Reading and spelling abilities of school-aged children with Williams syndrome

Reading and spelling abilities of school-aged children with Williams syndrome

First Author: Caroline Greiner de Magalhães -- University of Louisville
Additional authors/chairs: 
Carolyn B. Mervis; Cláudia Cardoso-Martins
Keywords: Spelling, Reading, Williams syndrome, reading and writing relationship, Intellectual Disability
Abstract / Summary: 

Purpose: We examined the relation between the reading and spelling abilities of school-aged children with Williams syndrome (WS), a genetic disorder associated with intellectual disability. Method: Sixty 9- to 14-year-olds with WS (M=11.35 years, SD=1.97) completed the Wechsler Individual Achievement Test-III Word Reading, Pseudoword Decoding, and Spelling subtests; the Differential Ability Scales-II (DAS-II) core, Rapid Naming (RAN), and Working Memory (WM) tests; the Peabody Picture Vocabulary Test-4 (PPVT-4); and the Expressive Vocabulary Test-2 (EVT-2). Reading instruction method was classified as Phonics (n=31) or Other (n=29) based on parent report and the child’s IEP. Results: Spelling standard scores (SSs) (M=69.27, SD=15.37) were significantly lower than Basic Reading SSs (M=73.40, SD=17.14), t(59) = 4.38, p<.001. Spelling SSs were significantly higher for the Phonics group (M=78.97, SD=12.65) than the Other group (M=57.83, SD=7.99), F(1,57) = 37.61, p<.001, even after controlling for DAS-II General Conceptual Ability (similar to IQ). Multiple regression analysis was performed with Spelling SS as the dependent variable. Basic Reading SS was entered first and accounted for 82% of the variance in Spelling SS (p<.001). Vocabulary SS (average of PPVT-4 and EVT-2 SSs), RAN T-score, and WM SS were entered as predictors in the second step but did not explain significant additional variance, R2 change = .022, p=.068. Conclusions: Reading ability is a strength for children with WS relative to spelling ability. Consistent with the literature for typically developing children in this age range, reading ability was the best predictor of spelling ability and phonics-based instruction was beneficial to spelling development.