R ECEPTIVE VOCABULARY DEVELOPMENT IN CHILDREN WITH COCHLEAR IMPLANTS : Achievement in an intensive, auditory-oral educational setting Heather Hayes, Ann E. Geers, Rebecca Treiman, & Jean S. Moog

30 June 08 Outline What do we know about vocabulary development in deaf children? Our study Implications for parents and professionals Future directions

30 June 08 General findings Cochlear implants vs. hearing aids CI kids have better performance in... speech perception (e.g., Blamey et al., 2001; Osberger et al., 1991) receptive language (e.g., Geers & Moog, 1994; Tomblin et al., 1999; Truy et al.,1998) Yet, is this the most appropriate comparison?

30 June 08 Findings: Receptive vocabulary (PPVT) CI kids have poorer receptive vocab than hearing peers (Blamey et al., 2001; Connor et al., 2000; Eisenberg et al., 2004; El-Hakim et al., 2001; Geers & Moog, 1994; Kirk et al., 2000; Miyamoto et al., 1999; Spencer, 2004)

30 June 08 Findings: Receptive vocabulary (PPVT) CI kids improve receptive vocab skills over time, but below rate of hearing peers  growth rates range from.45 to.72 year’s growth per year (Blamey et al., 2001; Connor et al., 2000; El-Hakim et al., 2001; Geers & Moog, 1994; Kirk et al., 2000)

30 June 08 Individual differences Does age at implant make a difference in outcome?  Theoretical implications critical period?  Practical implications surgery at 12 mos or surgery at 3 yrs?

30 June 08 Findings: Receptive vocabulary (PPVT) Some found (-) age at implant effect on overall receptive vocab level,  (Connor et al., 2000)...some have found (+) age at implant effect,  (El-Hakim et al., 2001; Kirk et al., 2002)...and others have found no effect.  (Miyamoto et al., 1999)

30 June 08 Findings: Receptive vocabulary (PPVT) Some found age at implant effect on growth rates...  5 (Connor et al., 2000)  < 2 better than 2-4 (Kirk et al., 2000)...but others didn’t.  (El-Hakim et al., 2001; Miyamoto et al., 1999)

30 June 08 Problems with previous research Sample populations  Small numbers of CI kids  Mixed communication methods Signed English, speech, ASL Tests given in preferred communication mode  Kids older at implantation (mean 3-5 years – not current)  Differing definitions of prelingual onset  Educational environment often overlooked  Advances in technology often overlooked Inadequate methods for investigating growth over time

30 June 08 Current study Moog Center for Deaf Education testing database  Receptive vocabulary test (PPVT)  NVIQ  Age at CI  Year of CI Controls for communication method, educational environment, access to audiologists, parental involvement

30 June 08 Study questions: How do implanted kids in an oral educational setting compare to hearing peers on a receptive language measure (PPVT)?  vocab level  growth rate Does age at implant affect...  vocab level?  growth rate?

Participants N kids65 N vocabulary scores231 Mean # vocab tests taken per child3.5 Mean age at implant2.69 yrs Range when children received implants Mean interval between tests1.01 yrs Mean age at 1 st test5.12 yrs Mean duration of implant experience at 1 st test 2.39 yrs Mean NVIQ108 Age at onset< 3 yrs Mean highest level of parent education16.36 yrs 30 June 08

Growth curve analysis More flexible than traditional approach  different numbers of tests per kid  unequal spacing between tests  takes autocorrelation into account  allows both intercepts and slopes to vary randomly between participants

30 June 08 Multilevel model Level 1: How do individuals change over time? Y ij = π 0i + π 1i TIME + π 2i TIME 2 + ɛ ij Level 2: How do these changes vary across individuals? π 0i = ɣ 00 + ɣ 01 PREDICTOR + ζ 0i π 1i = ɣ 10 + ɣ 11 PREDICTOR + ζ 1i π 2i = ɣ 20 + ɣ 21 PREDICTOR + ζ 2i

Results 30 June 08 Significant effects (in Standardized Scores) Initial vocabulary level57 Growth rate9 pts per yr Year of implant4 Age at implant (-)4 pts per yr

30 June 08 Expected growth curves: Average child from our sample

30 June 08 Expected curves: Age at implant effect

30 June 08 Language study summary CI kids are at disadvantage compared to hearing peers. However, CI kids make more than a year’s worth of progress in one year. Age at implant effect:  Younger is better for greater yearly progress and for achieving normal levels earlier.

Future directions Investigate whether these results generalize to other areas of language Investigate whether children maintain a normal level of language growth when they leave this very special environment and go into mainstream Encourage schools to conduct and maintain repeated assessment results over time to be used for practical research projects. 30 June 08