Structural brain differences between monolingual and multilingual patients with mild cognitive impairment and Alzheimer disease: Evidence for cognitive reserve

Two independent lines of research provide evidence that speaking more than one language may 1) contribute to increased grey matter in healthy younger and older adults and 2) delay cognitive symptoms in mild cognitive impairment (MCI) or Alzheimer disease (AD). We examined cortical thickness and tissue density in monolingual and multilingual MCI and AD patients matched (within Diagnosis Groups) on demographic and cognitive variables. In medial temporal disease-related (DR) areas, we found higher tissue density in multilingual MCIs versus monolingual MCIs, but similar or lower tissue density in multilingual AD versus monolingual AD, a pattern consistent with cognitive reserve in AD. In areas related to language and cognitive control (LCC), both multilingual MCI and AD patients had thicker cortex than the monolinguals. Results were largely replicated in our native-born Canadian MCI participants, ruling out immigration as a potential confound. Finally, multilingual patients showed a correlation between cortical thickness in LCC regions and performance on episodic memory tasks. Given that multilinguals and monolinguals were matched on memory functioning, this suggests that increased gray matter in these regions may provide support to memory functioning. Our results suggest that being multilingual may contribute to increased gray matter in LCC areas and may also delay the cognitive effects of disease-related atrophy

The Comprehensive Assessment of Neurodegeneration and Dementia: Canadian Cohort Study.

BackgroundThe Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) cohort study of the Canadian Consortium on Neurodegeneration in Aging (CCNA) is a national initiative to catalyze research on dementia, set up to support the research agendas of CCNA teams. This cross-country longitudinal cohort of 2310 deeply phenotyped subjects with various forms of dementia and mild memory loss or concerns, along with cognitively intact elderly subjects, will test hypotheses generated by these teams.MethodsThe COMPASS-ND protocol, initial grant proposal for funding, fifth semi-annual CCNA Progress Report submitted to the Canadian Institutes of Health Research December 2017, and other documents supplemented by modifications made and lessons learned after implementation were used by the authors to create the description of the study provided here.ResultsThe CCNA COMPASS-ND cohort includes participants from across Canada with various cognitive conditions associated with or at risk of neurodegenerative diseases. They will undergo a wide range of experimental, clinical, imaging, and genetic investigation to specifically address the causes, diagnosis, treatment, and prevention of these conditions in the aging population. Data derived from clinical and cognitive assessments, biospecimens, brain imaging, genetics, and brain donations will be used to test hypotheses generated by CCNA research teams and other Canadian researchers. The study is the most comprehensive and ambitious Canadian study of dementia. Initial data posting occurred in 2018, with the full cohort to be accrued by 2020.ConclusionAvailability of data from the COMPASS-ND study will provide a major stimulus for dementia research in Canada in the coming years

The Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) Study neuropsychology battery of the Canadian Consortium on Neurodegeneration in Aging (CCNA): Design overview and initial validation

The Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) is an observational study of 1100+ participants from across the dementia spectrum. We describe the development and features of the Neuropsychological Research Battery, which assesses learning and memory, processing speed, attention, executive function, visuoperceptual processing, and language. We report preliminary results (Fourth Data Release) from 60 cognitively unimpaired (CU) older adults, 56 participants with normal cognition but subjective cognitive decline (SCD), 104 with mild cognitive impairment (MCI), and 48 with Alzheimer’s dementia (AD). The tests were sensitive to performance differences between the diagnostic groups. Regression models indicated associations with age, education, and sex on multiple test scores. Future work will: (1) increase the educational diversity and sex balance of the participant cohorts, (2) determine the psychometric properties of the battery, (3) establish normative data from control participants, and (4) examine longitudinal data on individuals at risk for dementia and across the dementia spectrum. COMPASS-ND (Comprehensive Assessment of Neurodegeneration and Dementia) est une étude d'observation portant sur plus de 1,100 participants de l'ensemble du spectre des troubles neurocognitifs. Nous décrivons le développement et les caractéristiques de la batterie de recherche neuropsychologique, qui évalue l'apprentissage et la mémoire, la vitesse de traitement, l'attention, les fonctions exécutives, le traitement visuoperceptuel et le langage. Nous présentons les résultats préliminaires (quatrième publication des données) obtenus auprès de 60 personnes âgées sans trouble cognitif (CN), 56 participants ayant une cognition normale mais un déclin cognitif subjectif (SCD), 104 personnes atteintes d'un trouble cognitif léger (MCI) et 48 personnes atteintes de la maladie d'Alzheimer (AD). Les tests étaient sensibles aux différences de performance entre les groupes de diagnostic. Les modèles de régression ont indiqué des associations avec l'âge, l'éducation et le sexe sur les scores des tests multiples. Les travaux futurs viseront à (1) augmenter la diversité de l'éducation et l'équilibre entre les sexes dans les cohortes de participants, (2) déterminer les propriétés psychométriques de la batterie, (3) établir des données normatives à partir de contrôles, et (4) examiner les données longitudinales sur les individus à risque de troubles neurocognitifs et sur l'ensemble du spectre des troubles neurocognitifs