Discriminant Validity of the WAIS-R Digit Symbol Substitution Test in Subjective Cognitive Decline, Mild Cognitive Impairment (Amnestic Subtype) and Alzheimer's Disease Dementia (ADD) in Greece

Multiple chronic conditions and polypharmacy in cognitively unimpaired older adults are associated with subsequent cognitive decline: results from the national alzheimer's coordinating center data

Prior cross-sectional studies revealed that multiple chronic conditions (MCC) and polypharmacy are associated with cognitive impairment. The purpose of this study was to determine whether the number of chronic conditions and the number of medications are associated with longitudinal changes in cognition (memory, attention/working memory, semantic ability/language, processing speed, executive function). We analyzed data from 5671 individuals (age 71.4 ± 9.3, 68 % female) from the National Alzheimer's Coordinating Center database who were cognitively unimpaired at baseline and had 3 or more subsequent visits. 57 % had more than two chronic conditions, and 44 % were taking 5 or more medications at baseline. At baseline, we observed that individuals with MCC had lower memory, attention/working memory, semantic ability/language, processing speed, and executive function performance than those without MCC. Using mixed-effect modeling approaches, we found that having a higher number of chronic conditions was associated with greater decline in semantic ability/language and executive function, and having a higher number of medications was associated with greater decline in attention/working memory, semantic ability/language, and executive function. The findings suggest that healthcare professionals and service providers should be conscious of the fact that patients dealing with MCC and those on multiple medications are vulnerable and require careful monitoring. Future studies are warranted using more comprehensive multimorbidity data and advanced analytic approaches, and prospective, controlled trials are warranted to test whether managing MCC and reducing the number of unnecessary medications or certain medications can prevent decline.

Symbol Digit Modalities Test incidental learning: Concurrent validity and clinical utility

This project examined the Incidental Learning (IL) procedure from the Symbol-Digit Modalities Test (SDMT) as both a screening tool and as a measure of memory. Participants included undergraduate college students and stroke- and dementia-free older adult volunteers with and without hypertension or chronic kidney disease. In each sample, IL scores were correlated with performances from a variety of cognitive tasks. Results indicated that IL scores were more strongly associated with tests of memory than other cognitive abilities. As a screening instrument for older adults, scores of four or more recalled symbol-digit pairings strongly indicated a lack of difficulties on other tests of memory, whereas scores of three or fewer suggested a need for further assessment, though not necessarily impairment. A novel recognition (IL-r) procedure was introduced to older participants without kidney disease, and results indicated that IL-r uniquely predicted both delayed verbal and visual memory beyond standard IL. Our findings suggest that IL can be regarded as an efficient supplemental or screening test of memory that offers a complementary methodology to a comprehensive assessment of memory.

Individual Sleep Problems Are Associated With an Accelerated Decline in Multiple Cognitive Functions in Older Adults

Poor sleep is a known risk factor of cognitive disorders, but the role of individual sleep problems in age-related cognitive changes remains unclear. This study used two complementary statistical models to estimate nonlinear trajectories of decline in four domains of cognitive functioning in the age period between 55 and 100 years depending on the severity of problems with falling asleep, night awakenings, and early morning awakenings, and short/long sleep duration. The sample included 5132 older adults (M = 67 years, 48% male) from the Longitudinal Aging Study Amsterdam (LASA), assessed 4-10 times every 2-3 years. Sleep problems were self-reported, and cognitive functioning was measured with the 15-Word test (reflecting episodic memory as immediate and delayed recall), Coding task (information processing speed) and Mini-mental State Examination/MMSE (global cognition). Data were analysed using quadratic and piecewise changepoint mixed models. The piecewise models provided more precise and interpretable findings. Decline in information processing speed accelerated significantly earlier in participants with short sleep duration (regression coefficient (B) = -2.3[95% confidence interval (CI): -3.86; -0.81]; p < 0.01) and faster with more severe early morning awakenings (B = -0.07 [-0.1; -0.03]; p < 0.01). Decline in immediate recall accelerated earlier in those with short sleep (B = -2.8 [-4.44; -1.14]; p < 0.01) and severe problems with falling asleep (B = -1.22 [-2.06; -0.39]; p = 0.01). Decline in delayed recall was faster with long sleep (B = -0.06 [-0.08;-0.03]; p < 0.01). Decline in global cognition accelerated faster in those with short/long sleep duration (B = -0.07 [-0.13; -0.01]/-0.10 [-0.18; -0.03]; p < 0.01) and severe night awakenings (B = -0.04 [-0.07;-0.02]; p < 0.01). To conclude, this study showed that some sleep problems can differentially predict earlier acceleration of deterioration in specific cognitive functions in older adults.

