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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] [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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Characterization of the logopenic variant of Primary Progressive Aphasia: A systematic review and meta-analysis. Ageing Res Rev 2022; 82:101760. [PMID: 36244629 DOI: 10.1016/j.arr.2022.101760] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 10/11/2022] [Indexed: 01/31/2023]
Abstract
The linguistic and anatomical variability of the logopenic variant of Primary Progressive Aphasia (lv-PPA) as defined by current diagnostic criteria has been the topic of an intense debate. The present review and meta-analysis aims at characterizing the profile of lv-PPA, by a comprehensive analysis of the available literature on the neuropsychological, neuroimaging, electrophysiological, pathological, and genetic features of lv-PPA. We conducted a systematic bibliographic search, leading to the inclusion of 207 papers. Of them, 12 were used for the Anatomical Likelihood Estimation meta-analysis on grey matter revealed by magnetic resonance imaging data. The results suggest that the current guidelines outline a relatively consistent syndrome, characterized by a core set of linguistic and, to a lesser extent, non-linguistic deficits, mirroring the involvement of left temporal and parietal regions typically affected by Alzheimer Disease pathology. Variations of the lv-PPA profile are discussed in terms of heterogeneity of the neuropsychological instruments and the diagnostic criteria adopted.
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Irish M. Autobiographical memory in dementia syndromes—An integrative review. WIRES COGNITIVE SCIENCE 2022; 14:e1630. [DOI: 10.1002/wcs.1630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/18/2022] [Accepted: 09/19/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Muireann Irish
- School of Psychology and Brain & Mind Centre The University of Sydney Sydney Australia
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4
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Butts AM, Machulda MM, Martin P, Przybelski SA, Duffy JR, Graff-Radford J, Knopman DS, Petersen RC, Jack CR, Lowe VJ, Josephs KA, Whitwell JL. Temporal Cortical Thickness and Cognitive Associations among Typical and Atypical Phenotypes of Alzheimer's Disease. J Alzheimers Dis Rep 2022; 6:479-491. [PMID: 36186727 PMCID: PMC9484150 DOI: 10.3233/adr-220010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 06/29/2022] [Indexed: 11/15/2022] Open
Abstract
Background The hippocampus and temporal lobe are atrophic in typical amnestic Alzheimer's disease (tAD) and are used as imaging biomarkers in treatment trials. However, a better understanding of how temporal structures differ across atypical AD phenotypes and relate to cognition is needed. Objective Our goal was to compare temporal lobe regions between tAD and two atypical AD phenotypes (logopenic progressive aphasia (LPA) and posterior cortical atrophy (PCA)), and assess cognitive associations. Methods We age and gender-matched 77 tAD participants to 50 LPA and 27 PCA participants, all of which were amyloid-positive. We used linear mixed-effects models to compare FreeSurfer-derived hippocampal volumes and cortical thickness of entorhinal, inferior and middle temporal, and fusiform gyri, and to assess relationships between imaging and memory, naming, and visuospatial function across and within AD phenotype. Results Hippocampal volume and entorhinal thickness were smaller bilaterally in tAD than LPA and PCA. PCA showed greater right inferior temporal and bilateral fusiform thinning and LPA showed greater left middle and inferior temporal and left fusiform thinning. Atypical AD phenotypes differed with greater right hemisphere thinning in PCA and greater left hemisphere thinning in LPA. Verbal and visual memory related most strongly to hippocampal volume; naming related to left temporal thickness; and visuospatial related to bilateral fusiform thickness. Fewer associations remained when examined within AD group. Conclusion Atypical AD phenotypes are associated with greater thinning of lateral temporal structures, with relative sparing of medial temporal lobe, compared to tAD. These findings may have implications for future clinical trials in AD.
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Affiliation(s)
- Alissa M. Butts
- Department of Neurology, Division of Neuropsychology, Medical College of Wisconsin, Milwaukee, WI, USA,External Research Collaborator, Mayo Clinic, Rochester, MN, USA
| | - Mary M. Machulda
- Department of Psychiatry and Psychology, Division of Neuropsychology, Mayo Clinic, Rochester, MN, USA
| | - Peter Martin
- Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | | | | | | | | | | | | | - Val J. Lowe
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | - Jennifer L. Whitwell
- Department of Radiology, Mayo Clinic, Rochester, MN, USA,Correspondence to: Jennifer L. Whitwell, PhD, Professor of Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA. E-mail:
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Ramanan S, Irish M, Patterson K, Rowe JB, Gorno-Tempini ML, Lambon Ralph MA. Understanding the multidimensional cognitive deficits of logopenic variant primary progressive aphasia. Brain 2022; 145:2955-2966. [PMID: 35857482 PMCID: PMC9473356 DOI: 10.1093/brain/awac208] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/06/2022] [Accepted: 05/27/2022] [Indexed: 02/02/2023] Open
Abstract
The logopenic variant of primary progressive aphasia is characterized by early deficits in language production and phonological short-term memory, attributed to left-lateralized temporoparietal, inferior parietal and posterior temporal neurodegeneration. Despite patients primarily complaining of language difficulties, emerging evidence points to performance deficits in non-linguistic domains. Temporoparietal cortex, and functional brain networks anchored to this region, are implicated as putative neural substrates of non-linguistic cognitive deficits in logopenic variant primary progressive aphasia, suggesting that degeneration of a shared set of brain regions may result in co-occurring linguistic and non-linguistic dysfunction early in the disease course. Here, we provide a Review aimed at broadening the understanding of logopenic variant primary progressive aphasia beyond the lens of an exclusive language disorder. By considering behavioural and neuroimaging research on non-linguistic dysfunction in logopenic variant primary progressive aphasia, we propose that a significant portion of multidimensional cognitive features can be explained by degeneration of temporal/inferior parietal cortices and connected regions. Drawing on insights from normative cognitive neuroscience, we propose that these regions underpin a combination of domain-general and domain-selective cognitive processes, whose disruption results in multifaceted cognitive deficits including aphasia. This account explains the common emergence of linguistic and non-linguistic cognitive difficulties in logopenic variant primary progressive aphasia, and predicts phenotypic diversification associated with progression of pathology in posterior neocortex.
