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Varlokosta S, Fragkopoulou K, Arfani D, Manouilidou C. Methodologies for assessing morphosyntactic ability in people with Alzheimer's disease. INTERNATIONAL JOURNAL OF LANGUAGE & COMMUNICATION DISORDERS 2024; 59:38-57. [PMID: 36840629 DOI: 10.1111/1460-6984.12862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 01/27/2023] [Indexed: 05/26/2023]
Abstract
BACKGROUND The detection and description of language impairments in neurodegenerative diseases like Alzheimer's Disease (AD) play an important role in research, clinical diagnosis and intervention. Various methodological protocols have been implemented for the assessment of morphosyntactic abilities in AD; narrative discourse elicitation tasks and structured experimental tasks for production, offline and online structured experimental tasks for comprehension. Very few studies implement and compare different methodological protocols; thus, little is known about the advantages and disadvantages of each methodology. AIMS To discuss and compare the main behavioral methodological approaches and tasks that have been used in psycholinguistic research to assess different aspects of morphosyntactic production and comprehension in individuals with AD at the word and sentence levels. METHODS A narrative review was conducted through searches in the scientific databases Google Scholar, Scopus, Science Direct, MITCogNet, PubMed. Only studies written in English, that reported quantitative data and were published in peer-reviewed journals were considered with respect to their methodological protocol. Moreover, we considered studies that reported research on all stages of the disease and we included only studies that also reported results of a healthy control group. Studies that implemented standardized assessment tools were not considered in this review. OUTCOMES & RESULTS The main narrative discourse elicitation tasks implemented for the assessment of morphosyntactic production include interviews, picture-description and story narration, whereas the main structured experimental tasks include sentence completion, constrained sentence production, sentence repetition and naming. Morphosyntactic comprehension in AD has been assessed with the use of structured experimental tasks, both offline (sentence-picture matching, grammaticality judgment) and online (cross-modal naming,speeded sentence acceptability judgment, auditory moving window, word detection, reading). For each task we considered studies that reported results from different morphosyntactic structures and phenomena in as many different languages as possible. CONCLUSIONS & IMPLICATIONS Our review revealed strengths and weaknesses of these methods but also directions for future research. Narrative discourse elicitation tasks as well as structured experimental tasks have been used in a variety of languages, and have uncovered preserved morphosyntactic production but also deficits in people with AD. A combination of narrative discourse elicitation and structured production tasks for the assessment of the same morphosyntactic structure has been rarely used. Regarding comprehension, offline tasks have been implemented in various languages, whereas online tasks have been mainly used in English. Offline and online experimental paradigms have often produced contradictory results even within the same study. The discrepancy between the two paradigms has been attributed to the different working memory demands they impose to the comprehender or to the different parsing processes they tap. Strengths and shortcomings of each methodology are summarized in the paper, and comparisons between different tasks are attempted when this is possible. Thus, the paper may serve as a methodological guide for the study of morphosyntax in AD and possibly in other neurodegenerative diseases. WHAT THIS PAPER ADDS What is already known on this subject For the assessment of morphosyntactic abilities in AD, various methodological paradigms have been implemented: narrative discourse elicitation tasks and structured experimental tasks for production, and offline and online structured experimental tasks for comprehension. Very few studies implement and compare different methodological protocols; thus, little is known about the advantages and disadvantages of each methodology. What this paper adds to existing knowledge The paper presents an overview of methodologies that have been used to assess morphosyntactic production and comprehension of people with AD at the word and sentence levels. The paper summarizes the strengths and shortcomings of each methodology, providing both the researcher and the clinician with some directions in their endeavour of investigating language in AD. Also, the paper highlights the need for further research that will implement carefully scrutinized tasks from various experimental paradigms and will explore distinct aspects of the AD patients' morphosyntactic abilities in typologically different languages. What are the potential or actual clinical implications of this work? The paper may serve as a reference point for (psycho-)linguists who wish to study morphosyntactic abilities in AD, and for speech and language therapists who might need to apply morphosyntactic protocols to their patients in order to assess them or design appropriate therapeutic interventions for production and comprehension deficits.
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Affiliation(s)
- Spyridoula Varlokosta
- Department of Linguistics, Faculty of Philology, National and Kapodistrian University of Athens, Athens, Greece
| | - Katerina Fragkopoulou
- Department of Linguistics, Faculty of Philology, National and Kapodistrian University of Athens, Athens, Greece
| | - Dimitra Arfani
- Department of Linguistics, Faculty of Philology, National and Kapodistrian University of Athens, Athens, Greece
| | - Christina Manouilidou
- Department of Comparative and General Linguistics, Faculty of Arts, University of Ljubljana, Ljubljana, Slovenia
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Loss of speech and functional impairment in Alzheimer's disease-related primary progressive aphasia: predictive factors of decline. Neurobiol Aging 2022; 117:59-70. [DOI: 10.1016/j.neurobiolaging.2022.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 04/11/2022] [Accepted: 05/04/2022] [Indexed: 11/22/2022]
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Patel N, Peterson KA, Ingram RU, Storey I, Cappa SF, Catricala E, Halai A, Patterson KE, Lambon Ralph MA, Rowe JB, Garrard P. A 'Mini Linguistic State Examination' to classify primary progressive aphasia. Brain Commun 2021; 4:fcab299. [PMID: 35282164 PMCID: PMC8914496 DOI: 10.1093/braincomms/fcab299] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 09/27/2021] [Accepted: 12/17/2021] [Indexed: 11/13/2022] Open
Abstract
There are few available methods for qualitatively evaluating patients with primary progressive aphasia. Commonly adopted approaches are time-consuming, of limited accuracy or designed to assess different patient populations. This paper introduces a new clinical test-the Mini Linguistic State Examination-which was designed uniquely to enable a clinician to assess and subclassify both classical and mixed presentations of primary progressive aphasia. The adoption of a novel assessment method (error classification) greatly amplifies the clinical information that can be derived from a set of standard linguistic tasks and allows a five-dimensional profile to be defined. Fifty-four patients and 30 matched controls were recruited. Five domains of language competence (motor speech, phonology, semantics, syntax and working memory) were assessed using a sequence of 11 distinct linguistic assays. A random forest classification was used to assess the diagnostic accuracy for predicting primary progressive aphasia subtypes and create a decision tree as a guide to clinical classification. The random forest prediction model was 96% accurate overall (92% for the logopenic variant, 93% for the semantic variant and 98% for the non-fluent variant). The derived decision tree produced a correct classification of 91% of participants whose data were not included in the training set. The Mini Linguistic State Examination is a new cognitive test incorporating a novel and powerful, yet straightforward, approach to scoring. Rigorous assessment of its diagnostic accuracy confirmed excellent matching of primary progressive aphasia syndromes to clinical gold standard diagnoses. Adoption of the Mini Linguistic State Examination by clinicians will have a decisive impact on the consistency and uniformity with which patients can be described clinically. It will also facilitate screening for cohort-based research, including future therapeutic trials, and is suitable for describing, quantifying and monitoring language deficits in other brain disorders.
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Affiliation(s)
- Nikil Patel
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London SW17 0RE, UK
| | - Katie A. Peterson
- Department of Clinical Neurosciences and Cambridge University Hospitals NHS Trust, University of Cambridge, Cambridge CB2 0SP, UK
| | - Ruth U. Ingram
- Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester M13 9PL, UK
| | - Ian Storey
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London SW17 0RE, UK
| | - Stefano F. Cappa
- University Institute for Advanced Studies IUSS, Pavia, Italy
- IRCCS Mondino Foundation, Pavia, Italy
| | | | - Ajay Halai
- Department of Clinical Neurosciences and Cambridge University Hospitals NHS Trust, University of Cambridge, Cambridge CB2 0SP, UK
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge CB2 7EF, UK
| | - Karalyn E. Patterson
- Department of Clinical Neurosciences and Cambridge University Hospitals NHS Trust, University of Cambridge, Cambridge CB2 0SP, UK
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge CB2 7EF, UK
| | | | - James B. Rowe
- Department of Clinical Neurosciences and Cambridge University Hospitals NHS Trust, University of Cambridge, Cambridge CB2 0SP, UK
- MRC Cognition and Brain Sciences Unit, University of Cambridge, Cambridge CB2 7EF, UK
| | - Peter Garrard
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London SW17 0RE, UK
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Jellinger KA. Recent update on the heterogeneity of the Alzheimer’s disease spectrum. J Neural Transm (Vienna) 2021; 129:1-24. [DOI: 10.1007/s00702-021-02449-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 11/25/2021] [Indexed: 02/03/2023]
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Yamada Y, Shinkawa K, Kobayashi M, Nishimura M, Nemoto M, Tsukada E, Ota M, Nemoto K, Arai T. Tablet-Based Automatic Assessment for Early Detection of Alzheimer's Disease Using Speech Responses to Daily Life Questions. Front Digit Health 2021; 3:653904. [PMID: 34713127 PMCID: PMC8521899 DOI: 10.3389/fdgth.2021.653904] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 02/22/2021] [Indexed: 01/09/2023] Open
Abstract
Health-monitoring technologies for automatically detecting the early signs of Alzheimer's disease (AD) have become increasingly important. Speech responses to neuropsychological tasks have been used for quantifying changes resulting from AD and differentiating AD and mild cognitive impairment (MCI) from cognitively normal (CN). However, whether and how other types of speech tasks with less burden on older adults could be used for detecting early signs of AD remains unexplored. In this study, we developed a tablet-based application and compared speech responses to daily life questions with those to neuropsychological tasks in terms of differentiating MCI from CN. We found that in daily life questions, around 80% of speech features showing significant differences between CN and MCI overlapped those showing significant differences in both our study and other studies using neuropsychological tasks, but the number of significantly different features as well as their effect sizes from life questions decreased compared with those from neuropsychological tasks. On the other hand, the results of classification models for detecting MCI by using the speech features showed that daily life questions could achieve high accuracy, i.e., 86.4%, comparable to neuropsychological tasks by using eight questions against all five neuropsychological tasks. Our results indicate that, while daily life questions may elicit weaker but statistically discernable differences in speech responses resulting from MCI than neuropsychological tasks, combining them could be useful for detecting MCI with comparable performance to using neuropsychological tasks, which could help develop health-monitoring technologies for early detection of AD in a less burdensome manner.
