Mild behavioural impairment in Parkinson's disease: a systematic review

Behavioural symptoms are common manifestations of Parkinson's disease (PD). Early behavioural symptoms characterisemild behavioural impairment (MBI). The prevalence and intensity of MBI in people with PD (PwP) have been studied acrossvarious cohorts. However, methodological differences have obscured our understanding of MBI in these individuals. Thissystematic review examines and synthesises findings from relevant studies, enhancing understanding of the symptoms andimplications of MBI in PD. Nine studies from five separate research institutions were identified. The conceptualisation ofMBI varied considerably, affecting the reported prevalence rates of MBI in individuals with early-stage PD. Among PwP,MBI was associated higher education and impaired cognition. Affective dysregulation and impulse control disorders wereprimary contributors to MBI; abnormal perception was least contributor. This systematic review underscores the specificcharacteristics and incidence of MBI in early-stage PD. Mood and impulse control disorders are primary concerns associatedwith MBI. Future longitudinal studies are required to clarify the progression of these symptoms and evaluate MBI's potentialas an indicator for PD-related dementia or increased dependency.