Click-evoked otoacoustic emissions: response amplitude is associated with circulating testosterone levels in men

In rhesus monkeys, the magnitude of the cochlear response to auditory stimuli (click-evoked otoacoustic emissions, [CEOAEs]) is correlated with seasonal changes in circulating testosterone levels. The present study investigated the association between circulating testosterone and CEOAE production in men. CEOAEs were measured in 67 men and 37 women, and saliva was analyzed to quantify bioavailable testosterone. A sex difference in CEOAE response amplitude was found, confirming previous reports. In agreement with the monkey work, seasonal variation in the CEOAE response amplitude also was identified. CEOAEs were greater in summer and fall, the seasons that showed the lowest levels of circulating testosterone. On an individual basis, men who had higher levels of testosterone at the time of assessment exhibited smaller CEOAE response amplitudes. These findings support previous data from rhesus macaques and are consistent with the prospect of an activational effect of testosterone in the human cochlea.