Pilot study of the Greek Interventional Geriatric Initiative to Prevent Cognitive Impairment and Disability in individuals with subjective cognitive decline: paving the way towards brain health clinics in Greece

The pilot phase of the Greek Interventional Geriatric Initiative to Prevent Cognitive Impairment and Disability (GINGER) aims to assess the feasibility of a multi-level dementia risk reduction intervention in individuals with subjective cognitive decline (SCD) over a six-month period. The study design incorporates a comprehensive set of trans-disciplinary assessments and interventions in multiple centers across Greece. Individuals 55 years or older with subjective cognitive complaints who do not fulfill criteria for either mild cognitive impairment or dementia are screened for dementia risk factors in the following domains: nutrition, physical activities, vision and hearing, vascular and metabolic parameters, anxiety and depressive symptoms, and insomnia. All GINGER participants receive a cognitive empowerment intervention. Using a precision medicine approach, they receive up to three additional domain-specific interventions based on their individual risk factor profiles. Changes in cognition, dementia risk factors, quality of life and other measures compared to baseline are assessed at three- and six months after the initiation of the intervention. The GINGER protocol was designed and is run by a multi-disciplinary team of dieticians, neurologists, psychiatrists, psychologists, and physiotherapists, while computer scientists oversee data management. The objectives of this pilot phase are (i) evaluation of the protocol's feasibility, (ii) assessment of intervention effects on the individual risk domains targeted by the interventions, (iii) estimation of the overall effects of the intervention on cognitive function, dementia risk and quality of life. The GINGER findings will provide a solid foundation for paving the way towards a network of evidence-based brain health clinics in Greece.

Normative Data for the D-KEFS Tower Test in Greek Adult Population Between 20 and 85 Years Old

Background: The Delis-Kaplan Executive Function System (D-KEFS) Tower Test (TT) is a widely used neuropsychological tool that assesses complex executive functions, including planning, cognitive flexibility, inhibition, switching, and impulsivity-key abilities often impaired in individuals with frontal dysfunction. Aims: There is currently no normative data for the D-KEFS TT in the Greek population. Consequently, it cannot be effectively used to detect executive dysfunction in neurological and psychiatric populations or for research purposes. Methods: The study sample included 249 healthy adults (28.9% male, 71.1% female) aged 20 to 85 years (M = 46.53, SD = 17.41), with educational levels ranging from secondary school graduates to master's degree holders. Pearson correlation was used to examine the relationship between age and D-KEFS TT performance, while chi-square test assessed the effects of education and gender. Normative data were then derived from raw scores and converted into percentiles. Results: Norms were established for the following D-KEFS TT variables: Total Achievement Score, Total Rule Violations, Move Accuracy Ratio, Mean First Move Time, and Time-per-Move Ratio. Age was the strongest predictor of performance, and normative data were stratified accordingly for the Greek adult population. Conclusions: This study introduces the D-KEFS TT as a neuropsychological assessment tool for Greek adults across different age groups to evaluate complex executive functions throughout the lifespan. Unlike other D-KEFS tests, the TT had not previously been adapted for the Greek population. This study is the first to provide normative data, supporting its use in clinical practice and research.

