Estudo das respostas para o potencial evocado auditivo de estado estável em lactentes / Auditory steady state evoked response in young-infants

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Introduction: Auditory steady-state evoked response (ASSR) is a promising technique to early diagnosis of hearing loss, as an objective method to estimate hearing sensibility in different frequencies. This technique offers some particular features: the use of dichotic and simultaneous frequency stimulation, allowing a short-duration assessment in addition to the automatic response detection providing a reliable outcome. Objective: to obtain ASSR thresholds, for preterm and term young-infants, with normal hearing, to investigate the maturational process of response and to verify how the protocol could be adjusted, for clinical application for early detection of hearing loss. Method: a cohort and prospective analysis of ASSR thresholds obtained to 60 ears (30 per group) by Master® program using monotic and simultaneous frequency stimulation for 500, 1000, 2000 and 4000 Hz, with automatic response detection, by the F-test, at p-value <0.01 and 5 dB-step threshold seek. Results and Discussion: the thresholds for Preterm group were higher than Term and the mean values, in dB SPL, were 49.11 (± 9.44), 26.38 (± 6.59), 26.74 (± 7.57) and 35.9 (± 8. 3) for Preterm group and 44.30 (± 9.88), 27.8 (± 6.79), 26.77 (± 6.09) and 32.87 (± 6.12), for Term group at 500, 1000, 2000 and 4000 Hz, respectively. The adopted protocol was feasible and the average time collection was 1h 20 min. The time collection can be reduced to 40 min, for clinical application, considering the response detection at p-value <0.05 and 10 dB-step threshold seek, as the difference on thresholds were only 2 dB, when compared to the suggested protocol. The p-value <0.01 and 5-dB step threshold seek can be a strategy to confirm the presence of response, besides the automatic detection, which does not exclude the examiner interpretation for final outcomes. Conclusion: The ASSR thresholds in young-infants, with normal hearing, demonstrate a maturational effect from 35 to 39 weeks of age. The ASSR results were elevated, considering an electrophysiological response, especially for 500 and 4000 Hz, and therefore it has to be applied carefully to identify normal hearing neonates.

ASSUNTO(S)

lactentes potenciais evocados auditivos infant premature infant auditory evoked potentials prematuro triagem neonatal neonatal screening

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