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Children with Williams syndrome: Developmental trajectories for intellectual abilities, vocabulary abilities, and adaptive behavior
Author(s) -
Mervis Carolyn B.,
Pitts C. Holley
Publication year - 2015
Publication title -
american journal of medical genetics part c: seminars in medical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.419
H-Index - 101
eISSN - 1552-4876
pISSN - 1552-4868
DOI - 10.1002/ajmg.c.31436
Subject(s) - psychology , cohort , sss* , longitudinal study , longitudinal sample , demography , developmental psychology , population , intellectual disability , cohort study , medicine , psychiatry , pathology , sociology
To examine longitudinal trajectories of intellectual abilities, single‐word vocabulary abilities, and adaptive behavior for 76 children with Williams syndrome (WS) aged 4–15 years, we compared their standard scores (SSs) at two time points approximately 3 years apart on the same standardized measures. At the group level, mean SS declined significantly for 8 of the 12 measures and showed a slight (nonsignificant) increase or decrease for 4 measures. However, for most measures significant changes in SS were found for only a small proportion of the children, with some children evidencing significant declines and a smaller proportion evidencing significant increases. Significant SS changes were most common for adaptive behavior. For all measures, the mean magnitude of SS change was smaller for older children (>7.5 years at Time 1) than for younger children (<7.5 years at Time 1). Furthermore, correlations between Time 1 and Time 2 SSs were larger for the older cohort than for the younger cohort, indicating that SS stability was greater for older children than for younger children. Although mean SSs declined for most measures, indicating that children with WS as a group were not making the expected amount of progress relative to their general population peers who earned the same SS at Time 1, there was little evidence either of regression (loss of skills) or stagnation (failure to increase raw scores). The relations of these results to those of previous smaller‐sample longitudinal studies of children with WS and the implications of the findings are considered. © 2015 Wiley Periodicals, Inc.