Tracking development of speech recognition: longitudinal data from hierarchical assessments in the Childhood Development after Cochlear Implantation Study.

OBJECTIVE: To develop a speech recognition index that summarizes data collected through an array of age-appropriate hierarchical speech recognition tests in a longitudinal study. STUDY DESIGN: Prospective cohort. SETTING: Six tertiary referral centers in the Childhood Development after Cochlear Implantation (CDaCI) Study. PATIENTS: One hundred eighty-eight children implanted at age 5 years or younger and 97 age-comparable normal-hearing controls. INTERVENTION: Cochlear implantation. MAIN OUTCOME MEASURES: Outcome measures were the following: Infant-Toddler Meaningful Auditory Integration Scale, Meaningful Auditory Integration Scale, Early Speech Perception Test, Pediatric Speech Intelligibility Test, Multisyllabic Lexical Neighborhood Test, Lexical Neighborhood Test, and Hearing in Noise Test, obtained before implantation and at 6, 12, 18, and 24 months postimplant. RESULTS: A speech recognition cumulative index, speech recognition index in quiet (SRI-Q), was created to combine information from tests administered in quiet. This index allows simultaneous display of data from all tests in the speech recognition hierarchy and is sensitive to improvements in performance over time as a function of age. SRI-Q also provides a composite of performance on multiple tests, allowing both the tracking of "growth curve" in speech recognition across a wide age range over an extended follow-up period and the comparison of normal-hearing and implanted children on multiple measures. The data range for individual tests is also preserved for ease of interpretation. CONCLUSION: SRI-Q allows tracking of global development of speech recognition over time as children progress through a hierarchy of speech perception measures and complements the more detailed assessments obtained from individual tests within the hierarchy.