Author
Mario F. Mendez
Other affiliations: Ronald Reagan UCLA Medical Center, Western University of Health Sciences, University of California, San Francisco ...read more
Bio: Mario F. Mendez is an academic researcher from University of California, Los Angeles. The author has contributed to research in topics: Frontotemporal dementia & Dementia. The author has an hindex of 65, co-authored 351 publications receiving 18961 citations. Previous affiliations of Mario F. Mendez include Ronald Reagan UCLA Medical Center & Western University of Health Sciences.
Papers published on a yearly basis
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University of Pennsylvania1, University of New South Wales2, Mayo Clinic3, University of California, Los Angeles4, University of California, San Francisco5, Erasmus University Rotterdam6, Johns Hopkins University7, University of Western Ontario8, University of Southampton9, University Hospital Southampton NHS Foundation Trust10, University College London11, University of California, San Diego12, University of Toronto13, Northwestern University14, Harvard University15, Technische Universität München16, Lille University of Science and Technology17, VU University Amsterdam18, Favaloro University19, Kessler Foundation20, Vita-Salute San Raffaele University21
TL;DR: The revised criteria for behavioural variant frontotemporal dementia improve diagnostic accuracy compared with previously established criteria in a sample with known frontotmporal lobar degeneration and reflect the optimized diagnostic features, less restrictive exclusion features and a flexible structure that accommodates different initial clinical presentations.
Abstract: Based on the recent literature and collective experience, an international consortium developed revised guidelines for the diagnosis of behavioural variant frontotemporal dementia. The validation process retrospectively reviewed clinical records and compared the sensitivity of proposed and earlier criteria in a multi-site sample of patients with pathologically verified frontotemporal lobar degeneration. According to the revised criteria, 'possible' behavioural variant frontotemporal dementia requires three of six clinically discriminating features (disinhibition, apathy/inertia, loss of sympathy/empathy, perseverative/compulsive behaviours, hyperorality and dysexecutive neuropsychological profile). 'Probable' behavioural variant frontotemporal dementia adds functional disability and characteristic neuroimaging, while behavioural variant frontotemporal dementia 'with definite frontotemporal lobar degeneration' requires histopathological confirmation or a pathogenic mutation. Sixteen brain banks contributed cases meeting histopathological criteria for frontotemporal lobar degeneration and a clinical diagnosis of behavioural variant frontotemporal dementia, Alzheimer's disease, dementia with Lewy bodies or vascular dementia at presentation. Cases with predominant primary progressive aphasia or extra-pyramidal syndromes were excluded. In these autopsy-confirmed cases, an experienced neurologist or psychiatrist ascertained clinical features necessary for making a diagnosis according to previous and proposed criteria at presentation. Of 137 cases where features were available for both proposed and previously established criteria, 118 (86%) met 'possible' criteria, and 104 (76%) met criteria for 'probable' behavioural variant frontotemporal dementia. In contrast, 72 cases (53%) met previously established criteria for the syndrome (P < 0.001 for comparison with 'possible' and 'probable' criteria). Patients who failed to meet revised criteria were significantly older and most had atypical presentations with marked memory impairment. In conclusion, the revised criteria for behavioural variant frontotemporal dementia improve diagnostic accuracy compared with previously established criteria in a sample with known frontotemporal lobar degeneration. Greater sensitivity of the proposed criteria may reflect the optimized diagnostic features, less restrictive exclusion features and a flexible structure that accommodates different initial clinical presentations. Future studies will be needed to establish the reliability and specificity of these revised diagnostic guidelines.
3,706 citations
University of California, San Francisco1, University of Trento2, Johns Hopkins University3, Northwestern University4, University of Western Ontario5, University of California, Los Angeles6, Vita-Salute San Raffaele University7, University College London8, University of Toronto9, Mayo Clinic10, University of California, Davis11, Katholieke Universiteit Leuven12, University of Cambridge13, University of New South Wales14, University of Pennsylvania15
TL;DR: This article provides a classification of primary progressive aphasia (PPA) and its 3 main variants to improve the uniformity of case reporting and the reliability of research results.
