INTRODUCTION

1. Acoustic Aspects of Place Contrasts in Children with Cochlear ImplantsKelly Wagner, M.S., & Peter Flipsen Jr., Ph.D. Idaho State University ASHA 2012 Atlanta, GA • INTRODUCTION • Cochlear implants (CIs) provide individuals with significant hearing loss access to sound that is different from normal hearing. • Individuals who learn speech solely from CIs may do so differently than typical speakers. • The current study used acoustic analysis to examine selected speech sound contrasts relative to place of articulation in the speech of 17 deaf children fitted with CIs. • METHOD • Participants included 4 males and 13 females born with severe to profound bilateral hearing loss. • No other known handicaps. • Implantation age ranged from 1;2 to 8;4 (Mn = 3;9). • At time of testing the children ranged in age from 4;8 to 11;1 (Mn = 8;0). • At time of testing implant experience ranged from 1;0 to 7;10 (Mn = 4;3). • As part of a larger protocol, the children named pictures presented by a trained graduate student examiner. • Targets were a subset of the words from the Minimal Pairs Production Task (MPPT; Chin, Finnegan, & Chung, 2001). • pie/tie pea/key pat/cat fell/shell • METHOD (cont’d) • Samples were recorded on digital audiotape in a single wall sound treated booth. • Recordings were parsed into single word files using CSL 3.4.0 and analyzed using WaveSurfer 1.8.4. • Place contrasts were examined by looking at: • Spectral peak, spectral moments (mean, variance, skew, kurtosis), VOT, and relative amplitude. • Statistical tests were conducted with p < .05. • RESULTS • As a group, the speakers appeared to have been using the following features contrastively: • RESULTS (cont’d) • Correlations were conducted with feature distinctiveness and age of implantation, implant experience and chronological age. Results were limited and sometimes contradictory. • Age of implantation was sometimes associated with greater distinctions between skew and spectral peak. • Implant experience was sometimes associated with greater distinctions between relative amplitude; and less distinctiveness for variance, skew, mean and kurtosis. • Chronological agewas rarely associated with feature distinctiveness; when this did occur, older children tended to produce smaller distinctions overall. However, older speakers tended to be later implanted. • Comparisons to Normal Hearing Children • Group averages were compared with data from Nissen (2003), who reported on normal hearing children. • DISCUSSION • Phonemes in this study that do not correlate well with normative data (/k/, /f/, and /C/) are also those that frequently present problems for children with hearing impairments, either because the oral movements are difficult to see or because they are distinguished by their high frequency spectrum. • Speakers in this study succeeded in differentiating between place contrasts, but not necessarily in the same way as their normal-hearing peers. • Given similarities to normative values, moments analysis may be an appropriate tool for assessing disordered speech and identifying subphonemic contrasts. • A larger, more homogeneous sample is needed. • REFERENCES • Chin, S. B., Finnegan, K. R., & Chung, B. A. (2001). Relationships among types of speech intelligibility in pediatric users of cochlear implants. Journal of Communication Disorders, 34, 187-205. • Forrest, K., Weismer, G., Hodge, M., Dinnsen, D., & Elbert, M. (1990). Statistical analysis of word-initial /k/ and /t/ produced by normal and phonologically disordered children. Clinical Linguistics & Phonetics, 4, 4, 327-340. • Forrest, K., Weismer, G., Milenkovic, P., & Dougall, R. (1988). Statistical analysis of word-initial voiceless obstruents: preliminary data. Journal of the Acoustical Society of America, 84, 1, 115-123. • Jongman, A., Wayland, R., & Wong, S. (2000). Acoustic characteristics of English fricatives.Journal of the Acoustical Society of America, 108, 3(1), 1252-1263 • Nissen, S. L. (2003). An acoustic analysis of voiceless obstruents produced by adults and typically developing children. Unpublished doctoral dissertation.Columbus, Ohio: Ohio State University. • RESULTS (cont’d) • Note differences for /k/, /C/, and /f/. • In subjective assessments, these same speakers’ productions of /k/, /C/, and /f/ were judged to be correct > 90% of the time. This is similar to Forrest et al. (1990) and suggests that differences may persist even when the child’s error is “fixed”. Nissen Wagner Spectral mean distinguished all four word pairs from one another Acknowledgments Many thanks to Julie Beeler, Velvet Buehler, Molly Erickson, Mark Hedrick, Marge Hudson, GaylaHutsell, Kim Jenkins, Leslie Jolles, Christopher Loether, Tony Seikel, and SanetaThurman for their assistance. Special thanks to Rhonda Parker for participant testing. Many thanks also to the children and their parents who participated.