Quantitative and Comparative Analysis of Dream Content in Parkinson's Disease Patients Undergoing Deep Brain Stimulation: A Pilot Study.

Abstract

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra, resulting in motor and nonmotor symptoms including diminished sleep quality and altered dream content. The neurocircuitry underlying the latter remain poorly understood. The goal of this study is to assess the influence of deep brain stimulation (DBS) on sleep quality and, for the first time, dream characteristics. Ten PD patients undergoing bilateral DBS of the subthalamic nucleus prospectively completed questionnaires evaluating PD parameters, sleep quality, dream/nightmare frequency and content, preoperatively and 6-month post-DBS recovery. Participant quality of life and symptom severity improved following DBS. Participants reported sleeping for 5.8 hours per night, with an average of 3.2 interruptions per night, which did not change significantly after surgery. Prior to surgery, participants reported symptoms of rapid eye movement sleep behavior disorder, with no difference in sleep quality after DBS. Dream and nightmare frequency did not change significantly following DBS. Dream content was coded and analyzed using the Hall/Van de Castle System demonstrating a significant reversal of dream content featuring Aggressor and Negative Emotions (P < 0.01) and an increase in themes of Befriender, Physical Aggression, Familiar Setting, and Dreamer-Involved Success (P < 0.01). When analyzing dreams with a least one, a significant decrease was found for Failure (P < 0.05). This pilot study provides novel insights into the effects of DBS on dream content in PD patients. DBS may influence and even reverse PD-altered dream content potentially through modulation of brain networks involved in dream generation.