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Background Very-early-onset Alzheimer’s disease (young-AD) differentiates from late-onset AD (old-AD) by a predominant involvement of the parietal neocortex leading to atypical presentations. The diagnosis of AD is often not the first to be mentioned in such young patients. Methods We retrospectively reviewed the initial complaint and care pathways of 66 sporadic young-AD (age 65) and compared their neuropsychological profiles at the time of diagnosis (based on clinical-biological criteria) with 44 amyloid-negative controls. Results The initial complaint of young-AD was non-cognitive and mimicked a burnout in 32% of cases. Their main cognitive complaints were memory (38% vs 87% in old-AD) and language (17% vs 13%) impairment. The referral to a psychiatrist prior to AD diagnosis was more frequent in young-AD than in old-AD (26% vs 0%). At the time of diagnosis, young-AD were at a more severe stage of dementia than old-AD (24% vs 10% with CDR ≥ 1) but had less anosognosia. Conclusions Better identifying the initial signs of very-early-onset AD is crucial to improve the early diagnosis and develop new treatments.

Objective: Environmental dependency syndrome (EDS), including utilization (UB) and imitation (IB) behaviors, is often reported in behavioral variant frontotemporal dementia (bvFTD). These behaviors are commonly attributed to executive dysfunction. However, inconsistent associations between EDS and poor executive performance has led to an alternative “social hypothesis,” instead implicating patients’ misinterpretation of the examiner’s intention. We investigated the possible explanatory cognitive mechanisms of EDS in bvFTD by relating UB and IB to performance on tests of executive functioning and theory of mind (ToM). Method: This study analyzed retrospective data of 32 bvFTD patients. Data included scores of UB and IB, various executive measures, and ToM assessment using the faux pas test, from which we extracted a mental attribution score. Results: Of the patients, 15.6% and 40.6% exhibited UB and IB, respectively. We conducted an automatic linear modeling analysis with executive and mental attribution measures as predictor variables, and UB and IB sequentially considered as target variables. ToM mental attribution score, visual abstraction and flexibility measures from the Wisconsin Card Sorting Test, and motor sequence performance significantly (corrected ps < .05) predicted IB. No executive or ToM measures significantly predicted UB. Conclusions: These findings reveal a complex interaction between executive dysfunction and mental attribution deficits influencing the prevalence of EDS in bvFTD. Further investigation is required to improve our understanding of the mechanisms underlying these behaviors.