Investigação dos limiares de audibilidade das altas freqüências em crianças com histórico de intoxicação por chumbo

Abstract

Introduction: The ultra-high frequency pure-tone audiometry assists in the early diagnosis of the hearing alterations, which can be used as a prophylactic measure to preserve hearing, or, to avoid a possible progression of an existing hearing loss. These hearing losses may come from several etiologic agents like the aging process, the subjection to ototoxic drugs and job noise. Aim: The investigation of the audibility thresholds in children who had already experienced lead poisoning with levels which have exceeded 10 µg/dl, from 250 to 16000 Hz frequencies. Material and Method: For that, 30 children were selected, at the age group of 7 to 13, with whom it was carried out anamnesis, otological inspection, acoustic immitance measures, audiometry, the ultra-high frequencies and the conventional audiometry. Results: We can verify that the hearing thresholds were presented between –20 and 45 dB HL, and there was no hearing sharpening reduction due to the frequency increase at the major part of the analyzed population. It was also investigated the existence of differences between the hearing thresholds concerning about the interaural and genders’ variability and the correlation with the blood lead level (Pb). Conclusion: No significant correlation was found between lead concentration and the hearing threshold of the sujects, however, the study suggests that lead contamination became a risk factor for the auditory system.