Evaluation of the efficacy of hearing-assistive devices during group discussions

We evaluated speech intelligibility and sound impression via hearing aids (HAs) in 16 subjects with normal hearing during a group discussion in a simulated noisy classroom, and compared 3 types of hearing-assistive devices. Test sounds were recorded through the HAs worn on HATS (Head and Torso Stimulator), and presented to normal hearing subjects through earphones. The three hearing-assistive devices, the FM system, induction loop system, and Roger system were used for the test. The intelligibility was calculated from the score for correct monosyllables, and the hearing impression was determined from the analyzed semantic differential scores by factor analysis. A significantly higher intelligibility score was obtained for the Roger system than for the HAs alone, the induction loop and the FM hearing system. However, in regard to the hearing impression of a sentence, the FM hearing system and HAs alone were better for discerning the words “preference” and “nature” as compared to the induction loop system, and almost the same as with the Roger hearing system. Therefore, the Roger hearing system appears to offers a relatively good hearing condition under noise conditions.