Shadow Response of ABR and Masking
1988 Volume 31 Issue 3 Pages 145-156
Details
1988 Volume 31 Issue 3 Pages 145-156
The unilateral recording of ABRs required masking of the contralateral ear in order to eliminate shadow responses in those whose hearing levels on both ears show a certain discrepancy.
The effects of masking of the contralateral ear on ABRs were investigated in 35 patients with confirmed unilateral deafness.
In the first portion of this study, the shadow responses were recorded from the deaf ear with clicks of 110dBnHL or 80dBnHL, and masking with a narrow band noise of various intensity levels were applied to the healthy ear.
Secondly, ABRs were recorded from the healthy ear with clicks of 60dBnHL or 30dBnHL, and a narrow band noise of various intensity levels was applied to the deaf ear.
Results were as follows:
1) The latencies of fast and slow components of shadow responses were prolonged, and their amplitudes were decreased, when the intensity of the narrow band noise for the un-tested (healthy) ear increased.
2) The effective masking may be achieved when the narrow band noise is applied for the un-tested ear with the intensity at around ⌈stimulus intensity for the test ear-interaural attenuation (approximately 50dB)+10dB⌋.
