Do sleep deprivation and time of day interact with mild obstructive sleep apnea to worsen performance and neurobehavioral function?

STUDY OBJECTIVES: Sleep deprivation, time of day (circadian influences), and obstructive sleep apnea (OSA) all reduce performance and neurobehavioral function. We assessed the interactive effect of sleep deprivation and time of day on performance and neurobehavioral function in subjects with and without mild OSA. METHODS: This was a cross-over study in which 13 subjects with mild OSA and 16 subjects without OSA had performance and neurobehavioral testing after a normal night's sleep and after a night of supervised sleep deprivation. All subjects were studied in the sleep laboratory of a university teaching hospital. Subjects were administered questionnaires to collect demographic, physical, and medical information; completed actigraphy and sleep diaries to estimate prior sleep debt before testing periods; and were tested on the Neurobehavioral Assessment Battery, a personal computer-based driving simulator (AusEd), and the Oxford Sleep Resistance Test to assess performance and neurobehavioral function. RESULTS: Sleep deprivation resulted in poorer driving simulator and neurobehavioral performance for most outcome measures. The worst daytime performance was often seen at 3:00 PM. Subjects with mild OSA were less aware of their sleepiness due to sleep deprivation and, in 1 reaction time task, showed greater impairment than did subjects without OSA at certain times of the day after sleep deprivation. CONCLUSIONS: The results suggest that subjects with mild OSA are not primarily different than subjects without OSA in their response to sleep deprivation or time-of-day influences. Consistent with previous literature, there were clear effects of sleep deprivation and time of day in all subjects. The finding that perception of daytime sleepiness after sleep deprivation was blunted in subjects with OSA compared with subjects without OSA, despite similar performance decrements, warrants further study.