Gonadal steroids and auditory evoked responses during menstrual cycle

Introduction: Brainstem Auditory Evoked Potentials (BAEP) have been subject to effect by many physiological restrictions. The gonadal steroids may be one of them, but few electrophysiological studies have documented any evidence. This study was carried out to record the auditory evoked response in females of reproductive age group in different phases of the menstrual cycle. Materials and Methods: This was an observational cross sectional study. The BAEP were recorded in 50 subjects (age 17-37 years, no h/o hormonal therapy) during three different phases of the same menstrual cycle. The peak latencies of the waves, I, II, III, IV and V, IPL I-III, I-V and III-V and the amplitude ratio, V/I were recorded and statistically analyzed. Results: A statistically significant increase in the latencies of the waves, I-V in the mid cycle coinciding with high estrogen level was observed. A statistically significant decrease in the mid-luteal phase was observed which corresponds to high progesterone levels. IPL did not show any significant change in the said phases. Similarly, no significant changes in the menstrual phase was seen for all variables. Conclusion: The results point out the BAEP changes in the mid follicular and the mid luteal phases of the menstrual cycle suggestive of effects of oestrogen and progesterone.