Reliability of Acoustic Reflex Responses Obtained by a Relative Measurement Method

Abstract

Auditory thresholds and measures of stapedius-muscle reflex activity were obtained from one ear each of ten normal hearing adults. Levels at which reflex responses occurred were measured by a relative method (Madsen acoustic impedance meter, model Z061) at 250, 1000, and 4000 cps, and were compared with hearing thresholds at each of these frequencies. Both auditory and reflex responses were measured ten times per subject for each test frequency, using the psychophysical method known as the up-and-down method. The resulting data indicate that, in general, auditory thresholds are more stable between subjects than satpedius-muscle reflex responses, and that reflex responses are more variable at 250 and 4000 than at 1000 cps. The obtained data are interpreted in terms of response stability for clinical and experimental purposes. Inter- and intra-subject variability is examined, as are the kinds of diagnostic information that might be gained from this type of middle-ear-impedance measurement.