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Belder CRS, Marshall CR, Jiang J, Mazzeo S, Chokesuwattanaskul A, Rohrer JD, Volkmer A, Hardy CJD, Warren JD. Primary progressive aphasia: six questions in search of an answer. J Neurol 2024; 271:1028-1046. [PMID: 37906327 PMCID: PMC10827918 DOI: 10.1007/s00415-023-12030-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 09/27/2023] [Indexed: 11/02/2023]
Abstract
Here, we review recent progress in the diagnosis and management of primary progressive aphasia-the language-led dementias. We pose six key unanswered questions that challenge current assumptions and highlight the unresolved difficulties that surround these diseases. How many syndromes of primary progressive aphasia are there-and is syndromic diagnosis even useful? Are these truly 'language-led' dementias? How can we diagnose (and track) primary progressive aphasia better? Can brain pathology be predicted in these diseases? What is their core pathophysiology? In addition, how can primary progressive aphasia best be treated? We propose that pathophysiological mechanisms linking proteinopathies to phenotypes may help resolve the clinical complexity of primary progressive aphasia, and may suggest novel diagnostic tools and markers and guide the deployment of effective therapies.
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Affiliation(s)
- Christopher R S Belder
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
- UK Dementia Research Institute at UCL, UCL Queen Square Institute of Neurology, University College London, London, UK
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
| | - Charles R Marshall
- Preventive Neurology Unit, Wolfson Institute of Population Health, Queen Mary University of London, London, UK
| | - Jessica Jiang
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
| | - Salvatore Mazzeo
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Azienda Ospedaliera-Universitaria Careggi, Florence, Italy
| | - Anthipa Chokesuwattanaskul
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
- Division of Neurology, Department of Internal Medicine, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
- Cognitive Clinical and Computational Neuroscience Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Jonathan D Rohrer
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
| | - Anna Volkmer
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
| | - Chris J D Hardy
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
| | - Jason D Warren
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK.
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Hardy CJD, Taylor‐Rubin C, Taylor B, Harding E, Gonzalez AS, Jiang J, Thompson L, Kingma R, Chokesuwattanaskul A, Walker F, Barker S, Brotherhood E, Waddington C, Wood O, Zimmermann N, Kupeli N, Yong KXX, Camic PM, Stott J, Marshall CR, Oxtoby NP, Rohrer JD, Volkmer A, Crutch SJ, Warren JD. Symptom-led staging for semantic and non-fluent/agrammatic variants of primary progressive aphasia. Alzheimers Dement 2024; 20:195-210. [PMID: 37548125 PMCID: PMC10917001 DOI: 10.1002/alz.13415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/07/2023] [Accepted: 07/10/2023] [Indexed: 08/08/2023]
Abstract
INTRODUCTION Here we set out to create a symptom-led staging system for the canonical semantic and non-fluent/agrammatic variants of primary progressive aphasia (PPA), which present unique diagnostic and management challenges not well captured by functional scales developed for Alzheimer's disease and other dementias. METHODS An international PPA caregiver cohort was surveyed on symptom development under six provisional clinical stages and feedback was analyzed using a mixed-methods sequential explanatory design. RESULTS Both PPA syndromes were characterized by initial communication dysfunction and non-verbal behavioral changes, with increasing syndromic convergence and functional dependency at later stages. Milestone symptoms were distilled to create a prototypical progression and severity scale of functional impairment: the PPA Progression Planning Aid ("PPA-Squared"). DISCUSSION This work introduces a symptom-led staging scheme and functional scale for semantic and non-fluent/agrammatic variants of PPA. Our findings have implications for diagnostic and care pathway guidelines, trial design, and personalized prognosis and treatment for PPA. HIGHLIGHTS We introduce new symptom-led perspectives on primary progressive aphasia (PPA). The focus is on non-fluent/agrammatic (nfvPPA) and semantic (svPPA) variants. Foregrounding of early and non-verbal features of PPA and clinical trajectories is featured. We introduce a symptom-led staging scheme for PPA. We propose a prototype for a functional impairment scale, the PPA Progression Planning Aid.