The Drug Burden Index Is Associated With Measures of Cognitive Function Among Older Adults in the Health, Aging, and Body Composition Study

BACKGROUND

Anticholinergic and sedative medications affect cognition among older adults. The Drug Burden Index (DBI) is a validated measure of exposure to these medications, with higher DBI scores indicating higher drug burden. This ancillary analysis investigated the association between DBI and cognition assessed by the Modified Mini-Mental State Examination (3MS) and the Digit Symbol Substitution Test (DSST).

METHODS

The Health, Aging, and Body Composition Study was a prospective study of community-dwelling adults aged 70-79 years at enrollment. Using data from years 1, 5, and 10, DBI was calculated using medication data per participant. Linear mixed modeling was used to assess cross-sectional and longitudinal effects of DBI on 3MS and DSST. Adjusted models included biological sex, race, education level, APOE status, and death. Sensitivity analyses included testing the strength of the associations for each year and testing attrition due to death as a possible confounding factor via Cox-Proportional Hazard models.

RESULTS

After adjustment, DBI was inversely associated with 3MS and DSST scores. These associations became stronger in each subsequent year. Neither DBI at year 1 nor within-person change in DBI were predictive of longitudinal declines in either cognitive measure. Sensitivity analyses indicated that DBI, 3MS, and DSST were associated with a greater risk of attrition due to death.

CONCLUSIONS

Results suggest that in years when older adults had a higher DBI scores, they had significantly lower global cognition and slower processing speed. These findings further substantiate the DBI as a useful pharmacological tool for assessing the effect of medication exposure.

Association between cognitive function and body composition in older adults: data from NHANES (1999-2002)

Aim

To investigate the association between cognitive function and body composition in older adults.

Methods

We collected data on 2080 older adults (>60 years of age) from the National Health and Nutrition Examination Survey (NHANES) for the years 1999-2000 and 2001-2002. Candidate variables included: demographic data (sex, age, race, education level, marital status, poverty-to-income ratio), alcohol consumption, cardiovascular disease, diabetes, osteoporosis, total bone mineral density, and total fat mass. A logistic regression model was established to analyze the association between cognitive function and body composition in older adults. In addition, stratified logics regression analysis was performed by sex and age.

Results

Bone mineral density significantly affects cognitive function in older adults (p<0.01). When examining the data according to sex, this correlation is present for women (p < 0.01). For men, though, it is not significant (p = 0.081). Stratified by age, total bone mineral density was significantly correlated with cognitive function in 60-70 and 70-80 years old people, but not in older adults older than 80 years(for 60-70 years old, p = 0.019; for 70-80 years old, p = 0.022). There was no significant correlation between total bone mineral density and cognitive function (p = 0.575).

Conclusion

The decrease of total bone mineral density was significantly correlated with cognitive decline in the older adults, especially among women and older people in the 60 to 80 age group. There was no connection between total fat mass, total percent fat, total lean mass, appendicular lean mass, appendicular lean mass /BMI and cognitive function in the older adults.

Assessing processing speed and its neural correlates in the three variants of primary progressive aphasia with a non-verbal tablet-based task

Prior research has revealed distinctive patterns of impaired language abilities across the three variants of Primary Progressive Aphasia (PPA): nonfluent/agrammatic (nfvPPA), logopenic (lvPPA) and semantic (svPPA). However, little is known about whether, and to what extent, non-verbal cognitive abilities, such as processing speed, are impacted in PPA patients. This is because neuropsychological tests typically contain linguistic stimuli and require spoken output, being therefore sensitive to verbal deficits in aphasic patients. The aim of this study is to investigate potential differences in processing speed between PPA patients and healthy controls, and among the three PPA variants, using a brief non-verbal tablet-based task (Match) modeled after the WAIS-III digit symbol coding test, and to determine its neural correlates. Here, we compared performance on the Match task between PPA patients (n = 61) and healthy controls (n = 59) and across the three PPA variants. We correlated performance on Match with voxelwise gray and white matter volumes. We found that lvPPA and nfvPPA patients performed significantly worse on Match than healthy controls and svPPA patients. Worse performance on Match across PPA patients was associated with reduced gray matter volume in specific parts of the left middle frontal gyrus, superior parietal lobule, and precuneus, and reduced white matter volume in the left parietal lobe. To conclude, our behavioral findings reveal that processing speed is differentially impacted across the three PPA variants and provide support for the potential clinical utility of a tabled-based task (Match) to assess non-verbal cognition. In addition, our neuroimaging findings confirm the importance of a set of fronto-parietal regions that previous research has associated with processing speed and executive control. Finally, our behavioral and neuroimaging findings combined indicate that differences in processing speed are largely explained by the unequal distribution of atrophy in these fronto-parietal regions across the three PPA variants.

