[Correlation function and power spectrum analysis of auditory brainstem responses (ABR)].

Abstract

Correlation function and power spectrum analyses were made for ABR of 20 normal ears and 14 ears with retrocochlear lesions. Power spectrum of normal ABR had three peaks, F0, F1 and F2; their frequencies being 125, 552.5, 967.5Hz respectively; the spectrographic shapes were of good similitude. The curve of cross correlation function in normal ABR was V-shaped, with the valley at 6-8 ms delay. In ABR of the retrocochlear lesions, the peaks of power spectrogram appeared lower and smoother with F1, F2 shifting to left and varying obviously. Their curves of cross correlation function were even and had no regular pattern. We have found that, F1 and F2 shift may be a characteristic of hearing disorder and the analysis of cross correlation function could help for the detection of useful signal from distorted signals.