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Affiliation(s)
| | | | | | - Masafumi Nishimura
- Department of Informatics, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka, Japan
| | - Miyuki Nemoto
- Department of Psychiatry, University of Tsukuba Hospital, Ibaraki, Japan
| | - Eriko Tsukada
- Department of Psychiatry, University of Tsukuba Hospital, Ibaraki, Japan
| | - Miho Ota
- Department of Psychiatry, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Kiyotaka Nemoto
- Department of Psychiatry, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Tetsuaki Arai
- Department of Psychiatry, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
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Verbal Short-Term Memory Disturbance in the Primary Progressive Aphasias: Challenges and Distinctions in a Clinical Setting. Brain Sci 2021; 11:brainsci11081060. [PMID: 34439679 PMCID: PMC8391512 DOI: 10.3390/brainsci11081060] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/05/2021] [Accepted: 08/09/2021] [Indexed: 01/22/2023] Open
Abstract
Impaired verbal ‘phonological’ short-term memory is considered a cardinal feature of the logopenic variant of primary progressive aphasia (lv-PPA) and is assumed to underpin most of the language deficits in this syndrome. Clinically, examination of verbal short-term memory in individuals presenting with PPA is common practice and serves two objectives: (i) to help understand the possible mechanisms underlying the patient’s language profile and (ii) to help differentiate lv-PPA from other PPA variants or from other dementia syndromes. Distinction between lv-PPA and the non-fluent variant of PPA (nfv-PPA), however, can be especially challenging due to overlapping language profiles and comparable psychometric performances on verbal short-term memory tests. Here, we present case vignettes of the three PPA variants (lv-PPA, nfv-PPA, and the semantic variant (sv-PPA)) and typical Alzheimer’s disease (AD). These vignettes provide a detailed description of the short-term and working memory profiles typically found in these patients and highlight how speech output and language comprehension deficits across the PPA variants differentially interfere with verbal memory performance. We demonstrate that a combination of verbal short-term and working memory measures provides crucial information regarding the cognitive mechanisms underlying language disturbances in PPA. In addition, we propose that analogous visuospatial span tasks are essential for the assessment of PPA as they measure memory capacity without language contamination.
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Foxe D, Irish M, D'Mello M, Barhon L, Burrell JR, Kessels RPC, Piguet O. The Box Task: A novel tool to differentiate the primary progressive aphasias. Eur J Neurol 2021; 28:3945-3954. [PMID: 34310820 DOI: 10.1111/ene.15035] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 07/20/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Differentiating the primary progressive aphasia (PPA) variants in clinical settings remains complex and challenging, especially for the logopenic (lv-PPA) and non-fluent variants (nfv-PPA). Recent studies suggest that visuospatial memory is more compromised in lv-PPA than in nfv-PPA and is relatively spared in the semantic variant (sv-PPA). Accordingly, assessment of visuospatial memory performance may assist in the differential diagnosis of PPA variants. Here, we investigated the utility of a novel computerised visuospatial working memory test-the Box Task-to differentiate the three PPA variants and typical Alzheimer's disease (AD). METHODS Eighteen lv-PPA, 14 nfv-PPA, 23 sv-PPA, 33 AD patients, and 32 healthy controls matched for age and education were recruited. All participants completed the computerised Box Task and WMS-III Spatial Span as measures of visuospatial working memory. RESULTS The lv-PPA group made significantly more Box Task between-search errors than nfv-PPA, sv-PPA and control groups. The AD group, however, displayed the greatest impairments on this measure relative to the PPA variants. Logistic regression analyses in lv-PPA and nfv-PPA demonstrated that the combination of Box Task between-search error variables (i.e., 4- and 6-box levels) could correctly classify 72% of lv-PPA patients and nearly 79% of nfv-PPA patients. Area under the receiver operator characteristics curve (AUC) analyses revealed the Box Task was more sensitive than Spatial Span at differentiating lv-PPA from nfv-PPA. CONCLUSIONS Our findings suggest that a simple, computerised measure of visuospatial working memory-the Box Task-shows potential diagnostic utility in differentiating lv-PPA from the other PPA variants.
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Affiliation(s)
- David Foxe
- School of Psychology, The University of Sydney, Sydney, New South Wales, Australia.,Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Muireann Irish
- School of Psychology, The University of Sydney, Sydney, New South Wales, Australia.,Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Mirelle D'Mello
- School of Psychology, The University of Sydney, Sydney, New South Wales, Australia.,Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - Lucienne Barhon
- School of Psychology, The University of Sydney, Sydney, New South Wales, Australia.,Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - James R Burrell
- Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia.,Concord Clinical School, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Roy P C Kessels
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands.,Vincent van Gogh Institute for Psychiatry, Venray, The Netherlands.,Radboudumc Alzheimer Center, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Olivier Piguet
- School of Psychology, The University of Sydney, Sydney, New South Wales, Australia.,Brain and Mind Centre, The University of Sydney, Sydney, New South Wales, Australia
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Montreuil S, Poulin E, Bergeron D, Sellami L, Verret L, Fortin MP, Poulin S, Macoir J, Hudon C, Bouchard RW, Lavoie M, Laforce R. Cognitive Profile of the Logopenic Variant of Primary Progressive Aphasia Using the Dépistage Cognitif de Québec. Dement Geriatr Cogn Disord 2021; 49:410-417. [PMID: 33113530 DOI: 10.1159/000510501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 07/24/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS The logopenic variant of primary progressive aphasia (lvPPA) is characterized by impaired word-finding and sentence repetition with phonologic errors but spared motor speech and grammar and semantic knowledge. Although its language deficits have been well studied, the full spectrum of cognitive changes in the lvPPA remains to be defined. We aimed to explore the neurocognitive profile of the lvPPA using a newly developed cognitive screening tool for atypical dementias, the Dépistage Cognitif de Québec (DCQ). METHODS We compared 29 patients with lvPPA to 72 amnestic variant Alzheimer disease (aAD) to 438 healthy control (HC) participants. Performance on the 5 indexes of the DCQ (Memory, Visuospatial, Executive, Language and Behavioral) was compared between the 3 groups. RESULTS Results showed a significantly lower performance for lvPPA participants in all neurocognitive domains, when compared to HC. When compared to aAD, lvPPA participants had significantly lower scores for language, executive, and visuospatial abilities, but not for memory and behavior. CONCLUSION Altogether, these findings better define the neurocognitive changes of lvPPA.
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Affiliation(s)
- Sarah Montreuil
- Clinique Interdisciplinaire de Mémoire, CHU de Québec/Université Laval/Hôpital de l'Enfant-Jésus, Québec, Québec, Canada
| | - Elizabeth Poulin
- Clinique Interdisciplinaire de Mémoire, CHU de Québec/Université Laval/Hôpital de l'Enfant-Jésus, Québec, Québec, Canada
| | - David Bergeron
- Clinique Interdisciplinaire de Mémoire, CHU de Québec/Université Laval/Hôpital de l'Enfant-Jésus, Québec, Québec, Canada
| | - Leila Sellami
- Clinique Interdisciplinaire de Mémoire, CHU de Québec/Université Laval/Hôpital de l'Enfant-Jésus, Québec, Québec, Canada
| | - Louis Verret
- Clinique Interdisciplinaire de Mémoire, CHU de Québec/Université Laval/Hôpital de l'Enfant-Jésus, Québec, Québec, Canada
| | - Marie-Pierre Fortin
- Clinique Interdisciplinaire de Mémoire, CHU de Québec/Université Laval/Hôpital de l'Enfant-Jésus, Québec, Québec, Canada
| | - Stéphane Poulin
- Clinique Interdisciplinaire de Mémoire, CHU de Québec/Université Laval/Hôpital de l'Enfant-Jésus, Québec, Québec, Canada
| | - Joël Macoir
- Département de Réadaptation, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Carol Hudon
- École de Psychologie, Faculté des Sciences Sociales, Université Laval, Québec, Québec, Canada
| | - Rémi W Bouchard
- Clinique Interdisciplinaire de Mémoire, CHU de Québec/Université Laval/Hôpital de l'Enfant-Jésus, Québec, Québec, Canada
| | - Monica Lavoie
- Clinique Interdisciplinaire de Mémoire, CHU de Québec/Université Laval/Hôpital de l'Enfant-Jésus, Québec, Québec, Canada
| | - Robert Laforce
- Clinique Interdisciplinaire de Mémoire, CHU de Québec/Université Laval/Hôpital de l'Enfant-Jésus, Québec, Québec, Canada,
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Jellinger KA. Pathobiological Subtypes of Alzheimer Disease. Dement Geriatr Cogn Disord 2021; 49:321-333. [PMID: 33429401 DOI: 10.1159/000508625] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 05/11/2020] [Indexed: 11/19/2022] Open
Abstract
Alzheimer disease (AD), the most common form of dementia, is a heterogenous disorder with various pathobiological subtypes. In addition to the 4 major subtypes based on the distribution of tau pathology and brain atrophy (typical, limbic predominant, hippocampal sparing, and minimal atrophy [MA]), several other clinical variants showing distinct regional patterns of tau burden have been identified: nonamnestic, corticobasal syndromal, primary progressive aphasia, posterior cortical atrophy, behavioral/dysexecutive, and mild dementia variants. Among the subtypes, differences were found in age at onset, sex distribution, cognitive status, disease duration, APOE genotype, and biomarker levels. The patterns of key network destructions parallel the tau and atrophy patterns of the AD subgroups essentially. Interruption of key networks, in particular the default-mode network that is responsible for cognitive decline, is consistent in hetero-genous AD groups. AD pathology is often associated with co-pathologies: cerebrovascular lesions, Lewy pathology, and TDP-43 proteinopathies. These mixed pathologies essentially influence the clinical picture of AD and may accel-erate disease progression. Unraveling the heterogeneity among the AD spectrum entities is important for opening a window to pathogenic mechanisms affecting the brain and enabling precision medicine approaches as a basis for developing preventive and ultimately successful disease-modifying therapies for AD.
