[Study on cochlear microphonic potentials obtained by adaptive filtering technique].

In order to delete the contamination of acoustic stimulus artefact in average evoked cochlear microphonics by surface recording, an application of adaptive filtering technique for cancelling the stimulus artefact from the cochlear microphonics was proposed. The results demonstrated that in normal hearing ears, the cochlear microphonic potentials (CM) which was obtained by adaptive filtering technique was later than the ipsilateral response, whereas the AP response could be seen in the ipsilateral response to 2 kHz, 4 kHz and 8 kHz stimuli. In 31(77.5%) ears with profound sensorineural hearing loss and 29(27.5%) ears with moderate to severe sensorineural hearing loss, the CM was absent, but in the other ears the CM was as clear as in ears with normal hearing. It suggests that by this technique sensorineural hearing loss can be further differentiated into two kinds: neural hearing loss and sensory hearing loss.