MONDAY, Feb. 15 (HealthDay News) -- Patients with severe obstructive sleep apnea (OSA) report fewer nightmares, according to a study in the Feb. 15 issue of the Journal of Clinical Sleep Medicine.
James F. Pagel, M.D., from the University of Colorado, and Carol Kwiatkowski, Ph.D., from the Rocky Mountain Sleep Disorders Center, both in Pueblo, surveyed dream and nightmare recall frequency among 393 individuals with OSA undergoing clinical polysomnography. The mean Apnea-Hypopnea Index (AHI) score was 34.9, indicating a high frequency of severe OSA.
The researchers found that individuals with more severe OSA reported significantly lower nightmare frequency (less than once a month). Nightmare recall frequency fell linearly with increasingly severe OSA. In contrast, dream recall frequency was not associated with the severity of OSA. OSA severity was not associated with nightmare recall frequency in patients treated with continuous positive airway pressure.
"Patients with higher AHI report a lower nightmare frequency, indicating that significant OSA suppresses the cognitive experience of nightmare recall," Pagel and Kwiatkowski conclude. "Depressed nightmare recall may occur secondary to the rapid eye movement sleep suppression [known] to occur in patients with significant OSA."
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