Abstract Objective Rapid eye movement sleep behavior disorder (RBD), a prodromal synucleinopathy that precedes Parkinson’s disease and related dementias, can present with subtle cognitive difficulties. However, limited data on longitudinal cognitive change in individuals with RBD has been presented. Method The present analysis aimed to quantify cognitive change across approximately one year in a cohort of individuals with polysomnogram-confirmed RBD (n=60 from the North American Prodromal Synucleinopathy Consortium), using previously validated standardized regression-based change scores developed in cognitively unimpaired participants from the National Alzheimer's Coordinating Center. Results In the entire sample, the mean change scores across the 13 cognitive scores ranged from -.37 to .04 compared to demographically matched peers. One-sample two-tailed t-tests revealed a significant decline on 1 of the 13 cognitive scores, category fluency for vegetables (p=.01), with small to medium effect size (d=.34). Although not statistically significant, subtle declines were also present on measures of attention (Number Backward, p= .06, d=.21), memory (Craft Story Delayed Recall, p=.18, d=.17), processing speed (Trail Making A, p=.22, d=.16), and visuospatial skills (Benson Copy, p=.23, d=.16). Conclusion Overall, during this prodromal period, individuals with RBD appear to remain largely cognitively stable over approximately one year. Nonetheless, continued tracking of these individuals may provide important prognostic information and/or endophenotyping of patients. These results also have potential implications for clinical management and the design of clinical trials in RBD.
Khattab et al. (Fri,) studied this question.
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