[Cognitive development of children and adolescents after correction of transposition of great vessels]. 
To study the effect of transposition of the great arteries on later cognitive functioning.  Twentyeight children and adolescents underwent psychometric testing 3.5 to 13.7 years following operation.  A battery of intelligence, attention and visual memory tasks as well as the Draw-a-Man-Test were administered.  Parents completed standardized questionnaires on developmental milestones.  Both, mean verbal (93 +/- 15) and performance IQs (97 +/- 21) were normal.  The length of interval between operation and psychologic test but not age at repair was a significant predictor of intelligence quotient.  Half of the children (9/18) showed attention deficits, 7/11 (64%) were identified as suspect of brain dysfunction.  Performance on the Draw-a-Man-Test disclosed 12 (43%) as slightly mentally retarded. ( 1) Cognitive functions in children with TGA are more impaired than suggested by the results of intelligence tests. ( 2) Psychological and neurologic follow-up should be mandatory from early on. ( 3) Previous studies have overestimated children's intelligence due to unrecognized changes of test norms.