Reliability of spontaneous otoacoustic emission suppression tuning curve measures

The purpose of this investigation was to study the reliability of spontaneous otoacoustic emission (SOAE) suppression tuning curve (STC) measurements. Two repetitions of an SOAE STC, using a 4-dB suppression criterion, were obtained from 5 subjects who exhibited stable SOAE level (SD less than or equal to 1.5 dB) and SOAE frequency (+/- 5 Hz). Analyses of variance revealed no significant difference between the SOAE STC trials (p greater than .05). The SOAE frequency was below the SOAE STC tip, which is similar to the relationship between the probe frequency and a simultaneously masked psychophysical tuning curve. The mean slope of the SOAE STC low-frequency segment was 53.7 dB/octave, whereas the mean slope of the SOAE STC high-frequency segment was 124.8 dB/octave. The mean low- to high-frequency slope ratio was 2.4. The mean Q10 value for the 5 subjects was 5.3. The SOAE STC low- and high-frequency slopes and Q10 were similar to psychophysical tuning curve data obtained in simultaneous masking and physiological tuning curve data.