Effect of different phases of menstrual cycle on brainstem auditory evoked response.

Introduction: The change in the hormonal levels during the three phases of menstrual cycle, namely, menstrual phase (hormonal withdrawal), proliferative phase (estrogen peak), and secretory phase (progesterone peak), influences the conduction velocities in the central auditory pathways. Variable findings of brainstem auditory evoked response (BAER) have been reported during different phases of menstrual cycle by different researchers. Aim: To study the effect of different phases of menstrual cycle on BAER. Methodology: A prospective observational study on 80 audiometrically normal, healthy, eumenorrheic female students in age group of 18-24 years was done at a medical college of northern India. BAER was recorded across the three phases of the menstrual cycle, i.e., menstrual phase (day 1-3), proliferative phase (day 10-12), and secretory phase (day 20-22). Recordings of peak latencies, interpeak latencies, and amplitude of waves of BAER were taken and statistically analyzed. Results: In this study, significant decrease in the latencies of wave III, wave V, and interpeak latency I-III and a trend of decrease in latencies of wave I and interpeak latency I-V (which was statistically insignificant) were observed in proliferative (estrogen peak) phase as compared to menstrual and secretory phase. However, there was no statistically significant difference found in the amplitude of waves of BAER during all the three phases of menstrual cycle. Conclusion: The hormonal changes during different phases of menstrual cycle do seem to influence BAER. [ABSTRACT FROM AUTHOR]