Brainstem auditory evoked responses in newly diagnosed untreated hypothyroid females

Abstract

Background: Hypothyroidism stands as a prevalent endocrine disorder, affecting females more than males. Among the array of otolaryngological manifestations linked with thyroid dysfunctions, sensorineural hearing loss emerges as the most frequently encountered issue. Evoked potentials serve as valuable tools extensively utilized in studying brain disturbances. Among these evoked potentials, Brainstem Auditory Evoked Response (BAER) stands out as one of the methods employed for assessing the pathology within the brainstem auditory pathway. Aims and Objectives: The aim of the study is to evaluate the auditory sensory process in the brainstem using BAERs in newly diagnosed untreated hypothyroid individuals. Materials and Methods: Forty newly diagnosed untreated hypothyroid females of 20–50 years were taken as cases and forty age-matched females were considered controls. The hypothyroidism was diagnosed by estimating the serum levels of free T3 (fT3), free T4 (fT4), and thyroid-stimulating hormone. After getting informed written consent, the absolute latencies and interpeak latencies of BAER were recorded using NeuroPerfect EMG 2000 system with installed BAER in the research laboratory, Department of Physiology, Coimbatore Medical College, Coimbatore, and the data were analyzed by student unpaired t-test. Results: The absolute latencies I, III, V and interpeak latencies I- III, III- V, I – V were significantly prolonged in newly diagnosed untreated hypothyroid females (P < 0.0001) and also there was a direct correlation between thyroid profile changes and the BAER latencies. Conclusion: The results of the present study suggest that hypothyroidism impacts the auditory pathway diffusely and early identification of auditory pathway involvement in thyroid hormone deficiency can be achieved using BAER. Prolonged BAER latencies observed in newly diagnosed untreated hypothyroid females are attributed to defective myelination of neural pathways and diminished cerebral metabolism. Hence, integrating BAER recordings into screening protocols could enhance the accuracy and early assessment of neurological involvement in hypothyroid females.