Abstract: This article provides a classification of primary progressive aphasia (PPA) and its 3 main variants to improve the uniformity of case reporting and the reliability of research results. Criteria for the 3 variants of PPA—nonfluent/agrammatic, semantic, and logopenic—were developed by an international group of PPA investigators who convened on 3 occasions to operationalize earlier published clinical descriptions for PPA subtypes. Patients are first diagnosed with PPA and are then divided into clinical variants based on specific speech and language features characteristic of each subtype. Classification can then be further specified as “imaging-supported” if the expected pattern of atrophy is found and “with definite pathology” if pathologic or genetic data are available. The working recommendations are presented in lists of features, and suggested assessment tasks are also provided. These recommendations have been widely agreed upon by a large group of experts and should be used to ensure consistency of PPA classification in future studies. Future collaborations will collect prospective data to identify relationships between each of these syndromes and specific biomarkers for a more detailed understanding of clinicopathologic correlations.
3,635 citations
TL;DR: The results suggest that the dementia of PD is distinguishable from that of DAT: PD patients have prominent motor speech abnormalities, whereas DAT patients exhibit more profound language alterations.
Abstract: Speech and language alterations were assessed in 51 patients with Parkinson9s disease (PD) and 10 patients with dementia of the Alzheimer type (DAT). Thirty-five of the PD patients had no evidence of intellectual impairment on a conventional mental status questionnaire and 16 of the PD patients had dementia syndromes of comparable severity to the DAT patients. DAT produced significantly greater language disturbances, including anomia, decreased information content of spontaneous speech, and diminished word list generation. PD patients had significantly decreased phrase length, impaired speech melody, dysarthria, and agraphia. The results suggest that the dementia of PD is distinguishable from that of DAT: PD patients have prominent motor speech abnormalities, whereas DAT patients exhibit more profound language alterations.
404 citations
UCL Institute of Neurology1, University of California, San Francisco2, Mayo Clinic3, Salford Royal NHS Foundation Trust4, University of Manchester5, VU University Amsterdam6, Harvard University7, Katholieke Universiteit Leuven8, University of Oxford9, University of Edinburgh10, Vita-Salute San Raffaele University11, Aix-Marseille University12, Universidade Federal de Minas Gerais13, Pierre-and-Marie-Curie University14, University of California, San Diego15, Icahn School of Medicine at Mount Sinai16, University of Lyon17, University of California, Los Angeles18, German Center for Neurodegenerative Diseases19, Johns Hopkins University School of Medicine20, University of Colorado Denver21, University Health Network22, Alzheimer's Association23
TL;DR: A classification framework for posterior cortical atrophy (PCA) is proposed to improve the uniformity of definition of the syndrome in a variety of research settings.
Abstract: Introduction A classification framework for posterior cortical atrophy (PCA) is proposed to improve the uniformity of definition of the syndrome in a variety of research settings. Methods Consensus statements about PCA were developed through a detailed literature review, the formation of an international multidisciplinary working party which convened on four occasions, and a Web-based quantitative survey regarding symptom frequency and the conceptualization of PCA. Results A three-level classification framework for PCA is described comprising both syndrome- and disease-level descriptions. Classification level 1 (PCA) defines the core clinical, cognitive, and neuroimaging features and exclusion criteria of the clinico-radiological syndrome. Classification level 2 (PCA-pure, PCA-plus) establishes whether, in addition to the core PCA syndrome, the core features of any other neurodegenerative syndromes are present. Classification level 3 (PCA attributable to AD [PCA-AD], Lewy body disease [PCA-LBD], corticobasal degeneration [PCA-CBD], prion disease [PCA-prion]) provides a more formal determination of the underlying cause of the PCA syndrome, based on available pathophysiological biomarker evidence. The issue of additional syndrome-level descriptors is discussed in relation to the challenges of defining stages of syndrome severity and characterizing phenotypic heterogeneity within the PCA spectrum. Discussion There was strong agreement regarding the definition of the core clinico-radiological syndrome, meaning that the current consensus statement should be regarded as a refinement, development, and extension of previous single-center PCA criteria rather than any wholesale alteration or redescription of the syndrome. The framework and terminology may facilitate the interpretation of research data across studies, be applicable across a broad range of research scenarios (e.g., behavioral interventions, pharmacological trials), and provide a foundation for future collaborative work.
