The Age at Which Young Deaf Children Receive Cochlear Implants and Their Vocabulary and Speech-Production Growth: Is There an Added Value for Early Implantation? Carol McDonald Connor, Holly K. Craig, Stephen W. Raudenbush, Krista Heavner, and Teresa A. Zwolan Objective: The age at which a child receives a co- chlear implant seems to be one of the more impor- tant predictors of his or her speech and language outcomes. However, understanding the association between age at implantation and child outcomes is complex because a child’s age, length of device use, and age at implantation are highly related. In this study, we investigate whether there is an added value to earlier implantation or whether advan- tages observed in child outcomes are primarily attributable to longer device use at any given age. Design: Using hierarchical linear modeling, we exam- ined latent-growth curves for 100 children who had received their implants when they were between 1 and 10 yr of age, had used oral communication, and had used their devices for between 1 and 12 yr. Chil- dren were divided into four groups based on age at implantation: between 1 and 2.5 yr, between 2.6 and 3.5 yr, between 3.6 and 7 yr, and between 7.1 and 10 yr. Results: Investigation of growth curves and rates of growth over time revealed an additional value for earlier implantation over and above advantages attributable to longer length of use at any given age. Children who had received their implants before the age of 2.5 yr had exhibited early bursts of growth in consonant-production accuracy and vo- cabulary and also had significantly stronger out- comes compared with age peers who had received their implants at later ages. The magnitude of the early burst diminished systematically with increas- ing age at implantation and was not observed for children who were older than 7 yr at implantation for consonant-production accuracy or for children who were over 3.5 yr old at implantation for vocab- ulary. The impact of age at implantation on chil- dren’s growth curves differed for speech produc- tion and vocabulary. Conclusions: There seems to be a substantial benefit for both speech and vocabulary outcomes when children receive their implant before the age of 2.5 yr. This benefit may combine a burst of growth after implantation with the impact of increased length of use at any given age. The added advantage (i.e., burst of growth) diminishes systematically with increasing age at implantation. (Ear & Hearing 2006;27;628– 644) Children with profound sensorineural hearing loss are at significant risk for serious speech and language delays that can impact their communica- tion, academic, and social development (Allen, 1986; Holt, 1994; Karchmer, Milone, & Wolk, 1979). One treatment for profound hearing loss is the cochlear implant, which provides substantial, usable hearing for many children (NIH consensus conference, 1995). Use of a cochlear implant has been associated with stronger outcomes in speech perception (Tyler, Teagle, Kelsay, et al., 2001), speech production (Con- nor, Hieber, Arts, et al., 2000; Geers, 2002), language (Svirsky, 2001), and reading (Connor & Zwolan, 2004; Geers, 2002; Spencer, Tomblin, & Gantz, 1998) com- pared with children using conventional hearing aids. However, the variability in these results among chil- dren is high, and many factors seem to contribute to the successful use of cochlear implants. In particular, the age at which children receive a cochlear implant has been related to speech, language, and literacy outcomes (Connor, Hieber, Arts, et al., 2000; Connor & Zwolan, 2004; Lederberg & Spencer, 2005; Tomblin, Barker, Spencer, et al., 2005; Zwolan, Ashbaugh, Alarfaj, et al., 2004). One challenge in estimating the impact of chil- dren’s age at implantation on speech and language development is that the chronological age, length of cochlear implant use, and the age at which children receive the implant are all highly related. Indeed, at any given age, length of use, and age at implantation are perfectly correlated— children who receive im- plants at younger ages will have used the implant for a longer time compared with same-age peers. However, language theories of critical or sensitive periods (Lederberg & Spencer, 2005; Lenneberg, 1967; Newport, 1990) suggest that access to sound during the first few years of life may lead to accel- erated growth and stronger outcomes over and Florida State University and the Florida Center for Reading Research (C.M.C.); and the Department of Otolaryngology, Univer- sity of Michigan, Medical Center, Ann Arbor, Michigan (H.K.C., S.W.R., K.H., T.Z.). 0196/0202/06/2706-0628/0 • Ear & Hearing • Copyright © 2006 by Lippincott Williams & Wilkins • Printed in the U.S.A. 628