The effect of probe frequency on ipsilateral acoustic reflex thresholds

Abstract

This study was designed to evaluate the effect of probe frequency on the ipsilateral acoustic reflex thresholds. Five young female subjects with normal hearing participated in the study. Ipsilateral acoustic reflex thresholds were established for each subject using 226-, 678-, and 1000-Hz probe tones. The criteria for reflex thresholds were based on the lowest hearing levels (HL) at which the following minimum changes in baseline admit- tance were apparent on at least two trials: for 226 Hz, 0.02 ml; for 678 Hz, 0.06 mmho; and for 1000 Hz, 0.09 mmho. The reflex activator frequencies were 0.5, 1, and 2 kHz. The repeated measures multivariate analyses of variance were performed on the data. The results revealed a significant effect of probe frequency and a significant activator and probe interaction. Further analyses with the least significant difference (LSD) test revealed that the reflex thresholds obtained with the 678-Hz probe were significantly higher than those obtained with the 226- and 1000-Hz probes. In addition, for the activator frequency of 1 kHz, the lowest reflex thresholds were obtained with the 226-Hz probe, and for the activator frequency of 2000 Hz the lowest acoustic reflex thresholds were obtained with the 1000-Hz probe tone. [Work supported by a Bloomsburg University Grant for Research and Disciplinary projects.]