Validation of audiometric method for measuring temporary threshold shifts

Abstract

The proposed experiment aims at testing the audiometric method developed earlier [Ordoñez et al., Acta Acustica (Beijing) 88, 450–452 (2002)] by evaluating if it is able to reproduce some of the known aspects of temporary threshold shifts (TTS), such as: Immediate sensitization, the 2 min maximum of the recovery and the half-octave shift of the peak of TTS. The subjects will be exposed to pure tones of 500 Hz and 2 kHz for 2 to 5 min and the levels will cover the range between 40- to 100-dB SPL. The aim is to induce a maximum of 15 dB of TTS. For showing the half-octave shift, the threshold will be determined from one octave below the exposure frequency to one octave above in 1/2 octave steps. For the 2 min maximum, the threshold will be measured at the most affected frequency and it can be determined continuously for 4 min after the exposure. Sensitization at probe frequencies lower than the exposure frequencies will be tested by measuring the threshold at 1/2 and 1 octave below the exposure frequency.

Time and Frequency Characteristics of Temporary Threshold Shifts Caused by Pure Tone Exposures

“…The audiometric method used wasafi xedf requency Békésy method, as described by Ordoñez et al [34,35]. The resulting average (across 18 subjects)standard deviation between 10 repetitions for at hreshold determination was1.24 dB, with an average time for acomplete tracking (including afamiliarization descent)of44seconds, in the frequencyrange from 0.5 to 8kHz.…”