Sustained attention in adult phenylketonuria: the influence of the concurrent phenylalanine-blood-level.
The effect of concurrent phenylalanine levels (Phe-level) on sustained attention was tested in a group of 19 early treated adult PKU patients. Mean age was 20.5 years; WAIS IQs were in the normal range (M = 109.3). Phe-levels were manipulated in a high-low-high design by reintroduction of a strict phenylalanine-reduced diet for 4 to 5 weeks between test time 1 and 2 and returning to usual diet between test time 2 and 3. A control group of 20 healthy subjects, mean age 20.7 years was tested twice. Results of a sustained attention task are presented. In adult PKU patients with high concurrent Phe-levels, sustained attention is significantly impaired and reaction times are prolonged. In the low Phe-level condition, performance improved significantly. Nevertheless, the PKU group did not reach the level of performance of the control group. Results are not influenced by IQ and suggest a sustained attention deficit in adult PKU patients that varies according to the concurrent Phe-level. The partial reversibility of the deficits provides support for the hypothesis that biochemical mechanisms rather than structural changes of the brain underlie the relationship between concurrent Phe-level and sustained attention.
Department of Pediatrics, University Hospital of Heidelberg, Germany.
E
E
Schmidt
A
A
Rupp
P
P
Burgard
J
J
Pietz
J
J
Weglage
L
L
de Sonneville
D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010649:Phenylalanine / Q000008:administration & dosage / Q000097:blood*; D010661:Phenylketonurias / Q000097:blood* / Q000178:diet therapy; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D014888:Wechsler Scales
D010649:Phenylalanine