Detecção objetiva de respostas auditivas em regime permanente: aplicação em exames audiológicos

Abstract

In neuroscience, testing for of presence or absence of evoked response is a useful tool to access sensorial pathways integrity and for function evaluation. The auditory steady-state responses (ASSRs) are brain electrical activities driven by auditory, high repetition stimuli. These responses helps the diagnoses of several pathologies related to central nervous system and contributes to the study of the neural mechanisms of perception. However, the nowadays methods for quantifying the ASSRs fail in associate these responses with its neural substrates (this task can be archived, for example, by brainstem evoked response audiometry - BERA). Further, the utilization of mathematical tools for detection of such responses is still a matter of study. In this work, objective response detection (ORD) techniques were applied in ASSRs for auditory exam evaluation. Accordingly, limitations of such tools were identified and methods for prevention and correction of spectral leakage were developed. The ASSRs were recorded from Wistar rats for different stimuli content, regarding the determination of the relationship between the stimuli parameters and the respective evoked response. The results allow us to conclude that the application of spectral objective tools are useful for detection of ASSRs. However, care must be taken against the spectral leakage. The parameters variations and the new analysis procedures proposed in this work are promising tools regarding localization of neural generators of evoked responses and quantification of auditory thresholds using electrophysiological recordings.