Two Tests for Quantifying Aided Hearing at Low- and High-Input Levels

Under- and overamplification of sound is a common problem in hearing aid fitting. This paper describes the implementation of two new variants of the hearing in noise test for quantifying aided hearing at the lower and upper ends of the range of everyday-life sound levels. We present results from experiments carried out with 30 adult hearing aid users to determine the respective test-retest reliabilities. Participants completed a test battery consisting of the standard Danish hearing in noise test, a variant targeting the lower threshold of audibility and a variant targeting the limit of loudness discomfort. The participants completed the test battery twice for reliability analysis. The results revealed a significant difference between test and retest for both the hearing in noise test and the two hearing in noise test variants. However, the effect sizes for the differences were all very small. A calculation of Pearson correlation coefficients showed that both the hearing in noise test and the two new hearing in noise test variants had significant and strong correlations between test and retest. The within-subject standard deviations were determined to be 0.8 dB for hearing in noise test, 0.9 dB for lower-end test, and 2.2 dB for upper-end test. The findings demonstrate that both the lower-end test and upper-end test have high test-retest reliabilities, and thus can provide consistent and reliable results.