Background: Social cognition is critically compromised across neurodegenerative diseases, including the behavioral variant frontotemporal dementia (bvFTD), Alzheimer’s disease (AD), and Parkinson’s disease (PD). However, no previous study has used social cognition and other cognitive tasks to predict diagnoses of these conditions, let alone reporting the brain correlates of prediction outcomes. Objective: We performed a diagnostic classification analysis using social cognition, cognitive screening (CS), and executive function (EF) measures, and explored which anatomical and functional networks were associated with main predictors. Methods: Multiple group discriminant function analyses (MDAs) and ROC analyses of social cognition (facial emotional recognition, theory of mind), CS, and EF were implemented in 223 participants (bvFTD, AD, PD, controls). Gray matter volume and functional connectivity correlates of top discriminant scores were investigated. Results: Although all patient groups revealed deficits in social cognition, CS, and EF, our classification approach provided robust discriminatory characterizations. Regarding controls, probabilistic social cognition outcomes provided the best characterization for bvFTD (together with CS) and PD, but not AD (for which CS alone was the best predictor). Within patient groups, the best MDA probabilities scores yielded high classification rates for bvFTD versus PD (98.3% , social cognition), AD versus PD (98.6% , social cognition + CS), and bvFTD versus AD (71.7% , social cognition + CS). Top MDA scores were associated with specific patterns of atrophy and functional networks across neurodegenerative conditions. Conclusion: Standardized validated measures of social cognition, in combination with cognitive screening, can provide a dimensional classification with specific pathophysiological markers of neurodegeneration diagnoses.

Background With the global population aging and life expectancy increasing, dementia has turned a priority in the health care system. In Chile, dementia is one of the most important causes of disability in the elderly and the most rapidly growing cause of death in the last 20 years. Cognitive complaint is considered a predictor for cognitive and functional decline, incident mild cognitive impairment, and incident dementia. The GERO cohort is the Chilean core clinical project of the Geroscience Center for Brain Health and Metabolism (GERO). The objective of the GERO cohort is to analyze the rate of functional decline and progression to clinical dementia and their associated risk factors in a community-dwelling elderly with subjective cognitive complaint, through a population-based study. We also aim to undertake clinical research on brain ageing and dementia disorders, to create data and biobanks with the appropriate infrastructure to conduct other studies and facilitate to the national and international scientific community access to the data and samples for research. Methods The GERO cohort aims the recruitment of 300 elderly subjects (> 70 years) from Santiago (Chile), following them up for at least 3 years. Eligible people are adults not diagnosed with dementia with subjective cognitive complaint, which are reported either by the participant, a proxy or both. Participants are identified through a household census. The protocol for evaluation is based on a multidimensional approach including socio-demographic, biomedical, psychosocial, neuropsychological, neuropsychiatric and motor assessments. Neuroimaging, blood and stool samples are also obtained. This multidimensional evaluation is carried out in a baseline and 2 follow-ups assessments, at 18 and 36 months. In addition, in months 6, 12, 24, and 30, a telephone interview is performed in order to keep contact with the participants and to assess general well-being. Discussion Our work will allow us to determine multidimensional risks factors associated with functional decline and conversion to dementia in elderly with subjective cognitive complain. The aim of our GERO group is to establish the capacity to foster cutting edge and multidisciplinary research on aging in Chile including basic and clinical research. Trial registration NCT04265482 in ClinicalTrials.gov. Registration Date: February 11, 2020. Retrospectively Registered.

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Background: Two early basilar artery occlusion (BAO) randomized controlled trials did not establish superiority of endovascular thrombectomy (EVT) over medical management. While many providers continue to recommend EVT for acute BAO, perceptions of equipoise in randomizing patients with BAO to medical management may differ between clinician specialties. Methods: We conducted an international survey (1/1/22-3/31/22) regarding management strategies in acute BAO prior to the announcement of 2 trials indicating superiority of EVT, and compared responses between interventionalists (INT) and non-interventionalists (nINT). Selection practices for routine EVT based on neuroimaging and clinical features were compared between the two groups using descriptive statistics. Results: Among the 1245 respondents (nINT=702), INT more commonly believed that EVT was superior to medical management in acute BAO (98.5% vs. 95.1%, p<0.01). A similar proportion of INT and nINT responded that they would not randomize a patient with BAO to EVT (29.4% vs. 26.7%), or that they would only under specific circumstances (p=0.45). Among respondents who would recommend EVT, there was no difference in the maximum pre-stroke disability, minimum stroke severity, or infarct burden on computed tomography between the two groups (p>0.05), although nINT more commonly preferred perfusion imaging (24.2% vs. 19.7%, p=0.04). Among respondents who indicated they would randomize to medical management, INT were more likely to randomize when the NIHSS was ≥10 (15.9% vs. 6.9%, p<0.01). Conclusions: Following the publication of two neutral clinical trials in BAO EVT, most stroke providers believed EVT to be superior to medical management in carefully selected patients, with most indicating they would not randomize a patient to medical treatment. There were small differences in preference of advanced neuroimaging, although these preferences were unsupported by clinical trial data.