Effect of Gain and Digital Noise Reduction on Hearing Aid in Low Annoyance and High Annoyance Group

Abstract

The present study assesses the effect of Digital Noise Reduction and gain on Most Comfortable Level, Background Noise Level, Acceptable Noise Level and Speech in Noise Ratio 50 from within and between low and high annoyance groups. In addition, combined effect of DNR and gain was investigated on MCL, BNL, ANL and SNR 50 from within and between low and high annoyance groups. Two experiments were performed. In experiment-1 only five participants were involved on whom deviation of gain from user and prescriptive gain was obtained. This helped to assign the gain variation in experiment-2. Eight listeners in low annoyance group and twelve listeners in high annoyance group were participated in the study. In experiment-2, ANL and SNR-50 was obtained in aided condition with varying gain from prescriptive target gain in activating and deactiving DNR in hearing aid. It was found that the ANL and SNR-50 score was better in -3 dB gain in DNR activated condition than compared to DNR ‘off’ condition. It was also found that ANL and SNR-50 score was better in low annoyance group individuals compared to high annoyance group individuals. Overall, the results reveal that the annoyance level was reduced in -3 dB gain below the prescriptive formula in DNR activated condition for both low and high annoyance groups. Results showed that, annoyance level reduced for both groups of participants by activating DNR in hearing aid and also reducing 3 dB gain from prescribed target.