Pediatric Image-Guided Cochlear Implant Programming

Although children with cochlear implants (CIs) have significantly improved speech, language, and reading outcomes relative to previous generation CI recipients, too many pediatric CI users still display persistent speech, language, and reading difficulties despite early implantation and early intervention. Children with CIs typically lag behind their peers with normal hearing (NH) by 1 or more years on measures of speech, language and/or reading. Though these persistent delays can be attributed in part to a period of auditory deprivation prior to implantation, increasing evidence suggests that a degraded CI signal is also implicated in poorer development of auditory, speech, language, and reading skills for pediatric CI recipients. A related developmental path to reading also disrupted from the degraded CI signal is phonological awareness (PA) because PA is predicated, in part, on speech recognition.

A procedure developed by Noble and colleagues, image-guided CI programming (IGCIP), significantly improves auditory function, speech recognition, and distally, receptive language abilities for adult CI users. The investigators have preliminary evidence that pediatric CI recipients also significantly benefit from IGCIP. But there is a need to systematically investigate IGCIP in children to determine whether this individualized intervention yields a) associated benefits in auditory function and b) related improvements in speech, language, PA and/or reading. Thus, our primary goal is to evaluate the effects of IGCIP on auditory function, speech recognition, PA and reading, as well as speech and language abilities in pediatric CI recipients within the context of a double blind, waitlist controlled randomized clinical trial (RCT). The investigators obtained psychophysical estimates of auditory function and speech recognition, PA, reading, speech, and language abilities for 47 pediatric CI users in a baseline assessment and assessments 12 and 24 months to test the impact of IGCIP. The investigators examined the immediate (short-term) and longer-term effects over a 2-year period by comparing outcomes between groups for those randomly assigned to immediate (n = 24) or deferred (n = 23) IGCIP using a waitlist control study design (deferred IGCIP). The initial comparison was for immediate and deferred IGCIP groups at 12 months. The deferred group then received the IGCIP intervention and both groups were followed for an additional 12 months (total enrollment for 24 months). The proposed research includes the following aims and specific hypotheses:

Aim 1: Auditory function. The investigators compared auditory function and speech recognition of the immediate and waitlist control participants. Original hypotheses were as follows: Hypothesis 1a: There will be significant positive short-term gains (12 months) in spectral and/or temporal resolution as well as speech recognition-particularly in noise-for children immediately receiving IGCIP as compared to waitlist controls. This hypothesis will be tested by comparing the difference in the amount of change in scores within-subjects (pre- to post-IGCIP gain) between the groups (treated vs. untreated) controlling for initial scores. Hypothesis 1b: IGCIP gain in spectral and/or temporal resolution will significantly predict gain in speech recognition. This hypothesis was tested via regression analyses of change in speech recognition scores on change in resolution, controlling for baseline values and also controlling for baseline levels of speech recognition.

Aim 2: PA and reading. The investigators will explore the complex relationships amongst auditory function, speech recognition, PA, and reading ability. Hypothesis 2a: Differential growth in spectral/temporal resolution and/or speech recognition will predict growth in PA, which in turn will predict mediated growth in reading. Hypothesis 2b: Growth in PA will be associated with amount of IGCIP benefit (gain) and will mediate growth in reading, which will be tested via cross-legged panel and path analyses. Note that testing these hypotheses is not dependent on the outcomes of Aim 1 as only variable gain in the Aim 1 measures (e.g., speech recognition) are required for aim 2 analyses, not a significant between-group difference for IGCIP in Aim 1.

Aim 3: Speech and language. The investigators will compare pre- and post-IGCIP receptive and expressive language abilities and speech production of pediatric CI recipients to the waitlist control group. The investigators will test these skills at various time points on standardized and clinical measures of 1) receptive language, 2) expressive language, and 3) speech production (articulation and acoustic analyses). Hypothesis 3a: There will be significant differences between groups for positive growth in speech and language and this growth will be predicted by the relative improvement in auditory function (aim 1) from IGCIP while controlling for baseline levels of working memory. Hypothesis 3b: Spectral/temporal resolution and speech recognition and/or PA will serve as mediators of expressive and receptive language gains and speech production gains both within and between groups. 3a and 3b will also be tested using mixed effects modeling and regression analyses to examine these "downstream" effects. Even if no between group differences in Aim 1 and/or Aim 2 are seen, the investigators will nonetheless be able to test whether spectral/temporal resolution, speech recognition, and/or PA predict growth in receptive and/or expressive language and/or changes in speech production (including subclinical acoustic analyses).