Deaf children with cochlear implants are at a disadvantage in learning vocabulary when compared with hearing peers. Past research has reported that children with implants have lower receptive vocabulary scores and less growth over time than hearing children. Research findings are mixed as to the effects of age at implantation on vocabulary skills and development. One goal of the current study is to determine how children with cochlear implants educated in an auditory-oral environment compared with their hearing peers on a receptive vocabulary measure in overall achievement and growth rates. This study will also investigate the effects of age at implant on vocabulary abilities and growth rates. We expect that the children with implants will have smaller vocabularies than their hearing peers but will achieve similar rates of growth as their implant experience increases. We also expect that children who receive their implants at young ages will have better overall vocabulary and higher growth rates than older-at-implant children.
Repeated assessments using the Peabody Picture Vocabulary Test were given to 65 deaf children with cochlear implants who used oral communication, who were implanted under the age of 5 yr, and who attended an intensive auditory-oral education program. Multilevel modeling was used to describe overall abilities and rates of receptive vocabulary growth over time.
On average, the deaf children with cochlear implants had lower vocabulary scores than their hearing peers. However, the deaf children demonstrated substantial vocabulary growth, making more than 1 yr’s worth of progress in a year. This finding contrasts with those of previous studies of children with implants, which found lower growth rates. A negative quadratic trend indicated that growth decelerated with time. Age at implantation significantly affected linear and quadratic growth. Younger-at-implant children had steeper growth rates but more tapering off with time than children implanted later in life.
Growth curves indicate that children who are implanted by the age of 2 yr can achieve receptive vocabulary skills within the average range for hearing children.
The current study examined how implanted children educated in an auditory-oral environment compared with hearing peers on a receptive vocabulary measure (PPVT) in overall achievement and growth rates. We also investigated the effect of age at implant on vocabulary development. On average, implanted children had smaller vocabularies than hearing peers, but demonstrated substantial growth, making more than 1 yr worth of progress in a year. Age at implantation significantly affected vocabulary development. Growth curves indicated that children who are implanted under the age of 2 yr can achieve receptive vocabulary skills well within the average range for hearing children.
1Department of Psychology, Washington University in St. Louis, St. Louis, Missouri; 2Dallas Cochlear Implant Program, Department of Otolaryngology/Head and Neck Surgery, University of Texas Southwestern Medical Center, Dallas, and Callier Advanced Hearing Research Center, University of Texas at Dallas, Texas; and 3Moog Center for Deaf Education, St.Louis, Missouri.
This work was approved by the Hilltop Human Studies Committee (Approval Number X05-76) and supported in part by grants from March of Dimes Birth Defects Foundation.
Some of these results were presented at the meeting of the 11th International Conference on Cochlear Implants in Children, Charlotte, NC, April 2007.
Address for correspondence: Heather Hayes, Department of Psychology, Washington University in St. Louis, One Brookings Drive, Campus Box 1125, St. Louis, MO 63128. E-mail: firstname.lastname@example.org.
Received November 13, 2007; accepted September 3, 2008.