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Affiliation(s)
- Siddharth Ramanan
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - Muireann Irish
- The University of Sydney, Brain and Mind Centre and School of Psychology, Sydney, Australia
| | - Karalyn Patterson
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
| | - James B Rowe
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
- Department of Clinical Neurosciences, Cambridge University Centre for Frontotemporal Dementia, Cambridge, UK
- Cambridge University Hospitals NHS Trust, Cambridge, UK
| | | | - Matthew A Lambon Ralph
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, Cambridge, UK
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Comorbid Neurodegeneration in Primary Progressive Aphasia: Clinicopathological Correlations in a Single-Center Study. Behav Neurol 2022; 2022:6075511. [PMID: 36120397 PMCID: PMC9477586 DOI: 10.1155/2022/6075511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 08/05/2022] [Accepted: 08/10/2022] [Indexed: 11/17/2022] Open
Abstract
Introduction. Primary progressive aphasia (PPA) is a clinically variable syndrome manifesting as slow progressive loss of speech and language with multiple underlying neurodegenerative pathologies. Materials and Methods. We included data from nine PPA patients with available autopsies. We then retrospectively reviewed all available medical records, neuropsychology, and MRI results to confirm the corresponding subtypes of PPA and compared them with postmortem neuropathological results. Results. Clinical presentations corresponded to the nonfluent/agrammatic variant in six cases, the semantic variant in one case, the logopenic variant in one case, and the mixed variant (concomitant nonfluent/agrammatic plus semantic variant) in one case. Patients with a broader clinical presentation, i.e., combining manifestations of one PPA subtype and symptoms of another PPA variant, had autopsy comorbidities showing multiple neurodegenerative disorders. Of the nine subjects enrolled in the study, Alzheimer’s disease (AD) was found in eight cases; however, in only one case, AD was detected as an isolated neuropathological substrate of PPA. In eight brain samples, different comorbid neuropathologies were detected: three cases with comorbid AD and dementia with Lewy bodies, two cases with comorbid AD and TDP-43 pathology, one case with comorbid AD and complex tauopathies, and one case with comorbid AD with both tau and TDP-43 deposits. Finally, one case had comorbid tau and TDP-43 pathology but without comorbid AD pathology. Conclusions. Our observation suggests that PPA cases could be more heterogeneous in their etiology than previously thought and underlying neurodegenerative comorbidities should be considered in routine practice, especially if the clinical presentation of PPA is atypical.
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7
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Foxe D, Hu A, Cheung SC, Ahmed RM, Cordato NJ, Devenney E, Hwang YT, Halliday GM, Mueller N, Leyton CE, Hodges JR, Burrell JR, Irish M, Piguet O. Utility of the Addenbrooke’s Cognitive Examination III online calculator to differentiate the primary progressive aphasia variants. Brain Commun 2022; 4:fcac161. [PMID: 35912134 PMCID: PMC9336588 DOI: 10.1093/braincomms/fcac161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/11/2022] [Accepted: 06/16/2022] [Indexed: 12/22/2022] Open
Abstract
The Addenbrooke’s Cognitive Examination III is a brief cognitive screening tool that is widely used for the detection and monitoring of dementia. Recent findings suggest that the three variants of primary progressive aphasia can be distinguished based on their distinct profiles on the five subdomain scores of this test. Here, we investigated the utility of the Addenbrooke’s Cognitive Examination III to differentiate the primary progressive aphasia variants based on their item-by-item performance profiles on this test. From these results, we created an interactive primary progressive aphasia Addenbrooke’s Cognitive Examination III calculator which predicts the variant based on a patient’s unique item-by-item profile. Twenty-eight logopenic variant, 25 non-fluent variant and 37 semantic variant primary progressive aphasia patients and 104 healthy controls completed the Addenbrooke’s Cognitive Examination III at first clinical presentation. Multinomial regression analyses were conducted to establish performance profiles among groups, and R Shiny from RStudio was used to create the interactive Addenbrooke’s Cognitive Examination III diagnostic calculator. To verify its accuracy, probability values of the regression model were derived based on a 5-fold cross-validation of cases. The calculator’s accuracy was then verified in an independent sample of 17 logopenic, 19 non-fluent and 13 semantic variant primary progressive aphasia patients and 68 Alzheimer’s disease patients who had completed the Addenbrooke’s Cognitive Examination III (or an older version of this test: Revised) and had in vivo amyloid-PET imaging and/or brain autopsy pathological confirmation. Cross-validation of cases in the calculator model revealed different rates of sensitivity in classifying variants: semantic = 100%, non-fluent = 80.6% and logopenic = 79.9%; healthy controls were distinguished from primary progressive aphasia patients with 100% sensitivity. Verification of in vivo amyloid and/or autopsy-confirmed patients showed that the calculator correctly classified 10/13 (77%) semantic variant, 3/19 (16%) non-fluent variant and 4/17 (24%) logopenic variant patients. Importantly, for patients who were not classified, diagnostic probability values mostly pointed toward the correct clinical diagnosis. Furthermore, misclassified diagnoses of the primary progressive aphasia cohort were rare (1/49; 2%). Although 22 of the 68 Alzheimer’s disease patients (32%) were misclassified with primary progressive aphasia, 19/22 were misclassified with the logopenic variant (i.e. falling within the same neuropathological entity). The Addenbrooke’s Cognitive Examination III primary progressive aphasia diagnostic calculator demonstrates sound accuracy in differentiating the variants based on an item-by-item Addenbrooke’s Cognitive Examination III profile. This calculator represents a new frontier in using data-driven approaches to differentiate the primary progressive aphasia variants.
