Improving speech-in-noise recognition for children with hearing loss: Potential effects of language abilities, binaural summation, and head shadow

Abstract

Objective: This study examined speech recognition in noise for children with hearing loss, compared it to recognition for children with normal hearing, and examined mechanisms that might explain variance in children’s abilities to recognize speech in noise. Design: Word recognition was measured in two levels of noise, both when the speech and noise were co-located in front and when the noise came separately from one side. Four mechanisms were examined as factors possibly explaining variance: vocabulary knowledge, sensitivity to phonological structure, binaural summation, and head shadow. Study sample: Participants were 113 eight-year-old children. Forty-eight had normal hearing (NH) and 65 had hearing loss: 18 with hearing aids (HAs), 19 with one cochlear implant (CI), and 28 with two CIs. Results: Phonological sensitivity explained a significant amount of between-groups variance in speech-in-noise recognition. Little evidence of binaural summation was found. Head shadow was similar in magnitude for children with NH and with CIs, regardless of whether they wore one or two CIs. Children with HAs showed reduced head shadow effects. Conclusion: These outcomes suggest that in order to improve speech-in-noise recognition for children with hearing loss, intervention needs to be comprehensive, focusing on both language abilities and auditory mechanisms.

Individual differences in language and working memory affect children’s speech recognition in noise

“…There is support for both models in the literature, as children with higher scores on standardised tests of vocabulary have stronger speech recognition abilities in noise or conditions of stimulus degradation than peers with lower vocabulary in some studies (Garlock et al, 2001; Munson, 2001; Vance et al, 2009; McCreery & Stelmachowicz, 2011; Vance & Martindale, 2012). However, in other studies (Eisenberg et al, 2000; Stelmachowicz et al, 2000; Nittrouer et al, 2013), vocabulary has not been a consistent predictor of word recognition under degraded conditions.…”

“…Individual variability in speech recognition in noise, even in typically developing children with normal hearing, complicates the differentiation of normal from atypical performance. The protracted and variable developmental trajectory for speech recognition in noise has been attributed to the parallel maturation of cognitive and linguistic abilities during childhood (Wightman & Allen, 1992; Caldwell & Nittrouer, 2013; Nittrouer et al, 2013). Yet, several investigations have failed to find consistent relationships between cognitive and linguistic abilities and speech recognition in school-age children (Eisenberg et al, 2000; Fallon et al, 2000; Talarico et al, 2006).…”

What can we expect of normally-developing children implanted at a young age with respect to their auditory, linguistic and cognitive skills?

“…In general, the intervention showed positive effects on phoneme-grapheme correspondence. Nittrouer et al, 2013 report that about 30% of the variance of speech recognition scores can be explained by the (poorer) phonological awareness of children with a CI. Needless to say, speech understanding in noise is extremely important, both for training as well as for assessment .…”

Factors affecting the development of speech recognition in steady and modulated noise

“…In cases where the noise spectrum differs between the speech and the masker, the adults can be expected to take good advantage of parts of the speech spectrum that rise to audibility, but, because children require greater bandwidth, they will require additional signal level to bring that extra bandwidth into audibility. Although many developmental studies of masked speech recognition use masking noise that is filtered to have the same spectral shape as the test speech material it is not uncommon for the masker to have a different spectral shape (Stuart et al, 2006;Gustafson and Pittman, 2011;Nittrouer et al, 2013;Hall et al, 2014).…”