Cochlear function in ultra-high frequencies in parents of individuals with autosomal recessive hearing loss / Função coclear em frequências ultra-altas em pais de indivíduos com deficiência auditiva autossômica recessiva

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

14/12/2012

RESUMO

INTRODUCTION: In nonsyndromic hearing loss of recessive autosomal heritage, caused by changes in the gene GJB2 (Gap Junction Bet-2 Protein), parents of individuals with hearing loss are heterozygous carriers of a recessive allele which causes deafness, however, are asymptomatic, but may present early and mild hearing changes. OBJECTIVE: Assessing the cochlear function in parents of individuals with hearing loss of recessive autosomal heritage through Distortion Product Otoacoustic Emissions (DPOAE) in conventional frequencies and in ultra-high frequencies, comparing the responses of the control group paired by gender and age. METHOD: 56 individuals were assessed, aged between 20 and 58 years old, divided into two groups, the Study Group (GE), composed of 28 parents of hearing impaired people due to recessive autosomal heritage, 14 women being 20 to 55 years old (32.8 years old average) and 14 men being 20 to 58 years (35.2 years old average), and the Control Group (GC) formed by individuals without hearing complaints, composed of 14 men and 14 women being paired according to the age of GE. The individuals underwent examinations of Pure Tone Audiometry (PTA), Immittanciometry, including tympanometry and Acoustic Reflex (AR), and DPOAE in conventional frequencies and ultra-high frequencies. RESULTS: There was no statistically significant difference between the ears and the groups in the findings of PTA and AR; however, in the responses of DPOAE, the GE presented a statistically significant difference in all the frequencies compared to the GC. The Pearson Correlation between PTA and DPOAE, between the ears and between the groups, showed a negative correlation between the ears and the groups, indicating that, with the increase in the level of response of DPOAE, there is improvement in hearing thresholds. The Pearson Correlation between the results of AR and DPOAE showed no significant correlation for both groups assessed. The Pearson Correlation between age and DPOAE, in conventional frequencies, showed a significant negative correlation in some frequencies, however, there was no correlation between age and DPOAE in ultra-high frequencies. Reference range, scatter plots and discriminant analysis were used to investigate whether there was a difference between DPOAE in conventional frequencies and in ultra-high frequencies, given that DPOAE in conventional frequencies measured with greater precision the individuals from GE, in relation to the ultra-high frequencies. CONCLUSION: DPOAE, both for conventional frequencies and ultra-high frequencies, were able to distinguish individuals from GE and GC, suggesting that heterozygous individuals for the mutation of GJB2 gene may present damage in the active process of external ciliated cells before the clinical manifestation via altered results in the conventional hearing-aid assessment.

ASSUNTO(S)

genética genetics hearing tests mutation otoacoustic emission mutação hearing testes auditivos emissão otoacústica audição

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