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Affiliation(s)
- D Foxe
- School of Psychology, The University of Sydney , 94 Mallett St, Sydney, NSW 2006 , Australia
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
| | - A Hu
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
- School of Mathematics and Statistics, The University of Sydney , Sydney, NSW 2006 , Australia
| | - S C Cheung
- School of Psychology, The University of Sydney , 94 Mallett St, Sydney, NSW 2006 , Australia
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
| | - R M Ahmed
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
- Central Clinical School, The University of Sydney , Sydney, NSW 2006 , Australia
| | - N J Cordato
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
- St George Clinical School, University of New South Wales , Sydney, NSW 2217 , Australia
- The Department of Aged Care, St George Hospital , Sydney, NSW 2217 , Australia
- Calvary Health Care Kogarah, Calvary Community Health , Sydney, NSW 2217 , Australia
| | - E Devenney
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
- Central Clinical School, The University of Sydney , Sydney, NSW 2006 , Australia
| | - Y T Hwang
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
- Central Clinical School, The University of Sydney , Sydney, NSW 2006 , Australia
| | - G M Halliday
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
- Central Clinical School, The University of Sydney , Sydney, NSW 2006 , Australia
| | - N Mueller
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
- Central Clinical School, The University of Sydney , Sydney, NSW 2006 , Australia
| | - C E Leyton
- School of Psychology, The University of Sydney , 94 Mallett St, Sydney, NSW 2006 , Australia
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
| | - J R Hodges
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
| | - J R Burrell
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
- Concord Clinical School, Sydney Medical School, The University of Sydney , Sydney, NSW 2139 , Australia
| | - M Irish
- School of Psychology, The University of Sydney , 94 Mallett St, Sydney, NSW 2006 , Australia
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
| | - O Piguet
- School of Psychology, The University of Sydney , 94 Mallett St, Sydney, NSW 2006 , Australia
- Brain and Mind Centre, The University of Sydney , Sydney, NSW 2050 , Australia
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Jablonowski J, Rose M. The functional dissociation of posterior parietal regions during multimodal memory formation. Hum Brain Mapp 2022; 43:3469-3485. [PMID: 35397137 PMCID: PMC9248313 DOI: 10.1002/hbm.25861] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/14/2022] [Accepted: 03/22/2022] [Indexed: 01/15/2023] Open
Abstract
The incidental acquisition of multimodal associations is a key memory function for everyday life. While the posterior parietal cortex has been frequently shown to be involved for these memory functions, ventral and dorsal regions revealed differences in their functional recruitment and the precise difference in multimodal memory processing with respect to the associative process has not been differentiated. Using an incidental multimodal learning task, we isolated the associative process during multimodal learning and recollection. The result of the present functional magnetic resonance imaging (fMRI) study demonstrated that during both learning and recollection a clear functional differentiation between ventral and dorsal posterior parietal regions was found and can be related directly to the associative process. The recruitment of a ventral region, the angular gyrus, was specific for learning and recollection of multimodal associations. In contrast, a dorsal region, the superior parietal lobule, could be attributed to memory guided attentional processing. Independent of the memory stage, we assumed a general role for the angular gyrus in the generation of associative representations and updating of fixed association, episodic memory.
