Modulation of the sleep electroencephalogram by estrogen replacement in postmenopausal women

We performed an examination of the effects of estrogen replacement on the sleep electroencephalogram in postmenopausal women.

A sleep electroencephalogram was recorded in 11 postmenopausal women with and without estrogen administered by skin patch (50 microg of estradiol per day).

Estrogen enhanced rapid-eye-movement sleep (50 +/- 4 vs 39 +/- 5 minutes, P <.05) and reduced time awake (12 +/- 5 vs 20 +/- 6 minutes, P <.05) during the first 2 sleep cycles. The normal decrease in slow-wave sleep and delta activity from the first to the second cycle (in percentage from the first cycle) was restored by estrogen (-56% +/- 9% vs -5% +/- 14% and -20% +/- 6% vs -2% +/- 5%; P <.05, respectively). Sigma electroencephalographic activity was increased by estrogen from the first to the second half of the night but decreased during baseline.

Estrogen treatment after menopause can help to restore the normal sleep electroencephalogram pattern, which in turn might contribute to improved cognitive functioning.