Time-frequency analysis of transiently evoked otoacoustic emissions of subjects exposed to noise

Transiently evoked otoacoustic emissions (TEOAE) were measured from 124 ears from two subject groups: healthy subjects (62 ears), and workers (62 ears) exposed to noise of jet engines. The recordings were analyzed using the method of adaptive approximations based on a matching pursuit (MP) algorithm. The method allows for description of the signal components in terms of their amplitude, frequency, latency, and time-span (or duration). The purpose of this work was to determine the repeatability and usefulness of these parameters in studies of hearing impairment of populations exposed to potentially harmful noise. Good distinction between the two datasets was achieved in all investigated frequency bands when amplitude was used as a discrimination parameter. Also latency was affected in frequency bands starting at 2000 Hz, while the time-span parameter associated with the duration of the waveform was less influenced by noise.