Cochlear and brainstem auditory responses in patients with generalized epilepsy A cross-sectional studyRajeev Sharma, Smily Goyal, Ratul Dey, Ramandeep Singh Dang.
Background: Epilepsy being a neurological disorder is characterized by excessive abnormal discharge in neurons of brain. Such abnormal activity rapidly engages many cortical and subcortical structures. As a result, this could influence auditory information processing of neuronal pathways in brainstem.
Aims and Objectives: The objectives of the study were (1) To assess the cochlear responses transient evoked otoacoustic emissions (TEOAEs) in newly diagnosed drug-naive patients of epilepsy and (2) To assess the brainstem auditory evoked responses (ABR) in newly diagnosed drug-naive patients of epilepsy.
Materials and Methods: The study was done in the department of audiology in a tertiary care institute. Three audiological tests, i.e., pure tone audiometry (PTA), auditory brainstem evoked responses (ABR), and TEOAEs were recorded on 30 patients in the age group of 1545 years diagnosed with epilepsy and 30 age- and gender-matched controls.
Results: All the participants chosen for the study were having normal hearing thresholds bilaterally as confirmed by PTA (air conduction thresholds below 25 dB HL across the audiometric frequencies of 250 Hz8000 Hz). The absolute latency values of ABR were prolonged in patients of epilepsy (P < 0.05). The difference in interpeak latencies was found to be statistically non-significant. The amplitude values for waves III and V of ABR were reduced in epileptics (P < 0.05). The TEOAEs recorded in these patients of epilepsy showed no significant change in amplitude, noise floor, and signal-to-noise ratio.
Conclusion: The findings of this study suggest that the epileptic patients have delayed absolute peak latencies and decreased amplitudes of waves III and V, indicating the possible involvement of lower brainstem due to seizure activity. However, this study also suggests that epileptic seizure is less likely to result in any alteration at the level of outer hair cells.
Key words: Epilepsy; Auditory Brainstem Evoked Response; Hearing Threshold; Absolute Latency