Multimodal assessment of sleep-wake perception in insomnia disorder.

Insomnia disorder is a prevalent health problem. The primary diagnostic criterion is a subjective complaint about reduced quantity or quality of sleep, which is often not observed in objective sleep measurements. Here we show that patients with insomnia disorder, characterized by substantial subjective sleep complaints, did not differ on objective measures of sleep continuity, sleep architecture, spectral power, spectral slope, and phase-amplitude coupling of slow oscillatory and spindle activity. Perception of wakefulness following serial awakenings from NREM sleep was frequent in both patients and controls, with no significant group difference. High frequency spectral power, as an index of cortical arousal prior to awakening, but not standard measures of sleep, predicted the perception of wakefulness across groups, possibly related to physiological wake-like activity during sleep. Our results support the notion that sleep-wake regulatory systems and direct sleep-wake perception are often intact in patients with insomnia disorder. These results propose empirical support for cognitive behavioral therapy for insomnia as the first-line treatment.