.107593] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/10/2020] [Accepted: 08/26/2020] [Indexed: 01/18/2023]
Abstract
Bilingualism has been argued to have an impact on cognition and brain structure. Effects have been reported across the lifespan: from healthy children to ageing adults, including clinical (ageing) populations. It has been argued that active bilingualism may significantly contribute to the delaying of the expression of Alzheimer's disease symptoms. If bilingualism plays an ameliorative role against the expression of neurodegeneration in dementia, it is possible that it could have similar effects for other neurodegenerative disorders, including Multiple Sclerosis, Parkinson's and Huntington's Diseases. To date, however, direct relevant evidence remains limited, not least because the necessary scientific motivations for investigating this with greater depth have not yet been fully articulated. Herein, we provide a roadmap that reviews the relevant literatures, highlighting potential links across neurodegenerative disorders and bilingualism more generally.
Collapse
|
14
|
Celik S, Kokje E, Meyer P, Frölich L, Teichmann B. Does bilingualism influence neuropsychological test performance in older adults? A systematic review. Appl Neuropsychol Adult 2020; 29:855-873. [PMID: 32677470 DOI: 10.1080/23279095.2020.1788032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Using standardized tests which have been normed on monolinguals for the assessment of bilinguals presents challenges to the accurate characterization of cognitive profile as the literature provides compelling evidence for the influence of bilingualism on cognitive abilities. However, little is known about the generalizability of these findings to clinical neuropsychology. The aim of this review was to address this gap by summarizing current evidence on the performance of bilingual older adults on standardized tests routinely used in clinical practice. METHOD A systematic search of Web of Science, PsycINFO and PubMed was conducted. 27 cross-sectional and longitudinal studies which use at least one standardized neuropsychological test for cognitive impairment were included in the review. Potential demographic (cultural/linguistic background of the participants, immigrant status), clinical (diagnostic status), and methodological confounders (language of test administration, components of bilingualism) were also examined. The review protocol was registered at the PROSPERO International Prospective Register of Systematic Review with registration number CRD42018114658. RESULTS The results of this review revealed some bilingual advantage on measures of inhibitory control and bilingual disadvantage on measures of verbal fluency in cross-sectional studies. Bilingualism status was not associated with test performance in longitudinal studies. However, findings lack consistency due to demographic variables and methodological differences across studies. CONCLUSION Neuropsychological tests assessing language domains and, to some extent executive function act as clinically relevant features of bilingualism for neuropsychological evaluation. However, immigration status, acculturation level and language of test administration needs to be taken into account when assessing bilingual older adults.
Collapse
Affiliation(s)
- Simge Celik
- Network Aging Research, Heidelberg University, Heidelberg, Germany
| | - Eesha Kokje
- Network Aging Research, Heidelberg University, Heidelberg, Germany
| | - Patric Meyer
- Network Aging Research, Heidelberg University, Heidelberg, Germany.,Faculty of Applied Psychology, SRH University Heidelberg, Heidelberg, Germany
| | - Lutz Frölich
- Network Aging Research, Heidelberg University, Heidelberg, Germany.,Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Birgit Teichmann
- Network Aging Research, Heidelberg University, Heidelberg, Germany
| |
Collapse
|
15
|
Calabria M, Hernández M, Cattaneo G, Suades A, Serra M, Juncadella M, Reñé R, Sala I, Lleó A, Ortiz-Gil J, Ugas L, Ávila A, Ruiz IG, Ávila C, Costa A. Active bilingualism delays the onset of mild cognitive impairment. Neuropsychologia 2020; 146:107528. [PMID: 32540266 DOI: 10.1016/j.neuropsychologia.2020.107528] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 06/05/2020] [Accepted: 06/07/2020] [Indexed: 11/23/2022]
Abstract
Lifelong bilingualism may contribute to cognitive reserve (CR) in neurodegenerative diseases as shown by a delay of the age at symptom onset in bilinguals with Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI). However, some studies have failed to show this bilingual advantage, suggesting that it might depend on the type and degree of bilingualism. In the present study, we tested the hypothesis that active bilingualism, defined as the continuous use of the two languages as opposed to second language exposition only, may protect against cognitive decline. Moreover, we investigated whether bilingualism as a CR factor may be explained by an advantage within the executive control (EC) system. To do so, we collected clinical measures (age at onset of cognitive symptoms, age at the first medical visit for cognitive impairments, and age at diagnosis) in patients with MCI and patients with AD with different degrees of language experience and usage of Catalan and Spanish. Additionally, all participants were tested on four EC tasks and one long-term memory recognition task. First, results from multiple regression analyses showed that active bilingualism was a significant predictor of delay in the age at onset for all the clinical measures in MCI, but not AD patients. Second, the effect of active bilingualism was independent of occupation, educational level and job attainment across the individuals' lifespan. Finally, although we did not find an effect of active bilingualism across all EC tasks, we did find an effect for conflict resolution. These results are discussed in the context of CR hypotheses, suggesting that compensatory mechanisms may play a role in protecting against cognitive decline.
Collapse
|
16
|
Brini S, Sohrabi HR, Hebert JJ, Forrest MRL, Laine M, Hämäläinen H, Karrasch M, Peiffer JJ, Martins RN, Fairchild TJ. Bilingualism Is Associated with a Delayed Onset of Dementia but Not with a Lower Risk of Developing it: a Systematic Review with Meta-Analyses. Neuropsychol Rev 2020; 30:1-24. [PMID: 32036490 PMCID: PMC7089902 DOI: 10.1007/s11065-020-09426-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 01/03/2020] [Indexed: 12/14/2022]
Abstract
Some studies have linked bilingualism with a later onset of dementia, Alzheimer's disease (AD), and mild cognitive impairment (MCI). Not all studies have observed such relationships, however. Differences in study outcomes may be due to methodological limitations and the presence of confounding factors within studies such as immigration status and level of education. We conducted the first systematic review with meta-analysis combining cross-sectional studies to explore if bilingualism might delay symptom onset and diagnosis of dementia, AD, and MCI. Primary outcomes included the age of symptom onset, the age at diagnosis of MCI or dementia, and the risk of developing MCI or dementia. A secondary outcome included the degree of disease severity at dementia diagnosis. There was no difference in the age of MCI diagnosis between monolinguals and bilinguals [mean difference: 3.2; 95% confidence intervals (CI): -3.4, 9.7]. Bilinguals vs. monolinguals reported experiencing AD symptoms 4.7 years (95% CI: 3.3, 6.1) later. Bilinguals vs. monolinguals were diagnosed with dementia 3.3 years (95% CI: 1.7, 4.9) later. Here, 95% prediction intervals showed a large dispersion of effect sizes (-1.9 to 8.5). We investigated this dispersion with a subgroup meta-analysis comparing studies that had recruited participants with dementia to studies that had recruited participants with AD on the age of dementia and AD diagnosis between mono- and bilinguals. Results showed that bilinguals vs. monolinguals were 1.9 years (95% CI: -0.9, 4.7) and 4.2 (95% CI: 2.0, 6.4) older than monolinguals at the time of dementia and AD diagnosis, respectively. The mean difference between the two subgroups was not significant. There was no significant risk reduction (odds ratio: 0.89; 95% CI: 0.68-1.16) in developing dementia among bilinguals vs. monolinguals. Also, there was no significant difference (Hedges' g = 0.05; 95% CI: -0.13, 0.24) in disease severity at dementia diagnosis between bilinguals and monolinguals, despite bilinguals being significantly older. The majority of studies had adjusted for level of education suggesting that education might not have played a role in the observed delay in dementia among bilinguals vs. monolinguals. Although findings indicated that bilingualism was on average related to a delayed onset of dementia, the magnitude of this relationship varied across different settings. This variation may be due to unexplained heterogeneity and different sources of bias in the included studies. Registration: PROSPERO CRD42015019100.
