THE EFFECTS OF PHENYLKETONURIA AND HYPERPHENYLALANINEMIA ON COGNITION (PKU, INTELLIGENCE, COGNITION)

Abstract

Researchers studying the degree of success of low phenylalanine diets in preventing cognitive loss in phenylketonuric children have produced conflicting findings. Also, little research has been performed to determine whether hyperphenylalaninemia affects cognition. This study, therefore, examined optimally treated children with phenylketonuria and untreated children with hyperphenylalaninemia to determine: (1) their mean IQs; (2) their incidence of deficits in specific areas of functioning and specifically in perceptual-motor coordination; (3) their level of performance on school related tasks; and (4) their self concepts.;The treated school-aged phenylketonuric subjects began their diets by 14 days of age. They adhered to the New York University diet which is stricter than those prescribed by most PKU Clinics in this country whose subjects were studied by previous researchers. The untreated children with hyperphenylalaninemia had mean SPCs between 6 and 9-mg/100 ml and were not being treated by diet.;All children were administered the following tests: the WISC-R, the Bender Gestalt Test, The Wide Range Achievement Test, Memory for Designs test, Draw-A-Person test, and a self concept scale. Their performance was compared to those of control children. The data was analyzed using ANOVA and x('2) tests. The results of these analyses revealed that there were no significant differences between the groups.;This study found that early initiated, strict, and long term dietary treatment is successful in preventing cognitive deficits in phenylketonuric children. It also found that untreated children with hyperphenylalaninemia, who have mean SPCs between 6 and 9-mg/100 ml, do not suffer intellectual impairments and, therefore, do not require dietary treatment. Additionally, the subjects with phenylketonuria and hyperphenylalaninemia do not have significantly different self concepts than control children.