Lack of reliability of the SISI procedure for determining inner ear threshold.

Ten normally hearing subjects were tested using the conductive short increment sensitivity index procedure to evaluate the 60-dB constant as used in the test described by Byers (1974). Also investigated were the effects of frequency and order of presentation on the short increment sensitivity index at high sensation levels. Test frequencies included 1, 2, 4, and 6 kHz in random order. Means of all frequencies exceeded the 60-dB constant implemented by Byers (1974). Intersubject variability was large. Frequency and order of presentation were not statistically significant factors. It was recommended that the conductive short increment sensitivity index be used with caution.