Collapse
Affiliation(s)
- Stefano Brini
- Discipline of Psychology, Exercise Science, Chiropractic and Counselling, Murdoch University, Perth, Western Australia, Australia.
- Turku Brain and Mind Center, Turku, Finland.
- Health Services Research and Management School of Health Sciences, City, University of London, London, UK.
- Department of Psychology and Speech-Language Pathology, University of Turku, Turku, Finland.
| | - Hamid R Sohrabi
- Discipline of Psychology, Exercise Science, Chiropractic and Counselling, Murdoch University, Perth, Western Australia, Australia
- School of Medical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia
- Department of Biomedical Sciences, Macquarie University, Macquarie Park, New South Wales, Australia
| | - Jeffrey J Hebert
- Discipline of Psychology, Exercise Science, Chiropractic and Counselling, Murdoch University, Perth, Western Australia, Australia
- Faculty of Kinesiology, University of New Brunswick, Fredericton, Canada
| | - Mitchell R L Forrest
- Discipline of Psychology, Exercise Science, Chiropractic and Counselling, Murdoch University, Perth, Western Australia, Australia
| | - Matti Laine
- Turku Brain and Mind Center, Turku, Finland
- Department of Psychology, Åbo Akademi University, Turku, Finland
| | - Heikki Hämäläinen
- Turku Brain and Mind Center, Turku, Finland
- Department of Psychology and Speech-Language Pathology, University of Turku, Turku, Finland
| | - Mira Karrasch
- Department of Psychology, Åbo Akademi University, Turku, Finland
| | - Jeremiah J Peiffer
- Discipline of Psychology, Exercise Science, Chiropractic and Counselling, Murdoch University, Perth, Western Australia, Australia
| | - Ralph N Martins
- School of Medical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia
- Department of Biomedical Sciences, Macquarie University, Macquarie Park, New South Wales, Australia
- Australian Alzheimer's Research Foundation, Perth, Western Australia, Australia
| | - Timothy J Fairchild
- Discipline of Psychology, Exercise Science, Chiropractic and Counselling, Murdoch University, Perth, Western Australia, Australia
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Perth, Western Australia, Australia
| |
Collapse
|
17
|
Costumero V, Marin-Marin L, Calabria M, Belloch V, Escudero J, Baquero M, Hernandez M, Ruiz de Miras J, Costa A, Parcet MA, Ávila C. A cross-sectional and longitudinal study on the protective effect of bilingualism against dementia using brain atrophy and cognitive measures. Alzheimers Res Ther 2020; 12:11. [PMID: 31924269 PMCID: PMC6954576 DOI: 10.1186/s13195-020-0581-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 01/05/2020] [Indexed: 01/27/2023]
Abstract
Background Evidence from previous studies suggests that bilingualism contributes to cognitive reserve because bilinguals manifest the first symptoms of Alzheimer’s disease (AD) up to 5 years later than monolinguals. Other cross-sectional studies demonstrate that bilinguals show greater amounts of brain atrophy and hypometabolism than monolinguals, despite sharing the same diagnosis and suffering from the same symptoms. However, these studies may be biased by possible pre-existing between-group differences. Methods In this study, we used global parenchymal measures of atrophy and cognitive tests to investigate the protective effect of bilingualism against dementia cross-sectionally and prospectively, using a sample of bilinguals and monolinguals in the same clinical stage and matched on sociodemographic variables. Results Our results suggest that the two groups did not differ in their cognitive status at baseline, but bilinguals had less parenchymal volume than monolinguals, especially in areas related to brain atrophy in dementia. In addition, a longitudinal prospective analysis revealed that monolinguals lost more parenchyma and had more cognitive decline than bilinguals in a mean follow-up period of 7 months. Conclusion These results provide the first prospective evidence that bilingualism may act as a neuroprotective factor against dementia and could be considered a factor in cognitive reserve.
Collapse
Affiliation(s)
- Víctor Costumero
- Center for Brain and Cognition, University Pompeu Fabra, Barcelona, Spain.,Neuropsychology and Functional Neuroimaging Group, University Jaume I, Castellón, Spain.,ERI Lectura, University of Valencia, Valencia, Spain
| | - Lidon Marin-Marin
- Neuropsychology and Functional Neuroimaging Group, University Jaume I, Castellón, Spain
| | - Marco Calabria
- Center for Brain and Cognition, University Pompeu Fabra, Barcelona, Spain
| | | | - Joaquín Escudero
- Department of Neurology, General Hospital of Valencia, Valencia, Spain
| | - Miguel Baquero
- Neurology Unit, University and Polytechnic Hospital La Fe, Valencia, Spain
| | - Mireia Hernandez
- Department of Cognition, Development, and Educational Psychology Section of Cognitive Processes, University of Barcelona, Barcelona, Spain.,Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Spain
| | | | - Albert Costa
- Center for Brain and Cognition, University Pompeu Fabra, Barcelona, Spain
| | - Maria-Antònia Parcet
- Neuropsychology and Functional Neuroimaging Group, University Jaume I, Castellón, Spain
| | - César Ávila
- Neuropsychology and Functional Neuroimaging Group, University Jaume I, Castellón, Spain.
| |
Collapse
|
18
|
Mohammad N, Rezapour T, Kormi-Nouri R, Abdekhodaie E, Ghamsari AM, Ehsan HB, Hatami J. The effects of different proxies of cognitive reserve on episodic memory performance: aging study in Iran. Int Psychogeriatr 2020; 32:25-34. [PMID: 31656218 DOI: 10.1017/S1041610219001613] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The main aim of the present study is to investigate the association between different measures of cognitive reserve including bilingualism, mental activities, type of education (continuous versus distributed), age, educational level, and episodic memory in a healthy aging sample. METHODS Four hundred and fifteen participants aged between 50 and 83 years participated in this cross-sectional study and were assessed with the Psychology Experimental Building Language Test battery tapping episodic memory. Demographic variables were collected from a questionnaire designed by the research team. RESULTS Compared to participants with continuous type of education, those with distributed type performed better in tests of episodic memory, while no differences were found between bilingual and monolingual participants. We additionally found that age negatively predicts episodic memory, whereas playing mind teasers and educational level have positive relationships with episodic memory. CONCLUSIONS Our results indicate that higher cognitive reserve, as measured by distributed educational training, higher level of education, and doing regular mental activities, is associated with better performance on episodic memory tasks in older adults. These results were discussed in connection with successful aging and protection against memory decline with aging.
Collapse
|
19
|
Kim S, Jeon SG, Nam Y, Kim HS, Yoo DH, Moon M. Bilingualism for Dementia: Neurological Mechanisms Associated With Functional and Structural Changes in the Brain. Front Neurosci 2019; 13:1224. [PMID: 31798405 PMCID: PMC6868000 DOI: 10.3389/fnins.2019.01224] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 10/29/2019] [Indexed: 01/17/2023] Open
Abstract
As the number of older adults increases, the prevalence of dementias, such as Alzheimer’s dementia (AD), vascular dementia, dementia with Lewy bodies, and frontotemporal dementias, also increases. Despite research into pharmacological approaches for treating diverse diseases, there is still no cure. Recently, novel non-pharmacological interventions are attracting attention. Non-pharmacological approaches include cognitive stimulation, alterations in diet, physical activity, and social engagement. Cognitive stimulating activities protect against the negative effects of cognitive decline caused by age-related neurogenerative diseases. Bilingualism is one form of cognitive stimulation that requires multiple aspects of brain activity and has been shown to delay the onset of dementia symptoms in patients by approximately 4–5 years as compared with monolingual patients through cognitive reserve. The purpose of this review was to bilingualism protects against cognitive decline associated with AD and other dementias. We discuss potential underlying neurological mechanisms, including: (1) stimulating adult neurogenesis, (2) enhancing synaptogenesis, (3) strengthening functional connectivity that bilingualism may delay clinical AD symptoms, (4) protecting white matter integrity, and (5) preserving gray matter density.
