Pediatric Amplification Perspectives 2014: Part 1
Dillon, Ching, and Golding (2014) report three major reasons why special considerations are needed when fitting hearing aids to children.
- Small children have tiny ear canals that change all the time (during the first few years of life).
- Infants have limited ability to provide behavioral responses.
- Children rely on amplification "to develop speech and language and to acquire knowledge of the world around them…."
Dillon, Ching, and Golding note that children with hearing loss require a significantly more advantageous signal-to-noise ratio (SNR) than do adults. As such, they specifically recommend wireless remote-microphone hearing aids (i.e., FM and remote microphones) should be used anytime children need to listen attentively to a signal originating from more than a meter away. The authors point out that as hearing loss increases, and as difficulty understanding speech increases, the benefit obtained via wireless remote-microphone systems increases. Indeed, they report "a wireless signal can easily offer as much as a 20 dB improvement in SNR over acoustic reception."
With regard to wide dynamic range compression (WDRC), Dillon, Ching, and Golding note that although WDRC is widely (i.e., perhaps universally) used, there remains "uncertainty over the maximum compression ratios…and how fast the compression should be."
With regard to adaptive noise reduction (in modern hearing aids), they report many studies over decades have shown adults prefer adaptive noise reduction because listening comfort is greater, noise is less salient, and importantly, noise reduction has little or no effect on intelligibility. With specific regard to applying noise reduction to children, Dillon, Ching, and Golding report noise reduction generally does not negatively impact intelligibility and in some studies, adaptive noise reduction has improved intelligibility for children (Marcous, Yathiraj, Cote, and Logan, 2006; Pittman,2011; Stelmachowicz et al, 2010). The authors state there is no compelling reason why adaptive noise reduction should not be used for all children and in particular "We therefore recommend that noise reduction systems in hearing aids be routinely enabled for children of all ages…."
For More Information, References, and Recommendations
Dillon H, Ching T, Golding M. (2014) "Hearing Aids For Infants and Children." Chapter 20, pages 209 to 227, in Pediatric Audiology Diagnosis, Technology and Management. Second Edition. Editors; Jane Madell and Carol Flexer. Thieme Medical Publishers, Inc.