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Affiliation(s)
- Chris J. D. Hardy
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
| | - Cathleen Taylor‐Rubin
- Uniting War Memorial HospitalSydneyAustralia
- Faculty of MedicineHealth and Human SciencesMacquarie UniversitySydneyAustralia
| | - Beatrice Taylor
- Centre for Medical Image ComputingDepartment of Computer ScienceUCLLondonUK
| | - Emma Harding
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
| | | | - Jessica Jiang
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
| | | | | | - Anthipa Chokesuwattanaskul
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
- Division of NeurologyDepartment of Internal MedicineKing Chulalongkorn Memorial HospitalBangkokThailand
- Cognitive Clinical and Computational Neuroscience Research UnitFaculty of MedicineChulalongkorn UniversityBangkokThailand
| | | | - Suzie Barker
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
| | - Emilie Brotherhood
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
| | - Claire Waddington
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
| | - Olivia Wood
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
| | - Nikki Zimmermann
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
| | - Nuriye Kupeli
- Marie Curie Palliative Care Research DepartmentDivision of PsychiatryUCLLondonUK
| | - Keir X. X. Yong
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
| | - Paul M. Camic
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
| | - Joshua Stott
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
- ADAPT LabResearch Department of ClinicalEducational and Health PsychologyUCLLondonUK
| | | | - Neil P. Oxtoby
- Centre for Medical Image ComputingDepartment of Computer ScienceUCLLondonUK
| | - Jonathan D. Rohrer
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
| | - Anna Volkmer
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
- Psychology and Language Sciences (PALS)UCLLondonUK
| | | | - Jason D. Warren
- Dementia Research CentreUCL Queen Square Institute of NeurologyUCLLondonUK
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Jiang J, Johnson JCS, Requena-Komuro MC, Benhamou E, Sivasathiaseelan H, Chokesuwattanaskul A, Nelson A, Nortley R, Weil RS, Volkmer A, Marshall CR, Bamiou DE, Warren JD, Hardy CJD. Comprehension of acoustically degraded speech in Alzheimer's disease and primary progressive aphasia. Brain 2023; 146:4065-4076. [PMID: 37184986 PMCID: PMC10545509 DOI: 10.1093/brain/awad163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 04/20/2023] [Accepted: 04/27/2023] [Indexed: 05/17/2023] Open
Abstract
Successful communication in daily life depends on accurate decoding of speech signals that are acoustically degraded by challenging listening conditions. This process presents the brain with a demanding computational task that is vulnerable to neurodegenerative pathologies. However, despite recent intense interest in the link between hearing impairment and dementia, comprehension of acoustically degraded speech in these diseases has been little studied. Here we addressed this issue in a cohort of 19 patients with typical Alzheimer's disease and 30 patients representing the three canonical syndromes of primary progressive aphasia (non-fluent/agrammatic variant primary progressive aphasia; semantic variant primary progressive aphasia; logopenic variant primary progressive aphasia), compared to 25 healthy age-matched controls. As a paradigm for the acoustically degraded speech signals of daily life, we used noise-vocoding: synthetic division of the speech signal into frequency channels constituted from amplitude-modulated white noise, such that fewer channels convey less spectrotemporal detail thereby reducing intelligibility. We investigated the impact of noise-vocoding on recognition of spoken three-digit numbers and used psychometric modelling to ascertain the threshold number of noise-vocoding channels required for 50% intelligibility by each participant. Associations of noise-vocoded speech intelligibility threshold with general demographic, clinical and neuropsychological characteristics and regional grey matter volume (defined by voxel-based morphometry of patients' brain images) were also assessed. Mean noise-vocoded speech intelligibility threshold was significantly higher in all patient groups than healthy controls, and significantly higher in Alzheimer's disease and logopenic variant primary progressive aphasia than semantic variant primary progressive aphasia (all P < 0.05). In a receiver operating characteristic analysis, vocoded intelligibility threshold discriminated Alzheimer's disease, non-fluent variant and logopenic variant primary progressive aphasia patients very well from healthy controls. Further, this central hearing measure correlated with overall disease severity but not with peripheral hearing or clear speech perception. Neuroanatomically, after correcting for multiple voxel-wise comparisons in predefined regions of interest, impaired noise-vocoded speech comprehension across syndromes was significantly associated (P < 0.05) with atrophy of left planum temporale, angular gyrus and anterior cingulate gyrus: a cortical network that has previously been widely implicated in processing degraded speech signals. Our findings suggest that the comprehension of acoustically altered speech captures an auditory brain process relevant to daily hearing and communication in major dementia syndromes, with novel diagnostic and therapeutic implications.
