Effects of acute thyroxin depletion on hearing in humans

Objective: To study the physiologic effect of acute thyroid hormone depletion on hearing and the function of outer hair cells. Design: Audiologic and otoacoustic emission testing of subjects undergoing total thyroidectomy before surgery and up to 6 weeks after surgery. Magnitude of thyroxin depletion monitored by serum thyroid-stimulating hormone levels. Setting: Hearing research laboratory at a state university. Subjects: Ten patients undergoing total thyroidectomy. Main Outcome Measures: Detection of hearing loss on audiogram and decrease or disappearance of otoacoustic emissions as a result of acute thyroxin depletion. Results: No significant changes in the audiogram and otoacoustic emission configurations were detected, although thyroid-stimulating hormone levels became elevated after total thyroidectomy. Conclusion: Although thyroid hormone is thought to play a role in the physiology of hearing in humans, no deleterious effects on hearing can be identified up to 6 weeks after thyroxin depletion.