Factors associated with development of speech production skills in children implanted by age five

This study investigated speech production outcomes and the factors influencing the outcomes in children who had 4 to 6 yr of experience with a multichannel cochlear implant. Production variables examined included speech intelligibility, accuracy of consonant and vowel production, percentage of plosives and fricatives produced, duration of sentences, percentage of time involved in communication breakdowns during a communication sample, and responses to a speech usage questionnaire.

181 children between the ages of 8 and 9 yr who received a multichannel cochlear implant before age 5 yr participated as subjects. Independent variables were the amount and type of educational intervention and intervening variables were distributed across child, family and implant characteristics. Multiple regression analyses provided a measure of the amount of variance associated with speech production skills accounted for by the intervening and independent variables.

Performance for the key words in the speech intelligibility measured averaged 63.5% for the group of children. Accuracy of phoneme production was higher for consonants (68.0%) than for vowels (61.6%) for the group. More plosives were present for acoustic analyses (91.6%) than were fricatives (78.4%). Duration for the speech intelligibility sentences averaged 2572.3 msec. Communication breakdowns occurred on average 14.5% of the time involved in a language sample. Significant predictors of high levels of oral communication skills included higher nonverbal intelligence, gender, longer use of SPEAK processing strategy, a fully active electrode array, greater dynamic range, and greater growth of loudness. The primary rehabilitative factors contributing to high levels of oral communication were an emphasis on oral-aural communication and classrooms that emphasized dependence on speech and listening.

Speech production performance in children with cochlear implants is influenced by nonverbal intelligence, gender, implant characteristics including the length of time using the newest speech processing strategies, and educational programs emphasizing oral-aural communication. Factors previously thought to be major contributors to speech production performance, such as age of onset of deafness and age of implantation, did not appear to play significant roles in predicting levels of speech production performance.