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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.

International audience; Recruitment of executive attention is normally associated to a subjective feeling of mental effort. Here we investigate the nature of this coupling in a patient with a left mesio-frontal cortex lesion including the anterior cingulate cortex (ACC), and in a group of comparison subjects using a Stroop paradigm. We show that in normal subjects, subjective increases in effort associated with executive control correlate with higher skin-conductance responses (SCRs). However, our patient experienced no conscious feeling of mental effort and showed no SCR, in spite of exhibiting normal executive control, and residual right anterior cingulate activity measured with event-related potentials (ERPs). Finally, this patient demonstrated a pattern of impaired behavior and SCRs in the Iowa gambling task-elaborated by Damasio, Bechara and colleagues-replicating the findings reported by these authors for other patients with mesio-frontal lesions. Taken together, these results call for a theoretical refinement by revealing a decoupling between conscious cognitive control and consciously reportable feelings. Moreover, they reveal a fundamental distinction, observed here within the same patient, between the cognitive operations which are depending on normal somatic marker processing, and those which are withstanding to impairments of this system.