Gender differences in REM sleep behavior disorder: a clinical and polysomnographic study in China

Objective: Rapid eye movement (REM) sleep behavior disorder (RBD) has been considered a male-predominant parasomnia, and there is little comparative data on potential differences between males and females. Therefore, the aim of our study was to examine and characterize gender difference in RBD. Methods: Ninety patients diagnosed with RBD were consecutively recruited from a sleep medicine clinic. All patients were assessed by a RBD questionnaire and overnight video polysomnography. Demographic, clinical data, presence of dreams and dream-enacting behaviors, sleep parameters and electromyographic (EMG) activity were compared for male and female patients with RBD. Results: Females were significantly younger than males, both in the mean age of RBD onset (45.3 +/- 19.3 vs. 56.2 +/- 14.1; p = 0.027) and the mean age at diagnosis (50.4 +/- 18.2 vs. 61.1 +/- 14.1; p = 0.022). Secondary RBD was 21% in males and 44% in females (p = 0.021). Antidepressant use was more common among females (22%) than males (2%; p = 0.003). There was no significant gender difference in dream content (eg, violent and frightening dreams) of RBD patients. However, females had less dream-enacting behaviors, especially in movement related dreams and falling out of bed. Interestingly, no significant difference was found in the quantification of EMG activity during REM sleep between male and female patients. Conclusions: We found significant gender differences in demographics, associated comorbidities, and dream-related behaviors in patients with RBD. Female RBD patients reported significantly less behavior during dreams, but there was no significant gender difference in EMG activity during REM sleep. (C) 2014 Elsevier B.V. All rights reserved.