The influence of phase inversion on the auditory evoked response

Abstract

The amplitude of the auditory evoked response (N₁P₂) was measured over repeated tests on 24 normal hearing listeners. 200 and 2 000 Hz were presented in-phase (S₀) and out-of-phase (S_π) at moderate intensity levels. Response amplitude for S_π was significantly larger (p < 0.025) than that for S₀ when the tonal stimulus was 200 Hz. The results of psychophysical tests ruled out the possibility that this finding could be attributed to differences in loudness between S_π and S₀. No statistically significant difference in response amplitude was found between S_π and S₀ when 2 000 Hz was employed. These data are discussed with reference to the research on masking level differences.

Key Words:

• Electric Response Audiometry
• Masking level difference (MLD)
• N₁-P₂ amplitude
• Latencies of N₁ and P₂