Results Do Not Establish Causation
“Prior studies reported that EDS was associated with hallucinations in Parkinson’s disease, but we are not aware of other studies that found EDS to be a predictor of future psychotic symptoms,” said Dr. Barrett and colleagues.
“In univariate comparisons, participants with Parkinson’s disease with three or more psychotic events had worse visuospatial function, compared with those with two psychotic events. Considering the greater impairment in visuospatial and visuoperceptive function reported in Parkinson’s disease with visual hallucinations, this association should be evaluated in the future in the PPMI Parkinson’s disease cohort as additional follow-up visits occur.”
The current study’s finding of an association between autonomic dysfunction, RBD, and EDS and baseline Ch4 density in Parkinson’s disease is consistent with a recent analysis that found that the same symptoms were associated with a diffuse malignant subtype of Parkinson’s disease, said the authors. “Our finding that these three nonmotor symptoms are linked to future psychotic symptoms validates the prognostic value of these symptoms in predicting worse outcomes early in disease.”
Evidence does not support a causal relationship between lower Ch4 density and autonomic dysfunction, RBD, and EDS. These four characteristics may be associated with widespread subcortical pathology. “The relationship between this triad of clinical symptoms and lower Ch4 density supports the potential utility of this neuroimaging biomarker to identify a diffuse malignant subtype of Parkinson’s disease and to predict more rapid disease progression,” said Dr. Barrett and colleagues.
—Erik Greb
Suggested Reading
Barrett MJ, Blair JC, Sperling SA, et al. Baseline symptoms and basal forebrain volume predict future psychosis in early Parkinson disease. Neurology. 2018 Apr 4 [Epub ahead of print].
Bohnen NI, Teipel SJ. Cholinergic forebrain density loss in Parkinson disease: More than just cognitive changes. Neurology. 2018 Apr 4 [Epub ahead of print].
