Background
The objective of the study was to optimize the area of a time-frequency analysis and then investigate any stable patterns in the time-frequency structure of otoacoustic emissions in a population of 152 healthy adults sampled over one year.
Material and Method
TEOAE recordings were collected from 302 ears in subjects presenting normal hearing and normal impedance values. The responses were analyzed by the Wigner-Ville distribution (WVD). The TF region of analysis was optimized by examining the energy content of various rectangular and triangular TF regions. The TEOAE components from the initial and recordings 12 months later were compared in the optimized TF region.
Results
The best region for TF analysis was identified with base point 1 at 2.24 ms and 2466 Hz, base point 2 at 6.72 ms and 2466 Hz, and the top point at 2.24 ms and 5250 Hz. Correlation indices from the TF optimized region were higher, and were statistically significant, than the traditional indices in the selected time window.
Conclusions
An analysis of the TF data within a 12-month period indicated a 85% TEOAE component similarity in 90% of the tested subjects.

Keywords: Time Factors, young adult, Otoacoustic Emissions, Spontaneous - physiology, Evoked Potentials, Auditory - physiology