Comparison of Auditory Brainstem Evoked Responses between Migraine Patients and Healthy Controls: A Cross-sectional Study

Introduction: Migraine is a complex neurological disorder associated with noise hypersensitivity most evident during attacks (ictal), however persistent during the post-attack (interictal) period as well. Previous studies on cortical auditory potentials have established abnormal sensory processing during the interictal phase but findings related to subcortical (brainstem) involvement remain inconclusive. Aim: To compare Wave I and Wave V amplitude of Auditory Brainstem Evoked Responses (ABER) between migraineurs during the interictal phase and healthy controls at 40-, 50-, and 60-dB above Sensation Level (SL) for both ears. Materials and Methods: The present study was a crosssectional study conducted at the Department of Physiology, SMS Medical College, Jaipur, Rajasthan, India. Thirty-five diagnosed migraine patients during the interictal phase from the Neurology Outpatient Department (OPD) and 35 age and gender-matched healthy controls were enrolled. The Wave I and V amplitude (µV) were measured, at 40-, 50-, and 60-dB above SL bilaterally, in both groups. Statistical Package for Social Sciences (SPSS) software version 25 was used to analyse the results and an unpaired student’s t-test was employed for comparison in a side-specific manner. The significance level was assigned at a p-value <0.05. Results: The amplitudes of Wave V at 50-db SL (p-value: left ear=0.03, right ear=0.01) and 60-dB SL (p-value: left ear=0.005, right ear=0.013) were significantly higher among migraineurs during interictal phase than their matched controls. The amplitude difference for Wave I was statistically insignificant between the two groups at all recording intensities. At 40 dB SL, both Wave I (p-value: left ear=0.68, right ear=0.63) and Wave V (p-value: left ear=0.30, right ear=0.50) amplitudes did not exhibit any significant difference in results between migraine patients and healthy controls. Conclusion: The subcortical auditory dysfunction is significant for brainstem nuclei beyond the cochlear nucleus (peripheral auditory neurons) at higher intensities, indicating a more noticeable central processing disorder. This could eventually lead to irreversible auditory pathway damage, ABER can be utilised as a tool for early detection and localisation of the insult, providing an opportunity for early intervention and use of prophylactic measures.