1224 Non 24 Hour Sleep Wake Circadian Rhythm Disorder in a Sighted Patient with Normal Functioning and Intelligence

Abstract

Introduction: We present a rare case of Non 24-Hour Sleep Wake Rhythm Disorder (N24SWD) in a sighted patient with normal functioning and intelligence. N24SWD is rare in non-blind patients. Sighted patients reported in the literature have had significant psychiatric, intellectual, developmental, or medical comorbidities. Report of Case: A 23-year-old male PhD student presented with a 5-year history of difficulty falling asleep and excessive daytime sleepiness. His sleep and wake times were variable, but he averaged 8 hours of sleep in 24 hours. Two years before presenting to our sleep center, he underwent polysomnography and multiple sleep latency testing. It was significant for mean sleep latency of 5.5 minutes and normal AHI. Morning armodafinil was started for possible diagnosis of idiopathic hypersomnolence by his previous sleep specialist. For insomnia, temazepam, zolpidem, and diphenhydramine were prescribed with minimal success. His medical history was significant for mild depression and anxiety, diagnosed three years after the onset of his circadian symptoms. It is currently being managed nonpharmacologically with optimal symptom control. For workup, 20-weeks of sleep diary data was obtained. During this time, he was on leave from school and allowed himself to wake and sleep spontaneously. He also abstained from all pharmacotherapy. The data showed progressive delay in sleep and wake times between 1 to 3 hours, consistent with N24SWD. Two weeks of actigraphy were obtained, confirming these results. He responded well to nightly melatonin. Morning light therapy and armodafinil were also prescribed, which the patient has not yet started. His functioning at his graduate school has significantly improved. Conclusion(s): Unlike many previously reported cases of N24SWD in sighted patients, our patient does not have intellectual and developmental disabilities. His mild depression and anxiety are well-controlled and were perhaps secondary to N24SWD. In previously reported cases, limited or inappropriate exposure to light or other entraining cues was noted, which was not the case in this patient.