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Wang T, Hong Y, Wang Q, Su R, Ng ML, Xu J, Wang L, Yan N. Identification of Mild Cognitive Impairment Among Chinese Based on Multiple Spoken Tasks. J Alzheimers Dis 2021; 82:185-204. [PMID: 33998535 DOI: 10.3233/jad-201387] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Previous studies explored the use of noninvasive biomarkers of speech and language for the detection of mild cognitive impairment (MCI). Yet, most of them employed single task which might not have adequately captured all aspects of their cognitive functions. OBJECTIVE The present study aimed to achieve the state-of-the-art accuracy in detecting individuals with MCI using multiple spoken tasks and uncover task-specific contributions with a tentative interpretation of features. METHODS Fifty patients clinically diagnosed with MCI and 60 healthy controls completed three spoken tasks (picture description, semantic fluency, and sentence repetition), from which multidimensional features were extracted to train machine learning classifiers. With a late-fusion configuration, predictions from multiple tasks were combined and correlated with the participants' cognitive ability assessed using the Montreal Cognitive Assessment (MoCA). Statistical analyses on pre-defined features were carried out to explore their association with the diagnosis. RESULTS The late-fusion configuration could effectively boost the final classification result (SVM: F1 = 0.95; RF: F1 = 0.96; LR: F1 = 0.93), outperforming each individual task classifier. Besides, the probability estimates of MCI were strongly correlated with the MoCA scores (SVM: -0.74; RF: -0.71; LR: -0.72). CONCLUSION Each single task tapped more dominantly to distinct cognitive processes and have specific contributions to the prediction of MCI. Specifically, picture description task characterized communications at the discourse level, while semantic fluency task was more specific to the controlled lexical retrieval processes. With greater demands on working memory load, sentence repetition task uncovered memory deficits through modified speech patterns in the reproduced sentences.
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Affiliation(s)
- Tianqi Wang
- CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Guangdong-Hong Kong-Macao Joint Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen, China.,Speech Science Laboratory, The University of Hong Kong, Hong Kong, China
| | - Yin Hong
- Health Management Center, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Quanyi Wang
- CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Guangdong-Hong Kong-Macao Joint Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen, China
| | - Rongfeng Su
- CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Guangdong-Hong Kong-Macao Joint Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen, China
| | - Manwa Lawrence Ng
- Speech Science Laboratory, The University of Hong Kong, Hong Kong, China
| | - Jun Xu
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Lan Wang
- CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Guangdong-Hong Kong-Macao Joint Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen, China
| | - Nan Yan
- CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Guangdong-Hong Kong-Macao Joint Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen, China
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Sood A, Pavlik V, Darby E, Chan W, Doody R. Different Cognitive Profiles Are Associated with Progression Rate and Age at Death in Probable Alzheimer's Disease. J Alzheimers Dis 2021; 80:735-747. [PMID: 33579838 DOI: 10.3233/jad-201124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Cognitive profiles characterized by primarily language or visuospatial deficits have been documented in individuals meeting diagnostic criteria for probable Alzheimer's disease (AD), but their association with progression rate or overall survival is not well described. OBJECTIVE To compare time from diagnosis to severe disease stage and death in probable AD patients classified into three groups based on neuropsychological test performance: marked verbal impairment (Verb-PI) with relatively preserved visuospatial function, marked visuospatial impairment with preserved verbal function (Vis-PI), and balanced verbal and visuospatial impairments (Bal-PI). METHODS This prospective cohort study included 540 probable AD patients attending an academic memory clinic who were enrolled from 1995-2013 and followed annually. Eligible individuals had a Mini-Mental State Exam (MMSE) score ≥10 at baseline, and at least one annual follow up visit. We used Cox proportional hazards modeling to analyze the association of cognitive profiles with time to decline in MMSE and CDR Global Score. RESULTS Sixty-one (11.3%) individuals had a Verb-PI profile, 86 (16%) had a Vis-PI profile, and 393 (72.8%) a Bal-PI profile. MMSE decline to <10 was faster in Verb-PI than Vis-PI (HR 2.004, 95%CI, 1.062-3.780; p = 0.032). Progression to CDR-GS = 3 was faster in Verb-PI individuals compared to Bal-PI (HR 1.604, 95%CI, 1.022-2.515; p = 0.040) or Vis-PI (HR 2.388, 95%CI, 1.330-4.288; p = 0.004) individuals. Baseline cognitive profile did not affect mortality. CONCLUSION A recognition of different AD profiles may help to personalize care by providing a better understanding of pathogenesis and expected progression.
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Affiliation(s)
- Ajay Sood
- Rush Alzheimer's Disease Center (RADC), Rush University Medical Center, Chicago, IL, USA
| | - Valory Pavlik
- Department of Neurology and Alzheimer's Disease and Memory Disorders Center, Baylor College of Medicine, Houston, TX, USA
| | - Eveleen Darby
- Department of Neurology and Alzheimer's Disease and Memory Disorders Center, Baylor College of Medicine, Houston, TX, USA
| | - Wenyaw Chan
- Department of Biostatistics and Data Science, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Rachelle Doody
- Genentech, San Francisco, CA, USA.,Hoffmann-La Roche, Basel, Switzerland
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Lin H, Karjadi C, Ang TFA, Prajakta J, McManus C, Alhanai TW, Glass J, Au R. Identification of digital voice biomarkers for cognitive health. EXPLORATION OF MEDICINE 2020; 1:406-417. [PMID: 33665648 PMCID: PMC7929495 DOI: 10.37349/emed.2020.00028] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 09/04/2020] [Indexed: 01/03/2023] Open
Abstract
AIM Human voice contains rich information. Few longitudinal studies have been conducted to investigate the potential of voice to monitor cognitive health. The objective of this study is to identify voice biomarkers that are predictive of future dementia. METHODS Participants were recruited from the Framingham Heart Study. The vocal responses to neuropsychological tests were recorded, which were then diarized to identify participant voice segments. Acoustic features were extracted with the OpenSMILE toolkit (v2.1). The association of each acoustic feature with incident dementia was assessed by Cox proportional hazards models. RESULTS Our study included 6, 528 voice recordings from 4, 849 participants (mean age 63 ± 15 years old, 54.6% women). The majority of participants (71.2%) had one voice recording, 23.9% had two voice recordings, and the remaining participants (4.9%) had three or more voice recordings. Although all asymptomatic at the time of examination, participants who developed dementia tended to have shorter segments than those who were dementia free (P < 0.001). Additionally, 14 acoustic features were significantly associated with dementia after adjusting for multiple testing (P < 0.05/48 = 1 × 10-3). The most significant acoustic feature was jitterDDP_sma_de (P = 7.9 × 10-7), which represents the differential frame-to-frame Jitter. A voice based linear classifier was also built that was capable of predicting incident dementia with area under curve of 0.812. CONCLUSIONS Multiple acoustic and linguistic features are identified that are associated with incident dementia among asymptomatic participants, which could be used to build better prediction models for passive cognitive health monitoring.
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Affiliation(s)
- Honghuang Lin
- Section of Computational Biomedicine, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
- The Framingham Heart Study, Boston University School of Medicine, Boston, MA 02118, USA
| | - Cody Karjadi
- The Framingham Heart Study, Boston University School of Medicine, Boston, MA 02118, USA
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Ting F. A. Ang
- The Framingham Heart Study, Boston University School of Medicine, Boston, MA 02118, USA
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA
- Department of Epidemiology, Boston University School of Public Health, Boston, MA 02118, USA
- Slone Epidemiology Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Joshi Prajakta
- The Framingham Heart Study, Boston University School of Medicine, Boston, MA 02118, USA
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Chelsea McManus
- The Framingham Heart Study, Boston University School of Medicine, Boston, MA 02118, USA
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Tuka W. Alhanai
- Department of Electrical and Computer Engineering, New York University Abu Dhabi, Abu Dhabi, UAE
| | - James Glass
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Rhoda Au
- The Framingham Heart Study, Boston University School of Medicine, Boston, MA 02118, USA
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA
- Department of Epidemiology, Boston University School of Public Health, Boston, MA 02118, USA
- Slone Epidemiology Center, Boston University School of Medicine, Boston, MA 02118, USA
- Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA
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13
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Jellinger KA. Neuropathological assessment of the Alzheimer spectrum. J Neural Transm (Vienna) 2020; 127:1229-1256. [PMID: 32740684 DOI: 10.1007/s00702-020-02232-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 07/14/2020] [Indexed: 12/12/2022]
Abstract
Alzheimer disease (AD), the most common form of dementia globally, classically defined a clinicopathological entity, is a heterogenous disorder with various pathobiological subtypes, currently referred to as Alzheimer continuum. Its morphological hallmarks are extracellular parenchymal β-amyloid (amyloid plaques) and intraneuronal (tau aggregates forming neurofibrillary tangles) lesions accompanied by synaptic loss and vascular amyloid deposits, that are essential for the pathological diagnosis of AD. In addition to "classical" AD, several subtypes with characteristic regional patterns of tau pathology have been described that show distinct clinical features, differences in age, sex distribution, biomarker levels, and patterns of key network destructions responsible for cognitive decline. AD is a mixed proteinopathy (amyloid and tau), frequently associated with other age-related co-pathologies, such as cerebrovascular lesions, Lewy and TDP-43 pathologies, hippocampal sclerosis, or argyrophilic grain disease. These and other co-pathologies essentially influence the clinical picture of AD and may accelerate disease progression. The purpose of this review is to provide a critical overview of AD pathology, its defining pathological substrates, and the heterogeneity among the Alzheimer spectrum entities that may provide a broader diagnostic coverage of this devastating disorder as a basis for implementing precision medicine approaches and for ultimate development of successful disease-modifying drugs for AD.
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Affiliation(s)
- Kurt A Jellinger
- Institute of Clinical Neurobiology, Alberichgasse 5/13, 1150, Vienna, Austria.
