Sleep and impulsivity in Parkinson's disease.

Background: Impulsive behavior and poor sleep are important non-motor features of Parkinson's disease (PD) that negatively impact the quality of life of patients and their families. Previous research suggests a higher level of sleep complaints in PD patients who demonstrate impulsive behaviors, but the nature of the sleep disturbances has yet to be comprehensively tested.

Methods: Consecutive idiopathic PD patients (N = 143) completed the Minnesota Impulse Disorder Interview and a sleep questionnaire that assessed sleep efficiency, excessive daytime sleepiness, restless legs symptoms, snoring, dreams/nightmares, and nocturia. Patients were also given a Unified Parkinson's Disease Rating Scale motor examination and they completed cognitive testing.

Results: Impulsive PD patients endorsed more sleep complaints than non-impulsive PD patients. The group difference was primarily attributable to poor sleep efficiency (e.g., greater nocturnal awakenings), p < .01, and greater daytime sleepiness, p < .01, in the impulsive PD patients. Interestingly, restless legs symptoms were also greater in the impulsive PD patients, p < .05. The results could not be explained by medications or disease severity.

Conclusions: Poor sleep efficiency, restless legs symptoms, and increased daytime sleepiness are associated with impulsivity in PD. Longitudinal studies are needed to determine whether sleep disturbances precede impulsivity in PD.