Intelligibility of Speech Produced by Children with Hearing Loss: Conventional Amplification versus Nonlinear Frequency Compression in Hearing Aids

Abstract

Objective: This study aimed to 1) investigate the influence of nonlinear frequency compression (NLFC) in hearing aids on intelligibility of speech produced by children with hearing loss; and 2) examine whether clinicians' or parents' judgments might be correlated with those of inexperienced listeners.Methods: Twenty-seven adult listeners with normal hearing who reported no experience listening to speech produced by people with hearing loss were asked to judge the intelligibility of speech samples of eight hearingimpaired children under four aided conditions. Also, the parents and the clinicians who provided services to the children provided ratings. The children were enrolled in a four-period multi-site trial that was aimed to compare the effects of conventional processing with NLFC in hearing aids on children's performance. In that study, the children were familiarized with each of four hearing-aid setting for at least six weeks before they were evaluated using a range of tests, including the production of 20 sentences. The current study used the recorded sentences as stimuli for intelligibility judgments. Each listener heard sentences produced by two child-talkers, 40 from each talker. The stimuli were presented to listeners at 65 dB SPL via headphones. Four child-talkers received ratings from eight listeners and four from seven listeners.Results: Group-level results indicate that speech intelligibility was rated to be better by inexperienced listeners when children used NLFC than when they did not. Three child-talkers showed a significant advantage with NLFC activation. These results are consistent with the estimated audible bandwidth of hearing aids for individual talkers. Significant positive correlations for intelligibility ratings between inexperienced listeners and clinicians were found, but neither correlated with ratings from parents. Conclusions:The use of NLFC improved intelligibility of speech produced by children, on average, as rated by inexperienced listeners. Clinicians' judgment of children's speech production is a clinically viable tool for evaluating the effectiveness of amplification for children.

Effects of Adaptive Non-linear Frequency Compression in Hearing Aids on Mandarin Speech and Sound-Quality Perception

“…So far, there has been a number of studies examining the efficacy of NLFC on various aspects of speech perception including phoneme and word recognition, sentence perception, and sound-quality perception (Glista et al, 2009;Wolfe et al, 2010Wolfe et al, , 2011Wolfe et al, , 2017Ching et al, 2013;Parsa et al, 2013;Brennan et al, 2014Brennan et al, , 2017Hopkins et al, 2014;McCreery et al, 2014;Picou et al, 2015;Alexander and Rallapalli, 2017;Chen et al, 2020;Xu et al, 2020). While many studies reported lower detection thresholds and improved perceptual accuracies with NLFC-fitted hearing aids in comparison to hearing devices fitted with conventional processing (CP) (Ching et al, 2013;Alexander et al, 2014;Ching and Rattanasone, 2015), some studies reported no additional benefit in phoneme audibility, or sentence recognition with the NLFC algorithm (Perreau et al, 2013;Bentler et al, 2014;Picou et al, 2015). In addition, within those studies that found improved perceptual performance with NLFC, some reported that the benefit of NLFC was not ubiquitously shown in all tested subjects (Simpson et al, 2005;Glista et al, 2009;McCreery et al, 2014).…”