OBJECTIVES Various problems are encountered during audiometric testing. Deviation from reference threshold levels for supra-aural earphones is often a serious problem when hearing levels are measured. This paper reports the acoustic calibration of clinical audiometers used for special periodic health examination. METHODS ANSI S3.6-1996 Specification for Audiometers represents our most current and best resource for information regarding audiometers. The acoustic calibration was measured in 211 clinical audiometers and compared with the ANSI S3.6-1996 reference threshold levels for supra-aural earphones. RESULTS Among 211 clinical audiometers, 56 (26.5%) exceeded the permitted deviation from reference threshold levels at any test frequency in ANSI S3.6-1996 for left supra-aural earphones, and 54 (25.6%) for right. An exhaustive calibration was required for 16 audiometers (7.6%) in both supra-aural earphones. The absolute difference in dB deviation from reference threshold levels by performed acoustic calibration at least annually were statistically significant at any test frequency (p<.05). CONCLUSIONS The results of this study strongly indicate that clinical audiometry is being conducted with pure-tone audiometers having unallowable sound pressure levels deviations for supra-aural earphones. The validity of audiometric hearing thresholds are significantly affected by these deviations from the acoustic calibration levels of audiometers. Therefore audiometer calibration need to be checked functionally daily and acoustically at least annually.
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Development of Linux based Real-Time Spectrum Analyzer for Puretone Audiometer Deok-Hun Kang, Bum-Joo Shin, Gye-Rok Jeon, Soo-Geun Wang Journal of the Korea Academia-Industrial cooperation Society.2011; 12(6): 2830. CrossRef
Both to determine testing frequency in bone vibrator of audiometer for measurement of vibration perception threshold(VPT) and to evaluate factors influencing VPT, ninty seven healthy adults were tested on their second metacarpal head of both hands, at 250Hz, 500Hz, 1,000Hz and so on.
Measures of the VPTs at 1,000Hz were excluded in analysis because frequency 1,000Hz was not recognized as a vibration sense. Mean and standard deviation(S.D.) of the VPTs in the both hands measured at 250Hz were 19.9+/-6.7dB, 21.0+/-7.3dB, respectively and at 500Hz were 33.6+/-8.3dB, 34.9+/-8.1dB, respectively. Both mean and S.D. tended to be lower at 250Hz than 500Hz, and mean differences of VPTs between the left and the right hand at the both frequencies appeared statistically significant (p<0.01).
VPTs were significantly correlated with each other (p<0.01). Age was positively correlated(p<0.001) with VPTs and education was negatively(p<0.01). Multiple regression analysis showed that age was the only factor influenced on VPT.
These results suggest that, when using the bone vibrator of audiometer for measurement of VPT, the frequency 250Hz as a testing frequency may be more useful than frequency 500Hz, and VPT should be measured on both hands.