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Affiliation(s)
- Jessica Jiang
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
| | - Jeremy C S Johnson
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
| | - Maï-Carmen Requena-Komuro
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
- Kidney Cancer Program, UT Southwestern Medical Centre, Dallas, TX 75390, USA
| | - Elia Benhamou
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
| | - Harri Sivasathiaseelan
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
| | - Anthipa Chokesuwattanaskul
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
- Division of Neurology, Department of Internal Medicine, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand
| | - Annabel Nelson
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
| | - Ross Nortley
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
- Wexham Park Hospital, Frimley Health NHS Foundation Trust, Slough SL2 4HL, UK
| | - Rimona S Weil
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
| | - Anna Volkmer
- Division of Psychology and Language Sciences, University College London, London WC1H 0AP, UK
| | - Charles R Marshall
- Preventive Neurology Unit, Wolfson Institute of Population Health, Queen Mary University of London, London EC1M 6BQ, UK
| | - Doris-Eva Bamiou
- UCL Ear Institute and UCL/UCLH Biomedical Research Centre, National Institute of Health Research, University College London, London WC1X 8EE, UK
| | - Jason D Warren
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
| | - Chris J D Hardy
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
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Hardy CJD, Taylor-Rubin C, Taylor B, Harding E, Gonzalez AS, Jiang J, Thompson L, Kingma R, Chokesuwattanaskul A, Walker F, Barker S, Brotherhood E, Waddington C, Wood O, Zimmermann N, Kupeli N, Yong KXX, Camic PM, Stott J, Marshall CR, Oxtoby NP, Rohrer JD, Volkmer A, Crutch SJ, Warren JD. Symptom-led staging for primary progressive aphasia. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.03.13.23286972. [PMID: 36993460 PMCID: PMC10055437 DOI: 10.1101/2023.03.13.23286972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The primary progressive aphasias (PPA) present complex and diverse challenges of diagnosis, management and prognosis. A clinically-informed, syndromic staging system for PPA would take a substantial step toward meeting these challenges. This study addressed this need using detailed, multi-domain mixed-methods symptom surveys of people with lived experience in a large international PPA cohort. We administered structured online surveys to caregivers of patients with a canonical PPA syndromic variant (nonfluent/agrammatic (nvPPA), semantic (svPPA) or logopenic (lvPPA)). In an 'exploratory' survey, a putative list and ordering of verbal communication and nonverbal functioning (nonverbal thinking, conduct and wellbeing, physical) symptoms was administered to 118 caregiver members of the UK national PPA Support Group. Based on feedback, we expanded the symptom list and created six provisional clinical stages for each PPA subtype. In a 'consolidation' survey, these stages were presented to 110 caregiver members of UK and Australian PPA Support Groups, and refined based on quantitative and qualitative feedback. Symptoms were retained if rated as 'present' by a majority (at least 50%) of respondents representing that PPA syndrome, and assigned to a consolidated stage based on majority consensus; the confidence of assignment was estimated for each symptom as the proportion of respondents in agreement with the final staging for that symptom. Qualitative responses were analysed using framework analysis. For each PPA syndrome, six stages ranging from 1 ('Very mild') to 6 ('Profound') were identified; earliest stages were distinguished by syndromic hallmark symptoms of communication dysfunction, with increasing trans-syndromic convergence and dependency for basic activities of daily living at later stages. Spelling errors, hearing changes and nonverbal behavioural features were reported at early stages in all syndromes. As the illness evolved, swallowing and mobility problems were reported earlier in nfvPPA than other syndromes, while difficulty recognising familiar people and household items characterised svPPA and visuospatial symptoms were more prominent in lvPPA. Overall confidence of symptom staging was higher for svPPA than other syndromes. Across syndromes, functional milestones were identified as key deficits that predict the sequence of major daily life impacts and associated management needs. Qualitatively, we identified five major themes encompassing 15 subthemes capturing respondents' experiences of PPA and suggestions for staging implementation. This work introduces a prototypical, symptom-led staging scheme for canonical PPA syndromes: the PPA Progression Planning Aid (PPA 2 ). Our findings have implications for diagnostic and care pathway guidelines, trial design and personalised prognosis and treatment for people living with these diseases.