Recent contributions to the field of subjective cognitive decline in aging: A literature review

Subjective cognitive decline (SCD) is defined as self-experienced, persistent concerns of decline in cognitive capacity in the context of normal performance on objective cognitive measures. Although SCD was initially thought to represent the "worried well," these concerns can be linked to subtle brain changes prior to changes in objective cognitive performance and, therefore, in some individuals, SCD may represent the early stages of an underlying neurodegenerative disease process (e.g., Alzheimer's disease). The field of SCD research has expanded rapidly over the years, and this review aims to provide an update on new advances in, and contributions to, the field of SCD in key areas and themes identified by researchers in this field as particularly important and impactful. First, we highlight recent studies examining sociodemographic and genetic risk factors for SCD, including explorations of SCD across racial and ethnic minoritized groups, and examinations of sex and gender considerations. Next, we review new findings on relationships between SCD and in vivo markers of pathophysiology, utilizing neuroimaging and biofluid data, as well as associations between SCD and objective cognitive tests and neuropsychiatric measures. Finally, we summarize recent work on interventions for SCD and areas of future growth in the field of SCD.

Sex differences in the mediating role of chronic inflammation on the association between social isolation and cognitive functioning among older adults in the United States

BACKGROUND

Previous research has reported the association between social isolation and cognitive impairment. However, biological mechanisms underlying this association are understudied. It is also unclear whether there are sex differences in these biological mechanisms.

OBJECTIVES

To examine whether chronic inflammation biomarkers are potential mediators of the association between social isolation and cognitive functioning among older men and women.

METHODS

Data were the National Health and Nutrition Examination Survey 1999-2002. A total of 2535 older adults aged 60 and older were included. Chronic inflammation was measured by C-reactive protein (CRP), plasma fibrinogen, and serum albumin. Cognitive functioning was assessed by the Digit Symbol Substitution Test (DSST). Social isolation was defined using a 4-point composite index of items pertaining to the strength of social network and support. Linear regression models and formal mediation analysis were applied.

RESULTS

Social isolation was associated with lower DSST scores [β (SE) = -2.445 (1.180), p < 0.01 for men; β (SE) = -5.478 (1.167), p < 0.001 for women]. For older men, social isolation was associated with higher levels of CRP (β [SE] = 0.226 (0.110), p < 0.05) and fibrinogen (β [SE] = 0.058 (0.026), p < 0.05). In mediation analyses, among older men, CRP mediated 6.1% and fibrinogen mediated 12.0% of the association of social isolation with DSST.

CONCLUSION

Social isolation was associated with poorer cognitive functioning partially via heightened inflammatory responses in older men. Defining these associations' mechanisms in sex-specific contexts could inform preventive and therapeutic strategies for cognitive impairment in older adults.

Repeatable battery for the assessment of neuropsychological status and its relationship to biomarkers of Alzheimer's disease

The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) has been associated with commonly used biomarkers of Alzheimer's disease (AD). However, prior studies have typically utilized small and poorly characterized samples, and they have not analyzed the subtests of the RBANS. The current study sought to expand on prior work by examining the relationship between the Indexes and subtest scores of the RBANS and three AD biomarkers: amyloid deposition via positron emission tomography, hippocampal volume via magnetic resonance imaging, and APOE ε4 status.

