Effects of Stimulus Bandwidth on the Imitation of English Fricatives by Normal-Hearing Children

Abstract

Purpose-Recent studies from our laboratory have suggested that reduced audibility in the high frequencies (due to the bandwidth of hearing instruments) may play a role in the delays in phonological development often exhibited by children with hearing impairment. The goal of the current study was to extend previous findings on the effect of bandwidth on fricatives/affricates to more complex stimuli.Method-Nine fricatives/affricates embedded in 2-syllable nonsense words were filtered at 5 and 10 kHz and presented to normal-hearing 6-7 year olds who repeated words exactly as heard.Responses were recorded for subsequent phonetic and acoustic analyses.Results-Significant effects of talker gender and bandwidth were found, with better performance for the male talker and the wider bandwidth condition. In contrast to previous studies, relatively small (5%) mean bandwidth effects were observed for /s/ and /z/ spoken by the female talker. Acoustic analyses of stimuli used in the previous and the current studies failed to explain this discrepancy.Conclusions-It appears likely that a combination of factors (i.e., dynamic cues, prior phonotactic knowledge, and perhaps other unidentified cues to fricative identity) may have facilitated the perception of these complex nonsense words in the current study.Previous studies have shown that even mild-to-moderate hearing loss in young children can affect communication abilities, vocabulary development, verbal abilities, reasoning skills, and psychosocial development (Bess, Dodd-Murphy, & Parker, 1998;Davis, Elfenbein, Schum, & Bentler, 1986;Davis, Shepard, Stelmachowicz, & Gorga, 1981;Markides, 1970;. Particular difficulties demonstrated by these children are the production of fricatives and affricates (Elfenbein, Hardin-Jones, & Davis, 1994) and increased errors in noun and verb morphology (Davis et al., 1986;McGuckian & Henry, 2007;Norbury, Bishop, & Briscoe, 2001).Such performance deficits are often attributed to reduced signal audibility. One factor that influences audibility of the high-frequency components of speech is the bandwidth of hearing instruments. A wider bandwidth can be achieved in custom devices (e.g., in-the-canal and inthe-ear instruments) than in the behind-the-ear (BTE) instruments that are typically used with infants and young children. These differences occur because of tubing resonances associated Correspondence should be addressed to Patricia G. Stelmachowicz, 555 N. 30th St., Omaha, NE 68131; E-mail: stelmach@boystown.org. Patricia G. Stelmachowicz, Kanae Nishi, Sangsook Choi, Dawna E. Lewis, Brenda M. Hoover, and Darcia Dierking, Boys Town National Research Hospital. Andrew Lotto, University of Arizona, Speech, Language and Hearing Sciences.Sangsook Choi is now at the Department of Speech Language and Hearing Science, Purdue University. NIH Public Access NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscriptwith the earmold coupling for BTE instruments (Killion, 1980). Thus, even with digital technology, the usable upper limit o...

Production of contrast between sibilant fricatives by children with cochlear implants

“…Perhaps due to broad current spread of electrodes (Friesen et al, 2001) and an upper frequency limit that is lower than that of individuals with NH, individuals with CIs may not hear that /s/ has a high frequency spectral peak in some cases. This may happen more for speakers who produce higher frequency spectral peaks such as female speakers (e.g., Stelmachowicz et al, 2008). That an adult female produced the auditory stimuli in this study may have contributed to a perceptual confusion of /f/ for /s/.…”

Identification of high-pass filtered male, female, and child vowels: The use of high-frequency cues

“…It was felt that identification performance reported in previous work might have been limited by the inability to faithfully capture and represent highfrequency information in the vowel acoustic structure. Given evidence documenting the benefits of additional highfrequency information in both perceptual tasks for the hearingimpaired (Stelmachowicz et al, 2001;Stelmachowicz et al, 2007;Pittman, 2008) and computer recognition models Itakura, 1994, 1995;Hu and Wang, 2004), it was predicted that listeners would be able to identify the high-pass filtered vowels with greater accuracy than was found by Lehiste and Peterson (1959). This was confirmed.…”

“…It was of interest to examine identification performance with lower spectral resonances (F1-F3) removed from the hVd signal to evaluate the ability of normal-hearing listeners to utilize high-frequency information for determining vowel identity. More recent research documents benefits of including additional high-frequency information in the speech signal such as improvements in speech perception and novel word learning in children (Pittman, 2008;Stelmachowicz et al, 2001;Stelmachowicz et al, 2007), increases in identification accuracy of automatic speech/speaker identification systems Itakura, 1994, 1995;Hu and Wang, 2004), and improvements in qualitative judgments of speech quality/naturalness (Moore and Tan, 2003) and in some cases improvements in speech recognition for adults Moore et al, 2010).…”

The effects of frequency lowering on speech perception in noise with adult hearing-aid users

“…A significant amount of linguistic information is present in the high frequencies and audibility of high frequency speech sounds, particularly consonants, is crucial for optimal recognition of speech in quiet and noise (Wolfe et al, 2011; Stelmachowicz et al, 2007, 2008). Stelmachowicz and colleagues (2007) demonstrated that restricted stimulus bandwidth, such as that in hearing aids, can negatively affect the perception of /s/ and /z/ spoken by female talkers.…”