The Frequency-Latency Function of Evoked Otoacoustic Emission (EOAE) Using Instantaneous Time-varying Spectral Analysis

• Published in: AUDIOLOGY JAPAN Vol. 38; no. 3; pp. 207 - 214
• Main Authors: Yoshikawa, Hiroshi, Mishima, Takekazu, Takahashi, Akemi, Nishijima, Takashi, Ichikawa, Ginichiro, Ehara, Yoshiro
• Format: Journal Article
• Language: English
• Published: Japan Audiological Society 1995
• ISSN: 0303-8106; 1883-7301
• DOI: 10.4295/audiology.38.207

The Fast Fourier Transform (FFT) is the conventional method to analyze the power spectrum of evoked otoacoustic emission (EOAE) and it can be carried out conveniently. But in this conventional method, so called time-invariant spectrum, the power spectrum of EOAE depends on the modality of the averaged EOAE its self but lacks the information of the frequency-latency function. So the instantaneous time-varying spectral analysis was adopted and tried to evaluate the EOAE recorded from normal hearing young adults. The instantaneous spectrum was calculated mainly based on the method of Ackroyd (1970) and printed out in 3 dimensional display. The instantaneous spectrum was examined in two different ways, one was instantaneous spectrum of averaged EOAE and the other was ensemble average of instantaneous spectra of responses evoked with each stimulus. In the instantaneous spectrum of averaged EOAE, interpretation of the frequency-latency function was easier than the conventional maneuver because of its information for latency. In the ensemble average of instantaneous spectra, EOAE and spontaneous otoacoustic emission (SOAE) were simultaneously and clearly recorded.