Repetitive behaviors in syndromes associated with frontotemporal lobar degeneration

Background: Repetitive behaviors (RB) are purposeless movements, speech, or routines performed without self-awareness or conscious intent. Objective: The present study aims to investigate the prevalence and longitudinal changes of RB and to assess these symptoms in a large cohort of patients with frontotemporal lobar degeneration (FTLD)-associated syndromes using a newly developed caregiver-based questionnaire. Methods: This was a longitudinal cohort study conducted in tertiary frontotemporal dementia research clinics. A total of 210 FTLD patients were included, 68 of whom had follow-up evaluation. RB were assessed through structured caregiver interviews. Compulsive/impulsive behaviors, stereotypies, and ritualistic behaviors were recorded. Univariate and multiple generalized linear models and generalized linear mixed models were used to estimate predictors and longitudinal changes associated with RB. Results: RB were reported in 71% of patients, showing a progressive increase from the prodromal to moderate dementia stages. Notably, 30% of patients presented RB since the disease onset phase, especially in the form of compulsive/impulsive behaviors. Predictors included male gender, the behavioral variant of frontotemporal dementia and the semantic variant of primary progressive aphasia phenotypes, and higher scores on Frontal Behavioral Inventory scale, part B. A significant increase in total RB was observed in patients reassessed at 8 to 22 months follow-up from baseline (p = 0.0001), especially in the form of stereotypies and ritualistic behaviors. Conclusions: The questionnaire developed in this study effectively captures the prevalence and progression of RB. It could contribute to the standardization of the behavioral assessment in FTLD clinical trials and, consequently, to a deeper understanding of these syndromes.