0736 POLYSOMNOGRAHIC FINDINGS IN FIVE PATIENTS WITH EXPLODING HEAD SYNDROME

Exploding Head Syndrome (EHS) attacks are characterized by perception of sudden loud banging noises, occasionally accompanied by the sensation of a flash of light. Although these attacks themselves are usually not painful, it is reported that EHS attacks may precede migraine as auras. EHS is classified as a type of parasomnia in the International Classification of Sleep Disorders (ICSD) 3rd edition and its pathophysiology is still unclear. We describe the polysomnography (PSG) characteristics of EHS patients with special emphasis on respiratory events that were followed by EHS attacks. The subjects were consecutive 20,926 patients who presented sleep and/or wake problems at our sleep center between April 1998 and March 2013. The diagnosis of EHS was based on ICSD-3 criteria. During PSG, we instructed them to ring a bell when they noticed an attack (heard a sound). We found 5 cases (0.17%) with EHS. The mean age (2 men and 3 women) was 64.8 ± 16.4 years. Three of them had otorhinolaryngologic diseases (sudden hearing loss, deflected nasal septum and sinusitis). All five subjects rang the bell for their attacks during PSG. The events occurred during stage N1 and N2. In 2 cases, respiratory events preceded the attacks. In 1 case, respiratory effort related arousal was followed by the attack. In the other 2 cases snoring preceded the attacks. One subject noticed the attack during stage W. Various respiratory events were related to the EHS attacks. A variety of ear dysfunctions or brainstem neural dysfunction during the transition from wakefulness to sleep has been reported as the pathophysiology of EHS. Our PSG findings suggest that checking otolaryngological status on subjects and respiratory events during sleep may be helpful in understanding its pathophysiology and in choosing therapeutic strategies. None.