One-hundred twenty-one older adults across the AD continuum (intact, amnestic Mild Cognitive Impairment, mild AD), who were mostly Caucasian and well-educated, underwent assessment with the RBANS and collection of the three biomarkers.

Greater amyloid deposition was significantly related to lower scores on all five Indexes and the Total Scale score of the RBANS, as well as 11 of 12 subtests. For bilateral hippocampal volume, significant correlations were observed for 4 of the 5 Indexes, Total Scale score, and 9 of 12 subtests, with smaller hippocampi being related to lower RBANS scores. Participants with at least one APOE ε4 allele had significantly lower scores on 3 of the 5 Indexes, Total Scale score, and 8 of the 12 subtests.

In this sample of participants across the dementia spectrum, most RBANS Indexes and subtests showed relationships with the amyloid deposition, hippocampal volumes, and APOE status, with poorer performance on the RBANS being associated with biomarker positivity. Although memory scores on the RBANS have traditionally been linked to biomarkers in AD, other Index and subtest scores also hold promise as indicators of AD. Replication in a more diverse sample is needed.

Functional magnetic resonance imaging, deep learning, and Alzheimer's disease: A systematic review

Alzheimer's disease (AD) is currently diagnosed using a mixture of psychological tests and clinical observations. However, these diagnoses are not perfect, and additional diagnostic tools (e.g., MRI) can help improve our understanding of AD as well as our ability to detect the disease. Accordingly, a large amount of research has been invested into innovative diagnostic methods for AD. Functional MRI (fMRI) is a form of neuroimaging technology that has been used to diagnose AD; however, fMRI is incredibly noisy, complex, and thus lacks clinical use. Nonetheless, recent innovations in deep learning technology could enable the simplified and streamlined analysis of fMRI. Deep learning is a form of artificial intelligence that uses computer algorithms based on human neural networks to solve complex problems. For example, in fMRI research, deep learning models can automatically denoise images and classify AD by detecting patterns in participants' brain scans. In this systematic review, we investigate how fMRI (specifically resting-state fMRI) and deep learning methods are used to diagnose AD. In turn, we outline the common deep neural network, preprocessing, and classification methods used in the literature. We also discuss the accuracy, strengths, limitations, and future direction of fMRI deep learning methods. In turn, we aim to summarize the current field for new researchers, suggest specific areas for future research, and highlight the potential of fMRI to aid AD diagnoses.

Hypertension, dietary fiber intake, and cognitive function in older adults [from the National Health and Nutrition Examination Survey Data (2011–2014)]

Background

Dietary fiber was associated with hypertension (HYP) and cognitive function, but it was unknown whether the effect of HYP on cognitive function in older adults was modified by dietary fiber intake.

Methods

We recruited 2,478 participants from the 2011–2012 and 2013–2014 National Health and Nutrition Examination Survey (NHANES), with cognitive performance measured by Registry for Alzheimer's disease (CERAD), the Animal Fluency test (AFT), and the Digit Symbol Substitution test (DSST). Multivariate General linear model was used to estimate the interaction between dietary fiber intake and HYP status in association with low cognitive performance.

Results

Among 2,478 participants, 36% was Controlled HYP, 25% was Low uncontrolled HYP, 11% was High uncontrolled HYP, and 86% was low dietary fiber intake. The association between HYP status and DSST impairment differed by dietary fiber intake for those with high uncontrolled HYP compared to those without HYP. Among participants with low dietary fiber intake, those with uncontrolled HYP had higher risk of DSST impairment compared to those without HYP [HYP ≥ 90/140: OR (95% CI), 1.68 (1.15–2.45); HYP ≥ 100/160: OR (95%CI), 2.05 (1.29–3.23)]; however, there was no association between HYP status and DSST impairment among participants with high dietary fiber intake. Moreover, the interaction of HYP status and dietary fiber intake on DSST was close to statistical significance (P for interaction = 0.057).

Conclusions

Uncontrolled HYP was associated with poorer cognitive performance in older adults with low, but not high dietary fiber intake. Sufficient dietary fiber intake might be as a new nutrition strategy for the prevention of cognitive impairment in older adults with uncontrolled HYP.

