Auditory brainstem response in postmenopausal women treated with hormone replacement therapy: A pilot study

Objective: To research the nongenital audiological target for gonadal stero ids in postmenopausal women who are treated with hormone replacement therap y. Design: Fifty postmenopausal volunteers were treated with hormone replac ement therapy. Women with an intact uterus had sequential weekly transderma l estradiol plus nomegestrole acetate 5 mg orally for 12 days per month or a continuous daily oral dose of conjugated estrogen 0.625 mg and medroxypro gesterone acetate 5 mg tablet. Eighteen surgically postmenopausal women rec eived a weekly transdermal estradiol system. Twenty-five postmenopausal vol unteers-5 with a natural menopause and 10 with a surgical menopause-and 20 premenopausal normally cycling women were used as a control group. Each wom an performed auditory brainstem response by auditory-evoked potentials for waves I, III, and V and for interpeak I-III, I-V, and III-V intervals, Resu lts: Women who were treated with hormone replacement therapy showed wave la tencies and interpeak latencies shorter than those for postmenopausal women in the control group (I, 0,05), overlapping those of the premenopausal wom en (p > 0.05). Women who were treated with estrogen replacement therapy sho wed shorter time latencies than those treated with combined hormone replace ment therapy p, I 0.05), Conclusions: Our data suggest that fluctuating hor mone levels cause changes in auditory brainstem response waves, even if the exact mechanism of activity of the gonadal steroids is not clear, However, we believe that estrogen may influence the neuronal plasticity, the metabo lic levels of neurotransmitters, and thus the neuronal conduction time into the audiological system. (Menopause 2000,7:178-183. 2000, The North Americ an Menopause Society.)