Skip to main content


Table 3 Pearson r correlations between Phe measures taken at different points in time and adult cognitive performance (N participants = 51–56; N tasks = 16). Significant correlations are in bold. a = significant <.05; b significant <.01. To facilitate interpretation, positive correlations always indicate that high Phe was associated with worse performance. Thus, for IQ, digit span, Corsi span, and semantic fluency correlations were reversed

From: Adult cognitive outcomes in phenylketonuria: explaining causes of variability beyond average Phe levels

PHE Visual attention speedVisuo Motor coordinationEF /MonitoringSustainedLearning and memory
FSIQSimpleDetectionFeatureConjunctionPeg-DigitWCSTTMTDigitCorsiSemanticAttentionReyReyPaired Associate
 RTwith distractors RTSearch RTSearch RTboardSymbolTotal errorsB-AspanSpanFluencyRVP %a1-a5delayedVisual learning
0–10 yrs
11–16 yrs
17 yr to now
  1. Note. Correlations have been carried out using z scores. For the English PKU sample the number of participants and available Phe measures is slightly different across tests (range 31–37 participants), this means that the same value of r may have different probabilities