Preserved visuospatial abilities in absence of the right hemisphere: A case of cerebral hemiatrophy with minimal cognitive impairment

Cerebral hemiatrophy is a rare neurological condition, usually resulting in severe and diffuse cognitive impairment. In this paper we present a 69-year old woman with notable congenital hemiatrophy with strikingly preserved cognitive functions. Cognitive assessment indicated that although her executive functions were found impaired, the remaining cognitive domains were relatively unaffected. We argue that this unexpected cognitive profile may be explained by anomalous hemispheric lateralization, driven by neuroplasticity along the developmental course.

Memory Clinics and Day Care Centers in Thessaloniki, Northern Greece: 30 Years of Clinical Practice and Experience

Background: This review describes the diagnostic and interventional procedures conducted in two university memory clinics (established network of G. Papanikolaou Hospital: 1988–2017 and AHEPA hospital: 2017–today) and 2 day care centers (established network of DCCs: 2005–today) in North Greece and their contribution in the scientific field of dementia. The aims of this work are (1) to provide a diagnosis and treatment protocol established in the network of memory clinics and DCCs and (2) to present further research conducted in the aforementioned network during the last 30 years of clinical practice.

Methods: The guidelines to set a protocol demand a series of actions as follows: (1) set the diagnosis criteria, neuropsychological assessment, laboratory examinations, and examination of neurophysiological, neuroimaging, cerebrospinal fluid, blood, and genetic markers; and (2) apply non-pharmacological interventions according to the needs and specialized psychosocial interventions of the patient to the caregivers of the patient.

Results: In addition to the guidelines followed in memory clinics at the 1st and 3rd Department of Neurology and two DCCs, a database of patients, educational programs, and further participation in international research programs, including clinical trials, make our contribution in the dementia field strong.

Conclusion: In the current paper, we provide useful guidelines on how major and minor neurocognitive disorders are being treated in Thessaloniki, Greece, describing successful practices which have been adapted in the last 30 years.

Are There Any Cognitive and Behavioral Changes Potentially Related to Quarantine Due to the COVID-19 Pandemic in People with Mild Cognitive Impairment and AD Dementia? A Longitudinal Study

The aim of the study was to examine potential cognitive, mood (depression and anxiety) and behavioral changes that may be related to the quarantine and the lockdown applied during the COVID-19 pandemic in Greek older adults with mild cognitive impairment (MCI), and AD dementia in mild and moderate stages. Method: 407 older adults, diagnosed either with MCI or AD dementia (ADD), were recruited from the Day Centers of the Greek Association of Alzheimer Disease and Related Disorders (GAADRD). Neuropsychological assessment was performed at baseline (at the time of diagnosis) between May and July of 2018, as well as for two consecutive follow-up assessments, identical in period, in 2019 and 2020. The majority of participants had participated in non-pharmacological interventions during 2018 as well as 2019, whereas all of them continued their participation online in 2020. Results: Mixed measures analysis of variance showed that participants’ ‘deterioration difference—D’ by means of their performance difference in neuropsychological assessments between 2018–2019 (D1) and 2019–2020 (D2) did not change, except for the FUCAS, RAVLT, and phonemic fluency tests, since both groups resulted in a larger deterioration difference (D2) in these tests. Additionally, three path models examining the direct relationships between performance in tests measuring mood, as well as everyday functioning and cognitive measures, showed that participants’ worsened performance in the 2019 and 2020 assessments was strongly affected by NPI performance, in sharp contrast to the 2018 assessment. Discussion: During the lockdown period, MCI and ADD patients’ neuropsychological performance did not change, except from the tests measuring verbal memory, learning, and phonemic fluency, as well as everyday functioning. However, the natural progression of the MCI as well as ADD condition is the main reason for participants’ deterioration. Mood performance became increasingly closely related to cognition and everyday functioning. Hence, the role of quarantine and AD progression are discussed as potential factors associated with impairments.