Collapse
Affiliation(s)
- Sujin Kim
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Seong Gak Jeon
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Yunkwon Nam
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Hyeon Soo Kim
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Doo-Han Yoo
- Department of Occupational Therapy, Konyang University, Daejeon, South Korea
| | - Minho Moon
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| |
Collapse
|
20
|
Affiliation(s)
- Mario F. Mendez
- V.A. Greater Los Angeles Healthcare System, Los Angeles, CA, USA
- Departments of Neurology and Psychiatry & Biobehavioral Sciences, Los Angeles, CA, USA
- David Geffen School of Medicine, University of California at Los Angeles, CA, USA
| |
Collapse
|
21
|
Rosselli M, Loewenstein DA, Curiel RE, Penate A, Torres VL, Lang M, Greig MT, Barker WW, Duara R. Effects of Bilingualism on Verbal and Nonverbal Memory Measures in Mild Cognitive Impairment. J Int Neuropsychol Soc 2019; 25:15-28. [PMID: 30334507 DOI: 10.1017/S135561771800070X] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVES Maintaining two active languages may increase cognitive and brain reserve among bilingual individuals. We explored whether such a neuroprotective effect was manifested in the performance of memory tests for participants with amnestic mild cognitive impairment (aMCI). METHODS We compared 42 bilinguals to 25 monolinguals on verbal and nonverbal memory tests. We used: (a) the Loewenstein-Acevedo Scales for Semantic Interference and Learning (LASSI-L), a sensitive test that taps into proactive, retroactive, and recovery from proactive semantic interference (verbal memory), and (b) the Benson Figure delayed recall (nonverbal memory). A subsample had volumetric MRI scans. RESULTS The bilingual group significantly outperformed the monolingual group on two LASSI-L cued recall measures (Cued A2 and Cued B2). A measure of maximum learning (Cued A2) showed a correlation with the volume of the left hippocampus in the bilingual group only. Cued B2 recall (sensitive to recovery from proactive semantic interference) was correlated with the volume of the hippocampus and the entorhinal cortex of both cerebral hemispheres in the bilingual group, as well as with the left and right hippocampus in the monolingual group. The memory advantage in bilinguals on these measures was associated with higher inhibitory control as measured by the Stroop Color-Word test. CONCLUSIONS Our results demonstrated a superior performance of aMCI bilinguals over aMCI monolinguals on selected verbal memory tasks. This advantage was not observed in nonverbal memory. Superior memory performance of bilinguals over monolinguals suggests that bilinguals develop a different and perhaps more efficient semantic association system that influences verbal recall. (JINS, 2019, 25, 15-28).
Collapse
|
22
|
Mendez MF, Chavez D, Akhlaghipour G. Bilingualism Delays Expression of Alzheimer's Clinical Syndrome. Dement Geriatr Cogn Disord 2019; 48:281-289. [PMID: 32045913 PMCID: PMC7195235 DOI: 10.1159/000505872] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/10/2020] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE To evaluate the effects of bilingualism on the emergence of Alzheimer's clinical syndrome. BACKGROUND Studies have proposed an increase in cognitive and neural reserve from the management and control of two languages, with a consequent delayed expression of dementia. METHODS In a clinic with a large immigrant population, we identified 253 patients with probable Alzheimer's disease (AD) with intermediate or high evidence of AD pathophysiological process. These patients were reviewed for demographic variables, native language (L1) other than English, ages of onset and presentation, Mini-Mental State Examination (MMSE), digit spans, word fluencies, naming, and memory. RESULTS Among these patients, 74 (29.2%) were bilinguals with various L1s (Farsi, Spanish, Chinese, Tagalog, Arabic, others). When compared to the 179 monolingual AD patients, those who were bilingual had significant delays in ages of onset and presentation of approximately 4 years (p = 0.003). These delays persisted despite bilinguals having worse MMSE scores on presentation. There were no significant group differences on other variables except for worse naming in English among bilinguals versus monolinguals. Caregiver/informants reported that 66 (89.2%) of the 74 bilingual AD patients had gradually regressed to the predominant use of their L1. CONCLUSIONS In line with published reports worldwide, we found that bilingualism delays the expression of Alzheimer's clinical syndrome. We also found frequent reversion to the first learned language. These findings suggest that, among bilinguals, the availability of an L1 "back-up" either facilitates compensation or masks emergence of the early symptoms of dementia.
Collapse
Affiliation(s)
- Mario F. Mendez
- V.A. Greater Los Angeles Healthcare System, Los Angeles, CA, USA,Departments of Neurology, David Geffen School of Medicine, University of California at Los Angeles, CA, USA,Psychiatry & Biobehavioral Sciences, and Medicine, David Geffen School of Medicine, University of California at Los Angeles, CA, USA
| | - Diana Chavez
- Departments of Neurology, David Geffen School of Medicine, University of California at Los Angeles, CA, USA
| | - Golnoush Akhlaghipour
- Departments of Neurology, David Geffen School of Medicine, University of California at Los Angeles, CA, USA
| |
Collapse
|
23
|
Ramakrishnan S, Mekala S, Mamidipudi A, Yareeda S, Mridula R, Bak TH, Alladi S, Kaul S. Comparative Effects of Education and Bilingualism on the Onset of Mild Cognitive Impairment. Dement Geriatr Cogn Disord 2018; 44:222-231. [PMID: 29207387 DOI: 10.1159/000479791] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/25/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Increasing evidence suggests that life course factors such as education and bilingualism may have a protective role against dementia due to Alzheimer disease. This study aimed to compare the effects of education and bilingualism on the onset of cognitive decline at the stage of mild cognitive impairment (MCI). METHODS A total of 115 patients with MCI evaluated in a specialty memory clinic in Hyderabad, India, formed the cohort. MCI was diagnosed according to Petersen's criteria following clinical evaluation and brain imaging. Age at onset of MCI was compared between bilinguals and monolinguals, and across subjects with high and low levels of education, adjusting for possible confounding variables. RESULTS The bilingual MCI patients were found to have a clinical onset of cognitive complaints 7.4 years later than monolinguals (65.2 vs. 58.1 years; p = 0.004), while years of education was not associated with delayed onset (1-10 years of education, 59.1 years; 11-15 years of education, 62.6 years; >15 years of education, 62.2 years; p = 0.426). CONCLUSION The effect of bilingualism is protective against cognitive decline, and lies along a continuum from normal to pathological states. In comparison, the role of years of education is less robust.
