Evaluation of the Female Patients with Subclinical Hypothyroidism by Brainstem Auditory Evoked Potentials: Case-Control Study

Abstract

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.

Study of auditory brainstem evoked response at varying frequencies in subclinical hypothyroid subjects

“…Subclinical hypothyroidism leads to overt hypothyroidism. [ 10 ] The most important cause of hypothyroidism is autoimmunity. [ 12 ] Elevated levels of antibodies against thyroid peroxidase and thyroglobulin were reported in 60% subclinical hypothyroid subjects.…”

Neonatal thyrotropin levels and auditory neural maturation in full-term newborns

“…These data are scarcer and more conflicting for subclinical hypothyroidism (SCH). Recently, it was shown that adult women with SCH had increased absolute latency of waves I, III, and V in ABR and increased interpeak latency of intervals III-V and I-V bilaterally, when compared to age-and sex-matched controls [30]. Paladugu et al (2015) also showed an impairment of the cognitive function in individuals aged 12 to 45 years by analyzing evoked auditory potentials (P300), with increased latency in patients with SCH.…”