Evaluation of methods for the estimation of the auditory amplitude modulation following responses

Abstract

The study of the temporal processing of acoustic signals by the auditory system becomes increasingly important for the development of new strategies for diagnosis and treatment of people who are deaf or hearing impaired. In this work we evaluated different methodologies ─chirp analyzer (AFM), short time Fourier transform (TFTC) and continuous wavelet transform (TWC)─ for the reliable estimation of an auditory electrophysiological response known as envelope following response (RSM). These methods could be used in the study or diagnosis or both of hearing problems in clinical practice. Using simulated and real data, the autors compare the robustness and reliability of the three methods to analyze data with different levels of noise and response forms. We found that in general, the three methods provide a reliable estimate (in the sense of accurately recovering the simulated response) of the RSM simulated with different shapes, when there are low levels of noise. The AFM method is the fastest and most robust to noise, while the TFTC estimates the amplitude of the response with a systematical bias. The TWC is very sensitive to noise, overestimating the amplitude of null or very small responses. The RSM estimated with the three methods, from electrophysiological recordings of adult rats, were similar to those given by the method most commonly used in the literature. The results suggest that the AFM is a useful tool for estimating the RSM and should be validated for application in the clinical practice.