Results of psychological testing of patients aged 3–6 years

Abstract
Cognitive development of early treated PKU children (132) was investigated by intelligence tests, tests for visual perception, motor and language development. Deviations from test norms occurred at 5 years of age concerning performance IQ, mathematical thinking, and visual perception. With the exception of mathematical thinking, “normal” results were obtained at the age of 6 years. Correlation with levels of plasma Phe revealed a relation between qualitiy of dietary control and performance IQ. Results are discussed in light of methodological aspects and with respect to treatment consequence.