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Affiliation(s)
- Julia Jablonowski
- NeuroImage Nord, Department for Systems Neuroscience, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Michael Rose
- NeuroImage Nord, Department for Systems Neuroscience, University Medical Center Hamburg Eppendorf, Hamburg, Germany
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Watanabe H, Hikida S, Ikeda M, Mori E. OUP accepted manuscript. Brain Commun 2022; 4:fcac015. [PMID: 35686225 PMCID: PMC9171501 DOI: 10.1093/braincomms/fcac015] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 09/07/2021] [Accepted: 01/31/2022] [Indexed: 11/26/2022] Open
Abstract
Primary progressive aphasia, a neurodegenerative syndrome, presents mainly with language impairment. Both semantic and logopenic variants are fluent variants of primary progressive aphasia. Before the research criteria of primary progressive aphasia were proposed, progressive fluent aphasias, such as progressive anomic aphasia, transcortical sensory aphasia and Wernicke’s aphasia, were reported as classical progressive fluent aphasias seen in Alzheimer’s disease. However, since the research criteria of primary progressive aphasia were established, classical fluent variants (other than semantic and logopenic variants) have been neglected and have not been included in the current classification of primary progressive aphasia. This study aimed to determine whether unclassified fluent variants (other than semantic and logopenic variants) can be manifestations of primary progressive aphasia. This study also reconfirmed the characteristics of classical progressive fluent aphasia, such as progressive anomic aphasia, progressive transcortical sensory aphasia and progressive Wernicke’s aphasia as unclassified fluent variants of primary progressive aphasia, using comparison with the current model of primary progressive aphasia. Twelve consecutive patients with an unclassified fluent variant other than semantic or logopenic variant underwent language, neurological, neuropsychological and neuroimaging (MRI and single-photon emission computed tomography) testing. Based on comprehensive language tests, we redefined the diagnoses as primary progressive anomic aphasia (n = 8), primary progressive transcortical sensory aphasia (n = 3) and primary progressive Wernicke’s aphasia (n = 1). Anomic aphasia was characterized by anomia but preserved repetition and comprehension; transcortical sensory aphasia by relatively preserved repetition but poor word comprehension; and Wernicke’s aphasia by poor repetition and word comprehension. In patients with anomic aphasia, voxel-based morphometry of MRI data revealed cortical atrophy, which was most prominent in the temporoparietal lobes, with no obvious lateralization; in two-thirds of patients with transcortical sensory aphasia and in one patient with Wernicke’s aphasia, it revealed atrophy, predominantly in the left temporoparietal lobe. Statistical analysis of single-photon emission computed tomography using three-dimensional stereotactic surface projections revealed patterns of left-sided hypoperfusion in the majority of patients. The temporal and parietal lobes were involved in all cases; the degree of hypoperfusion was higher in patients with transcortical sensory aphasia or Wernicke’s aphasia than in patients with anomic aphasia. The present study demonstrated the clinical and imaging features of 12 patients with an unclassified fluent variant of primary progressive aphasia, which we redefined as primary progressive anomic aphasia, primary progressive transcortical sensory aphasia and primary progressive Wernicke’s aphasia. Classical fluent variants other than semantic and logopenic variants can be found in primary progressive aphasia.
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Affiliation(s)
- Hiroyuki Watanabe
- Correspondence to: Hiroyuki Watanabe Department of Behavioral Neurology and Neuropsychiatry Osaka University United Graduate School of Child Development 2-2, Yamadaoka, Suita Osaka 565-0871, Japan E-mail:
| | - Sakura Hikida
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
- Brain Function Center, Nippon Life Hospital, Osaka, Japan
| | - Manabu Ikeda
- Department of Psychiatry, Osaka University Graduate School of Medicine, Suita, Japan
- Brain Function Center, Nippon Life Hospital, Osaka, Japan
| | - Etsuro Mori
- Department of Behavioral Neurology and Neuropsychiatry, Osaka University United Graduate School of Child Development, Suita, Japan
- Brain Function Center, Nippon Life Hospital, Osaka, Japan
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Ramanan S, Foxe D, El-Omar H, Ahmed RM, Hodges JR, Piguet O, Irish M. Evidence for a pervasive autobiographical memory impairment in Logopenic Progressive Aphasia. Neurobiol Aging 2021; 108:168-178. [PMID: 34653892 DOI: 10.1016/j.neurobiolaging.2021.09.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 08/31/2021] [Accepted: 09/03/2021] [Indexed: 11/17/2022]
Abstract
Although characterized primarily as a language disorder, mounting evidence indicates episodic amnesia in Logopenic Progressive Aphasia (LPA). Whether such memory disturbances extend to information encoded pre-disease onset remains unclear. To address this question, we examined autobiographical memory in 10 LPA patients, contrasted with 18 typical amnestic Alzheimer's disease and 16 healthy Control participants. A validated assessment, the Autobiographical Interview, was employed to explore autobiographical memory performance across the lifespan under free and probed recall conditions. Relative to Controls, LPA patients showed global impairments across all time periods for free recall, scoring at the same level as disease-matched cases of Alzheimer's disease. Importantly, these retrieval deficits persisted in LPA, even when structured probing was provided, and could not be explained by overall level of language disruption or amount of information generated during autobiographical narration. Autobiographical memory impairments in LPA related to gray matter intensity decrease in predominantly posterior parietal brain regions implicated in memory retrieval. Together, our results suggest that episodic memory disturbances may be an under-appreciated clinical feature of LPA.
