Discrepancy in improvement of hearing loss between left and right ears after postmenopausal hormone therapy

Physiological levels of estrogen would seem to have a possible protective effect on hearing function and estrogen replacement therapy may delay hearing loss in menopausal women. Treatment of healthy menopausal women with Tibolone for 6 months resulted in improvement in audiometry results at low frequencies which was more prominent on the right side. The reason of better improvement on the right side is not known. There might be some other factors modifying the condition or effect of the drug such as laterality. There might be hearing lateralization in menopausal women. Especially significant improvement on right ear might be explained by differences in distribution of estrogen receptor (ER) in the ear, in another words lateralization of ER concentration. ER-α and -β might be more dense in the right ear, so give better response to estrogen treatment. Another reason might be difference in bone mineral density of sides of body which is lower on the right side. Similarly lower bone mineral density right ear bones would cause better response to estrogen therapy and better improvement in audiometry results on that side.