The contribution of the acoustic reflex to the ascending-descending most comfortable loudness gap

Abstract

The contribution of the acoustic reflex (AR) contraction to the ascending-descending (A-D) gap was explored. 15 normal listeners traced ascending and descending most comfortable loudness (MCL) levels for continuous (C) and interrupted (I) tones at 250, 1000 and 4000 Hz. Reflex thresholds were obtained for each subject at the test frequencies. No evidence was found to implicate the AR as the causative agent in the A-D gap. Two important trends emerged: (1) an ordering of MCL conditions occurred which was consistent across frequencies and (2) there was a consistent difference between AR level and MCL for a given stimulus condition which was constant across frequencies. The findings suggest that a predictive relationship may exist between AR and pure-tone MCL.

Key Words:

• Acoustic reflex
• Most comfortable loudness (MCL)
• Ascending-descending MCL gap