Vocabulary acquisition rate after pediatric cochlear implantation and the impact of age at implantation.
OBJECTIVE
studies of early vocabulary development after pediatric cochlear implantation show growth rates that approach normality. Do these growth rates continue to rise over time and, therefore, allow a 'catch up' with ideal scores for age, or do they decline after an initial peak. Could age at implantation be a decisive factor in that process?


METHODS
retrospective study (mean follow-up 4 years).


METHODS
pre-lingually deaf children implanted between 1988 and1999, who serially performed Peabody Picture Vocabulary Test-Revised (PPVT), (37 patients) and Expressive One-word Picture Vocabulary Test-Revised (EOWPVT), (35 patients).


METHODS
the mean rates of age equivalent scores were determined for the whole follow-up period and analyzed further for two post-implant periods (the two halves of follow-up duration of individual patients). After sub-grouping by age at implantation (younger or older than 5 years old), the same analysis was executed for each subgroup.


RESULTS
the mean EOWPVT rate of the earlier period was higher than that of the later period (1.33 vs. 0.67, P<0.01) and the mean PPVT rate of the earlier period was higher than that of the later period (0.72 vs. 0.5). The latter difference was not statistically significant (P>0.05). Within subgroups by age at implantation, the PPVT mean rates were stable for younger implanted patients (0.56 for both periods) and dropped for the older implanted sub-group (0.87-0.43, P>0.05). The EOWPVT mean rates declined significantly for the older patients group (1.72-0.55, P<0.01) but insignificantly for the younger patients (0.99-0.77, P>0.05).


CONCLUSIONS
vocabulary acquisition rates decline in the post-implantation period. This is more pronounced with older implanted children and the EOWPVT rates. This information on the time course development of vocabulary after implantation would be valuable in counseling and planning habilitation in addition to candidate selection.
El-Hakim
H
H
Department of Otolaryngology, The Hospital for Sick Children, 555 University Avenue, M5G 1X8, Toronto, Canada. helhakim@aol.com
Papsin
B
B
Mount
R J
RJ
Levasseur
J
J
Panesar
J
J
Stevens
D
D
Harrison
R V
RV
D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D019929:Cochlear Implantation; D003638:Deafness / Q000209:etiology / Q000534:rehabilitation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007807:Language Tests; D008297:Male; D012189:Retrospective Studies; D014825:Vocabulary