Collapse
Affiliation(s)
- Subasree Ramakrishnan
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Calvo N, Ibáñez A, Muñoz E, García AM. A core avenue for transcultural research on dementia: on the cross-linguistic generalization of language-related effects in Alzheimer's disease and Parkinson's disease. Int J Geriatr Psychiatry 2018; 33:814-823. [PMID: 28370288 DOI: 10.1002/gps.4712] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 03/02/2017] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Language is a key source of cross-cultural variability, which may have both subtle and major effects on neurocognition. However, this issue has been largely overlooked in two flourishing lines of research assessing the relationship between language-related neural systems and dementia. This paper assesses the limitations of the evidence on (i) the neuroprotective effects of bilingualism in Alzheimer's disease and (ii) specific language deficits as markers of Parkinson's disease. DESIGN First, we outline the rationale behind each line of research. Second, we review available evidence and discuss the potential impact of cross-linguistic factors. Third, we outline ideas to foster progress in both fields and, with it, in cross-cultural neuroscience at large. RESULTS On the one hand, studies on bilingualism suggest that sustained use of more than one language may protect against Alzheimer's disease symptoms. On the other hand, insights from the embodied cognition framework point to syntactic and action-verb deficits as early (and even preclinical) markers of Parkinson's disease. However, both fields share a key limitation that lies at the heart of cultural neuroscience: the issue of cross-linguistic generalizability. CONCLUSION Relevant evidence for both research trends comes from only a handful of (mostly Indo-European) languages, which are far from capturing the full scope of structural and typological diversity of the linguistic landscape worldwide. This raises questions on the external validity of reported findings. Greater collaboration between linguistic typology and cognitive neuroscience seems crucial as a first step to assess the impact of transcultural differences on language-related effects across neurodegenerative diseases. Copyright © 2017 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Noelia Calvo
- Institute of Philosophy, School of Philosophy, Humanities and Arts
- , National University of San Juan, San Juan, Argentina.,Faculty of Psychology, National University of Córdoba, Córdoba, Argentina.,Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University, Buenos Aires, Argentina.,National Scientific and Technical Research Council, Buenos Aires, Argentina
| | - Agustín Ibáñez
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University, Buenos Aires, Argentina.,National Scientific and Technical Research Council, Buenos Aires, Argentina.,Universidad Autónoma del Caribe, Barranquilla, Colombia.,Center for Social and Cognitive Neuroscience (CSCN), School of Psychology, Universidad Adolfo Ibáñez, Santiago de Chile, Chile.,Centre of Excellence in Cognition and its Disorders, Australian Research Council (ARC), Sydney, Australia
| | - Edinson Muñoz
- Departamento de Lingüística y Literatura, Facultad de Humanidades, Universidad de Santiago de Chile, Santiago, Chile
| | - Adolfo M García
- Laboratory of Experimental Psychology and Neuroscience (LPEN), Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University, Buenos Aires, Argentina.,National Scientific and Technical Research Council, Buenos Aires, Argentina.,Faculty of Education, National University of Cuyo, Mendoza, Argentina
| |
Collapse
|
25
|
Abstract
A review of the current literature regarding bilingualism demonstrates that bilingualism is linked to higher levels of controlled attention and inhibition in executive control and can protect against the decline of executive control in aging by contributing to cognitive reserve. Bilinguals may also have smaller vocabulary size and slower lexical retrieval for each language. The joint activation theory is proposed to explain these results. Older trilingual adults experience more protection against cognitive decline and children and young adults showed similar cognitive advantages to bilinguals in inhibitory control. Second language learners do not yet show cognitive changes associated with multilingualism. The Specificity Principle states that the acquisition of multiple languages is moderated by multiple factors and varies between experiences. Bilingualism and multilingualism are both associated with immigration but different types of multilingualism can develop depending on the situation. Cultural cues and language similarity also play a role in language switching and multiple language acquisition.
Collapse
|
26
|
Duncan HD, Nikelski J, Pilon R, Steffener J, Chertkow H, Phillips NA. Structural brain differences between monolingual and multilingual patients with mild cognitive impairment and Alzheimer disease: Evidence for cognitive reserve. Neuropsychologia 2018; 109:270-282. [DOI: 10.1016/j.neuropsychologia.2017.12.036] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 10/19/2017] [Accepted: 12/22/2017] [Indexed: 01/17/2023]
|
27
|
Sörman DE, Josefsson M, Marsh JE, Hansson P, Ljungberg JK. Longitudinal effects of bilingualism on dual-tasking. PLoS One 2017; 12:e0189299. [PMID: 29281654 DOI: 10.1371/journal.pone.0189299] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 11/22/2017] [Indexed: 11/19/2022] Open
Abstract
An ongoing debate surrounds whether bilinguals outperform monolinguals in tests of executive processing. The aim of this study was to investigate if there are long-term (10 year) bilingual advantages in executive processing, as indexed by dual-task performance, in a sample that were 40–65 years at baseline. The bilingual (n = 24) and monolingual (n = 24) participants were matched on age, sex, education, fluid intelligence, and study sample. Participants performed free-recall for a 12-item list in three dual-task settings wherein they sorted cards either during encoding, retrieval, or during both encoding and retrieval of the word-list. Free recall without card sorting was used as a reference to compute dual-task costs. The results showed that bilinguals significantly outperformed monolinguals when they performed card-sorting during both encoding and retrieval of the word-list, the condition that presumably placed the highest demands on executive functioning. However, dual-task costs increased over time for bilinguals relative to monolinguals, a finding that is possibly influenced by retirement age and limited use of second language in the bilingual group.
Collapse
|
28
|
Antoniou M, Wright SM. Uncovering the Mechanisms Responsible for Why Language Learning May Promote Healthy Cognitive Aging. Front Psychol 2017; 8:2217. [PMID: 29326636 PMCID: PMC5736569 DOI: 10.3389/fpsyg.2017.02217] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 12/07/2017] [Indexed: 01/08/2023] Open
Abstract
One of the great challenges facing humankind in the 21st century is preserving healthy brain function in our aging population. Individuals over 60 are the fastest growing age group in the world, and by 2050, it is estimated that the number of people over the age of 60 will triple. The typical aging process involves cognitive decline related to brain atrophy, especially in frontal brain areas and regions that subserve declarative memory, loss of synaptic connections, and the emergence of neuropathological symptoms associated with dementia. The disease-state of this age-related cognitive decline is Alzheimer's disease and other dementias, which may cause older adults to lose their independence and rely on others to live safely, burdening family members and health care systems in the process. However, there are two lines of research that offer hope to those seeking to promote healthy cognitive aging. First, it has been observed that lifestyle variables such as cognitive leisure activities can moderate the risk of Alzheimer's disease, which has led to the development of plasticity-based interventions for older adults designed to protect against the adverse effects of cognitive decline. Second, there is evidence that lifelong bilingualism acts as a safeguard in preserving healthy brain function, possibly delaying the incidence of dementia by several years. In previous work, we have suggested that foreign language learning programs aimed at older populations are an optimal solution for building cognitive reserve because language learning engages an extensive brain network that is known to overlap with the regions negatively affected by the aging process. Here, we will outline potential future lines of research that may uncover the mechanism responsible for the emergence of language learning related brain advantages, such as language typology, bi- vs. multi-lingualism, age of acquisition, and the elements that are likely to result in the largest gains.
Collapse
Affiliation(s)
- Mark Antoniou
- The MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Sydney, NSW, Australia
| | - Sarah M Wright
- The MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Sydney, NSW, Australia
| |
Collapse
|
29
|
Abstract
The purpose of this study is to explore original studies which provide evidence about the effects of bilingualism on the delay of the onset of dementia, specifically Alzheimer’s disease (AD). A literature review was conducted in the world’s acknowledged databases: Web of Science, Scopus, and MEDLINE. Altogether, 14 original studies focusing on the research topic were detected. These included six prospective cohort studies and eight retrospective studies. Both types of studies suggest different conclusions. The findings from the prospective cohort studies state that there is no association between bilingualism and the delay of the onset of AD, while the retrospective studies claim the opposite. Despite the negative results of the prospective cohort studies, more research should be conducted on bilingualism and its impact on the delay of the onset of AD, since the brain studies have brought positive findings as far as the enhancement of cognitive reserve is concerned.
