Evaluation of wideband frequency responses and non-linear frequency compression for children with mild to moderate high-frequency hearing loss

Abstract

Objective: To evaluate wideband amplification and non-linear frequency compression (NLFC) as a means to improve speech recognition for children with mild/moderate hearing loss. Design: Randomized within-subject design with repeated measures across test conditions. Study sample: Eleven children with mild to moderate hearing loss were evaluated with: (1) Phonak BTE without NLFC, (2) Phonak BTE with NLFC, and (3) Oticon BTE with wideband response extending to 8000 Hz. Results: Use of NLFC provided better detection and recognition of high-frequency stimuli (e.g. /sh/ and /s/). No difference in performance between conditions was observed for speech recognition when measured with the University of Western Ontario (UWO) plurals test and the UWO distinctive features difference test. Finally, there were no differences between conditions on the BKB-SIN test. Conclusions: Children with mild to moderate hearing loss have good access to high-frequency phonemes presented at fixed levels (e.g. 50 to 60 dBA) with both wideband and NLFC technology. Similarly, sentence recognition in noise was similar with wideband and NLFC. Adaptive test procedures that probe performance at lower input levels showed small but significant improvements in the detection and recognition of the phonemes /s/ and /sh/ with NLFC condition when compared to the NLFC Off and wideband conditions.

Key Words::

• Nonlinear frequency compression
• moderate hearing loss
• hearing aids

Acknowledgements

The authors would like to express gratitude to Danielle Glista, Steve Beaulac, and David Lee for the development of the UWO plurals and DFD test materials used, as well as for the provision of their support and expertise throughout the planning and implementation stages of this study. We would also like to thank the anonymous reviewers of this paper and the editors of this journal for making several suggestions that improved the quality of the manuscript. This study was funded by a grant from Phonak AG to the first and second authors. The fourth author is employed by Phonak AG.

Declaration of interest: Michael Boretski is an employee of one of the manufacturers of the hearing instruments evaluated in this study. It should also state that this study was partially funded by a small grant from Phonak AG.