Middle components of the AER to tone-pips in normal-hearing and hearing-impaired subjects

Tone-pips of 500, 1000, and 3000 Hz were presented at 0-, 10-, 20-, 35-, and 50-dB HL to 10 normal-hearing subjects and at 0-, 10-, 20-, 35-, and 50-dB SL to 10 subjects with conductive, sensorineural, or mixed hearing losses. Middle component (latencies 8-90 msec) averaged electroencephalic responses to the tone-pips were analyzed in terms of peak latencies and peak-to-peak amplitudes. Properties of the responses were generally the same for both normal-hearing and hearing-impaired subjects except that the hearing-impaired subjects showed slightly greater amplitudes overall. The small reduction in latencies with increasing stimulus frequency seen in the normal-hearing subjects was not observed in the hearing-impaired subjects.