The frequency of observer dreams in Parkinson's disease patients and relation with clinical variables.

Abstract

Contrary to common believe, some studies have reported the existence of observer dreams, in which the dreamer does not intervene. Parkinson's disease (PD) patients frequently report alterations in dream content, but nothing is known regarding this feature. Our objective was to assess the frequency of observer dreams in PD and correlation with clinical features. Dreams reports were collected from a 15-day diary and classified in non-observer and observer dreams. Patients were assessed for disease related variables, including motor and non-motor dysfunction. We collected a total of 120 dreams from 24 PD patients. Eleven had at least one observer dream. There was a total of 14 (11.7%) observer dreams, which is line with studies performed in younger patients. The relative frequency of observer dreams was negatively and significantly associated with motor function scores, bradykinesia in particular. This hints at a complex relation between dream content and neurodegeneration of motor function circuits.