![]() The children who show exceptional progress appear to acquire spoken language quickly and easily and seem to be on a developmental trajectory that parallels children with normal hearing ( Svirsky, Robbins, Kirk, Pisoni, & Miyamoto, 2000). In some of our earlier research we have looked in detail at several of the factors distinguishing children who display exceptionally good performance with their cochlear implants, from those who derive only minimal benefit ( Pisoni, Cleary, Geers, & Tobey, 2000). The observed individual differences can be extremely striking. It may be fruitful to investigate these complex interactions directly using measures that assess individual component processes of speech and language behavior if we want to explain why some pediatric cochlear implant users do so well while others struggle and achieve only small benefits after receiving a cochlear implant. Identifying the reasons for the wide variability in outcome measures after cochlear implantation is a challenging research problem because a large number of complex sensory, perceptual, cognitive and linguistic processes affect speech and language performance in any particular behavioral task. Although large individual differences in outcome after implantation have been well documented for many years in the clinical literature, the factors responsible for variation in performance are still not well understood ( Blamey et al., 2001 Hodges, Dolan-Ash, Balkany, Scholffman, & Butts, 1999 Kirk, 2000 Pisoni, 2000 Sarant, Blamey, Dowell, Clark, & Gibson, 2001). Some children do extremely well with their cochlear implant, whereas others derive only minimal benefits. Individual Differences and Variation in Outcomeĭespite the success of cochlear implants in many prelingually deafened, early-implanted children, enormous individual differences have been reported on a wide range of speech and language outcome measures. Results indicate that a substantial portion of the currently unexplained variance may be independently accounted for by individual differences in working memory capacity and other cognitive factors related to the speed and efficiency with which phonological and lexical representations of spoken words are maintained in and retrieved from working memory. Estimates of working memory capacity and articulation rate were obtained for 176 children with cochlear implants using the digit span scores from the Wechsler Intelligence Scale for Children and speaking rate measurements from productions of the McGarr sentences. These authors maintain that to explain further variance we must focus on the underlying cognitive information processing skills that are used to support the perception and production of spoken language. We discuss how these relationships may arise and their contribution to subsequent speech and language development in prelingually deaf children who use cochlear implants.Īlthough previous articles in this supplement have examined child, family, implant, and educational variables that account for significant variance in outcome, these factors account for only about half of the total variance. A smaller percentage, perhaps about 7% of the currently unexplained variance in spoken word recognition scores, may be accounted for in terms of working memory capacity. The results suggest that perhaps as much as 20% of the currently unexplained variance in spoken word recognition scores may be independently accounted for by individual differences in cognitive factors related to the speed and efficiency with which phonological and lexical representations of spoken words are maintained in and retrieved from working memory. Strong correlations were also observed between speaking rate and both forward and backward digit span, a result that is similar to previously reported findings in normal-hearing adults and children. The pooled data indicate that despite statistical “partialling-out” of differences in chronological age, communication mode, duration of deafness, duration of device use, age at onset of deafness, number of active electrodes, and speech feature discrimination, significant correlations still remain between digit span and several measures of spoken word recognition. The present study replicates and extends these initial findings to the full set of 176 participants in the CID cochlear implant study. Recently, Pisoni and Geers (2000) reported that simple forward digit span measures of verbal working memory were significantly correlated with spoken word recognition scores even after potentially confounding variables were statistically controlled for. Large individual differences in spoken word recognition performance have been found in deaf children after cochlear implantation. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |