Brainstem Auditory Evoked Responses in Different Phases of Menstrual Cycle

Abstract

Background and Objectives: Brainstem Auditory Evoked Potentials (BAEP) show variations with age, sex and other physiological factors. The gonadal steroids may also alter the neuronal functioning, but an electrophysiological evidence is sparse. This study was undertaken to analyze the auditory evoked response in females of the reproductive age group during four different hormonal states of the menstrual cycle. Methods:This was a prospective, single centered, longitudinal study. The waves of BAEP were recorded in 50 young females (of the ages of 19-36 years, who used no hormonal therapy) during four 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 significant increase in the peak latencies of the waves, I-V in the oestrogen peak mid cycle was observed, while a significant decrease in the progesterone peak mid-luteal phase was observed. However, IPL did not show any statistically significant change in the above two phases. All the parameters did not show significant changes in the menstrual and the premenstrual phases. Interpretation and Conclusion:The results indicated the BAEP changes in the mid follicular and the mid luteal phases of the menstrual cycle, thus suggesting the changes which were attributable to oestrogen and progesterone. INTRODUCTIONThe hormonal changes that occur in a short time span during a menstrual cycle, promote modifications all over a woman's body, with physical and emotional manifestations being frequently observed. There is a controversy over how the hormonal conditions influence the cerebral electrophysiology. Auditory Evoked Potentials (AEP) may serve as a non-invasive clinical tool in characterizing the electrophysiological phenomena of neural excitation, conduction and transmission across the auditory pathway.Ovarian hormones have long been known to affect the sensory information processing in the brain. The auditory perception being one of the sensory modalities, it also gets influenced by the sex hormones. Clinical observations strongly suggest that the changes in the gonadal function modify the auditory, olfactory and the taste thresholds [1]. The thresholds for touch, two point discrimination and the perception of light have also been found to vary during the follicular and the luteal phases of the menstrual cycle [2]. Variations in the different hormonal levels, especially in the levels of oestrogen and progesterone across the menstrual cycle, have been proposed to be responsible for the latency changes of the waves of the auditory evoked potentials [3].Several researchers have reported that the changes in the auditory acuity occur during the menstrual cycle. In an attempt to specify the critical functional components which are involved in the menstrual fluctuations, the evidence of a better performance in a variety of tasks at mid-cycle, was obtained in a study. It was also shown that some tasks were particularly s...

Role of sex hormones produced during menstrual cycle on brainstem encoding of speech stimulus

“…Similar results were obtained for ABR, MLR and LLR changes during menstrual cycle [1,4,5]. This could be because of the differences in levels of female sex hormones.…”

“…Estrogen enhances the secretion of inhibitory neurotransmitter-GABA during proliferative phase leading to prolongation of latencies. Progesterone decreases the estrogen-potentiated GABA release leading to decrease in latency during mid-luteal phase [1,12].…”

“…The changes in ovarian hormones during menstrual cycle are reported to influence the processing of sensory information in the brain [1]. There are studies which report that changes in female hormones can affect auditory, olfactory and taste sensations [2].…”

“…They also report that the inter-peak latencies are prolonged during mid-cycle. Mann et al [1] studied MLR and LLR and reported that menstrual cycle affects the central auditory neural conduction time due to differences in the levels of hormones during menstrual cycle. The varied levels of estrogen and progesterone during menstrual cycle could be the reason for latency and amplitude changes in waves of auditory-evoked potentials [10].…”

Brainstem auditory evoked responses in severely malnourished children

“…We took average of the mean value of latencies of both ears as there is insignificant difference between the latencies of both ears. 5 Data was collected by the investigators, compiled and analysed using descriptive analysis using Microsoft Excel ™ and statistical tests. Student t test was used for analysis.…”