Impulsivity Trait Profiles in Patients With Cerebellar Ataxia and Parkinson Disease

Background and Objectives: Individuals with cerebellar ataxia (CA) can develop impulsive behavioral symptoms, often resulting in negative interpersonal consequences, detrimentally impacting their quality of life. Limited evidence exists concerning impulsivity in CA and its associated behavioral changes. We assessed impulsive traits in CA using the Barratt impulsivity scale (BIS-11) and compared them with those of Parkinson disease (PD), in order to investigate the differences in the impulsive trait profiles between CA and PD. Methods: We conducted a dual-center cross-sectional study with CA and PD subjects enrolled through consecutive sampling from movement disorders clinics at Columbia University Medical Center and Vanderbilt University Medical Center, respectively. Age-matched controls were recruited at the respective institutions. Participants were excluded if they had prior or comorbid neurological and psychiatric diseases known to be associated with impulsivity. All subjects completed the BIS-11 questionnaire as a measure of impulsive traits. We used a general linear model and a least absolute shrinkage and selection operation regression to compare the total, subscale, and individual items of the BIS-11 scores between groups. Subgroup analyses were performed to isolate cerebellar contributions to impulsivity from potential effects of extracerebellar pathology and dopaminergic dysfunction or medications. Results: A total of 190 participants: 90 age-matched controls, 50 CA, and 50 PD participants completed the assessments. Persons with CA reported 9.7% greater BIS-11 scores than controls ( p < 0.001), while persons with PD participants reported 24.9% higher than controls ( p < 0.001). In CA, the most impacted domain of impulsivity was non-planning. In contrast, persons with PD noted greater impulsivity across the non-planning, attentional, and motor domains. Discussion: Impulsivity in CA is uniquely driven by the non-planning trait, unlike in PD. This suggests that the cerebellum and basal ganglia may differentially govern impulsive behaviors with the cerebellum contributing to the brain circuitry of impulsivity in a domain-specific manner.