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Ramanan S, Halai AD, Garcia-Penton L, Perry AG, Patel N, Peterson KA, Ingram RU, Storey I, Cappa SF, Catricala E, Patterson K, Rowe JB, Garrard P, Ralph MAL. The neural substrates of transdiagnostic cognitive-linguistic heterogeneity in primary progressive aphasia. Alzheimers Res Ther 2023; 15:219. [PMID: 38102724 PMCID: PMC10724982 DOI: 10.1186/s13195-023-01350-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 11/08/2023] [Indexed: 12/17/2023]
Abstract
BACKGROUND Clinical variants of primary progressive aphasia (PPA) are diagnosed based on characteristic patterns of language deficits, supported by corresponding neural changes on brain imaging. However, there is (i) considerable phenotypic variability within and between each diagnostic category with partially overlapping profiles of language performance between variants and (ii) accompanying non-linguistic cognitive impairments that may be independent of aphasia magnitude and disease severity. The neurobiological basis of this cognitive-linguistic heterogeneity remains unclear. Understanding the relationship between these variables would improve PPA clinical/research characterisation and strengthen clinical trial and symptomatic treatment design. We address these knowledge gaps using a data-driven transdiagnostic approach to chart cognitive-linguistic differences and their associations with grey/white matter degeneration across multiple PPA variants. METHODS Forty-seven patients (13 semantic, 15 non-fluent, and 19 logopenic variant PPA) underwent assessment of general cognition, errors on language performance, and structural and diffusion magnetic resonance imaging to index whole-brain grey and white matter changes. Behavioural data were entered into varimax-rotated principal component analyses to derive orthogonal dimensions explaining the majority of cognitive variance. To uncover neural correlates of cognitive heterogeneity, derived components were used as covariates in neuroimaging analyses of grey matter (voxel-based morphometry) and white matter (network-based statistics of structural connectomes). RESULTS Four behavioural components emerged: general cognition, semantic memory, working memory, and motor speech/phonology. Performance patterns on the latter three principal components were in keeping with each variant's characteristic profile, but with a spectrum rather than categorical distribution across the cohort. General cognitive changes were most marked in logopenic variant PPA. Regardless of clinical diagnosis, general cognitive impairment was associated with inferior/posterior parietal grey/white matter involvement, semantic memory deficits with bilateral anterior temporal grey/white matter changes, working memory impairment with temporoparietal and frontostriatal grey/white matter involvement, and motor speech/phonology deficits with inferior/middle frontal grey matter alterations. CONCLUSIONS Cognitive-linguistic heterogeneity in PPA closely relates to individual-level variations on multiple behavioural dimensions and grey/white matter degeneration of regions within and beyond the language network. We further show that employment of transdiagnostic approaches may help to understand clinical symptom boundaries and reveal clinical and neural profiles that are shared across categorically defined variants of PPA.
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Affiliation(s)
- Siddharth Ramanan
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge, CB2 7EF, UK.
| | - Ajay D Halai
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge, CB2 7EF, UK
| | - Lorna Garcia-Penton
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge, CB2 7EF, UK
| | - Alistair G Perry
- Department of Clinical Neurosciences and Cambridge University Hospitals NHS Trust, University of Cambridge, Cambridge, UK
| | - Nikil Patel
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK
| | - Katie A Peterson
- Department of Clinical Neurosciences and Cambridge University Hospitals NHS Trust, University of Cambridge, Cambridge, UK
| | - Ruth U Ingram
- Division of Psychology and Mental Health, University of Manchester, Manchester, UK
| | - Ian Storey
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK
| | - Stefano F Cappa
- IUSS Cognitive Neuroscience Center (ICoN), University Institute of Advanced Studies IUSS, Pavia, Italy
- Dementia Research Center, IRCCS Mondino Foundation, Pavia, Italy
| | - Eleonora Catricala
- IUSS Cognitive Neuroscience Center (ICoN), University Institute of Advanced Studies IUSS, Pavia, Italy
- Dementia Research Center, IRCCS Mondino Foundation, Pavia, Italy
| | - Karalyn Patterson
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge, CB2 7EF, UK
| | - James B Rowe
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge, CB2 7EF, UK
- Department of Clinical Neurosciences and Cambridge University Hospitals NHS Trust, University of Cambridge, Cambridge, UK
| | - Peter Garrard
- Molecular and Clinical Sciences Research Institute, St. George's, University of London, London, UK
| | - Matthew A Lambon Ralph
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge, CB2 7EF, UK
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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] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 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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Peterson KA, Patel N, Barrick TR, Cappa SF, Catricala E, Ralph ML, Patterson K, Rowe JB, Garrard P. P4‐115: DEVELOPMENT OF THE STANDARDISED, MULTILINGUAL MINI LINGUISTIC STATE EXAMINATION (MLSE) TO CLASSIFY AND MONITOR PRIMARY PROGRESSIVE APHASIA. Alzheimers Dement 2018. [DOI: 10.1016/j.jalz.2018.06.2519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
| | - Nikil Patel
- St. George's University of LondonLondonUnited Kingdom
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