HEARING THRESHOLD IN AUDIOMETRY TESTING: PURE TONE VERSUS WARBLE TONE
It has long been debated among audiologists whether pure tone and warble tone can be used interchangeably in clinical settings to quantify the amount of hearing threshold. The disputes on this issue inspired this study to investigate the differences in hearing threshold between pure tone and warble tone in audiometry testing. Audiometric test was conducted on 20 normal hearing adults (40 ears) at six frequencies at octave intervals from 250 Hz to 8 kHz with three different stimuli presentation; (i) pure-tone stimulus (PT); (ii) warble tone stimulus presented for 2-3second (WT3); and. (iii) warble tone stimulus presented for 4 seconds and more (WT4). This study found that WT4 elicited the lowest threshold as compared to the other two stimulus presentation; PT and WT3. No significant differences observed between PT and WT3 thresholds. There were significant differences between PT and WT4 at all frequencies except for 250 Hz and 8 kHz; as well as between WT3 and WT4 at all frequencies except for 2 kHz and 8 kHz. However, all differences were not clinically significant. These findings support the notion that warble tone can be used to measure thresholds since the substitutions did not violate the 5-dB step size in clinical application.