[Medium-latency acoustically evoked brain potentials used for examination of the auditory pathway (author's transl)]

Potentials of the 10-15 ms latency range evoked by acoustic clicks and Gauss-shaped tone bursts habe been investigated in normal hearing adults, 20 patients with cochlear damages, and 6 cases of temporal lobe processes. Methods and results are compared to those of brain stem audiometry. Mean and standard latency ranges are calculated for the different peaks (Fig. 1). Amplitudes should be used only for side difference evaluation in the same patient, because of their big interindividual variation. In cases of profound high frequency hearing loss (Fig. 2) medium-latency potentials yield true threshold values in the low frequency range, where brainstem potentials are failing. The medium latency potentials show a substantial decrease of amplitude for stimuli contralateral to the damaged side (Fig. 3). So this method can be a functional hearing test to detect or at least suspect temporal damages.