Cognitive and Achievement Abilities of Individuals with Prader-Willi Syndrome
versus Others with Early Morbid Obesity 

Sarah M. Graman¹, John H. Kranzler¹, Ann S. Hatfield², Susan E. Thompson² and Daniel J. Driscoll².  ¹Box 117047, College of Education, University of Florida, Gainesville, FL 32611-7047 

²Pediatric Genetics and the Center for Mammalian Genetics, University of Florida College of Medicine, Box 100296, Gainesville, FL, 32610, USA.   

Introduction:  The Prader-Willi Syndrome (PWS) is a complex neurobehavioral syndrome whose main clinical features include obesity, cognitive impairment and a distinct behavioral phenotype.  Past psychological studies have reported below average intelligence; differences in performance on cognition subtests; possible correlations between weight and IQ and molecular class and IQ; maladaptive behaviors; and evidence of autistic features.  However, there has been a lack of published studies detailing patterns of abilities across general and broad cognitive abilities and academic achievement skills in these individuals.  As part of a 5 year study we are conducting comprehensive psychoeducational testing and behavioral evaluations in individuals with PWS, as well as patients with early morbid obesity (EMO) who do not have PWS.  Both the PWS and EMO groups are being compared with a normal control sibling when available. 

Due to the significant heritablility of cognitive abilities, findings of significant difference between the PWS individual and their control sibling will be of paramount interest.  Furthermore, there has been a lack of systematic studies regarding academic achievement in this population.  Therefore, information concerning the specific cognitive and academic strengths and weaknesses for these individuals has the potential to have lasting effects for their educational and vocational futures.  The similarities and differences in evaluating intelligence with various measures are also of importance as several different scales have been used in past studies of individuals with PWS.  Past studies, for example, have not adequately measured the full range of broad cognitive abilities in contemporary theories of the structure of intelligence. 

Methods:  Cognitive and academic achievement levels were evaluated through administration of the Woodcock-Johnson Psychoeducational Battery–III with PWS, EMO and normal control sibling participants.  In addition, behavior for each individual was evaluated through the Behavior Assessment System for Children (BASC) using parent, teacher and self-report.  All testing will be repeated in one year.   

Results:  We have found commonalities among the PWS individuals with reference to cognitive and achievement profiles.  Individuals with PWS have significantly lower cognitive scores than the EMO and control sibling groups, and demonstrate a unique pattern of achievement scores in relation to their intelligence scores.  Behavior problems were noted in both the PWS and EMO groups. 

Discussion:  The characteristics of PWS and EMO individuals when considering their intelligence, academic achievement and behavioral profiles may have significant affects on their schooling and vocational futures when considered in conjunction with other important individual factors.  

This research is supported by the American Diabetes Association, NIH grant K24HD1361 and the NIH funded General Clinical Research Center at the University of Florida.

July 2003