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Affiliation(s)
- Siddharth Ramanan
- The University of Sydney, Brain and Mind Centre, Sydney, New South Wales, Australia; The University of Sydney, School of Psychology, Sydney, New South Wales, Australia; ARC Centre of Excellence in Cognition and its Disorders, Sydney, New South Wales, Australia; Medical Research Council Cognition and Brain Sciences Unit at The University of Cambridge, Cambridge, UK.
| | - David Foxe
- The University of Sydney, Brain and Mind Centre, Sydney, New South Wales, Australia; The University of Sydney, School of Psychology, Sydney, New South Wales, Australia; ARC Centre of Excellence in Cognition and its Disorders, Sydney, New South Wales, Australia
| | - Hashim El-Omar
- The University of Sydney, Brain and Mind Centre, Sydney, New South Wales, Australia
| | - Rebekah M Ahmed
- The University of Sydney, Brain and Mind Centre, Sydney, New South Wales, Australia; Memory and Cognition Clinic, Department of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - John R Hodges
- The University of Sydney, Brain and Mind Centre, Sydney, New South Wales, Australia; ARC Centre of Excellence in Cognition and its Disorders, Sydney, New South Wales, Australia; The University of Sydney, School of Medical Sciences, Sydney, New South Wales, Australia
| | - Olivier Piguet
- The University of Sydney, Brain and Mind Centre, Sydney, New South Wales, Australia; The University of Sydney, School of Psychology, Sydney, New South Wales, Australia; ARC Centre of Excellence in Cognition and its Disorders, Sydney, New South Wales, Australia
| | - Muireann Irish
- The University of Sydney, Brain and Mind Centre, Sydney, New South Wales, Australia; The University of Sydney, School of Psychology, Sydney, New South Wales, Australia; ARC Centre of Excellence in Cognition and its Disorders, Sydney, New South Wales, Australia.
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Macoir J, Martel-Sauvageau V, Bouvier L, Laforce R, Monetta L. Heterogeneity of repetition abilities in logopenic variant primary progressive aphasia. Dement Neuropsychol 2021; 15:405-412. [PMID: 34630930 PMCID: PMC8485642 DOI: 10.1590/1980-57642021dn15-030014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 03/09/2021] [Indexed: 11/21/2022] Open
Abstract
The differential diagnosis of primary progressive aphasia (PPA) is challenging due to overlapping clinical manifestations of the different variants of the disease. This is particularly true for the logopenic variant of PPA (lvPPA), in which such overlap was reported with regard to impairments in repetition abilities. In this study, four individuals with lvPPA underwent standard neuropsychological and language assessments. The influence of psycholinguistic variables on their performance of in word, nonword and sentence repetition tasks was also specifically explored. Some level of heterogeneity was found in cognitive functions and in language. The four participants showed impairment in sentence repetition in which their performance was negatively affected by semantic reversibility and syntactic complexity. This study supports the heterogeneity of lvPPA with respect to the cognitive and linguistic status of participants. It also shows that sentence repetition is influenced not only by length, but also by semantic reversibility and syntactic complexity, two psycholinguistic variables known to place additional demands on phonological working memory.
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Affiliation(s)
- Joel Macoir
- Faculty of Medicine, Department of Rehabilitation, Laval University - Quebec, QC, Canada.,CERVO, Brain Research Centre - Quebec, QC, Canada
| | - Vicent Martel-Sauvageau
- Faculty of Medicine, Department of Rehabilitation, Laval University - Quebec, QC, Canada.,Center for Interdisciplinary Research in Rehabilitation and Social Integration - Quebec, QC, Canada
| | - Liziane Bouvier
- Faculty of Medicine, Department of Rehabilitation, Laval University - Quebec, QC, Canada.,CERVO, Brain Research Centre - Quebec, QC, Canada
| | - Robert Laforce
- Faculty of Medicine, Department of Medicine, Laval University - Quebec, QC, Canada.,Interdisciplinary Memory Clinic, Laval University Hospital Center - Quebec, QC, Canada.,Research Chair in Progressive Primary Aphasias, Lemaire Family Foundation - Quebec, QC, Canada
| | - Laura Monetta
- Faculty of Medicine, Department of Rehabilitation, Laval University - Quebec, QC, Canada.,CERVO, Brain Research Centre - Quebec, QC, Canada
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12
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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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13
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Mesulam MM, Coventry C, Kuang A, Bigio EH, Mao Q, Flanagan ME, Gefen T, Sridhar J, Geula C, Zhang H, Weintraub S, Rogalski EJ. Memory Resilience in Alzheimer Disease With Primary Progressive Aphasia. Neurology 2021; 96:e916-e925. [PMID: 33441454 PMCID: PMC8105903 DOI: 10.1212/wnl.0000000000011397] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/25/2020] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine whether memory is preserved longitudinally in primary progressive aphasia (PPA) associated with Alzheimer disease (AD) and to identify potential factors that maintain memory despite underlying neurofibrillary degeneration of mediotemporal memory areas. METHODS Longitudinal memory assessment was done in 17 patients with PPA with autopsy or biomarker evidence of AD (PPA-AD) and 14 patients with amnestic dementia of the Alzheimer type with AD at autopsy (DAT-AD). RESULTS In PPA-AD, episodic memory, tested with nonverbal items, was preserved at the initial testing and showed no decline at retesting 2.35 ± 0.78 years later, at which time symptoms had been present for 6.26 ± 2.21 years. In contrast, language functions declined significantly during the same period. In DAT-AD, both verbal memory and language declined with equal severity. Although imaging showed asymmetric left-sided mediotemporal atrophy in PPA-AD, autopsy revealed bilateral hippocampo-entorhinal neurofibrillary degeneration at Braak stages V and VI. Compared to DAT-AD, however, the PPA-AD group had lower incidence of APOE ε4 and of mediotemporal TAR DNA-binding protein 43 (TDP-43) pathology. CONCLUSIONS Memory preservation in PPA is not just an incidental finding at onset but a core feature that persists for years despite the hippocampo-entorhinal AD neuropathology that is as severe as that of DAT-AD. Asymmetry of mediotemporal atrophy and a lesser impact of APOE ε4 and of TDP-43 on the integrity of memory circuitry may constitute some of the factors underlying this resilience. Our results also suggest that current controversies on memory in PPA-AD reflect inconsistencies in the diagnosis of logopenic PPA, the clinical variant most frequently associated with AD. CLINICALTRIALSGOV IDENTIFIER NCT00537004 and NCT03371706.