Collapse
Affiliation(s)
- Blanka Klimova
- Department of Applied Linguistics, Faculty of Informatics and Management, University of Hradec Kralove.,Department of Neurology
| | | | - Kamil Kuca
- Biomedical Research Centre, University Hospital Hradec Kralove.,Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic
| |
Collapse
|
30
|
Li L, Abutalebi J, Emmorey K, Gong G, Yan X, Feng X, Zou L, Ding G. How bilingualism protects the brain from aging: Insights from bimodal bilinguals. Hum Brain Mapp 2017; 38:4109-4124. [PMID: 28513102 DOI: 10.1002/hbm.23652] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 03/16/2017] [Accepted: 05/04/2017] [Indexed: 12/11/2022] Open
Abstract
Bilingual experience can delay cognitive decline during aging. A general hypothesis is that the executive control system of bilinguals faces an increased load due to controlling two languages, and this increased load results in a more "tuned brain" that eventually creates a neural reserve. Here we explored whether such a neuroprotective effect is independent of language modality, i.e., not limited to bilinguals who speak two languages but also occurs for bilinguals who use a spoken and a signed language. We addressed this issue by comparing bimodal bilinguals to monolinguals in order to detect age-induced structural brain changes and to determine whether we can detect the same beneficial effects on brain structure, in terms of preservation of gray matter volume (GMV), for bimodal bilinguals as has been reported for unimodal bilinguals. Our GMV analyses revealed a significant interaction effect of age × group in the bilateral anterior temporal lobes, left hippocampus/amygdala, and left insula where bimodal bilinguals showed slight GMV increases while monolinguals showed significant age-induced GMV decreases. We further found through cortical surface-based measurements that this effect was present for surface area and not for cortical thickness. Moreover, to further explore the hypothesis that overall bilingualism provides neuroprotection, we carried out a direct comparison of GMV, extracted from the brain regions reported above, between bimodal bilinguals, unimodal bilinguals, and monolinguals. Bilinguals, regardless of language modality, exhibited higher GMV compared to monolinguals. This finding highlights the general beneficial effects provided by experience handling two language systems, whether signed or spoken. Hum Brain Mapp 38:4109-4124, 2017. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Le Li
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, People's Republic of China
| | - Jubin Abutalebi
- Centre for Neurolinguistics and Psycholinguistics, University Vita Salute San Raffaele, Milan, Italy
| | - Karen Emmorey
- Laboratory for Language and Cognitive Neuroscience, School of Speech, Language, and Hearing Sciences, San Diego State University, San Diego, California
| | - Gaolang Gong
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, People's Republic of China
| | - Xin Yan
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, People's Republic of China
| | - Xiaoxia Feng
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, People's Republic of China
| | - Lijuan Zou
- College of Psychology and Education, Zaozhuang University, Zaozhuang, 277100, People's Republic of China
| | - Guosheng Ding
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, 100875, People's Republic of China
| |
Collapse
|
31
|
Mukadam N, Sommerlad A, Livingston G. The Relationship of Bilingualism Compared to Monolingualism to the Risk of Cognitive Decline or Dementia: A Systematic Review and Meta-Analysis. J Alzheimers Dis 2017; 58:45-54. [DOI: 10.3233/jad-170131] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
32
|
Alladi S, Bak TH, Shailaja M, Gollahalli D, Rajan A, Surampudi B, Hornberger M, Duggirala V, Chaudhuri JR, Kaul S. Bilingualism delays the onset of behavioral but not aphasic forms of frontotemporal dementia. Neuropsychologia 2017; 99:207-212. [PMID: 28322905 DOI: 10.1016/j.neuropsychologia.2017.03.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/04/2017] [Accepted: 03/16/2017] [Indexed: 12/14/2022]
Abstract
Bilingualism has been found to delay onset of dementia and this has been attributed to an advantage in executive control in bilinguals. However, the relationship between bilingualism and cognition is complex, with costs as well as benefits to language functions. To further explore the cognitive consequences of bilingualism, the study used Frontotemporal dementia (FTD) syndromes, to examine whether bilingualism modifies the age at onset of behavioral and language variants of Frontotemporal dementia (FTD) differently. Case records of 193 patients presenting with FTD (121 of them bilingual) were examined and the age at onset of the first symptoms were compared between monolinguals and bilinguals. A significant effect of bilingualism delaying the age at onset of dementia was found in behavioral variant FTD (5.7 years) but not in progressive nonfluent aphasia (0.7 years), semantic dementia (0.5 years), corticobasal syndrome (0.4 years), progressive supranuclear palsy (4.3 years) and FTD-motor neuron disease (3 years). On dividing all patients predominantly behavioral and predominantly aphasic groups, age at onset in the bilingual behavioral group (62.6) was over 6 years higher than in the monolingual patients (56.5, p=0.006), while there was no difference in the aphasic FTD group (60.9 vs. 60.6 years, p=0.851). The bilingual effect on age of bvFTD onset was shown independently of other potential confounding factors such as education, gender, occupation, and urban vs rural dwelling of subjects. To conclude, bilingualism delays the age at onset in the behavioral but not in the aphasic variants of FTD. The results are in line with similar findings based on research in stroke and with the current views of the interaction between bilingualism and cognition, pointing to advantages in executive functions and disadvantages in lexical tasks.
Collapse
Affiliation(s)
- Suvarna Alladi
- Department of Neurology, Nizam's Institute of Medical Sciences, Punjagutta, Hyderabad 500082, India.
| | - Thomas H Bak
- Department of Psychology, Centre for Cognitive Aging and Cognitive Epidemiology (CCACE) and Centre for Clinical Brain Sciences (CCBS), University of Edinburgh, Edinburgh, UK.
| | - Mekala Shailaja
- Department of Neurology, Nizam's Institute of Medical Sciences, Punjagutta, Hyderabad 500082, India.
| | - Divyaraj Gollahalli
- Department of Neurology, Nizam's Institute of Medical Sciences, Punjagutta, Hyderabad 500082, India.
| | - Amulya Rajan
- Department of Neurology, Nizam's Institute of Medical Sciences, Punjagutta, Hyderabad 500082, India.
| | - Bapiraju Surampudi
- Cognitive Science Lab, International Institute of Information Technology, Hyderabad & Centre for Neural and Cognitive Sciences, University of Hyderabad, Hyderabad, India.
| | | | | | | | - Subhash Kaul
- Department of Neurology, Nizam's Institute of Medical Sciences, Punjagutta, Hyderabad 500082, India.
| |
Collapse
|
33
|
Padilla C, Mendez MF, Jimenez EE, Teng E. Bilingualism in older Mexican-American immigrants is associated with higher scores on cognitive screening. BMC Geriatr 2016; 16:189. [PMID: 27881073 PMCID: PMC5122008 DOI: 10.1186/s12877-016-0368-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 11/16/2016] [Indexed: 12/02/2022] Open
Abstract
Background Bilingualism may protect against cognitive aging and delay the onset of dementia. However, studies comparing monolinguals and bilinguals on such metrics have produced inconsistent results complicated by confounding variables and methodological concerns. Methods We addressed this issue by comparing cognitive performance in a more culturally homogeneous cohort of older Spanish-speaking monolingual (n = 289) and Spanish-English bilingual (n = 339) Mexican-American immigrants from the Sacramento Longitudinal Study on Aging. Results After adjusting for demographic differences and depressive symptoms, both groups performed similarly at baseline on verbal memory but the bilingual group performed significantly better than the monolingual group on a cognitive screening test, the Modified Mini-Mental State Examination (3MS; p < 0.001). Group differences on the 3MS were driven by language/executive and language/praxis factors. Within the bilingual group, neither language of testing nor degree of bilingualism was significantly associated with 3MS or verbal memory scores. Amongst individuals who performed in the normal or better range on both tests at baseline and were followed for an average of 6 years, both monolinguals and bilinguals exhibited similar rates of cognitive decline on both measures. Conclusions These findings suggest that bilingualism is associated with modest benefits in cognitive screening performance in older individuals in cross-sectional analyses that persist across longitudinal analyses. The effects of bilingualism should be considered when cognitively screening is performed in aging immigrant populations. Electronic supplementary material The online version of this article (doi:10.1186/s12877-016-0368-1) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Claudia Padilla
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Mario F Mendez
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Elvira E Jimenez
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Edmond Teng
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA. .,Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
| |
Collapse
|
34
|
Abstract
PURPOSE OF REVIEW We discuss the role of bilingualism as a source of cognitive reserve and we propose the putative neural mechanisms through which lifelong bilingualism leads to a neural reserve that delays the onset of dementia. RECENT FINDINGS Recent findings highlight that the use of more than one language affects the human brain in terms of anatomo-structural changes. It is noteworthy that recent evidence from different places and cultures throughout the world points to a significant delay of dementia onset in bilingual/multilingual individuals. This delay has been reported not only for Alzheimer's dementia and its prodromal mild cognitive impairment phase, but also for other dementias such as vascular and fronto-temporal dementia, and was found to be independent of literacy, education and immigrant status. SUMMARY Lifelong bilingualism represents a powerful cognitive reserve delaying the onset of dementia by approximately 4 years. As to the causal mechanism, because speaking more than one language heavily relies upon executive control and attention, brain systems handling these functions are more developed in bilinguals resulting in increases of gray and white matter densities that may help protect from dementia onset. These neurocognitive benefits are even more prominent when second language proficiency and exposure are kept high throughout life.
