Prodromal characteristics of Dementia with Lewy Bodies: baseline results of the Memento nationwide cohort

Background: Isolated subjective cognitive impairment (SCI) and mild neurocognitive impairment (MCI) are prodromal phase of dementia with Lewy bodies (DLB). Memento is a nationwide study of patients with SCI and MCI with clinic, neuropsychology, biology and brain imaging data. We aimed to compare SCI and MCI patients with symptoms of prodromal DLB to others in this study at baseline. Methods: Participants of the French Memento cohort study recruited for either SCI or MCI. Among them, 892 were included in the Lewy sub-study, designed to search specifically for symptoms of DLB. Probable prodromal DLB group (pro-DLB) was done using a two-criteria cut-off score among the four core clinical features of DLB. This Pro-DLB group was compared to two other groups at baseline: one without any core symptoms (NS group), and the one with one core symptom (1S group). A comprehensive cognitive battery, questionnaires on behavior, neurovegetative and neurosensory symptoms, brain 3D volumetric MRI, CSF, FDG PET and amyloid PET were done. Results: The Pro-DLB group comprised 148 patients (16.6%). This group showed more multidomain (59.8%) MCI with slower processing speed and a higher proportion of patients with depression, anxiety, apathy, constipation, rhinorrhea, sicca syndrome, and photophobia. The Pro-DLB group had isolated lower P-Tau and on brain MRI widening of sulci including fronto-insular, occipital, and olfactory sulci (FDR corrected). Conclusions: Patients with symptoms of prodromal DLB are cognitively slower, with more behavioral disorders, autonomic symptoms, and photophobia. Biomarkers confirmed the non-Alzheimer profile. The occipital, fronto-insular, and olfactory bulb involvement on brain MRI was consistent with symptoms and known neuropathology. The next step will be to study the clinical, biological, and imaging evolution of these patients. Trial registration: Clinicaltrials.gov, NCT01926249 .