No abstract

Background: Widespread metabolic derangements in overt hypothyroidism have also been suggested to involve adult human brain with the involvement of cochlea and other inner ear structures. More interestingly, abnormal electrophysiological alterations in patients with normal hearing have also been documented. Aims and Objectives: This study is an attempt to detect auditory pathway dysfunctions by brainstem auditory evoked potential (BAEP) tests in overt hypothyroidism patients without clinical evidence of hearing defects. Materials and Methods: BAEP was performed in 25 female patients with overt hypothyroidism in the age-group of 30-50 years and 25 age-matched healthy females. BAEP absolute latencies I, II, III, IV and V, interpeak latencies (IPLs) I-III, III-V and I-V and BAEP amplitudes of wave I, wave V and amplitude ratios were compared and analyzed in the two groups by unpaired t-test. Statistical significance was considered at P < 0.05. Results: BAEP responses revealed statistically significant prolongation of mean absolute latencies (I, III and V) as compared to controls (P < 0.05) (both the ears) by unpaired t-test. IPLs prolonged too with statistical significance for I-V IPL prolongation (P < 0.05). Furthermore, wave V amplitude was found to be reduced in overt hypothyroidism with statistical significance (P < 0.05). Conclusion: BAEP documents abnormal alterations in patients with overt hypothyroidism with normal hearing with central as well as peripheral auditory pathway impairment. BAEP can be a useful objective tool to assess the patients for central nervous system involvement in overt hypothyroidism.

Background: Gender is a known physiological variable reported to have influences on brainstem auditory evoked potential (BAEP) latencies irrespective of age. Anatomical differences have been suggested for such variations. Aims and Objectives: The present study was, hence, undertaken to evaluate the influence of gender on BAEP latencies and to assess the role of head size and body mass index (BMI) on BAEP responses and in gender variations. Materials and Methods: BAEP was recorded in 100 healthy adults (50 males and 50 females) in the age group of 18-70 years. Comparisons of absolute and interpeak latencies (IPLs) in the genders and between the groups with different head sizes and BMI were performed by unpaired t-test. Correlations between head size and BMI with BAEP latencies were obtained by Pearson correlation coefficient. P < 0.05 was considered as significant statistically. Results: A statistically significant increase in BAEP absolute latencies I, III, and V and IPLs I-III and I-V was found in males as compared to females. A significant positive correlation of head size was obtained with absolute latency I, III, V and I-V IPL. P < 0.05 for comparison of groups with different head sizes for absolute latencies I, III, V, I-V IPL and that with different BMI for I, III, V and I-III and I-V IPLs. Gender differences turned non-significant (P > 0.05) in males and females of comparable head sizes. Conclusion: Gender has significant influence on BAEP latencies. Head size and BMI are independent physical variables affecting BAEP latencies with the former having important role in gender differences.

Introduction: Hypothyroidism, a common endocrinological disorder is quite prevalent in its subclinical state in the adult population. Nervous system involvement is frequent in hypothyroidism with documentation of peripheral and central conduction delays as abnormal latency prolongations in Brainstem Auditory Evoked Potential (BAEP) records. Subclinical hypothyroidism however, has been less extensively studied for investigating the involvement of the auditory functions. Aim:To assess the auditory functions and Central Nervous System (CNS) involvement in the patients with subclinical hypothyroidism by recording BAEP. Materials and Methods:The study comprised of 50 females (25 females with subclinical hypothyroidism and 25 age-matched healthy females) in the age-group of 30-50 years. BAEP absolute and Interpeak Latencies (IPLs) (I, III and V, I-III, III-V and I-V) were com pared between the two groups by unpaired t-test. The p<0.05 was considered as statistically significant.Results: Mean BAEP absolute latencies (III and V) increased in the subjects with subclinical hypothyroidism as compared to controls (p<0.001) (both the ears) and wave I absolute latency also increased with p<0.001 (both the ears) by unpaired t-test. Among IPLs (interpeak latencies), III-V and I-V IPLs exhibited increase (p<0.01), while I-III IPL did not vary with statistical significance (both the ears) in the two groups. Conclusion:Patients with subclinical hypothyroidism were found to demonstrate central as well as peripheral auditory pathway affections. BAEPs can prove valuable and sensitive tests to detect involvement of the CNS and auditory dysfunctions earlier in hypothyroidism.