[Cross correlation function of BAEP for objective assessment of hearing threshold].

Brainstem auditory evoked potentials (BAEP) recorded were equally divided into two subensembles and a cross correlation function R (lambda) was calculated for them. The average amplitude of R (lambda) around lambda = 0 was chosen as the criterion for hearing threshold measurement. A linear regression equation which represented the relationship between the criterion and stimulus intensity above threshold was obtained on 21 normal and abnormal ears and thus a equation for assessment of hearing threshold was derived. When the equation was applied to ears to be evaluated, the criteria obtained at three different stimulus intensities above threshold were put into the equation and the mean value was calculated for assessment of hearing threshold. The results from 8 ears with different degrees of hearing loss demonstrated that the differences between estimated thresholds and corresponding subjective thresholds are 4.6 dB on the average.