77 Symptoms of RBD and Cognitive Performance in Healthy Young Adults

Abstract

Objective:

REM sleep behavior disorder (RBD) is a parasomnia characterized by vivid dreams and motor behavior such that people appear to “act out their dreams.” These are sudden and often violent bodily movements such as punching or kicking, or vocalizations such as laughing or shouting. RBD is mostly associated with the older adult male population. However, recent studies show that RBD and REM sleep without atonia (RSWA) also occur in other populations, including women, children, and adolescents. Given the prodromal period before an individual can develop the classic symptoms of RBD and that RBD is not just limited to older adult males, it is important to study subclinical features of RBD. RBD is a parasomnia and poor sleep is well known to affect cognitive domains. Additionally, RBD is separately shown to negatively affect cognition in older adults. Given these connections, the association between RBD symptoms and cognition among young adults warrants further study. The purpose of this study was to evaluate the association between RBD symptoms and cognitive domains, specifically attention, processing speed, executive function, and working memory.

Participants and Methods:

University students from the Bronx, NY (N=50, mean age = 19.8, female = 78.4%) completed the REM Sleep Behavior Disorder Screening Questionnaire (RBDSQ). Estimated intellectual ability was assessed using the Wechsler Test of Adult Reading (WTAR). Cognitive assessment included the Delis-Kaplan Executive Function System (D-KEFS) Color-Word Interference Test (attention and executive function) and the Cogstate battery (Groton Maze Learning Test (executive function), Chase Test (processing speed), Identification Test (attention), One Back Test (attention), and Two Back Test (working memory)). Psychosocial assessment included the Perceived Stress Scale (PSS), Beck Depression Inventory-II (BDI-II), and Beck Anxiety Inventory (BAI).

Results:

A series of general linear models were used to determine the relationship between RBD symptoms and cognition. Race/ethnicity, depressive symptoms, and estimated intellectual ability were included as covariates. Using a cutoff score of five (range: 0-13) on the RBDSQ, the ANCOVAs determined that there was no association between RBD symptoms and the cognitive domains of attention, processing speed, executive function, and working memory. However, there was a trend for attention as measured by the Identification task (F(1,41) = 3.85, p = 0.057). Interestingly, Pearson’s chi-square test revealed that the relationship between depressive symptoms and RBD symptoms was significant (x2 = 6.87, p = 0.009). Those who had high RBD symptoms were more likely to have high depressive symptoms.

Conclusions:

Our analyses indicated that in healthy young adults, RBD symptoms are not associated with the cognitive domains of attention, processing speed, executive function, or working memory. However, there may be a trend for attention, which warrants further research with a larger sample size. Of interest, young adults with RBD symptoms were more likely to have clinically significant depressive symptoms. Given that RBD in older adults is associated with incident dementia with Lewy body and Parkinson’s disease, which are associated with cognitive decline and depression, further work is necessary to explore the mechanisms of this connection as well as the development of clinical disorders.