Collapse
|
35
|
|
36
|
Abstract
AIMS AND OBJECTIVES The objectives of the present research were to examine the cognitive consequences of trilingualism and explain them relative to the cognitive consequences of bilingualism. APPROACH A comparison of cognitive abilities in trilinguals and bilinguals was conducted. In addition, we proposed a cognitive plasticity framework to account for cognitive differences and similarities between trilinguals and bilinguals. DATA AND ANALYSIS Three aspects of cognition were analyzed: (1) cognitive reserve in older adults, as measured by age of onset of Alzheimer's disease and mild cognitive impairment; (2) inhibitory control in children and younger adults, as measured by response times on behavioral Simon and flanker tasks; and (3) memory generalization in infants and toddlers, as measured by accuracy on behavioral deferred imitation tasks. Results were considered within a framework of cognitive plasticity, which took into account several factors that may affect plasticity, including the age of learning a third language and the extent to which additional cognitive resources are needed to learn the third language. FINDINGS A mixed pattern of results was observed. In some cases, such as cognitive reserve in older adults, trilinguals showed larger advantages than bilinguals. On other measures, for example inhibitory control in children and younger adults, trilinguals were found to exhibit the same advantages as bilinguals. In still other cases, like memory generalization in infants and toddlers, trilinguals did not demonstrate the advantages seen in bilinguals. ORIGINALITY This study is the first comprehensive analysis of how learning a third language affects the cognitive abilities that are modified by bilingual experience, and the first to propose a cognitive plasticity framework that can explain and predict trilingual-bilingual differences. SIGNIFICANCE This research shows that the cognitive consequences of trilingualism are not simply an extension of bilingualism's effects; rather, trilingualism has distinct consequences, with theoretical implications for our understanding of linguistic and cognitive processes and their plasticity, as well as applied-science implications for using second and third language learning in educational and rehabilitative contexts to foster successful cognitive development and aging.
Collapse
Affiliation(s)
- Scott R Schroeder
- Department of Communication Sciences and Disorders, Northwestern University
| | - Viorica Marian
- Department of Communication Sciences and Disorders, Northwestern University
| |
Collapse
|
37
|
Calvo N, García AM, Manoiloff L, Ibáñez A. Bilingualism and Cognitive Reserve: A Critical Overview and a Plea for Methodological Innovations. Front Aging Neurosci 2016; 7:249. [PMID: 26793100 PMCID: PMC4709424 DOI: 10.3389/fnagi.2015.00249] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 12/18/2015] [Indexed: 02/03/2023] Open
Abstract
The decline of cognitive skills throughout healthy or pathological aging can be slowed down by experiences which foster cognitive reserve (CR). Recently, some studies on Alzheimer's disease have suggested that CR may be enhanced by life-long bilingualism. However, the evidence is inconsistent and largely based on retrospective approaches featuring several methodological weaknesses. Some studies demonstrated at least 4 years of delay in dementia symptoms, while others did not find such an effect. Moreover, various methodological aspects vary from study to study. The present paper addresses contradictory findings, identifies possible lurking variables, and outlines methodological alternatives thereof. First, we characterize possible confounding factors that may have influenced extant results. Our focus is on the criteria to establish bilingualism, differences in sample design, the instruments used to examine cognitive skills, and the role of variables known to modulate life-long cognition. Second, we propose that these limitations could be largely circumvented through experimental approaches. Proficiency in the non-native language can be successfully assessed by combining subjective and objective measures; confounding variables which have been distinctively associated with certain bilingual groups (e.g., alcoholism, sleep disorders) can be targeted through relevant instruments; and cognitive status might be better tapped via robust cognitive screenings and executive batteries. Moreover, future research should incorporate tasks yielding predictable patterns of contrastive performance between bilinguals and monolinguals. Crucially, these include instruments which reveal bilingual disadvantages in vocabulary, null effects in working memory, and advantages in inhibitory control and other executive functions. Finally, paradigms tapping proactive interference (which assess the disruptive effect of long-term memory on newly learned information) could also offer useful data, since this phenomenon seems to be better managed by bilinguals and it becomes conspicuous in early stages of dementia. Such considerations may shed light not just on the relationship between bilingualism and CR, but also on more general mechanisms of cognitive compensation.
Collapse
Affiliation(s)
- Noelia Calvo
- School of Philosophy, Humanities and Arts, Institute of Philosophy, National University of San JuanSan Juan, Argentina
- Cognitive Psychology of Language and Psycholinguistics Research Group, Laboratory of Cognitive Psychology, CIPSI (CIECS-CONICET), National University of CórdobaCórdoba, Argentina
| | - Adolfo M. García
- Laboratory of Experimental Psychology and Neuroscience, Institute of Cognitive Neurology, Favaloro UniversityBuenos Aires, Argentina
- National Scientific and Technical Research CouncilBuenos Aires, Argentina
- Faculty of Elementary and Special Education, National University of CuyoMendoza, Argentina
- UDP-INECO Foundation Core on Neuroscience, Diego Portales UniversitySantiago, Chile
| | - Laura Manoiloff
- Cognitive Psychology of Language and Psycholinguistics Research Group, Laboratory of Cognitive Psychology, CIPSI (CIECS-CONICET), National University of CórdobaCórdoba, Argentina
| | - Agustín Ibáñez
- Laboratory of Experimental Psychology and Neuroscience, Institute of Cognitive Neurology, Favaloro UniversityBuenos Aires, Argentina
- National Scientific and Technical Research CouncilBuenos Aires, Argentina
- UDP-INECO Foundation Core on Neuroscience, Diego Portales UniversitySantiago, Chile
- Universidad Autónoma del CaribeBarranquilla, Colombia
- Centre of Excellence in Cognition and its Disorders, Australian Research CouncilSydney, NSW, Australia
| |
Collapse
|
38
|
Kowoll ME, Degen C, Gorenc L, Küntzelmann A, Fellhauer I, Giesel F, Haberkorn U, Schröder J. Bilingualism as a Contributor to Cognitive Reserve? Evidence from Cerebral Glucose Metabolism in Mild Cognitive Impairment and Alzheimer's Disease. Front Psychiatry 2016; 7:62. [PMID: 27148091 PMCID: PMC4831977 DOI: 10.3389/fpsyt.2016.00062] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 03/29/2016] [Indexed: 12/04/2022] Open
Abstract
OBJECTIVE Bilingualism is discussed as one factor contributing to "cognitive reserve" (CR), as it enhances executive control functions. To elucidate the underlying cerebral correlates, regional glucose uptake was compared between bilinguals and monolinguals with mild cognitive impairment (MCI) and beginning-stage Alzheimer's disease (AD) by using [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET). METHODS Thirty patients (73.2 ± 7.4) diagnosed with MCI or probable AD received physical and neuropsychological examinations, blood tests, and FDG-PET scans. Sixteen patients were classified as lifelong bilinguals, following the criterion of Bialystok et al., and groups were matched for age, sex, and mini mental state examination scores. Analyses were conducted using statistical parametric mapping version 8. The whole brain was used as reference region for intensity normalization and years of education were controlled for. RESULTS Bilingual patient groups showed substantially greater impairment of glucose uptake in frontotemporal and parietal regions [including Brodmann areas (BAs) 9, 47, 40, and 21] and in the left cerebellum relative to monolingual patients. CONCLUSION Bilingualism is likely to contribute to CR, given that bilingual patients showed more severe brain changes than monolinguals when adjusting for severity of cognitive impairment. The latter did not only comprise BAs relevant to speech and language but also structures typically involved in AD pathology, such as the temporal and the parietal cortices.
