Longitudinal Assessment of Intellectual Abilities of Children With Williams Syndrome: Multilevel Modeling of Performance on the Kaufman Brief Intelligence Test—Second Edition

Abstract

Multilevel modeling was used to address the longitudinal stability of standard scores (SSs) measuring intellectual ability for children with Williams syndrome (WS). Participants were 40 children with genetically-confirmed WS who completed the Kaufman Brief Intelligence Test-2 (KBIT-2; Kaufman & Kaufman, 2004) 4–7 times over a mean of 5.06 years. Mean age at first assessment was 7.44 years (range: 4.00–13.97 years). On average KBIT-2 Composite IQ, Verbal SS, and Nonverbal SS were stable from 4–17 years, although there were significant individual differences in intercept (Composite IQ, Verbal SS, Nonverbal SS) and slope (Composite IQ, Nonverbal SS). Maternal education was significantly related to Verbal SS intercept. No significant sex differences were obtained. Implications for studies of genotype/phenotype correlations in WS are discussed.

Resting-State Functional Connectivity in Individuals with Down Syndrome and Williams Syndrome Compared with Typically Developing Controls

“…Standard scores (verbal, nonverbal, and composite IQ) were obtained from 22 of our 40 TD participants, 17 of the 18 WS participants, and all 10 DS participants. KBIT-2 scores correlate highly with other full-scale IQ tests and have successfully been used to estimate intelligence in individuals with neurodevelopmental disorders, including DS and WS (Edgin et al, 2010;Kaufman and Kaufman, 2004;Mervis et al, 2012). Group mean scores from each of the three participant groups were tested for differences using an independent samples t-test (Table 1).…”

Developmental trajectories of pitch-related music skills in children with Williams syndrome

“…Measurements of vocabulary and matrix reasoning have often been used to assess cognitive development in WS (e.g., Jarrold, Baddeley, & Hewes, 1998;Mervis, Kistler, John, & Morris, 2012) and, importantly, have also been employed to evaluate claims regarding the separability of music skills and cognition in this population (Don et al, 1999;Hopyan et al, 2001). This explains why such measurements were taken.…”

Who reports it best? A comparison between parent-report, self-report, and the real life social behaviors of adults with Williams syndrome

“…The K-BIT includes a composite IQ as well as standard scores for verbal and non-verbal knowledge. The K-BIT-2 has been used with persons with Williams syndrome in previous studies (e.g., Dykens, Rosner, & Ly, 2001; Mervis, Kistler, John, & Morris, 2012). …”