Elisabeth M. Dykens, Elizabeth Roof, and Tara Lerner 

Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt Kennedy University Center of Excellence on Developmental Disabilities 

Introduction:  The beneficial effects of growth hormone treatment (GHT) on body composition in PWS are striking and unequivocal, but it is less clear what the effects of GHT are on the cognitive or adaptive functioning of children or adults with PWS.  Compared to randomized, untreated controls, infants with PWS tested before and 1 year after GHT showed greater gains in language, mental, and motor skills (Festen et al., 2007; Meyers et al., 2006).  In older children, GHT is not associated with changes in behavior problems (Whitman et al., 2002), yet the possible sequalae of GHT on the cognitive or adaptive skills in older children with PWS have yet to be studied.  

Method:  We examined 40 children with PWS aged 4 to 11 years who either had never been treated with GHT (N = 22, M age = 8.16 years), or who were on GHT (N = 18, M age = 7.23 years) for 2 to 6-½ years (M= 4.47 years on GHT). Children were administered IQ and other tests, and parents completed standardized questionnaires or interviews of their children’s adaptive skills, problem behaviors, compulsivity, hyperphagia, and recreational activities.  

Results:  No significant differences emerged across treated versus untreated groups in problems behaviors, hyperphagia, or visuo-spatial tasks.  Compared to the untreated group, however, treated children had significantly higher Verbal IQ’s (78.00 versus 64.83, p < .05), and higher composite scores on the Vineland Adaptive Behavior Scales (M’s = 71.16 versus 58.00, p < .01) and all three Vineland domains: Communication Skills (M’s = 77.39 versus 66.95, p < .05); Daily Living Skills (M’s = 70.66 versus 54.44, p < .01); and Socialization (M’s = 79.55 versus 68.50, p < .05).  Children in the treated group were also significantly more apt to read books and engage in pretend play.  Duration of GHT was associated with increased bike-riding, but not with other physical or cognitive effects.  No effects were found for gender or PWS genetic subtypes.

Discussion:  GHT in 4 to 11 year old children with PWS may be associated with enhanced verbal and adaptive skills, pretense, and recreational reading and bike-riding.  Other performance based problem-solving skills, compulsivity or maladaptive behaviors may be less strongly associated with GHT.  These preliminary findings underscore the need for rigorous, longitudinal studies on the effects of GHT on the cognitive and adaptive functioning of children and adults with PWS. 

The research was supported by NICHD grants R01HD135681 and P30HD15052.  The authors thank the families and children with PWS who participated in this project.

Edited: 02/09/2012