Collapse
Affiliation(s)
- Magdalena Eva Kowoll
- Section for Geriatric Psychiatry, University Clinic Heidelberg , Heidelberg , Germany
| | - Christina Degen
- Section for Geriatric Psychiatry, University Clinic Heidelberg , Heidelberg , Germany
| | - Lina Gorenc
- Section for Geriatric Psychiatry, University Clinic Heidelberg , Heidelberg , Germany
| | - Anika Küntzelmann
- Department of Psychiatry and Psychotherapy, University Hospital Leipzig , Leipzig , Germany
| | - Iven Fellhauer
- Section for Geriatric Psychiatry, University Clinic Heidelberg , Heidelberg , Germany
| | - Frederik Giesel
- Department of Nuclear Medicine, University Clinic , Heidelberg , Germany
| | - Uwe Haberkorn
- Department of Nuclear Medicine, University Clinic , Heidelberg , Germany
| | - Johannes Schröder
- Section for Geriatric Psychiatry, University Clinic Heidelberg , Heidelberg , Germany
| |
Collapse
|
39
|
Hindle JV, Martin-Forbes PA, Bastable AJ, Pye KL, Martyr A, Whitaker CJ, Craik FI, Bialystok E, Thomas EM, Mueller Gathercole VC, Clare L. Cognitive reserve in Parkinson's disease: the effects of welsh-english bilingualism on executive function. Parkinsons Dis 2015; 2015:943572. [PMID: 25922786 DOI: 10.1155/2015/943572] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 03/03/2015] [Accepted: 03/11/2015] [Indexed: 11/20/2022]
Abstract
Objective. Bilingualism has been shown to benefit executive function (EF) and delay the onset of Alzheimer's disease. This study aims at examining whether a bilingual advantage applies to EF in Parkinson's disease (PD). Method. In a cross-sectional outpatient cohort of monolingual English (n = 57) and bilingual Welsh/English (n = 46) speakers with PD we evaluated the effects of bilingualism compared with monolingualism on performance on EF tasks. In bilinguals we also assessed the effects of the degree of daily usage of each language and the degree of bilingualism. Results. Monolinguals showed an advantage in performance of language tests. There were no differences in performance of EF tests in monolinguals and bilinguals. Those who used Welsh less in daily life had better performance on one test of English vocabulary. The degree of bilingualism correlated with one test of nonverbal reasoning and one of working memory but with no other tests of EF. Discussion. The reasons why the expected benefit in EF in Welsh-English bilinguals with PD was not found require further study. Future studies in PD should include other language pairs, analysis of the effects of the degree of bilingualism, and longitudinal analysis of cognitive decline or dementia together with structural or functional neuroimaging.
Collapse
|
40
|
Abstract
In recent years bilingualism has been linked to both advantages in executive control and positive impacts on aging. Such positive cognitive effects of bilingualism have been attributed to the increased need for language control during bilingual processing and increased cognitive reserve, respectively. However, a mechanistic explanation of how bilingual experience contributes to cognitive reserve is still lacking. The current paper proposes a new focus on bilingual memory as an avenue to explore the relationship between executive control and cognitive reserve. We argue that this focus will enhance our understanding of the functional and structural neural mechanisms underlying bilingualism-induced cognitive effects. With this perspective we discuss and integrate recent cognitive and neuroimaging work on bilingual advantage, and suggest an account that links cognitive control, cognitive reserve, and brain reserve in bilingual aging and memory.
Collapse
Affiliation(s)
- Angela Grant
- Department of Psychology, Pennsylvania State University, University Park PA, USA ; Center for Brain, Behavior and Cognition, Pennsylvania State University, University Park PA, USA
| | - Nancy A Dennis
- Department of Psychology, Pennsylvania State University, University Park PA, USA ; Center for Brain, Behavior and Cognition, Pennsylvania State University, University Park PA, USA
| | - Ping Li
- Department of Psychology, Pennsylvania State University, University Park PA, USA ; Center for Brain, Behavior and Cognition, Pennsylvania State University, University Park PA, USA
| |
Collapse
|
41
|
Clare L, Whitaker CJ, Craik FIM, Bialystok E, Martyr A, Martin-Forbes PA, Bastable AJM, Pye KL, Quinn C, Thomas EM, Gathercole VCM, Hindle JV. Bilingualism, executive control, and age at diagnosis among people with early-stage Alzheimer's disease in Wales. J Neuropsychol 2014; 10:163-85. [PMID: 25420578 DOI: 10.1111/jnp.12061] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Revised: 09/12/2014] [Indexed: 11/28/2022]
Abstract
The observation of a bilingual advantage in executive control tasks involving inhibition and management of response conflict suggests that being bilingual might contribute to increased cognitive reserve. In support of this, recent evidence indicates that bilinguals develop Alzheimer's disease (AD) later than monolinguals, and may retain an advantage in performance on executive control tasks. We compared age at the time of receiving an AD diagnosis in bilingual Welsh/English speakers (n = 37) and monolingual English speakers (n = 49), and assessed the performance of bilinguals (n = 24) and monolinguals (n = 49) on a range of executive control tasks. There was a non-significant difference in age at the time of diagnosis, with bilinguals being on average 3 years older than monolinguals, but bilinguals were also significantly more cognitively impaired at the time of diagnosis. There were no significant differences between monolinguals and bilinguals in performance on executive function tests, but bilinguals appeared to show relative strengths in the domain of inhibition and response conflict. Bilingual Welsh/English speakers with AD do not show a clear advantage in executive function over monolingual English speakers, but may retain some benefits in inhibition and management of response conflict. There may be a delay in onset of AD in Welsh/English bilinguals, but if so, it is smaller than that found in some other clinical populations. In this Welsh sample, bilinguals with AD came to the attention of services later than monolinguals, and reasons for this pattern could be explored further.
Collapse
Affiliation(s)
| | | | | | - Ellen Bialystok
- Rotman Research Institute, Toronto, ON, Canada.,York University, Toronto, ON, Canada
| | | | - Pamela A Martin-Forbes
- Bangor University, UK.,National Institute for Social Care and Health Research Clinical Research Centre, North Wales Research Network, Bangor, UK
| | | | | | | | | | | | - John V Hindle
- Bangor University, UK.,Betsi Cadwaladr University Health Board, Llandudno Hospital, Conwy, UK
| |
Collapse
|
42
|
Grady CL, Luk G, Craik FIM, Bialystok E. Brain network activity in monolingual and bilingual older adults. Neuropsychologia 2014; 66:170-81. [PMID: 25445783 DOI: 10.1016/j.neuropsychologia.2014.10.042] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Revised: 10/30/2014] [Accepted: 10/31/2014] [Indexed: 10/24/2022]
Abstract
Bilingual older adults typically have better performance on tasks of executive control (EC) than do their monolingual peers, but differences in brain activity due to language experience are not well understood. Based on studies showing a relation between the dynamic range of brain network activity and performance on EC tasks, we hypothesized that life-long bilingual older adults would show increased functional connectivity relative to monolinguals in networks related to EC. We assessed intrinsic functional connectivity and modulation of activity in task vs. fixation periods in two brain networks that are active when EC is engaged, the frontoparietal control network (FPC) and the salience network (SLN). We also examined the default mode network (DMN), which influences behavior through reduced activity during tasks. We found stronger intrinsic functional connectivity in the FPC and DMN in bilinguals than in monolinguals. Although there were no group differences in the modulation of activity across tasks and fixation, bilinguals showed stronger correlations than monolinguals between intrinsic connectivity in the FPC and task-related increases of activity in prefrontal and parietal regions. This bilingual difference in network connectivity suggests that language experience begun in childhood and continued throughout adulthood influences brain networks in ways that may provide benefits in later life.
