Graduation Year

2013

Document Type

Dissertation

Degree

Ph.D.

Degree Granting Department

Communication Sciences and Disorders

Major Professor

Theresa Chisolm

Keywords

auditory perceptual development, imitation, OlimSpac, pediatric hearing loss, speech audiometry

Abstract

With reductions in the age criterion for cochlear implantation, the need for age-appropriate measures of speech perception skills has increased. One recently developed tool that shows great promise for the clinical assessment of auditory speech perception capacity in young children with cochlear implants is the On-Line Imitative Test of Speech-Pattern Contrast Perception (OlimSpac). The OlimSpac requires a child to imitate nonword utterances by providing a verbal response. The child's perceptual abilities are inferred from the child's productions through having a listener, who is masked to the stimulus select the utterance produced by the child in an eight-alternative force-choice task. Although the OlimSpac has the potential for use in children with cochlear implants, the specific role of measured speech production abilities on performance has yet to be systematically examined. Thus, the main objective of the present study was to examine the influence of speech production abilities on OlimSpac performance in an auditory-visual (A-V) and auditory-only (A-O) condition in young children with cochlear implants relative to an articulation-matched sample of normal hearing peers. A secondary objective was to determine whether the presentation modality affected a child's OlimSpac performance.

A matched pair design was used to compare the OlimSpac performance of ten children with cochlear implants (ages 29 to 76 months) to normal hearing peers (ages 27 to 73 months). Each child with cochlear implants was matched to a child with normal hearing from a sampled population of 22 normal hearing participants based on word-level articulation skills, as measured by the GFTA-2, accounting for hearing age and gender. The OlimSpac software generated a score for a single contrast and a single presentation modality (A-V or A-O). The score was based on eight binary trials. Due to the small trial size, individual contrast scores were interpreted as pass/fail, given that only a score of seven or eight is significantly better than chance. Therefore, OlimSpac performance was determined by a composite score reflecting the average across all six contrasts, based on 48 binary trials.

Average composite scores for both the A-V and A-O conditions were lower, albeit not significant, for young children with cochlear implants compared to their articulation-matched controls. Examination of individual phonemic contrast scores revealed that the articulation-matched sample of normal hearing participants most often failed the post-alveolar consonant place contrast, whereas children with cochlear implants most often failed the consonant voicing contrast. There were also no significant within group difference in speech perception performance between the A-V and A-O conditions of the OlimSpac.

The results of this study demonstrated that children with cochlear implants achieved similar speech perception performance to their articulation-matched normal hearing peers. Although children's speech production abilities partially influenced their OlimSpac performance, knowledge of word-level articulation skills allows clinicians to make appropriate judgments when interpreting composite scores, thus validating the OlimSpac as an indirect measure of a child's speech perception capacity and a direct measure of speech perception skills. Objective scores obtained from a child's OlimSpac performance may be used to assess outcomes of cochlear implant use, guide cochlear implant mapping, and plan habilitative intervention. A greater understanding of the potential effect of speech production performance on estimates of speech perception ability may also assist in highlighting other developmental, linguistic and/or cognitive delays masked by a child's hearing loss.

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