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14
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Ramanan S, Marstaller L, Hodges JR, Piguet O, Irish M. Understanding the neural basis of episodic amnesia in logopenic progressive aphasia: A multimodal neuroimaging study. Cortex 2020; 125:272-287. [DOI: 10.1016/j.cortex.2019.12.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 07/19/2019] [Accepted: 12/21/2019] [Indexed: 12/13/2022]
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15
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Yamada Y, Shinkawa K, Shimmei K. Atypical Repetition in Daily Conversation on Different Days for Detecting Alzheimer Disease: Evaluation of Phone-Call Data From Regular Monitoring Service. JMIR Ment Health 2020; 7:e16790. [PMID: 31934870 PMCID: PMC6996758 DOI: 10.2196/16790] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/04/2019] [Accepted: 12/16/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Identifying signs of Alzheimer disease (AD) through longitudinal and passive monitoring techniques has become increasingly important. Previous studies have succeeded in quantifying language dysfunctions and identifying AD from speech data collected during neuropsychological tests. However, whether and how we can quantify language dysfunction in daily conversation remains unexplored. OBJECTIVE The objective of this study was to explore the linguistic features that can be used for differentiating AD patients from daily conversations. METHODS We analyzed daily conversational data of seniors with and without AD obtained from longitudinal follow-up in a regular monitoring service (from n=15 individuals including 2 AD patients at an average follow-up period of 16.1 months; 1032 conversational data items obtained during phone calls and approximately 221 person-hours). In addition to the standard linguistic features used in previous studies on connected speech data during neuropsychological tests, we extracted novel features related to atypical repetition of words and topics reported by previous observational and descriptive studies as one of the prominent characteristics in everyday conversations of AD patients. RESULTS When we compared the discriminative power for AD, we found that atypical repetition in two conversations on different days outperformed other linguistic features used in previous studies on speech data during neuropsychological tests. It was also a better indicator than atypical repetition in single conversations as well as that in two conversations separated by a specific number of conversations. CONCLUSIONS Our results show how linguistic features related to atypical repetition across days could be used for detecting AD from daily conversations in a passive manner by taking advantage of longitudinal data.
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Affiliation(s)
| | | | - Keita Shimmei
- IBM Research, Tokyo, Japan.,Poverty and Equity Global Practice, The World Bank, Washington, DC, United States
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16
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Abstract
PURPOSE OF REVIEW Early-onset Alzheimer disease (AD) is defined as having an age of onset younger than 65 years. While early-onset AD is often overshadowed by the more common late-onset AD, recognition of the differences between early- and late-onset AD is important for clinicians. RECENT FINDINGS Early-onset AD comprises about 5% to 6% of cases of AD and includes a substantial percentage of phenotypic variants that differ from the usual amnestic presentation of typical AD. Characteristics of early-onset AD in comparison to late-onset AD include a larger genetic predisposition (familial mutations and summed polygenic risk), more aggressive course, more frequent delay in diagnosis, higher prevalence of traumatic brain injury, less memory impairment and greater involvement of other cognitive domains on presentation, and greater psychosocial difficulties. Neuroimaging features of early-onset AD in comparison to late-onset AD include greater frequency of hippocampal sparing and posterior neocortical atrophy, increased tau burden, and greater connectomic changes affecting frontoparietal networks rather than the default mode network. SUMMARY Early-onset AD differs substantially from late-onset AD, with different phenotypic presentations, greater genetic predisposition, and differences in neuropathologic burden and topography. Early-onset AD more often presents with nonamnestic phenotypic variants that spare the hippocampi and with greater tau burden in posterior neocortices. The early-onset AD phenotypic variants involve different neural networks than typical AD. The management of early-onset AD is similar to that of late-onset AD but with special emphasis on targeting specific cognitive areas and more age-appropriate psychosocial support and education.
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17
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Alzheimer's disease clinical variants show distinct regional patterns of neurofibrillary tangle accumulation. Acta Neuropathol 2019; 138:597-612. [PMID: 31250152 DOI: 10.1007/s00401-019-02036-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 06/16/2019] [Accepted: 06/16/2019] [Indexed: 10/26/2022]
Abstract
The clinical spectrum of Alzheimer's disease (AD) extends well beyond the classic amnestic-predominant syndrome. The previous studies have suggested differential neurofibrillary tangle (NFT) burden between amnestic and logopenic primary progressive aphasia presentations of AD. In this study, we explored the regional distribution of NFT pathology and its relationship to AD presentation across five different clinical syndromes. We assessed NFT density throughout six selected neocortical and hippocampal regions using thioflavin-S fluorescent microscopy in a well-characterized clinicopathological cohort of pure AD cases enriched for atypical clinical presentations. Subjects underwent apolipoprotein E genotyping and neuropsychological testing. Main cognitive domains (executive, visuospatial, language, and memory function) were assessed using an established composite z score. Our results showed that NFT regional burden aligns with the clinical presentation and region-specific cognitive scores. Cortical, but not hippocampal, NFT burden was higher among atypical clinical variants relative to the amnestic syndrome. In analyses of specific clinical variants, logopenic primary progressive aphasia showed higher NFT density in the superior temporal gyrus (p = 0.0091), and corticobasal syndrome showed higher NFT density in the primary motor cortex (p = 0.0205) relative to the amnestic syndrome. Higher NFT burden in the angular gyrus and CA1 sector of the hippocampus were independently associated with worsening visuospatial dysfunction. In addition, unbiased hierarchical clustering based on regional NFT densities identified three groups characterized by a low overall NFT burden, high overall burden, and cortical-predominant burden, respectively, which were found to differ in sex ratio, age, disease duration, and clinical presentation. In comparison, the typical, hippocampal sparing, and limbic-predominant subtypes derived from a previously proposed algorithm did not reproduce the same degree of clinical relevance in this sample. Overall, our results suggest domain-specific functional consequences of regional NFT accumulation. Mapping these consequences presents an opportunity to increase understanding of the neuropathological framework underlying atypical clinical manifestations.
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18
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Margolis SA, Festa EK, Papandonatos GD, Korthauer LE, Gonsalves MA, Oberman L, Heindel WC, Ott BR. A pilot study of repetitive transcranial magnetic stimulation in primary progressive aphasia. Brain Stimul 2019; 12:1340-1342. [DOI: 10.1016/j.brs.2019.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 06/02/2019] [Indexed: 10/26/2022] Open
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19
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Slegers A, Filiou RP, Montembeault M, Brambati SM. Connected Speech Features from Picture Description in Alzheimer's Disease: A Systematic Review. J Alzheimers Dis 2019; 65:519-542. [PMID: 30103314 DOI: 10.3233/jad-170881] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The language changes that occur over the course of Alzheimer's disease (AD) can impact communication abilities and have profound functional consequences. Picture description tasks can be used to approximate everyday communication abilities of AD patients. As various methods and variables have been studied over the years, current knowledge about the most affected features of AD discourse in the context of picture descriptions is difficult to summarize. This systematic review aims to provide researchers with an overview of the most common areas of impairment in AD discourse as they appear in picture description tasks. Based on the 44 articles fulfilling inclusion criteria, our findings reflect a multidimensional pattern of changes in the production (speech rate), syntactic (length of utterance), lexical (word-frequency and use of pronouns), fluency (repetitions and word-finding difficulties), semantic (information units), and discourse (efficiency) domains. We discuss our findings in the light of current research and point to potential scientific and clinical uses of picture description tasks in the context of AD.
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Affiliation(s)
- Antoine Slegers
- Département de Psychologie, Université de Montréal, Montréal, QC, Canada.,Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal (CRIUGM), CIUSSS du Centre-Sud-de-l'Île-de-Montréal, Montréal, QC, Canada
| | - Renée-Pier Filiou
- Département de Psychologie, Université de Montréal, Montréal, QC, Canada.,Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal (CRIUGM), CIUSSS du Centre-Sud-de-l'Île-de-Montréal, Montréal, QC, Canada
| | - Maxime Montembeault
- Département de Psychologie, Université de Montréal, Montréal, QC, Canada.,Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal (CRIUGM), CIUSSS du Centre-Sud-de-l'Île-de-Montréal, Montréal, QC, Canada
| | - Simona Maria Brambati
- Département de Psychologie, Université de Montréal, Montréal, QC, Canada.,Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal (CRIUGM), CIUSSS du Centre-Sud-de-l'Île-de-Montréal, Montréal, QC, Canada
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20
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Abstract
BACKGROUND The semantic variant of primary progressive aphasia (svPPA) is a form of dementia, mainly featuring language impairment, for which the extent of white matter (WM) damage is less described than its associated grey matter (GM) atrophy. Our study aimed to characterise the extent of this damage using a sensitive and unbiased approach. METHODS We conducted a between-group study comparing 10 patients with a clinical diagnosis of svPPA, recruited between 2011 and 2014 at a tertiary reference centre, with 9 cognitively healthy, age-matched controls. From diffusion tensor imaging (DTI) data, we extracted fractional anisotropy (FA) values using a tract-based spatial statistics approach. We further obtained GM volumetric data using the Freesurfer automated segmentation tool. We compared both groups using non-parametric Wilcoxon rank-sum tests, correcting for multiple comparisons. RESULTS Demographic data showed that patients and controls were comparable. As expected, clinical data showed lower results in svPPA than controls on cognitive screening tests. Tractography showed impaired diffusion in svPPA patients, with FA mostly decreased in the longitudinal, uncinate, cingulum and external capsule fasciculi. Volumetric data show significant atrophy in svPPA patients, mostly in the left entorhinal, amygdala, inferior temporal, middle temporal, superior temporal and temporal pole cortices, and bilateral fusiform gyri. CONCLUSIONS This syndrome appears to be associated not only with GM but also significant WM degeneration. Thus, DTI could play a role in the differential diagnosis of atypical dementia by specifying WM damage specific to svPPA.
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21
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Effects of morphological family on word recognition in normal aging, mild cognitive impairment, and Alzheimer's disease. Cortex 2019; 116:91-103. [DOI: 10.1016/j.cortex.2018.10.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 07/21/2018] [Accepted: 10/31/2018] [Indexed: 11/20/2022]
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22
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Jokel R, Seixas Lima B, Fernandez A, Murphy K. Language in Amnestic Mild Cognitive Impairment and Dementia of Alzheimer’s Type: Quantitatively or Qualitatively Different? Dement Geriatr Cogn Dis Extra 2019. [DOI: 10.1159/000496824] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Background/Aims: The purpose of this study was to explore language differences between individuals diagnosed with amnestic mild cognitive impairment multiple domain (aMCIm) and those with probable Alzheimer’s disease, with a goal of (i) characterizing the language profile of aMCIm and (ii) determining whether the profiles of dementia of Alzheimer’s type (DAT) and aMCIm individuals are on a continuum of one diagnostic entity or represent two distinct cognitive disorders. Methods: Language data from 28 patients with consensus diagnosis of aMCIm and DAT derived from a retrospective chart review were compared to that of healthy controls. Results: A non-parametric statistic established that there was no significant difference between groups in age, years of education or duration of symptoms and that expressive language was found to be relatively intact in both patient groups. In contrast, both groups exhibited significant impairments on receptive language tests and on linguistically complex tasks that rely on episodic memory and executive functions. Individuals with aMCIm and DAT present with configurations of language features that are largely in parallel to each other and reflect predominantly quantitative differences. Conclusion: Language tests provide an important contribution to the diagnostic process in their capacity to identify language impairments at an early stage. Understanding the nature of language decline is critically important to the intervention process as this information would inform cognitive intervention approaches aimed at promoting quality of life in people living with MCI and dementia.