Collapse
Affiliation(s)
- Cheryl L Grady
- Rotman Research Institute at Baycrest, 3560 Bathurst Street, Toronto, Ontario, Canada M6A2E1; University of Toronto, Toronto, Ontario, Canada.
| | - Gigi Luk
- Harvard Graduate School of Education, Cambridge, MA, USA
| | - Fergus I M Craik
- Rotman Research Institute at Baycrest, 3560 Bathurst Street, Toronto, Ontario, Canada M6A2E1; University of Toronto, Toronto, Ontario, Canada
| | - Ellen Bialystok
- Rotman Research Institute at Baycrest, 3560 Bathurst Street, Toronto, Ontario, Canada M6A2E1; York University, Toronto, Ontario, Canada
| |
Collapse
|
43
|
Wilson RS, Boyle PA, Yang J, James BD, Bennett DA. Early life instruction in foreign language and music and incidence of mild cognitive impairment. Neuropsychology 2014; 29:292-302. [PMID: 25110933 DOI: 10.1037/neu0000129] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVE To test the hypothesis that foreign language and music instruction in early life are associated with lower incidence of mild cognitive impairment (MCI) and slower rate of cognitive decline in old age. METHOD At enrollment in a longitudinal cohort study, 964 older persons without cognitive impairment estimated years of foreign language and music instruction by age 18. Annually thereafter they completed clinical evaluations that included cognitive testing and clinical classification of MCI. RESULTS There were 264 persons with no foreign language instruction, 576 with 1-4 years, and 124 with > 4 years; 346 persons with no music instruction, 360 with 1-4 years, and 258 with > 4 years. During a mean of 5.8 years of observation, 396 participants (41.1%) developed MCI. In a proportional hazards model adjusted for age, sex, and education, higher levels (> 4 years) of foreign language (hazard ratio [HR] = 0.687, 95% confidence interval [CI] [0.482, 0.961]) and music (HR = 0.708, 95% CI [0.539, 0.930]) instruction by the age of 18 were each associated with reduced risk of MCI. The association persisted after adjustment for other early life indicators of an enriched cognitive environment, and it was stronger for nonamnestic than amnestic MCI. Both foreign language and music instruction were associated with higher initial level of cognitive function, but neither instruction measure was associated with cognitive decline. CONCLUSIONS Higher levels of foreign language and music instruction during childhood and adolescence are associated in old age with lower risk of developing MCI but not with rate of cognitive decline.
Collapse
Affiliation(s)
- Robert S Wilson
- Rush Alzheimer's Disease Center, Rush University Medical Center
| | | | - Jingyun Yang
- Rush Alzheimer's Disease Center, Rush University Medical Center
| | - Bryan D James
- Rush Alzheimer's Disease Center, Rush University Medical Center
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center
| |
Collapse
|
44
|
Abstract
OBJECTIVE Cognitive reserve refers to how individuals actively utilize neural resources to cope with neuropathology to maintain cognitive functioning. The present review aims to critically examine the literature addressing the relationship between bilingualism and cognitive reserve to elucidate whether bilingualism delays the onset of cognitive and behavioral manifestations of dementia. Potential neural mechanisms behind this relationship are discussed. METHOD PubMed and PsycINFO databases were searched (through January 2014) for original research articles in English or Spanish languages. The following search strings were used as keywords for study retrieval: "bilingual AND reserve," "reserve AND neural mechanisms," and "reserve AND multilingualism." RESULTS Growing scientific evidence suggests that lifelong bilingualism contributes to cognitive reserve and delays the onset of Alzheimer's disease symptoms, allowing bilingual individuals affected by Alzheimer's disease to live an independent and richer life for a longer time than their monolingual counterparts. Lifelong bilingualism is related to more efficient use of brain resources that help individuals maintain cognitive functioning in the presence of neuropathology. We propose multiple putative neural mechanisms through which lifelong bilinguals cope with neuropathology. The roles of immigration status, education, age of onset, proficiency, and frequency of language use on the relationship between cognitive reserve and bilingualism are considered. CONCLUSIONS Implications of these results for preventive practices and future research are discussed.
Collapse
|
45
|
|
46
|
Abstract
Typically, studies of cognitive advantages in bilinguals have been conducted previously by using executive and inhibitory tasks (e.g. Simon task) and applying cross-sectional designs. This study longitudinally investigated bilingual advantages on episodic memory recall, verbal letter and categorical fluency during the trajectory of life. Monolingual and bilingual participants (n = 178) between 35–70 years at baseline were drawn from the Betula Prospective Cohort Study of aging, memory, and health. Results showed that bilinguals outperformed monolinguals at the first testing session and across time both in episodic memory recall and in letter fluency. No interaction with age was found indicating that the rate of change across ages was similar for bilinguals and monolinguals. As predicted and in line with studies applying cross-sectional designs, no advantages associated with bilingualism were found in the categorical fluency task. The results are discussed in the light of successful aging.
Collapse
Affiliation(s)
- Jessica K. Ljungberg
- Department of Psychology, Umeå University, Umeå, Sweden
- School of Psychology, Cardiff University, Cardiff, United Kingdom
- * E-mail:
| | | | - Pilar Andrés
- Department of Psychology, University of the Balearic Islands, Palma, Spain
| | - Maria Josefsson
- Department of Statistics, Umeå School of Business and Economics, Umeå University, Umeå, Sweden
| | | |
Collapse
|
47
|
Perquin M, Vaillant M, Schuller AM, Pastore J, Dartigues JF, Lair ML, Diederich N. Lifelong exposure to multilingualism: new evidence to support cognitive reserve hypothesis. PLoS One 2013; 8:e62030. [PMID: 23646113 PMCID: PMC3640029 DOI: 10.1371/journal.pone.0062030] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 03/17/2013] [Indexed: 11/28/2022] Open
Abstract
Objective Investigate the protective effect of multilingualism on cognition in seniors. Methods As part of the MemoVie study conducted on 232 non-demented volunteers aged 65 and more, neurogeriatric and neuropsychological evaluations were performed. Participants were classified as presenting either cognitive impairment without dementia (CIND) or being free of any cognitive impairment (CIND-free). Language practices, socio-demographic data and lifestyle habits were recorded. In this retrospective nested case-control design, we used as proxies of multilingualism: number of languages practiced, age of acquisition and duration of practice, emphasizing the temporal pattern of acquisition, and the resulting practice of several languages sequentially or concomitantly during various periods of life. This special angle on the matter offered to our work a dimension particularly original and innovative. Results 44 subjects (19%) had CIND, the others were cognitively normal. All practiced from 2 to 7 languages. When compared with bilinguals, participants who practiced more than 2 languages presented a lower risk of CIND, after adjustment for education and age (odds ratio (OR) = 0.30, 95% confidence limits (95%CL) = [0.10–0.92]). Progressing from 2 to 3 languages, instead of staying bilingual, was associated with a 7-fold protection against CIND (OR = 0.14, 95%CL = [0.04–0.45], p = 0.0010). A one year delay to reach multilingualism (3 languages practiced being the threshold) multiplied the risk of CIND by 1.022 (OR = 1.022, 95%CL = [1.01–1.04], p = 0.0044). Also noteworthy, just as for multilingualism, an impact of cognitively stimulating activities on the occurrence of CIND was found as well (OR = 0.979, 95%CL = [0.961–0.998], p = 0.033). Conclusion The study did not show independence of multilingualism and CIND. Rather it seems to show a strong association toward a protection against CIND. Practicing multilingualism from early life on, and/or learning it at a fast pace is even more efficient. This protection might be related to the enhancement of cognitive reserve and brain plasticity, thereby preserving brain functions from alterations during aging.
Collapse
Affiliation(s)
- Magali Perquin
- Centre for Health Studies, Centre de Recherche Public-Santé-CRP-Santé, Strassen, Luxembourg.
| | | | | | | | | | | | | |
Collapse
|