Measuring Auditory Performance of Pediatric Cochlear Implant Users: What can be Learned for Children who use Hearing Instruments?

Demonstration of successful outcomes from use of a sensory device by individuals with hearing loss depends to a large extent on quantifiable improvements in auditory performance. Quantifiable improvements are typically characterized by speech perception outcomes, which involve speech awareness/detection, reception, discrimination, identification or recognition of speechtype materials (e.g., phonemes, syllables, words or sentences). Although performance outcomes are most often conceptualized in terms of percent-correct scores, speech perception outcomes may also be represented by dB level (as used in the speech reception threshold or when testing in background noise), reaction time, and other such metrics used to characterize the data. Improvements with the sensory device can be demonstrated by comparing performance preand post device activation, or by tracking performance over time with the device. With specific reference to children who have hearing loss, there are several reasons why assessment of speech perception can be valuable as a means of documenting success (or lack thereof) with an auditory sensory device. Speech perception results may be of some use in determining whether a very young child should continue to use hearing aids or be considered for a cochlear implant. After fitting of the device, follow-up assessments can be beneficial for tracking rate of improvement. Lastly, speech perception data in combination with speech-language outcomes and other indices of development are essential for establishing guidelines for (re)habilitation. Characterization of communication outcomes, with emphasis on speech perception, has become one of the hallmarks of pediatric cochlear implantation. Originating with the manufacturer-sponsored clinical trials required by the U.S. Food and Drug Administration (FDA) and progressing to independent studies funded by the National Institutes of Health (NIH), long-standing pediatric implant centers have become accustomed to conducting follow-up assessment protocols as part of their standard clinical practice. It is far from evident that this model has been extended to children who use hearing aids. As a consequence, parents of children with hearing aids may not feel as committed to a long-standing partnership with their audiological center as do parents of children with cochlear implants; such a commitment is often a requirement of the pediatric implant program. Speech perception assessment in children with cochlear implants forms the focus of this chapter from both a clinical and research perspective. Considerations in measuring speech perception in the pediatric hearingimpaired population provide important background information. The evolving nature of auditory evaluation in cochlear implant candidates and recipients is discussed, including development of speech perception tests and test batteries for adult and pediatric cochlear implant users. New directions in behavioral test development for infants and toddlers follow.