Electroencephalographic findings in children with phenylketonuria

Long-term development of intelligence (IQ) and EEG in 34 children with phenylketonuria treated early

In 34 children with phenylketonuria (PKU) treated early the prognostic value of the age on institution of the diet (within the first 3 months of life) and of the quality of dietary treatment was determined in two different ways: 1) following intelligence closely (IQ) and (2) evaluating the EEG development up to their 12th (n = 34) and 15th (n = 18) years of life as appropriate. In general, IQ scores were found to be normal from the 4th-15th years of life. In our group of patients there was no effect on the IQ of the timing of diet onset. Children with "strict" dietary control showed a significantly higher IQ than those with "loose" control. One hundred and fifty-four EEGs (10/20 system, awake with eyes closed) were recorded at intervals of 2 years and conventionally evaluated. The development of alpha-activity was found to be normal. Beta-activity was enhanced. Abnormal EEG findings like general slowing and generalized paroxysmal activity (GPA) with or without spikes were more frequent in children with PKU than in controls, with the exception of focal abnormalities. EEG abnormalities increased with advancing age independently of IQ development and showed no relation to either the age at the onset nor the quality of dietary treatment.

Diet termination in children with phenylketonuria: a review of psychological assessments used to determine outcome

This paper reviews the 19 published studies that have utilized psychological assessments in determining the outcome of children with phenylketonuria who have discontinued a phenylalanine-restricted diet. About half the studies showed that, after diet termination, the intellectual performance of children decreased, while the other studies indicated that the intellectual performance of the children did not change. Difficulties in the use of intelligence tests to answer questions about diet termination are outlined. Due to the methodological difficulties and the varying results reported, the issue concerning the safety of diet discontinuation remains unresolved. The conclusion is that the task now is to differentiate those children who should remain on the diet from those who may safely terminate.