LOUDNESS TRACKING BY NORMAL HEARERS VIA BEKESY AUDIOMETER.

Abstract

Bekesy audiometry employing the method of compensatory loudness tracking was used to investigate the levels at which 12 normal hearing subjects traced loudness configurations for interrupted and continuous tonal stimuli monaurally. Two types of task were given. One was the most comfortable loudness (MCL) task. Here, tracking was monitored entirely according to the subjects “internal standard” for a comfortable level of loudness. The second was the recalled loudness (RL) task in which the subject tracked based on his memory of the loudness of a 1 000 cps reference tone heard only once at the beginning of the task. Each subject participated in two sessions separated by about a week and during each session performed five auditory tasks. Statistical analysis of the data demonstrated that in both loudness tasks (MCL and RL) significantly greater intensity was required from interrupted than from continuous tonal stimuli to accomplish the tracking. This discrepancy, in a manner not explained by current information on auditory integration of energy at supra-threshold levels, implies that the two stimuli required different intensity levels to achieve equivalent loudness. However, the discrepancy is in the proper direction and of the magnitude which characterizes many Type V Bekesy audiograms encountered clinically.