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23
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Convery R, Mead S, Rohrer JD. Review: Clinical, genetic and neuroimaging features of frontotemporal dementia. Neuropathol Appl Neurobiol 2019; 45:6-18. [DOI: 10.1111/nan.12535] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 12/10/2018] [Indexed: 12/12/2022]
Affiliation(s)
- R. Convery
- Dementia Research Centre; Department of Neurodegenerative Disease; UCL Queen Square Institute of Neurology; London UK
| | - S. Mead
- UCL Institute of Prion Diseases; MRC Prion Unit at UCL; London UK
| | - J. D. Rohrer
- Dementia Research Centre; Department of Neurodegenerative Disease; UCL Queen Square Institute of Neurology; London UK
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24
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Mueller KD, Koscik RL, Clark LR, Hermann BP, Johnson SC, Turkstra LS. The Latent Structure and Test-Retest Stability of Connected Language Measures in the Wisconsin Registry for Alzheimer's Prevention (WRAP). Arch Clin Neuropsychol 2018; 33:993-1005. [PMID: 29186313 PMCID: PMC6455482 DOI: 10.1093/arclin/acx116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/02/2017] [Accepted: 11/07/2017] [Indexed: 11/14/2022] Open
Abstract
INTRODUCTION While it is well known that discourse-related language functions are impaired in the dementia phase of Alzheimer's Disease (AD), the presymptomatic temporal course of discourse dysfunction are not known earlier in the course of AD. To conduct discourse-related studies in this phase of AD, validated psychometric instruments are needed. This study investigates the latent structure, validity, and test-retest stability of discourse measures in a late-middle-aged normative group who are relatively free from sporadic AD risk factors. METHODS Using a normative sample of 399 participants (mean age = 61), exploratory factor analyses (EFA) and confirmatory factor analyses (CFA) were conducted on 18 measures of connected language derived from picture descriptions. Factor invariance across sex and family history and longitudinal test-retest stability measures were calculated. RESULTS The EFA revealed a four-factor solution, consisting of semantic, syntax, fluency, and lexical constructs. The CFA model substantiated the structure, and factors were invariant across sex and parental history of AD status. Test-retest stability measures were within acceptable ranges. CONCLUSIONS Results confirm a factor structure that is invariant across sex and parental AD history. The factor structure could be useful in similar cohorts designed to detect early language decline in investigations of preclinical or clinical AD or as outcome measures in clinical prevention trials.
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Affiliation(s)
- Kimberly D Mueller
- Wisconsin Alzheimer’s Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Communication Sciences and Disorders, University of Wisconsin – Madison, Madison, WI, USA
| | - Rebecca L Koscik
- Wisconsin Alzheimer’s Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Lindsay R Clark
- Wisconsin Alzheimer’s Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Alzheimer’s Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Geriatric Research Education and Clinical Center, Wm.S. Middleton Veterans Hospital, Madison, WI, USA
| | - Bruce P Hermann
- Department of Neurology, University of Wisconsin – Madison, Madison, WI, USA
| | - Sterling C Johnson
- Wisconsin Alzheimer’s Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Alzheimer’s Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Geriatric Research Education and Clinical Center, Wm.S. Middleton Veterans Hospital, Madison, WI, USA
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Lyn S Turkstra
- Department of Communication Sciences and Disorders, University of Wisconsin – Madison, Madison, WI, USA
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, USA
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, USA
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25
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Mueller KD, Hermann B, Mecollari J, Turkstra LS. Connected speech and language in mild cognitive impairment and Alzheimer's disease: A review of picture description tasks. J Clin Exp Neuropsychol 2018; 40:917-939. [PMID: 29669461 PMCID: PMC6198327 DOI: 10.1080/13803395.2018.1446513] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
INTRODUCTION The neuropsychological profile of people with mild cognitive impairment (MCI) and Alzheimer's disease (AD) dementia includes a history of decline in memory and other cognitive domains, including language. While language impairments have been well described in AD dementia, language features of MCI are less well understood. Connected speech and language analysis is the study of an individual's spoken discourse, usually elicited by a target stimulus, the results of which can facilitate understanding of how language deficits typical of MCI and AD dementia manifest in everyday communication. Among discourse genres, picture description is a constrained task that relies less on episodic memory and more on semantic knowledge and retrieval, within the cognitive demands of a communication context. Understanding the breadth of evidence across the continuum of cognitive decline will help to elucidate the areas of strength and need in terms of using this method as an evaluative tool for both cognitive changes and everyday functional communication. METHOD We performed an extensive literature search of peer-reviewed journal articles that focused on the use of picture description tasks for evaluating language in persons with MCI or AD dementia. We selected articles based on inclusion and exclusion criteria and described the measures assessed, the psychometric properties that were reported, the findings, and the limitations of the included studies. RESULTS 36 studies were selected and reviewed. Across all 36 studies, there were 1, 127 patients with AD dementia and 274 with MCI or early cognitive decline. Multiple measures were examined, including those describing semantic content, syntactic complexity, speech fluency, vocal parameters, and pragmatic language. Discriminant validity widely reported and distinct differences in language were observable between adults with dementia and controls; fewer studies were able to distinguish language differences between typically aging adults and those with MCI. DISCUSSION Our review shows that picture description tasks are useful tools for detecting differences in a wide variety of language and communicative measures. Future research should expand knowledge about subtle changes to language in preclinical AD and Mild Cognitive Impairment (MCI) which may improve the utility of this method as a clinically meaningful screening tool.
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Affiliation(s)
- Kimberly D. Mueller
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, USA
- Wisconsin Alzheimer’s Institute, University of Wisconsin-Madison, USA
| | - Bruce Hermann
- Department of Neurology, University of Wisconsin-Madison, USA
| | - Jonilda Mecollari
- Wisconsin Alzheimer’s Institute, University of Wisconsin-Madison, USA
| | - Lyn S. Turkstra
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, USA
- School of Rehabilitation Science, McMaster University, Canada
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26
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Marshall CR, Hardy CJD, Volkmer A, Russell LL, Bond RL, Fletcher PD, Clark CN, Mummery CJ, Schott JM, Rossor MN, Fox NC, Crutch SJ, Rohrer JD, Warren JD. Primary progressive aphasia: a clinical approach. J Neurol 2018; 265:1474-1490. [PMID: 29392464 PMCID: PMC5990560 DOI: 10.1007/s00415-018-8762-6] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/18/2018] [Accepted: 01/19/2018] [Indexed: 12/12/2022]
Abstract
The primary progressive aphasias are a heterogeneous group of focal 'language-led' dementias that pose substantial challenges for diagnosis and management. Here we present a clinical approach to the progressive aphasias, based on our experience of these disorders and directed at non-specialists. We first outline a framework for assessing language, tailored to the common presentations of progressive aphasia. We then consider the defining features of the canonical progressive nonfluent, semantic and logopenic aphasic syndromes, including 'clinical pearls' that we have found diagnostically useful and neuroanatomical and other key associations of each syndrome. We review potential diagnostic pitfalls and problematic presentations not well captured by conventional classifications and propose a diagnostic 'roadmap'. After outlining principles of management, we conclude with a prospect for future progress in these diseases, emphasising generic information processing deficits and novel pathophysiological biomarkers.
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Affiliation(s)
- Charles R Marshall
- Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK.
| | - Chris J D Hardy
- Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Anna Volkmer
- Division of Psychology and Language Sciences, University College London, London, UK
| | - Lucy L Russell
- Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Rebecca L Bond
- Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Phillip D Fletcher
- Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Camilla N Clark
- Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Catherine J Mummery
- Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Jonathan M Schott
- Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Martin N Rossor
- Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Nick C Fox
- Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Sebastian J Crutch
- Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Jonathan D Rohrer
- Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Jason D Warren
- Department of Neurodegenerative Disease, Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK.
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27
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Functional Connectivity Changes in Behavioral, Semantic, and Nonfluent Variants of Frontotemporal Dementia. Behav Neurol 2018; 2018:9684129. [PMID: 29808100 PMCID: PMC5902123 DOI: 10.1155/2018/9684129] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 01/02/2018] [Accepted: 02/12/2018] [Indexed: 02/04/2023] Open
Abstract
Frontotemporal dementia (FTD) affects behavior, language, and personality. This study aims to explore functional connectivity changes in three FTD variants: behavioral (bvFTD), semantic (svPPA), and nonfluent variant (nfvPPA). Seventy-six patients diagnosed with FTD by international criteria and thirty-two controls were investigated. Functional connectivity from resting functional magnetic resonance imaging (fMRI) was estimated for the whole brain. Two types of analysis were done: network basic statistic and topological measures by graph theory. Several hubs in the limbic system and basal ganglia were compromised in the behavioral variant apart from frontal networks. Nonfluent variants showed a major disconnection with respect to the behavioral variant in operculum and parietal inferior. The global efficiency had lower coefficients in nonfluent variants than behavioral variants and controls. Our results support an extensive disconnection among frontal, limbic, basal ganglia, and parietal hubs.
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Harris JM, Saxon JA, Jones M, Snowden JS, Thompson JC. Neuropsychological differentiation of progressive aphasic disorders. J Neuropsychol 2018; 13:214-239. [PMID: 29424041 PMCID: PMC6618014 DOI: 10.1111/jnp.12149] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 12/10/2017] [Indexed: 12/02/2022]
Abstract
The differentiation of subtypes of primary progressive aphasia (PPA) remains challenging. We aimed to identify optimum neuropsychological measures for characterizing PPA, to examine the relationship between behavioural change and subtypes of PPA and to determine whether characteristic profiles of language, working memory, and behavioural changes occur in PPA. Forty‐seven patients with PPA and multi‐domain Alzheimer's disease (AD) together with 19 age‐matched controls underwent a large battery of working memory and language tests. We found that simple tasks of sentence ordering, narrative production, and buccofacial praxis were particularly useful in differentiating non‐fluent/agrammatic variant PPA (nfvPPA) from other PPA subtypes, whereas a test of single word comprehension was useful in detecting semantic dementia (SD). No individual tests were discriminating for logopenic variant PPA (lvPPA) relative to nfvPPA. LvPPA and multidomain AD exhibited similar language profiles. A principal components analysis revealed that characteristic PPA profiles extended beyond the realms of language, in particular, the presence of apraxia in nfvPPA, behavioural changes in SD, and working memory deficits in lvPPA. These findings suggest that not all tests are equally discriminatory for PPA and highlight the importance of a test profile in differentiating PPA. These results also support the view that lvPPA is a focal form of AD and emphasize the difficulties classifying lvPPA.
