The Best-Matched Pure Tone Average and Speech Recognition Threshold for Different Audiometric Configurations

Kim, Jeong Min; Na, Mi Sun; Jung, Ki Hwan; Lee, Soo Hyeong; Han, Jae Sang; Lee, Oh Hyeong; Park, So Young

Abstract

BACKGROUND AND OBJECTIVES
The agreement between pure-tone average (PTA) and speech recognition threshold (SRT) has become more important with the increasing demands for medical certification. The purpose of this study was to explore the relationships between the SRT and several variations of PTA, and to determine which PTA formula would provide the best agreement with SRT for different audiometric configurations.
SUBJECTS AND METHOD
Audiological data on 783 ears were retrospectively collected. The air-conduction PTAs were calculated using five different formulas: three-frequency average (3FA), weighted three-frequency average (W3FA), four-frequency average (4FA), weighted four-frequency average (W4FA), and six-frequency average (6FA). The audiometric configuration was classified into five categories. The PTA-SRT relationships were analyzed using correlation and simple linear regression for each audiometric configuration.
RESULTS
Highest correlation was observed between the SRT and W3FA for all audiometric configurations with the correlation coefficient of 0.964 as a whole. The SRT and 3FA were best-matched in the linear regression models for overall/flat/high frequency gently sloping/low frequency ascending; the SRT and W3FA were best-matched for high frequency steeply sloping (HFSS); the SRT and 4FA were best-matched for miscellaneous audiograms.
CONCLUSION
The most stable PTA variations that make the best-matched pairs with SRT for any audiogram are the conventional 3FA and W3FA doubling 1 kHz threshold. The addition of frequencies higher than 2 kHz to a PTA formula seems to have impeded the PTA-SRT agreement, especially for HFSS audiograms. W3FA should be the method of choice in predicting SRT from PTA for HFSS audiograms.