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Affiliation(s)
- M-Marsel Mesulam
- From the Mesulam Center for Cognitive Neurology and Alzheimer's Disease (M.-M.M., C.C., E.H.B., Q.M., M.E.F., T.G., J.S., C.G., H.Z., S.W., E.J.R.), Department of Preventive Medicine (A.K., H.Z.), Department of Pathology (E.H.B., Q.M., M.E.F.), and Department of Psychiatry and Behavioral Sciences (T.G., S.W., E.J.R.), Northwestern University Feinberg School of Medicine, Chicago. IL.
| | - Christina Coventry
- From the Mesulam Center for Cognitive Neurology and Alzheimer's Disease (M.-M.M., C.C., E.H.B., Q.M., M.E.F., T.G., J.S., C.G., H.Z., S.W., E.J.R.), Department of Preventive Medicine (A.K., H.Z.), Department of Pathology (E.H.B., Q.M., M.E.F.), and Department of Psychiatry and Behavioral Sciences (T.G., S.W., E.J.R.), Northwestern University Feinberg School of Medicine, Chicago. IL
| | - Alan Kuang
- From the Mesulam Center for Cognitive Neurology and Alzheimer's Disease (M.-M.M., C.C., E.H.B., Q.M., M.E.F., T.G., J.S., C.G., H.Z., S.W., E.J.R.), Department of Preventive Medicine (A.K., H.Z.), Department of Pathology (E.H.B., Q.M., M.E.F.), and Department of Psychiatry and Behavioral Sciences (T.G., S.W., E.J.R.), Northwestern University Feinberg School of Medicine, Chicago. IL
| | - Eileen H Bigio
- From the Mesulam Center for Cognitive Neurology and Alzheimer's Disease (M.-M.M., C.C., E.H.B., Q.M., M.E.F., T.G., J.S., C.G., H.Z., S.W., E.J.R.), Department of Preventive Medicine (A.K., H.Z.), Department of Pathology (E.H.B., Q.M., M.E.F.), and Department of Psychiatry and Behavioral Sciences (T.G., S.W., E.J.R.), Northwestern University Feinberg School of Medicine, Chicago. IL
| | - Qinwen Mao
- From the Mesulam Center for Cognitive Neurology and Alzheimer's Disease (M.-M.M., C.C., E.H.B., Q.M., M.E.F., T.G., J.S., C.G., H.Z., S.W., E.J.R.), Department of Preventive Medicine (A.K., H.Z.), Department of Pathology (E.H.B., Q.M., M.E.F.), and Department of Psychiatry and Behavioral Sciences (T.G., S.W., E.J.R.), Northwestern University Feinberg School of Medicine, Chicago. IL
| | - Margaret E Flanagan
- From the Mesulam Center for Cognitive Neurology and Alzheimer's Disease (M.-M.M., C.C., E.H.B., Q.M., M.E.F., T.G., J.S., C.G., H.Z., S.W., E.J.R.), Department of Preventive Medicine (A.K., H.Z.), Department of Pathology (E.H.B., Q.M., M.E.F.), and Department of Psychiatry and Behavioral Sciences (T.G., S.W., E.J.R.), Northwestern University Feinberg School of Medicine, Chicago. IL
| | - Tamar Gefen
- From the Mesulam Center for Cognitive Neurology and Alzheimer's Disease (M.-M.M., C.C., E.H.B., Q.M., M.E.F., T.G., J.S., C.G., H.Z., S.W., E.J.R.), Department of Preventive Medicine (A.K., H.Z.), Department of Pathology (E.H.B., Q.M., M.E.F.), and Department of Psychiatry and Behavioral Sciences (T.G., S.W., E.J.R.), Northwestern University Feinberg School of Medicine, Chicago. IL
| | - Jaiashre Sridhar
- From the Mesulam Center for Cognitive Neurology and Alzheimer's Disease (M.-M.M., C.C., E.H.B., Q.M., M.E.F., T.G., J.S., C.G., H.Z., S.W., E.J.R.), Department of Preventive Medicine (A.K., H.Z.), Department of Pathology (E.H.B., Q.M., M.E.F.), and Department of Psychiatry and Behavioral Sciences (T.G., S.W., E.J.R.), Northwestern University Feinberg School of Medicine, Chicago. IL
| | - Changiz Geula
- From the Mesulam Center for Cognitive Neurology and Alzheimer's Disease (M.-M.M., C.C., E.H.B., Q.M., M.E.F., T.G., J.S., C.G., H.Z., S.W., E.J.R.), Department of Preventive Medicine (A.K., H.Z.), Department of Pathology (E.H.B., Q.M., M.E.F.), and Department of Psychiatry and Behavioral Sciences (T.G., S.W., E.J.R.), Northwestern University Feinberg School of Medicine, Chicago. IL
| | - Hui Zhang
- From the Mesulam Center for Cognitive Neurology and Alzheimer's Disease (M.-M.M., C.C., E.H.B., Q.M., M.E.F., T.G., J.S., C.G., H.Z., S.W., E.J.R.), Department of Preventive Medicine (A.K., H.Z.), Department of Pathology (E.H.B., Q.M., M.E.F.), and Department of Psychiatry and Behavioral Sciences (T.G., S.W., E.J.R.), Northwestern University Feinberg School of Medicine, Chicago. IL
| | - Sandra Weintraub
- From the Mesulam Center for Cognitive Neurology and Alzheimer's Disease (M.-M.M., C.C., E.H.B., Q.M., M.E.F., T.G., J.S., C.G., H.Z., S.W., E.J.R.), Department of Preventive Medicine (A.K., H.Z.), Department of Pathology (E.H.B., Q.M., M.E.F.), and Department of Psychiatry and Behavioral Sciences (T.G., S.W., E.J.R.), Northwestern University Feinberg School of Medicine, Chicago. IL
| | - Emily J Rogalski
