The effect of experimentally induced sleep fragmentation and estradiol suppression on neurobehavioral performance and subjective sleepiness in premenopausal women.

Study Objectives: Menopause is associated with nighttime sleep fragmentation, declining estradiol, and impaired cognition. In a model of pharmacologically induced estradiol suppression mimicking menopause, we examined the impact of menopause-pattern sleep fragmentation on daytime neurobehavioral performance and sleepiness in premenopausal women.

Methods: Twenty premenopausal women completed two five-night inpatient studies in the mid-to-late follicular phase (estrogenized) and after pharmacological estradiol suppression (hypo-estrogenized). During each study, participants had an uninterrupted 8-hour sleep opportunity for two nights, followed by three nights where sleep was experimentally fragmented to mimic menopause-pattern sleep disturbance, and during which the sleep opportunity was extended to prevent shortening of the sleep duration. Neurobehavioral performance and subjective sleepiness were measured using the Psychomotor Vigilance Task and Karolinska Sleepiness Scale (KSS).

Results: Compared to unfragmented sleep, sleep fragmentation increased attentional lapses (+ 0.6 lapses, p < .05), slowed reaction time (+ 9.4 milliseconds, p < .01), and increased daytime sleepiness (+ 0.5 KSS score, p < .001). Estradiol suppression increased attentional lapses (+ 0.8; p < .001) and reaction time (+ 12.3, p < .01) but did not significantly affect daytime sleepiness. The effect of sleep fragmentation on neurobehavioral performance differed by estradiol state, such that the adverse effects of sleep fragmentation on attentional lapses (+ 0.9, trend p = .06) and reaction time (+ 15, p < .05) were observed only when estrogenized.

Conclusions: Menopause-pattern sleep fragmentation and estradiol suppression worsened neurobehavioral performance and daytime sleepiness, even while sleep duration was not reduced. The adverse effects of sleep fragmentation in the context of an adequate sleep duration highlight the importance of sleep continuity as a vital aspect of good sleep health.