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Affiliation(s)
- Jennifer M Harris
- Manchester Academic Health Sciences Centre, Cerebral Function Unit, Greater Manchester Neuroscience Centre, Salford Royal NHS Foundation Trust, UK.,Division of Neurosciences and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Jennifer A Saxon
- Manchester Academic Health Sciences Centre, Cerebral Function Unit, Greater Manchester Neuroscience Centre, Salford Royal NHS Foundation Trust, UK.,Division of Neurosciences and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Matthew Jones
- Manchester Academic Health Sciences Centre, Cerebral Function Unit, Greater Manchester Neuroscience Centre, Salford Royal NHS Foundation Trust, UK.,Division of Neurosciences and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Julie S Snowden
- Manchester Academic Health Sciences Centre, Cerebral Function Unit, Greater Manchester Neuroscience Centre, Salford Royal NHS Foundation Trust, UK.,Division of Neurosciences and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Jennifer C Thompson
- Manchester Academic Health Sciences Centre, Cerebral Function Unit, Greater Manchester Neuroscience Centre, Salford Royal NHS Foundation Trust, UK.,Division of Neurosciences and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, UK
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Mueller KD, Koscik RL, Turkstra LS, Riedeman SK, LaRue A, Clark LR, Hermann B, Sager MA, Johnson SC. Connected Language in Late Middle-Aged Adults at Risk for Alzheimer's Disease. J Alzheimers Dis 2018; 54:1539-1550. [PMID: 27636838 DOI: 10.3233/jad-160252] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Connected language is often impaired among people with Alzheimer's disease (AD), yet little is known about when language difficulties first emerge on the path to a clinical diagnosis. The objective of this study was to determine whether individuals with psychometric (preclinical) evidence of amnestic mild cognitive impairment (pMCI) showed deficits in connected language measures. Participants were 39 pMCI and 39 cognitively healthy (CH) adults drawn from the Wisconsin Registry for Alzheimer's Prevention, who were matched for age, literacy, and sex. Participants completed a connected language task in which they described the Cookie Theft picture from the Boston Diagnostic Aphasia Examination. Language samples were analyzed across three language domains: content, syntactic complexity, and speech fluency. Paired t-tests were used to compare CH and pMCI groups on all variables, and Cohen's d effect sizes were calculated for each comparison. The CH and pMCI groups differed significantly on measures of content (e.g., CH group produced more semantic units, more unique words and had larger idea density, on average, than the pMCI group). The picture description findings are consistent with previous retrospective studies showing semantic language differences in adults with autopsy-confirmed AD. Given that these comparisons are between cognitively healthy and pMCI individuals (before a clinical MCI diagnosis), these findings may represent subtle language difficulty in spontaneous speech, and may be predictive of larger language changes over time.
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Affiliation(s)
- Kimberly Diggle Mueller
- Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.,Department of Communication Sciences & Disorders, University of Wisconsin, Madison, WI, USA
| | - Rebecca L Koscik
- Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Lyn S Turkstra
- Department of Communication Sciences & Disorders, University of Wisconsin, Madison, WI, USA
| | - Sarah K Riedeman
- Department of Communication Sciences & Disorders, University of Wisconsin, Madison, WI, USA
| | - Asenath LaRue
- Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Lindsay R Clark
- Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.,Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Bruce Hermann
- Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.,Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Mark A Sager
- Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Sterling C Johnson
- Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.,Geriatric Research Education and Clinical Center, William S. Middleton Memorial VA Hospital, Madison WI, USA.,Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
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30
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Mueller KD, Koscik RL, Hermann BP, Johnson SC, Turkstra LS. Declines in Connected Language Are Associated with Very Early Mild Cognitive Impairment: Results from the Wisconsin Registry for Alzheimer's Prevention. Front Aging Neurosci 2018; 9:437. [PMID: 29375365 PMCID: PMC5767238 DOI: 10.3389/fnagi.2017.00437] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/18/2017] [Indexed: 12/29/2022] Open
Abstract
Changes to everyday spoken language ("connected language") are evident in persons with AD dementia, yet little is known about when these changes are first detectable on the continuum of cognitive decline. The aim of this study was to determine if participants with very early, subclinical memory declines were also showing declines in connected language. We analyzed connected language samples obtained from a simple picture description task at two time points in 264 participants from the Wisconsin Registry for Alzheimer's Prevention (WRAP). In parallel, participants were classified as either "Cognitively Healthy" or "Early Mild Cognitive Impairment" based on longitudinal neuropsychological test performance. Linear mixed effects models were used to analyze language parameters that were extracted from the connected language samples using automated feature extraction. Participants with eMCI status declined faster in features of speech fluency and semantic content than those who were cognitively stable. Measures of lexical diversity and grammatical complexity were not associated with eMCI status in this group. These findings provide novel insights about the relationship between cognitive decline and everyday language, using a quick, inexpensive, and performance-based method.
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Affiliation(s)
- Kimberly D. Mueller
- Wisconsin Alzheimer’s Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Rebecca L. Koscik
- Wisconsin Alzheimer’s Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Bruce P. Hermann
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Sterling C. Johnson
- Wisconsin Alzheimer’s Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
- Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, WI, United States
- Wisconsin Alzheimer’s Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Lyn S. Turkstra
- Department of Communication Sciences and Disorders, University of Wisconsin–Madison, Madison, WI, United States
- Neuroscience Training Program and Department of Surgery, University of Wisconsin–Madison, Madison, WI, United States
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Abstract
Early-onset Alzheimer disease (EOAD), with onset in individuals younger than 65 years, although overshadowed by the more common late-onset AD (LOAD), differs significantly from LOAD. EOAD comprises approximately 5% of AD and is associated with delays in diagnosis, aggressive course, and age-related psychosocial needs. One source of confusion is that a substantial percentage of EOAD are phenotypic variants that differ from the usual memory-disordered presentation of typical AD. The management of EOAD is similar to that for LOAD, but special emphasis should be placed on targeting the specific cognitive areas involved and more age-appropriate psychosocial support and education.
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Affiliation(s)
- Mario F Mendez
- Behavioral Neurology Program, David Geffen School of Medicine at UCLA, 300 Westwood Plaza, Suite B-200, Box 956975, Los Angeles, CA 90095, USA; Neurobehavior Unit, VA Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Building 206, Los Angeles, CA 90073, USA.
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32
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Clinical and genetic analyses of familial and sporadic frontotemporal dementia patients in Southern Italy. Alzheimers Dement 2017; 13:858-869. [PMID: 28264768 DOI: 10.1016/j.jalz.2017.01.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/17/2016] [Accepted: 01/02/2017] [Indexed: 12/12/2022]
Abstract
INTRODUCTION We investigated the clinical differences between familial and sporadic frontotemporal dementia (FTD), screening for mutations in known FTD genes. METHODS We diagnosed 22 affected individuals belonging to eight families and 43 sporadic cases with FTD in Apulia, Southern Italy, in 2 years. Mutations in common causative FTD genes (GRN, MAPT, VCP, and TARDBP) and C9ORF72 expansions were screened. RESULTS Behavioral variant of FTD was the most common clinical subtype (50% and 69% in familial and sporadic cases, respectively). Social conduct impairment/disinhibition, loss of insight, and inflexibility were the most frequent clinical features observed at onset. One new mutation was identified in GRN in family A. DISCUSSION Disease onset in sporadic FTD was more frequently characterized by a clustering of behavioral symptoms with apathy and loss of personal hygiene. Mutations in common causative FTD genes are not a major cause of familial and sporadic FTD in the Southern Italian population.
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Leyton CE, Hodges JR, Piguet O, Ballard KJ. Common and divergent neural correlates of anomia in amnestic and logopenic presentations of Alzheimer's disease. Cortex 2017; 86:45-54. [DOI: 10.1016/j.cortex.2016.10.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 10/12/2016] [Accepted: 10/24/2016] [Indexed: 11/16/2022]
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Ramanan S, Flanagan E, Leyton CE, Villemagne VL, Rowe CC, Hodges JR, Hornberger M. Non-Verbal Episodic Memory Deficits in Primary Progressive Aphasias are Highly Predictive of Underlying Amyloid Pathology. J Alzheimers Dis 2016; 51:367-76. [PMID: 26890745 DOI: 10.3233/jad-150752] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Diagnostic distinction of primary progressive aphasias (PPA) remains challenging, in particular for the logopenic (lvPPA) and nonfluent/agrammatic (naPPA) variants. Recent findings highlight that episodic memory deficits appear to discriminate these PPA variants from each other, as only lvPPA perform poorly on these tasks while having underlying amyloid pathology similar to that seen in amnestic dementias like Alzheimer's disease (AD). Most memory tests are, however, language based and thus potentially confounded by the prevalent language deficits in PPA. The current study investigated this issue across PPA variants by contrasting verbal and non-verbal episodic memory measures while controlling for their performance on a language subtest of a general cognitive screen. A total of 203 participants were included (25 lvPPA; 29 naPPA; 59 AD; 90 controls) and underwent extensive verbal and non-verbal episodic memory testing, with a subset of patients (n = 45) with confirmed amyloid profiles as assessed by Pittsburgh Compound B and PET. The most powerful discriminator between naPPA and lvPPA patients was a non-verbal recall measure (Rey Complex Figure delayed recall), with 81% of PPA patients classified correctly at presentation. Importantly, AD and lvPPA patients performed comparably on this measure, further highlighting the importance of underlying amyloid pathology in episodic memory profiles. The findings demonstrate that non-verbal recall emerges as the best discriminator of lvPPA and naPPA when controlling for language deficits in high load amyloid PPA cases.
