A bstract A total of 33 patients with early and continuously-treated phenylketonuria (PKU) between 7 and 16 years of age and 33 matched controls participated in a study ex amining perceptual, central, and re sponse-related mechanisms of infor mation processing. The specific mechanisms studied were: perceptual filtering, memory search, response selection, response execution, and motor presetting. In addition, groups were compared on mean intelligence level and task oriented behaviour. The performance of the PKU pa tients practically matched that of the controls on all three tasks, suggest ing that PKU patients who are con tinuously maintained on a well-con trolled phenylalanine-restricted diet are not impaired in the elementary mechanisms of information process ing. Furthermore, groups did not dif fer in mean IQ or task-oriented be haviour. ConclusionThese results under line the importance of continued, well-controlled dietary treatment. Further studies are recommended to obtain a more complete evaluation of the potential of PKU patients un der these stricter dietary treatment conditions.

Thirty‐three children with classical phenylketonuria were treated from 9 to 21 days of age onward. The standard for phenylalanine concentration was 0.2‐0.5 mmol/1. During the first years of life phenylalanine concentrations were measured once every two to six weeks. For each child these values were graphically plotted in so‐called phenylalanine response curve. Growth and mental development indices were assessed at about one and two years of age. Measurements for weight, height and head circumference were normal at one month of age, showed significant decline at the age of one year but were restored for normal values at the age of two. No associations were found with phenylalanine parameters. Mental development indices at one and two years were not different from normal. Significant negative correlations were found between mental development indices at one year and phenylalanine values above 0.5 mmol/1. Changes in mental development indices between the first and second years of life are significantly related to the phenylalanine levels during the second year of life.

Kalverboer AF, van der Schot LWA, Hendrikx MMH, Huisman J, Slijper FME, Stemerdink BA. Social behaviour and task orientation in early-treated PKU. Acta Pzdiatr 1994;(Suppl 407): 104-5. Stockholm. ISSN 0803-5326In the context of the Dutch Collaborative Study on the Psychological Development of Children, early treated for Phenylketonuria (PKU), data were obtained on children's behaviour as perceived by parents (n = 53) and teachers (n = 57), using standardized behavioural questionnaires. Results are compared with a group representative of Dutch school-aged children (n = 1381) with a matched control group (n = 38), and with a group, to be considered as "Attention Deficit Hyperactivity Disorder" (ADHD, n = 38). Especially the clusters "negative task orientation" and "extraversion" distinguish between PKU children and controls. In parents' descriptions as well as in teachers' descriptions PKU children score higher in both clusters. Intriguing differences are found between PKU and ADHD. In parents' but not in teachers' descriptions PKU children show signs of negative task orientation almost to a similar degree as children with ADHD, but not of the signs of "negative social behaviour", characteristic for ADHD children. Data are discussed in terms of the effectiveness of early treatment and guidance.

Early dietary treatment of phenylketonuria (PKU) prevents intellectual retardation and gross neurological impairment although not all neuropsychological problems. This study investigates to what extent the illness and its treatment imposes a burden on emotional development of early-treated PKU patients and on rearing practices of their parents. It is concluded that in early-treated PKU it is particularly difficult to find constructive ways to adapt to the situation for children as well as for parents. As coping with PKU and its treatment is so complicated, paediatric control should be combined with psychocounselling.

Early dietary treatment of phenylketonuria (PKU) prevents intellectual retardation and gross neurological impairment although not all neuropsychological problems. This study investigates to what extent the illness and its treatment imposes a burden on emotional development of early-treated PKU patients and on rearing practices of their parents. It is concluded that in early-treated PKU it is particularly difficult to find constructive ways to adapt to the situation for children as well as for parents. As coping with PKU and its treatment is so complicated, paediatric control should be combined with psychocounselling.