Cochlear dysfunction evidenced by reduction of amplitude of otoacoustic responses in patients with congenital hypothyroidism.

INTRODUCTION

The investigation of amplitudes of otoacoustic emissions in congenital hypothyroidism can provide information on cochlear function with more sensibility, when compared to other methods of auditory evaluation.

AIM: To investigate cochlear function through the amplitude of distortion product otoacoustic emissions in individuals with congenital hypothyroidism and to correlate with clinical aspects.

METHODS

An exploratory, analytical, cross-sectional study with a convenience sample, composed of 50 individuals with congenital hypothyroidism and a group of 42 individuals without the disease, mean age of 8.4 (±3.1) years. The subjects of the research were evaluated by means of tonal and speech audiometry, immittance and distortion product otoacoustic emissions (DPOAEs). Continuous variables were described as mean or median and standard deviation. The Spearman test evaluated the correlations between the variables.

RESULTS

Otoacoustic emission amplitudes were significantly reduced in the exposed group, with congenital hypothyroidism, when compared to the group of individuals without the disease, especially in the medium frequencies. The Spearman test showed a slight correlation between the amplitude values of the otoacoustic emissions of some frequencies and the variables: disease time, diagnostic age, irregular serum free thyroxine hormone levels and thyroid stimulating hormone, especially in the condition of less treatment, whose correlation was negative.

CONCLUSION

There was a correlation between the levels of signal amplitudes of otoacoustic emissions with clinical conditions and hormonal follow-up, suggesting probable subclinical auditory impairment in this population, as well as influence of some clinical aspects of congenital hypothyroidism on auditory function.