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Affiliation(s)
| | | | - Cristian E Leyton
- Neuroscience Research Australia, Sydney, Australia.,Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia.,Faculty of Health Sciences, University of Sydney, NSW, Australia
| | - Victor L Villemagne
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia.,Department of Nuclear Medicine and Centre for PET, Austin Health, Heidelberg, VIC, Australia.,Department of Medicine, Austin Health, Heidelberg, VIC, Australia
| | - Christopher C Rowe
- Department of Nuclear Medicine and Centre for PET, Austin Health, Heidelberg, VIC, Australia.,Department of Medicine, Austin Health, Heidelberg, VIC, Australia
| | - John R Hodges
- Neuroscience Research Australia, Sydney, Australia.,Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia.,School of Medical Sciences, University of New South Wales, NSW, Australia
| | - Michael Hornberger
- Australian Research Council Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia.,Norwich Medical School, University of East Anglia, Norwich, UK
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35
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Fraser KC, Meltzer JA, Rudzicz F. Linguistic Features Identify Alzheimer's Disease in Narrative Speech. J Alzheimers Dis 2016; 49:407-22. [PMID: 26484921 DOI: 10.3233/jad-150520] [Citation(s) in RCA: 237] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Although memory impairment is the main symptom of Alzheimer's disease (AD), language impairment can be an important marker. Relatively few studies of language in AD quantify the impairments in connected speech using computational techniques. OBJECTIVE We aim to demonstrate state-of-the-art accuracy in automatically identifying Alzheimer's disease from short narrative samples elicited with a picture description task, and to uncover the salient linguistic factors with a statistical factor analysis. METHODS Data are derived from the DementiaBank corpus, from which 167 patients diagnosed with "possible" or "probable" AD provide 240 narrative samples, and 97 controls provide an additional 233. We compute a number of linguistic variables from the transcripts, and acoustic variables from the associated audio files, and use these variables to train a machine learning classifier to distinguish between participants with AD and healthy controls. To examine the degree of heterogeneity of linguistic impairments in AD, we follow an exploratory factor analysis on these measures of speech and language with an oblique promax rotation, and provide interpretation for the resulting factors. RESULTS We obtain state-of-the-art classification accuracies of over 81% in distinguishing individuals with AD from those without based on short samples of their language on a picture description task. Four clear factors emerge: semantic impairment, acoustic abnormality, syntactic impairment, and information impairment. CONCLUSION Modern machine learning and linguistic analysis will be increasingly useful in assessment and clustering of suspected AD.
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Affiliation(s)
- Kathleen C Fraser
- Department of Computer Science, University of Toronto, Toronto, Canada
| | | | - Frank Rudzicz
- Department of Computer Science, University of Toronto, Toronto, Canada.,Toronto Rehabilitation Institute-UHN, Toronto, Canada
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36
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Mattsson N, Schott JM, Hardy J, Turner MR, Zetterberg H. Selective vulnerability in neurodegeneration: insights from clinical variants of Alzheimer's disease. J Neurol Neurosurg Psychiatry 2016; 87:1000-4. [PMID: 26746185 DOI: 10.1136/jnnp-2015-311321] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 12/05/2015] [Indexed: 11/04/2022]
Abstract
Selective vulnerability in the nervous system refers to the fact that subpopulations of neurons in different brain systems may be more or less prone to abnormal function or death in response to specific types of pathological states or injury. The concept has been used extensively as a potential way of explaining differences in degeneration patterns and the clinical presentation of different neurodegenerative diseases. Yet the increasing complexity of molecular histopathology at the cellular level in neurodegenerative disorders frequently appears at odds with phenotyping based on clinically-directed, macroscopic regional brain involvement. While cross-disease comparisons can provide insights into the differential vulnerability of networks and neuronal populations, we focus here on what is known about selective vulnerability-related factors that might explain the differential phenotypic expressions of the same disease-in this case, typical and atypical forms of Alzheimer's disease. Whereas considerable progress has been made in this area, much is yet to be elucidated; further studies comparing different phenotypic variants aimed at identifying both vulnerability and resilience factors may provide valuable insights into disease pathogenesis, and suggest novel targets for therapy.
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Affiliation(s)
- Niklas Mattsson
- Clinical Memory Research Unit, Faculty of Medicine, Lund University, Lund, Sweden
| | | | - John Hardy
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Martin R Turner
- Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, UK
| | - Henrik Zetterberg
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK Clinical Neurochemistry Laboratory, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden
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37
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Woollacott IOC, Rohrer JD. The clinical spectrum of sporadic and familial forms of frontotemporal dementia. J Neurochem 2016; 138 Suppl 1:6-31. [PMID: 27144467 DOI: 10.1111/jnc.13654] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/10/2016] [Accepted: 04/27/2016] [Indexed: 12/11/2022]
Abstract
The term frontotemporal dementia (FTD) describes a clinically, genetically and pathologically diverse group of neurodegenerative disorders. Symptoms of FTD can present in individuals in their 20s through to their 90s, but the mean age at onset is in the sixth decade. The most common presentation is with a change in personality and impaired social conduct (behavioural variant FTD). Less frequently patients present with language problems (primary progressive aphasia). Both of these groups of patients can develop motor features consistent with either motor neuron disease (usually the amyotrophic lateral sclerosis variant) or parkinsonism (most commonly a progressive supranuclear palsy or corticobasal syndrome). In about a third of cases FTD is familial, with mutations in the progranulin, microtubule-associated protein tau and chromosome 9 open reading frame 72 genes being the major causes. Mutations in a number of other genes including TANK-binding kinase 1 are rare causes of familial FTD. This review aims to clarify the often confusing terminology of FTD, and outline the various clinical features and diagnostic criteria of sporadic and familial FTD syndromes. It will also discuss the current major challenges in FTD research and clinical practice, and potential areas for future research. This review clarifies the terminology of frontotemporal dementia (FTD) and summarizes the various clinical features and most recent diagnostic criteria of sporadic and familial FTD syndromes. It also discusses the current major challenges in FTD research and clinical practice, and highlights potential areas for future research.
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Affiliation(s)
- Ione O C Woollacott
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
| | - Jonathan D Rohrer
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
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Magnin E, Teichmann M, Martinaud O, Moreaud O, Ryff I, Belliard S, Pariente J, Moulin T, Vandel P, Démonet JF. Particularités du variant logopénique au sein des aphasies progressives primaires. Rev Neurol (Paris) 2015; 171:16-30. [DOI: 10.1016/j.neurol.2014.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/16/2014] [Accepted: 08/29/2014] [Indexed: 11/26/2022]
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Do NIA‐AA criteria distinguish Alzheimer's disease from frontotemporal dementia? Alzheimers Dement 2014; 11:207-15. [DOI: 10.1016/j.jalz.2014.04.516] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 03/27/2014] [Accepted: 04/28/2014] [Indexed: 11/23/2022]
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40
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Abstract
Logopenic progressive aphasia is the most recently described clinical variant of primary progressive aphasia (PPA), defined by impairment of lexical retrieval and sentence repetition. Unlike other PPA variants, the logopenic variant of PPA (lv-PPA) is commonly associated with Alzheimer's disease (AD), a fact that is relevant to the selection of patients for clinical trials and disease-modifying therapies. Despite the straightforward definition and coherent pathological association, the existence of lv-PPA has been challenged, as its distinction from AD or other PPA variants can be difficult. Despite these issues, lv-PPA patients display characteristic linguistic deficits, a pattern of brain atrophy, and possibly genetic susceptibility, which warrant considering this variant as a discrete AD endophenotype. More specific clinical and anatomical markers can strengthen the consistency of this syndrome.
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Affiliation(s)
- Cristian E Leyton
- Neuroscience Research Australia, Barker Street, PO Box 1165, Randwick, NSW, 2031, Australia,
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41
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Tree J, Kay J. Longitudinal assessment of short-term memory deterioration in a logopenic variant primary progressive aphasia with post-mortem confirmed Alzheimer's Disease pathology. J Neuropsychol 2014; 9:184-202. [PMID: 24751373 DOI: 10.1111/jnp.12045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Revised: 03/08/2014] [Indexed: 11/30/2022]
Abstract
In the field of dementia research, there are reports of neurodegenerative cases with a focal loss of language, termed primary progressive aphasia (PPA). Currently, this condition has been further sub-classified, with the most recent sub-type dubbed logopenic variant (PPA-LV). As yet, there remains somewhat limited evaluation of the characteristics of this condition, with no studies providing longitudinal assessment accompanied by post-mortem examination. Moreover, a key characteristic of the PPA-LV case is a deterioration of phonological short-term memory, but again little work has scrutinized the nature of this impairment over time. The current study seeks to redress these oversights and presents detailed longitudinal examination of language and memory function in a case of PPA-LV, with special focus on tests linked to components of phonological short-term memory function. Our findings are then considered with reference to a contemporary model of the neuropsychology of phonological short-term memory. Additionally, post-mortem examinations indicated Alzheimer's disease type pathology, providing further evidence that the PPA-LV presentation may reflect an atypical presentation of this condition.
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Affiliation(s)
- Jeremy Tree
- Department of Psychology, Swansea University, Swansea, UK
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De Oliveira TCG, Soares FC, De Macedo LDED, Diniz DLWP, Bento-Torres NVO, Picanço-Diniz CW. Beneficial effects of multisensory and cognitive stimulation on age-related cognitive decline in long-term-care institutions. Clin Interv Aging 2014; 9:309-20. [PMID: 24600211 PMCID: PMC3933247 DOI: 10.2147/cia.s54383] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The aim of the present report was to evaluate the effectiveness and impact of multisensory and cognitive stimulation on improving cognition in elderly persons living in long-term-care institutions (institutionalized [I]) or in communities with their families (noninstitutionalized [NI]). We compared neuropsychological performance using language and Mini-Mental State Examination (MMSE) test scores before and after 24 and 48 stimulation sessions. The two groups were matched by age and years of schooling. Small groups of ten or fewer volunteers underwent the stimulation program, twice a week, over 6 months (48 sessions in total). Sessions were based on language and memory exercises, as well as visual, olfactory, auditory, and ludic stimulation, including music, singing, and dance. Both groups were assessed at the beginning (before stimulation), in the middle (after 24 sessions), and at the end (after 48 sessions) of the stimulation program. Although the NI group showed higher performance in all tasks in all time windows compared with I subjects, both groups improved their performance after stimulation. In addition, the improvement was significantly higher in the I group than the NI group. Language tests seem to be more efficient than the MMSE to detect early changes in cognitive status. The results suggest the impoverished environment of long-term-care institutions may contribute to lower cognitive scores before stimulation and the higher improvement rate of this group after stimulation. In conclusion, language tests should be routinely adopted in the neuropsychological assessment of elderly subjects, and long-term-care institutions need to include regular sensorimotor, social, and cognitive stimulation as a public health policy for elderly persons.