398 citations
TL;DR: These findings show that cohorts of patients can be combined using new research criteria for FTLD and demonstrate striking demographic differences among FTLD subgroups, including frontotemporal dementia, semantic dementia, and progressive nonfluent aphasia.
Abstract: Background Until recently, frontotemporal lobar degeneration (FTLD) was considered a rare neurodegenerative disorder that was difficult to diagnose. The publication of consensus criteria for FTLD, however, prompted systematic studies. The criteria categorize FTLD into 3 subgroups: frontotemporal dementia, semantic dementia, and progressive nonfluent aphasia. Objective To compare demographic characteristics of patients in the 3 FTLD subgroups. Design We compared diagnostic breakdown, age at onset, sex, Mini-Mental State Examination score at first visit, education, and neuropathological diagnoses in a large sample of FTLD patients from 3 different university dementia clinics, including 2 neurologic clinics in the United States and 1 psychiatric clinic in Germany. Results The frontotemporal dementia subgroup represented approximately half of all FTLD diagnoses. Patients diagnosed as having frontotemporal dementia (mean age, 57.5 years) and semantic dementia (mean age, 59.3 years) had an earlier age at onset than patients diagnosed as having progressive nonfluent aphasia (mean age, 63.0 years). There were significantly more men diagnosed as having frontotemporal dementia (63.5%) and semantic dementia (66.7%) when compared with progressive nonfluent aphasia (39.1%) ( P = .005 for frontotemporal dementia vs progressive nonfluent aphasia and P = .002 for semantic dementia vs progressive nonfluent aphasia). Generally, the demographic features and diagnostic categories of the patient populations across the 3 sites were comparable. There were 68 deaths and 37 autopsies. Frontotemporal lobar degeneration with ubiquitin-positive τ-negative inclusions (48.5%), dementia lacking distinctive histopathological features (18.2%), and Pick disease (15.2%) were the most common neuropathological diagnoses. Conclusions These findings show that cohorts of patients can be combined using new research criteria for FTLD and demonstrate striking demographic differences among FTLD subgroups. The sex and age-at-onset differences suggest that there may be biological differences among FTLD subgroups. In this sample, FTLD with ubiquitin-positive inclusions accounted for half of all neuropathological diagnoses.
365 citations
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Johns Hopkins University School of Medicine1, Johns Hopkins University2, Mayo Clinic3, McGill University4, Harvard University5, University of California, Irvine6, University of Pittsburgh7, Columbia University Medical Center8, Eli Lilly and Company9, Washington University in St. Louis10, UCL Institute of Neurology11, VU University Medical Center12, Alzheimer's Association13, Northwestern University14, National Institutes of Health15
TL;DR: The workgroup sought to ensure that the revised criteria would be flexible enough to be used by both general healthcare providers without access to neuropsychological testing, advanced imaging, and cerebrospinal fluid measures, and specialized investigators involved in research or in clinical trial studies who would have these tools available.
Abstract: The National Institute on Aging and the Alzheimer's Association charged a workgroup with the task of revising the 1984 criteria for Alzheimer's disease (AD) dementia. The workgroup sought to ensure that the revised criteria would be flexible enough to be used by both general healthcare providers without access to neuropsychological testing, advanced imaging, and cerebrospinal fluid measures, and specialized investigators involved in research or in clinical trial studies who would have these tools available. We present criteria for all-cause dementia and for AD dementia. We retained the general framework of probable AD dementia from the 1984 criteria. On the basis of the past 27 years of experience, we made several changes in the clinical criteria for the diagnosis. We also retained the term possible AD dementia, but redefined it in a manner more focused than before. Biomarker evidence was also integrated into the diagnostic formulations for probable and possible AD dementia for use in research settings. The core clinical criteria for AD dementia will continue to be the cornerstone of the diagnosis in clinical practice, but biomarker evidence is expected to enhance the pathophysiological specificity of the diagnosis of AD dementia. Much work lies ahead for validating the biomarker diagnosis of AD dementia.
13,710 citations
9,362 citations
TL;DR: It is shown that TDP-43 is the major disease protein in both frontotemporal lobar degeneration with ubiquitin-positive inclusions and amyotrophic lateral sclerosis.
