REM sleep behavior disorder (RBD), excessive daytime sleepiness (EDS), and a high burden of autonomic symptoms are associated with increased risk of future psychotic symptoms in patients with Parkinson’s disease, according to research published online ahead of print April 4 in Neurology. These symptoms also correlate with low density of the cholinergic nucleus 4 (Ch4) of the basal forebrain.
Data From the Parkinson’s Progression Markers Initiative
Parkinson’s disease psychosis indicates advanced disease and is associated with dementia and increased mortality. Research indicates that degeneration of the nucleus basalis of Meynert is characteristic of Parkinson’s disease and Parkinson’s disease dementia, but this brain region is difficult to measure with MRI because of its size. It is possible, however, to measure Ch4, which incorporates the nucleus basalis of Meynert.
Matthew J. Barrett, MD, Assistant Professor of Neurology at the University of Virginia in Charlottesville, and colleagues studied a cohort of patients with de novo Parkinson’s disease to identify baseline clinical risk factors for future psychotic symptoms and to assess the relationship between baseline Ch4 density and future psychotic symptoms. All participants were untreated at baseline and had enrolled in the Parkinson’s Progression Markers Initiative (PPMI), a prospective, longitudinal, observational study.
Physicians assessed participants with the Movement Disorders Society-Unified Parkinson Disease Rating Scale (MDS-UPDRS) at each visit. Item 1.2 assesses hallucinations and psychosis during the previous week. The investigators considered any score above 0 on this item to indicate the presence of psychotic symptoms.
Investigators evaluated patients’ autonomic symptoms with the Scales for Outcomes in Parkinson’s Disease-Autonomic (SCOPA-AUT) and administered the RBD screening questionnaire and the Epworth Sleepiness Scale. They determined the density of each participant’s basal forebrain using brain MRI sequences that they obtained from the PPMI database.
Ch4 Density Could Predict Psychotic Symptoms
The investigators included 423 participants in their analysis. The population’s mean age at enrollment was approximately 61.5, and about 35% of the population was female. Mean disease duration was 0.57 years. The population’s median number of clinical visits was 11, and the median last visit occurred at 54 months after baseline.
In all, 138 participants (32.6%) reported psychotic symptoms at least once, and 84 (19.9%) reported them more than once. Dr. Barrett and colleagues identified 17 patients who, having once reported psychotic symptoms, reported these symptoms at each subsequent visit. Among patients who reported psychotic symptoms, approximately 79% reported them at only one visit.
The investigators categorized patients into three groups according to the number of psychotic events. The groups included participants with no psychotic events, those with one psychotic event, and those with two or more psychotic events.
