Hearing Loss in Acquired Hypopthyroidism

Both clinical and laboratory evidence confirm that hearing loss can result from congenital and acquired hypothyroidism. There is a confirmed correlation between congenital hypothyroidism and hearing loss, but significant controversy still surrounds the association between acquired hypothyroidism and hearing loss.The aim of this study was to evaluate this relationship. Fifty patients with confirmed primary hypothyroidism, were studied and compared with 50 age- and sex- matched controls. All patients were evaluated in the hypothyroidism state before treatment with thyroxine. Auditory assessments included: Toutine ENT examinations, speech reception threshold, pure tone audiometry, speech discrimination score, acoustic reflex and tympanometery. The hearing thresholds in all frequencies in both ears of the case group were higher than in controls. Also hearing loss frequencies, i.e. 2000, 4000, 8000 dB in the left and 4000, 8000 dB in the right ears in the case group, were higher than in controls. Hearing loss was symmetric, sensory neural and mild to moderate. Mean speech reception threshold in the right and left ears in the case group were 15 and 15.1 respectively and in controls, 10.6 dB for both the right and left ears. Mean speech discrimination score in the right and left ears in the case group was 97 and in the control group was 99 dB. Results demonstrate a strong correlation between acquired primary hypothyroidism and hearing loss.