- From the Mesulam Center for Cognitive Neurology and Alzheimer's Disease (M.-M.M., C.C., E.H.B., Q.M., M.E.F., T.G., J.S., C.G., H.Z., S.W., E.J.R.), Department of Preventive Medicine (A.K., H.Z.), Department of Pathology (E.H.B., Q.M., M.E.F.), and Department of Psychiatry and Behavioral Sciences (T.G., S.W., E.J.R.), Northwestern University Feinberg School of Medicine, Chicago. IL
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14
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Longitudinal cognitive and functional changes in primary progressive aphasia. J Neurol 2021; 268:1951-1961. [PMID: 33417000 DOI: 10.1007/s00415-020-10382-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/17/2020] [Accepted: 12/19/2020] [Indexed: 10/22/2022]
Abstract
OBJECTIVE The variants of primary progressive aphasia (PPA) are predominantly diagnosed on the basis of specific profiles of language impairments. Deficits in other cognitive domains and their evolution over time are less well documented. This study examined the cognitive profiles of the PPA variants over time and determined the contribution of cognition on functional capacity. METHODS Longitudinal performance on the Addenbrooke's Cognitive Examination-III (ACE-III) total and cognitive subdomains were investigated in 147 PPA individuals (41 logopenic [lv-PPA], 44 non-fluent [nfv-PPA], and 62 semantic variants [sv-PPA]). The relative contribution of ACE-III subdomain scores to overall functional capacity over time was identified using mixed and hierarchical regression modelling. RESULTS The annual rate of global ACE-III decline was twice that in lv-PPA than in nfv-PPA and sv-PPA, despite lv-PPA performing intermediate to the other variants at baseline assessment. Notably, attention and visuospatial subdomains declined faster in lv-PPA than in nfv-PPA and sv-PPA; and memory impairment was more severe in lv-PPA than in nfv-PPA at all time points. Functional decline was comparable across PPA variants; however, the contribution of cognition on functional capacity varied across variants and over time. CONCLUSION The cognitive profiles of the PPA variants are distinct at baseline and over time. Crucially, cognitive decline in lv-PPA was more widespread and pervasive than in nfv-PPA and sv-PPA. Our findings also demonstrate the complex interplay between cognition and functional capacity. This study underscores the importance of routinely assessing cognition and functional capacity in PPA to improve diagnostic accuracy and provide targeted support services.
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15
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Liu L, Roquet D, Ahmed RM, Hodges JR, Piguet O, Irish M. Examining prefrontal contributions to past- and future-oriented memory disturbances in daily life in dementia. Cortex 2020; 134:307-319. [PMID: 33333361 DOI: 10.1016/j.cortex.2020.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 09/24/2020] [Accepted: 11/10/2020] [Indexed: 01/17/2023]
Abstract
Deficits in episodic memory are commonplace in dementia, yet mounting evidence indicates pervasive impairments in future-oriented thinking in these syndromes. How such impairments manifest in the daily lives of people with dementia remain unclear, as do their neural bases. This study aimed to determine the neurocognitive mechanisms of past- and future-oriented memory performance across a large sample of dementia syndromes, each of which is characterised by distinct clinical and cognitive profiles. Carer-rated memory changes in everyday life in Alzheimer's disease, behavioural-variant frontotemporal dementia, semantic dementia, progressive non-fluent aphasia, and logopenic progressive aphasia were assessed using the Prospective and Retrospective Memory Questionnaire (PRM-Q). Participants underwent neuropsychological testing and whole-brain structural MRI. Relative to Controls, past- and future-oriented memory were compromised exclusively in AD and bvFTD, with no impairments reported for the other groups. For AD, atrophy in a distributed network of prefrontal, lateral and medial temporal regions including the hippocampus, correlated with past- and future-oriented memory impairments. In contrast, lateral and medial prefrontal regions correlated with past- and future-oriented memory difficulties in bvFTD. Notably, the orbitofrontal cortex emerged as a common neural substrate implicated in memory disturbances across the AD and bvFTD groups. This study confirms the presence of episodic amnesia in bvFTD across a host of everyday activities, mirroring the profile typically observed in AD. Of note, the orbitofrontal cortex emerged as a common region implicated in past- and future-oriented memory deficits in both patient groups, underscoring a critical role for prefrontal regions in supporting complex aspects of memory function in everyday life.
