Improving the Predictive Strength of Better-Ear Four-Frequency Pure-Tone Average With the Addition of the Tinnitus and Hearing Survey-Hearing Subscale
Authors: Ellis Gregory M. , Bieber Rebecca , Davidson Alyssa , Sherlock LaGuinn , Spencer Michele , Brungart Douglas 
Published: January 2025

Objectives:
The objective of this project was to quantify the relative efficacy of a four-frequency pure-tone average in the better ear (PTA4), the Hearing subscale of the Tinnitus and Hearing Survey (THS-H), and a combination of the two in predicting speech-in-noise performance, hearing aid recommendation, and hearing aid use among United States service members (SMs).

Design:
A two-analysis retrospective study was performed. The first analysis examined the degree to which better-ear PTA4 alone, THS-H alone, and better-ear PTA4 in conjunction with THS-H predicted performance on a speech-in-noise test, the modified rhyme test. Three binomial mixed-effects models were fitted using better-ear PTA4 alone, THS-H alone, and both measures as primary predictors of interest. Age and sex were included as covariates in all models. The models were compared to one another using Chi-square goodness-of-fit tests and the best-fitting model was examined. Data from 5988 SMs were analyzed in the first analysis. The second analysis examined the degree to which better-ear PTA4 alone, THS-H alone, and better-ear PTA4 in conjunction with THS-H predicted two hearing aid-related outcomes: recommendation for hearing aids by a clinician and hearing aid use. Three receiver operating characteristic curves were fit for each question for better-ear PTA4 alone, THS-H alone, and better-ear PTA4 + THS-H. The area under the curve was bootstrapped to generate confidence intervals to compare the three measures. Data from 8001 SMs were analyzed in the second analysis.

Results:
In the first analysis, all three models explained more variance than chance; however, the better-ear PTA4 + THS-H model was a significantly better fit than either the better-ear PTA4 alone or the THS-H alone models. Significant main effects of better-ear PTA4 and THS-H indicated that proportion correct decreased as better-ear PTA4 and THS-H increased. A significant interaction was observed such that proportion correct decreased more rapidly if both better-ear PTA4 and THS-H were increasing in tandem. In the second analysis, better-ear PTA4 + THS-H showed good predictive discrimination of a prior hearing aid recommendation. For predicting hearing aid use, better-ear PTA4 was the only predictor with an area under the curve bootstrapped confidence interval that overlapped 0.50, indicating better-ear PTA4 alone is a chance predictor for hearing aid use. Both THS-H alone and better-ear PTA4 + THS-H predicted hearing aid use better than chance, but had poor discrimination overall.

Conclusions:
Adding the THS-H to the better-ear PTA4 improves predictions of speech intelligibility in noise, has good predictive strength for hearing aid recommendations, and predicts hearing aid use better than chance. This study provides evidence for using surveys in conjunction with objective data when evaluating hearing ability and recommending interventions. These findings are relevant to discourse regarding self-administered hearing healthcare.