Investigating the possible audiological effects of hypothyroidism

Objective: We investigated audiological function in patients diagnosed with primary hypothyroidism secondary to Hashimoto’s thyroiditis. Methods: Forty-one patients diagnosed with primary hypothyroidism secondary to Hashimoto’s thyroiditis and 20 control subjects participated in this study. Otoscopic examination, immittance testing, pure tone audiometry, and otoacoustic emission testing were completed on all participants. In addition, all participants were screened for the presence of tinnitus. Results: All participants’ demonstrated normal otoscopic examination and 0.226-kHz tympanometry test findings. Pure tone audiometric (PTA) testing revealed mild sensorineural hearing loss (SNHL) in 16 patients diagnosed with primary hypothyroidism (39%) compared to only one participant in the control group. Eight patients with primary hypothyroidism reported bothersome tinnitus (19.5%), and transient evoked otoacoustic emissions (TEOAE) were absent in 8 left ears (19.5%) and 4 right ears (9.75%). Conclusion: Hypothyroidism secondary to Hashimoto’s thyroiditis may be a cause of mild SNHL, particularly at high frequencies, in addition to bothersome tinnitus. Absent otoacoustic emissions suggest cochlear outer hair cells as the possible lesion site in patients with hypothyroidism