Abstract: Ubiquitin-positive, tau- and alpha-synuclein-negative inclusions are hallmarks of frontotemporal lobar degeneration with ubiquitin-positive inclusions and amyotrophic lateral sclerosis. Although the identity of the ubiquitinated protein specific to either disorder was unknown, we showed that TDP-43 is the major disease protein in both disorders. Pathologic TDP-43 was hyper-phosphorylated, ubiquitinated, and cleaved to generate C-terminal fragments and was recovered only from affected central nervous system regions, including hippocampus, neocortex, and spinal cord. TDP-43 represents the common pathologic substrate linking these neurodegenerative disorders.
5,440 citations
Camden and Islington NHS Foundation Trust1, University College London2, King's College London3, University of Melbourne4, University of Exeter5, Brighton and Sussex Medical School6, University of Manchester7, Tel Aviv University8, Johns Hopkins University9, University of Michigan10, Kaiser Permanente11, University of Washington12, University of Edinburgh13, University of Montpellier14, Dalhousie University15, University of Southern California16, Innlandet Hospital Trust17, University of Oslo18
TL;DR: The Lancet Commission on Dementia Prevention, Intervention, and Care met to consolidate the huge strides that have been made and the emerging knowledge as to what the authors should do to prevent and manage dementia.
3,826 citations
University of Pennsylvania1, University of New South Wales2, Mayo Clinic3, University of California, Los Angeles4, University of California, San Francisco5, Erasmus University Rotterdam6, Johns Hopkins University7, University of Western Ontario8, University of Southampton9, University Hospital Southampton NHS Foundation Trust10, University College London11, University of California, San Diego12, University of Toronto13, Northwestern University14, Harvard University15, Technische Universität München16, Lille University of Science and Technology17, VU University Amsterdam18, Favaloro University19, Kessler Foundation20, Vita-Salute San Raffaele University21
TL;DR: The revised criteria for behavioural variant frontotemporal dementia improve diagnostic accuracy compared with previously established criteria in a sample with known frontotmporal lobar degeneration and reflect the optimized diagnostic features, less restrictive exclusion features and a flexible structure that accommodates different initial clinical presentations.
Abstract: Based on the recent literature and collective experience, an international consortium developed revised guidelines for the diagnosis of behavioural variant frontotemporal dementia. The validation process retrospectively reviewed clinical records and compared the sensitivity of proposed and earlier criteria in a multi-site sample of patients with pathologically verified frontotemporal lobar degeneration. According to the revised criteria, 'possible' behavioural variant frontotemporal dementia requires three of six clinically discriminating features (disinhibition, apathy/inertia, loss of sympathy/empathy, perseverative/compulsive behaviours, hyperorality and dysexecutive neuropsychological profile). 'Probable' behavioural variant frontotemporal dementia adds functional disability and characteristic neuroimaging, while behavioural variant frontotemporal dementia 'with definite frontotemporal lobar degeneration' requires histopathological confirmation or a pathogenic mutation. Sixteen brain banks contributed cases meeting histopathological criteria for frontotemporal lobar degeneration and a clinical diagnosis of behavioural variant frontotemporal dementia, Alzheimer's disease, dementia with Lewy bodies or vascular dementia at presentation. Cases with predominant primary progressive aphasia or extra-pyramidal syndromes were excluded. In these autopsy-confirmed cases, an experienced neurologist or psychiatrist ascertained clinical features necessary for making a diagnosis according to previous and proposed criteria at presentation. Of 137 cases where features were available for both proposed and previously established criteria, 118 (86%) met 'possible' criteria, and 104 (76%) met criteria for 'probable' behavioural variant frontotemporal dementia. In contrast, 72 cases (53%) met previously established criteria for the syndrome (P < 0.001 for comparison with 'possible' and 'probable' criteria). Patients who failed to meet revised criteria were significantly older and most had atypical presentations with marked memory impairment. In conclusion, the revised criteria for behavioural variant frontotemporal dementia improve diagnostic accuracy compared with previously established criteria in a sample with known frontotemporal lobar degeneration. Greater sensitivity of the proposed criteria may reflect the optimized diagnostic features, less restrictive exclusion features and a flexible structure that accommodates different initial clinical presentations. Future studies will be needed to establish the reliability and specificity of these revised diagnostic guidelines.
3,706 citations