Question

Question: What proportion of people with polysomnogram-diagnosed idiopathic rapid eye movement (REM) sleep behaviour disorder (iRBD) report RBD among their first-degree relatives compared with controls?

Population: In total, 316 people with iRBD and 316 age-matched and sex-matched controls without iRBD were present. People with iRBD met International Classification of Sleep Disorders criteria of having enhanced REM muscle tone on a polysomnogram, with a history of dream-enactment or complex behaviours during REM sleep. Controls included those with other sleep conditions (n=206) and those without sleep disorders (n=110). The absence of RBD was confirmed by a polysomnogram for all controls with other sleep conditions and 41 controls without sleep disorders.

Setting: Twelve international RBD study group centres; time period not stated.

Assessment: Participants completed a self-report questionnaire assessing demographic, medical history and lifestyle factors and including a single question to screen for the presence of RBD in family members. This question was “Do (or did) any of your family members ‘act out’ their dreams at night? (eg, punching, kicking, or flailing during sleep while dreaming).” Responses options were ‘yes’ …