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Affiliation(s)
- Chris JD Hardy
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Cathleen Taylor-Rubin
- Uniting War Memorial Hospital, Sydney, Australia
- Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, Australia
| | - Beatrice Taylor
- Centre for Medical Image Computing, Department of Computer Science, UCL, London, UK
| | - Emma Harding
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Aida Suarez Gonzalez
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Jessica Jiang
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
| | | | | | - Anthipa Chokesuwattanaskul
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
- Division of Neurology, Department of Internal Medicine, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
- Cognitive Clinical and Computational Neuroscience Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | | | - Suzie Barker
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Emilie Brotherhood
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Claire Waddington
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Olivia Wood
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Nikki Zimmermann
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Nuriye Kupeli
- Marie Curie Palliative Care Research Department, Division of Psychiatry, UCL, London, UK
| | - Keir XX Yong
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Paul M Camic
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Josh Stott
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
- ADAPTlab, Research Department of Clinical, Educational and Health Psychology, UCL, London, UK
| | | | - Neil P. Oxtoby
- Centre for Medical Image Computing, Department of Computer Science, UCL, London, UK
| | - Jonathan D Rohrer
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Anna Volkmer
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
- Psychology and Language Sciences (PALS), UCL, London, UK
| | - Sebastian J Crutch
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
| | - Jason D Warren
- Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, UK
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Requena-Komuro MC, Jiang J, Dobson L, Benhamou E, Russell L, Bond RL, Brotherhood EV, Greaves C, Barker S, Rohrer JD, Crutch SJ, Warren JD, Hardy CJ. Remote versus face-to-face neuropsychological testing for dementia research: a comparative study in people with Alzheimer's disease, frontotemporal dementia and healthy older individuals. BMJ Open 2022; 12:e064576. [PMID: 36428012 PMCID: PMC9702828 DOI: 10.1136/bmjopen-2022-064576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 10/20/2022] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVES We explored whether adapting neuropsychological tests for online administration during the COVID-19 pandemic was feasible for dementia research. DESIGN We used a longitudinal design for healthy controls, who completed face-to-face assessments 3-4 years before remote assessments. For patients, we used a cross-sectional design, contrasting a prospective remote cohort with a retrospective face-to-face cohort matched for age/education/severity. SETTING Remote assessments were conducted using video-conferencing/online testing platforms, with participants using a personal computer/tablet at home. Face-to-face assessments were conducted in testing rooms at our research centre. PARTICIPANTS The remote cohort comprised 25 patients (n=8 Alzheimer's disease (AD); n=3 behavioural variant frontotemporal dementia (bvFTD); n=4 semantic dementia (SD); n=5 progressive non-fluent aphasia (PNFA); n=5 logopenic aphasia (LPA)). The face-to-face patient cohort comprised 64 patients (n=25 AD; n=12 bvFTD; n=9 SD; n=12 PNFA; n=6 LPA). Ten controls who previously participated in face-to-face research also took part remotely. OUTCOME MEASURES The outcome measures comprised the strength of evidence under a Bayesian framework for differences in performances between testing environments on general neuropsychological and neurolinguistic measures. RESULTS There was substantial evidence suggesting no difference across environments in both the healthy control and combined patient cohorts (including measures of working memory, single-word comprehension, arithmetic and naming; Bayes Factors (BF)01 >3), in the healthy control group alone (including measures of letter/category fluency, semantic knowledge and bisyllabic word repetition; all BF01 >3), and in the combined patient cohort alone (including measures of working memory, episodic memory, short-term verbal memory, visual perception, non-word reading, sentence comprehension and bisyllabic/trisyllabic word repetition; all BF01 >3). In the control cohort alone, there was substantial evidence in support of a difference across environments for tests of visual perception (BF01=0.0404) and monosyllabic word repetition (BF01=0.0487). CONCLUSIONS Our findings suggest that remote delivery of neuropsychological tests for dementia research is feasible.
