Rapid Eye Movement Sleep Behavior Disorder-like Symptoms Due to Arousal Responses Associated with Severe Obstructive Sleep Apnea-hypopnea

A 78-year-old man suspected of having α-synucleinopathies received a high score on a validated questionnaire for rapid eye movement (REM) sleep behavior disorder (RBD). Although he did in fact have unpleasant dreams and vigorous behaviors, polysomnography (PSG) found only obstructive sleep apnea-hypopnea (OSAH). The RBD-like symptoms corresponded with arousal responses, namely augmented inspiratory effort and leg movements, to his frequent apnea-hypopnea events during REM sleep. Thus, severe OSAH might cause RBD-like symptoms. PSG can discriminate real RBD from RBD-like symptoms associated with severe OSAH and therefore may be essential for determining an appropriate course of treatment in certain patients.