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Affiliation(s)
- Thaís Cristina Galdino De Oliveira
- Laboratory of Investigations in Neurodgeneration and Infection, Biological Sciences Institute, University Hospital João de Barros Barreto, Belém, Brazil
| | - Fernanda Cabral Soares
- Laboratory of Investigations in Neurodgeneration and Infection, Biological Sciences Institute, University Hospital João de Barros Barreto, Belém, Brazil
| | - Liliane Dias E Dias De Macedo
- Laboratory of Investigations in Neurodgeneration and Infection, Biological Sciences Institute, University Hospital João de Barros Barreto, Belém, Brazil
| | - Domingos Luiz Wanderley Picanço Diniz
- Laboratory of Investigations in Neurodgeneration and Infection, Biological Sciences Institute, University Hospital João de Barros Barreto, Belém, Brazil
| | - Natáli Valim Oliver Bento-Torres
- Laboratory of Investigations in Neurodgeneration and Infection, Biological Sciences Institute, University Hospital João de Barros Barreto, Belém, Brazil ; College of Physical Therapy and Occupational Therapy, Federal University of Pará, Belém, Brazil
| | - Cristovam Wanderley Picanço-Diniz
- Laboratory of Investigations in Neurodgeneration and Infection, Biological Sciences Institute, University Hospital João de Barros Barreto, Belém, Brazil
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Ahmed S, Haigh AMF, de Jager CA, Garrard P. Connected speech as a marker of disease progression in autopsy-proven Alzheimer's disease. Brain 2013; 136:3727-37. [PMID: 24142144 PMCID: PMC3859216 DOI: 10.1093/brain/awt269] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 07/10/2013] [Accepted: 08/02/2013] [Indexed: 11/12/2022] Open
Abstract
Although an insidious history of episodic memory difficulty is a typical presenting symptom of Alzheimer's disease, detailed neuropsychological profiling frequently demonstrates deficits in other cognitive domains, including language. Previous studies from our group have shown that language changes may be reflected in connected speech production in the earliest stages of typical Alzheimer's disease. The aim of the present study was to identify features of connected speech that could be used to examine longitudinal profiles of impairment in Alzheimer's disease. Samples of connected speech were obtained from 15 former participants in a longitudinal cohort study of ageing and dementia, in whom Alzheimer's disease was diagnosed during life and confirmed at post-mortem. All patients met clinical and neuropsychological criteria for mild cognitive impairment between 6 and 18 months before converting to a status of probable Alzheimer's disease. In a subset of these patients neuropsychological data were available, both at the point of conversion to Alzheimer's disease, and after disease severity had progressed from the mild to moderate stage. Connected speech samples from these patients were examined at later disease stages. Spoken language samples were obtained using the Cookie Theft picture description task. Samples were analysed using measures of syntactic complexity, lexical content, speech production, fluency and semantic content. Individual case analysis revealed that subtle changes in language were evident during the prodromal stages of Alzheimer's disease, with two-thirds of patients with mild cognitive impairment showing significant but heterogeneous changes in connected speech. However, impairments at the mild cognitive impairment stage did not necessarily entail deficits at mild or moderate stages of disease, suggesting non-language influences on some aspects of performance. Subsequent examination of these measures revealed significant linear trends over the three stages of disease in syntactic complexity, semantic and lexical content. The findings suggest, first, that there is a progressive disruption in language integrity, detectable from the prodromal stage in a subset of patients with Alzheimer's disease, and secondly that measures of semantic and lexical content and syntactic complexity best capture the global progression of linguistic impairment through the successive clinical stages of disease. The identification of disease-specific language impairment in prodromal Alzheimer's disease could enhance clinicians' ability to distinguish probable Alzheimer's disease from changes attributable to ageing, while longitudinal assessment could provide a simple approach to disease monitoring in therapeutic trials.
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Affiliation(s)
- Samrah Ahmed
- 1 Stroke and Dementia Research Centre, St George's, University of London, Cranmer Terrace, London, SW17 0RE UK
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Funayama M, Nakagawa Y, Yamaya Y, Yoshino F, Mimura M, Kato M. Progression of logopenic variant primary progressive aphasia to apraxia and semantic memory deficits. BMC Neurol 2013; 13:158. [PMID: 24176108 PMCID: PMC4228422 DOI: 10.1186/1471-2377-13-158] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 10/30/2013] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Due to the nature of neurodegenerative disorders, patients with primary progressive aphasia develop cognitive impairment other than aphasia as the disorder progresses. The progression of logopenic variant primary progressive aphasia (lvPPA), however, has not been well described. In particular, praxic disorders and semantic memory deficits have rarely been reported. CASE PRESENTATIONS We report three patients in the initial stage of lvPPA who subsequently developed apraxia in the middle stage and developed clinically evident semantic memory deficits in the advanced stages. CONCLUSIONS The present case series suggests that some patients with lvPPA develop an atypical type of dementia with apraxia and semantic memory deficits, suggesting that these cases should be classified as a type of early-onset Alzheimer's disease.
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Affiliation(s)
- Michitaka Funayama
- Department of Neuropsychiatry, Ashikaga Red Cross Hospital, Ashikaga-City, Japan.
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Garrard P, Rentoumi V, Lambert C, Owen D. Linguistic biomarkers of Hubris syndrome. Cortex 2013; 55:167-81. [PMID: 24074886 DOI: 10.1016/j.cortex.2013.08.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/06/2013] [Accepted: 08/28/2013] [Indexed: 11/26/2022]
Abstract
Owen and Davidson coined the term 'Hubris Syndrome' (HS) for a characteristic pattern of exuberant self-confidence, recklessness, and contempt for others, shown by some individuals holding substantial power. Meaning, emotion and attitude are communicated intentionally through language, but psychological and cognitive changes can be reflected in more subtle ways, of which a speaker remains unaware. Of the fourteen symptoms of HS, four imply lexical choices: use of the third person/'royal we'; excessive confidence; exaggerated self-belief; and supposed accountability to God or History. One other feature (recklessness) could influence language complexity if impulsivity leads to unpredictability. These hypotheses were tested by examining transcribed spoken discourse samples produced by two British Prime Ministers (Margaret Thatcher and Tony Blair) who were said to meet criteria for HS, and one (John Major) who did not. We used Shannon entropy to reflect informational complexity, and temporal correlations (words or phrases whose relative frequency correlated negatively with time in office) and keyness values to identify lexical choices corresponding to periods during which HS was evident. Entropy fluctuated in all three subjects, but consistent (upward) trends in HS-positive subjects corresponded to periods of hubristic behaviour. The first person pronouns 'I' and 'me' and the word 'sure' were among the strongest positive temporal correlates in Blair's speeches. Words and phrases that correlated in the speeches of Thatcher and Blair but not in those of Major included the phrase 'we shall' and 'duties' (both negative). The keyness ratio of 'we' to 'I' was clearly higher throughout the terms of office of Thatcher and Blair that at any point in the premiership of Major, and this difference was particularly marked in the case of Blair. The findings are discussed in the context of historical evidence and ideas for enhancing the signal to noise ratio put forward.
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Affiliation(s)
- Peter Garrard
- Stroke and Dementia Research Centre, St George's University of London, UK.
| | - Vassiliki Rentoumi
- Stroke and Dementia Research Centre, St George's University of London, UK
| | - Christian Lambert
- Stroke and Dementia Research Centre, St George's University of London, UK
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Garrard P, Rentoumi V, Gesierich B, Miller B, Gorno-Tempini ML. Machine learning approaches to diagnosis and laterality effects in semantic dementia discourse. Cortex 2013; 55:122-9. [PMID: 23876449 DOI: 10.1016/j.cortex.2013.05.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 03/12/2013] [Accepted: 05/15/2013] [Indexed: 11/18/2022]
Abstract
Advances in automatic text classification have been necessitated by the rapid increase in the availability of digital documents. Machine learning (ML) algorithms can 'learn' from data: for instance a ML system can be trained on a set of features derived from written texts belonging to known categories, and learn to distinguish between them. Such a trained system can then be used to classify unseen texts. In this paper, we explore the potential of the technique to classify transcribed speech samples along clinical dimensions, using vocabulary data alone. We report the accuracy with which two related ML algorithms [naive Bayes Gaussian (NBG) and naive Bayes multinomial (NBM)] categorized picture descriptions produced by: 32 semantic dementia (SD) patients versus 10 healthy, age-matched controls; and SD patients with left- (n = 21) versus right-predominant (n = 11) patterns of temporal lobe atrophy. We used information gain (IG) to identify the vocabulary features that were most informative to each of these two distinctions. In the SD versus control classification task, both algorithms achieved accuracies of greater than 90%. In the right- versus left-temporal lobe predominant classification, NBM achieved a high level of accuracy (88%), but this was achieved by both NBM and NBG when the features used in the training set were restricted to those with high values of IG. The most informative features for the patient versus control task were low frequency content words, generic terms and components of metanarrative statements. For the right versus left task the number of informative lexical features was too small to support any specific inferences. An enriched feature set, including values derived from Quantitative Production Analysis (QPA) may shed further light on this little understood distinction.
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Affiliation(s)
- Peter Garrard
- Stroke and Dementia Research Centre, St George's, University of London, Cranmer Terrace, London SW17 ORE, UK.
| | - Vassiliki Rentoumi
- Stroke and Dementia Research Centre, St George's, University of London, Cranmer Terrace, London SW17 ORE, UK
| | - Benno Gesierich
- UCSF Memory and Aging Center, Sandler Neurosciences Center, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, USA
| | - Bruce Miller
- UCSF Memory and Aging Center, Sandler Neurosciences Center, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, USA
| | - Maria Luisa Gorno-Tempini
- UCSF Memory and Aging Center, Sandler Neurosciences Center, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, USA
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