Stapedial Reflex Action in Normal Subjects

Abstract

This study reports the findings relating to stapedial reflex activity in 47 audiologically normal young adults. The mean stapedial reflex threshold over the frequency range 500Hz-4kHz was found to be 88dB hearing level in agreement with values obtained by previous workers. There was a much larger variation about the mean than had previously been suggested.Stapedial reflex decay under prolonged acoustic stimulation was studied in comparison with a previous study. The results, measured by a method similar to that used in the earlier study, suggest 50% decrement times of 7.6 seconds at 4kHz, 14.6 seconds at 2kHz, 32 seconds at 1kHz and negligible decay in a 30 second period at 500Hz, which are close to the earlier results. However, careful analysis suggests that these results may be too small by as much as 30%.Closer analysis of the stapedial reflex decay curve suggests the existence of a temporal integration effect. This is shown to be complete within about 1.2 seconds.