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Affiliation(s)
- Lulu Liu
- The University of Sydney, School of Psychology, Sydney, Australia; The University of Sydney, Brain and Mind Centre, Sydney, Australia
| | - Daniel Roquet
- The University of Sydney, School of Psychology, Sydney, Australia; The University of Sydney, Brain and Mind Centre, Sydney, Australia
| | - Rebekah M Ahmed
- The University of Sydney, Brain and Mind Centre, Sydney, Australia; Royal Prince Alfred Hospital, Sydney, Australia
| | - John R Hodges
- The University of Sydney, Brain and Mind Centre, Sydney, Australia
| | - Olivier Piguet
- The University of Sydney, School of Psychology, Sydney, Australia; The University of Sydney, Brain and Mind Centre, Sydney, Australia
| | - Muireann Irish
- The University of Sydney, School of Psychology, Sydney, Australia; The University of Sydney, Brain and Mind Centre, Sydney, Australia.
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16
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Ramanan S, Roquet D, Goldberg ZL, Hodges JR, Piguet O, Irish M, Lambon Ralph MA. Establishing two principal dimensions of cognitive variation in logopenic progressive aphasia. Brain Commun 2020; 2:fcaa125. [PMID: 33376980 PMCID: PMC7750924 DOI: 10.1093/braincomms/fcaa125] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/25/2020] [Accepted: 07/13/2020] [Indexed: 12/28/2022] Open
Abstract
Logopenic progressive aphasia is a neurodegenerative syndrome characterized by sentence repetition and naming difficulties arising from left-lateralized temporoparietal atrophy. Clinical descriptions of logopenic progressive aphasia largely concentrate on profiling language deficits, however, accumulating evidence points to the presence of cognitive deficits even on tasks with minimal language demands. Although non-linguistic cognitive deficits in logopenic progressive aphasia are thought to scale with disease severity, patients at discrete stages of language dysfunction display overlapping cognitive profiles, suggesting individual-level variation in cognitive performance, independent of primary language dysfunction. To address this issue, we used principal component analysis to decompose the individual-level variation in cognitive performance in 43 well-characterized logopenic progressive aphasia patients who underwent multi-domain neuropsychological assessments and structural neuroimaging. The principal component analysis solution revealed the presence of two, statistically independent factors, providing stable and clinically intuitive explanations for the majority of variance in cognitive performance in the syndrome. Factor 1 reflected 'speech production and verbal memory' deficits which typify logopenic progressive aphasia. Systematic variations were also confirmed on a second, orthogonal factor mainly comprising visuospatial and executive processes. Adopting a case-comparison approach, we further demonstrate that pairs of patients with comparable Factor 1 scores, regardless of their severity, diverge considerably on visuo-executive test performance, underscoring the inter-individual variability in cognitive profiles in comparably 'logopenic' patients. Whole-brain voxel-based morphometry analyses revealed that speech production and verbal memory factor scores correlated with left middle frontal gyrus, while visuospatial and executive factor scores were associated with grey matter intensity of right-lateralized temporoparietal, middle frontal regions and their underlying white matter connectivity. Importantly, logopenic progressive aphasia patients with poorer visuospatial and executive factor scores demonstrated greater right-lateralized temporoparietal and frontal atrophy. Our findings demonstrate the inherent variation in cognitive performance at an individual- and group-level in logopenic progressive aphasia, suggesting the presence of a genuine co-occurring cognitive impairment that is statistically independent of language function and disease severity.
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Affiliation(s)
- Siddharth Ramanan
- The University of Sydney, Brain and Mind Centre, Sydney, NSW, Australia
- The University of Sydney, School of Psychology, Sydney, NSW, Australia
- ARC Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia
| | - Daniel Roquet
- The University of Sydney, Brain and Mind Centre, Sydney, NSW, Australia
- The University of Sydney, School of Psychology, Sydney, NSW, Australia
- ARC Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia
| | - Zoë-Lee Goldberg
- The University of Sydney, Brain and Mind Centre, Sydney, NSW, Australia
| | - John R Hodges
- The University of Sydney, Brain and Mind Centre, Sydney, NSW, Australia
- ARC Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia
- The University of Sydney, School of Medical Sciences, Sydney, NSW, Australia
| | - Olivier Piguet
- The University of Sydney, Brain and Mind Centre, Sydney, NSW, Australia
- The University of Sydney, School of Psychology, Sydney, NSW, Australia
- ARC Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia
| | - Muireann Irish
- The University of Sydney, Brain and Mind Centre, Sydney, NSW, Australia
- The University of Sydney, School of Psychology, Sydney, NSW, Australia
- ARC Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia
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