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Affiliation(s)
- Maï-Carmen Requena-Komuro
- Dementia Research Centre, University College London, London, UK
- Kidney Cancer Program, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Jessica Jiang
- Dementia Research Centre, University College London, London, UK
| | - Lucianne Dobson
- Dementia Research Centre, University College London, London, UK
| | - Elia Benhamou
- Dementia Research Centre, University College London, London, UK
- Cognition and Brain Sciences Unit, Cambridge University, Cambridge, UK
| | - Lucy Russell
- Dementia Research Centre, University College London, London, UK
| | - Rebecca L Bond
- Dementia Research Centre, University College London, London, UK
| | | | | | - Suzie Barker
- Dementia Research Centre, University College London, London, UK
| | | | | | - Jason D Warren
- Dementia Research Centre, University College London, London, UK
| | - Chris Jd Hardy
- Dementia Research Centre, University College London, London, UK
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Jiang J, Johnson JCS, Requena-Komuro MC, Benhamou E, Sivasathiaseelan H, Sheppard DL, Volkmer A, Crutch SJ, Hardy CJD, Warren JD. Phonemic restoration in Alzheimer's disease and semantic dementia: a preliminary investigation. Brain Commun 2022; 4:fcac118. [PMID: 35611314 PMCID: PMC9123842 DOI: 10.1093/braincomms/fcac118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 12/20/2021] [Accepted: 05/04/2022] [Indexed: 11/15/2022] Open
Abstract
Phonemic restoration-perceiving speech sounds that are actually missing-is a fundamental perceptual process that 'repairs' interrupted spoken messages during noisy everyday listening. As a dynamic, integrative process, phonemic restoration is potentially affected by neurodegenerative pathologies, but this has not been clarified. Here, we studied this phenomenon in 5 patients with typical Alzheimer's disease and 4 patients with semantic dementia, relative to 22 age-matched healthy controls. Participants heard isolated sounds, spoken real words and pseudowords in which noise bursts either overlaid a consonant or replaced it; a tendency to hear replaced (missing) speech sounds as present signified phonemic restoration. All groups perceived isolated noises normally and showed phonemic restoration of real words, most marked in Alzheimer's patients. For pseudowords, healthy controls showed no phonemic restoration, while Alzheimer's patients showed marked suppression of phonemic restoration and patients with semantic dementia contrastingly showed phonemic restoration comparable to real words. Our findings provide the first evidence that phonemic restoration is preserved or even enhanced in neurodegenerative diseases, with distinct syndromic profiles that may reflect the relative integrity of bottom-up phonological representation and top-down lexical disambiguation mechanisms in different diseases. This work has theoretical implications for predictive coding models of language and neurodegenerative disease and for understanding cognitive 'repair' processes in dementia. Future research should expand on these preliminary observations with larger cohorts.
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Affiliation(s)
- Jessica Jiang
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3AR, UK
| | - Jeremy C. S. Johnson
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3AR, UK
| | - Maï-Carmen Requena-Komuro
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3AR, UK
| | - Elia Benhamou
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3AR, UK
| | - Harri Sivasathiaseelan
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3AR, UK
| | - Damion L. Sheppard
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3AR, UK
| | - Anna Volkmer
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3AR, UK
| | - Sebastian J. Crutch
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3AR, UK
| | - Chris J. D. Hardy
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3AR, UK
| | - Jason D Warren
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3AR, UK
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