Cognitive, adaptive, and behavioral characteristics of Williams syndrome.

Williams syndrome is a genetic disorder linked to cognitive and behavioral patterns of varying consistency; this study was conducted to clarify further the strengths and weaknesses of children with Williams syndrome. Fifteen subjects with the characteristic features of Williams syndrome were evaluated using the Stanford-Binet Intelligence Scale for Children, Fourth Edition; the Vineland Adaptive Behavior Scales, Interview Edition; and the Child Behavior Checklist. Cognitive skills ranged from the Moderate Range of Mental Retardation to the Low Average range, with relative strengths in nonverbal and quantitative reasoning. Adaptive skills were delayed, with strengths in communication and socialization. Behaviorally, clinically significant levels of attention problems, borderline-significant levels of social and thought problems, and significantly low levels of social contacts and structured activities were found. In contrast to the findings of many other studies of Williams syndrome, language skills and short-term memory skills were weak. Children with Williams syndrome may present a more evenly developed intellectual profile, with verbal and nonverbal skills being commensurate. In conclusion, a variety of cognitive, adaptive, and behavioral patterns have been shown to be possible in Williams syndrome; therefore, a single predictable cognitive or behavioral phenotype cannot be assumed.