Linguistic contributions to frequency importance functions in children with normal hearing

Abstract

Frequency-importance functions represent the contribution of an individual frequency band to speech recognition and are used to generate weighted estimates of audibility in the Speech Intelligibility Index (SII). To date, nearly all frequency-importance functions have been derived from adult speech perception data. Estimates of audibility based on these functions are increasingly being applied to children who wear hearing aids. Frequency-importance functions based on perceptual data from children and adults do not differ on average (McCreery & Stelmachowicz, 2011), but importance functions derived from children are more variable than those obtained from adults. Numerous factors could influence individual variability in frequency-importance functions for children. The purpose of this study was to examine the influence of language abilities on individual differences in importance functions obtained from children. We hypothesized that children with stronger vocabulary knowledge would have importance-functions that were more adult-like than peers with more limited vocabulary abilities. Frequency-importance functions were derived from a group of 105 children with normal hearing who were between 5-12 years of age and a group of 20 adults with normal hearing. Children with higher vocabulary abilities had frequency-importance functions that were more adult-like than peers with lower vocabulary abilities, after controlling for age.