Speed of processing and executive functions in adults with phenylketonuria: quick in finding the word, but not the ladybird

Research output: Contribution to journalArticle

View graph of relations Save citation



Research units


A reduction in processing speed is widely reported in phenylketonuria (PKU), possibly due to white matter pathology. We investigated possible deficits and their relationships with executive functions in a sample of 37 early-treated adults with PKU (AwPKUs). AwPKUs were not characterized by a generalized speed deficit, but instead their performance could be explained by two more specific impairments: (a) a deficit in the allocation of visuo-spatial attention that reduced speed in visual search tasks, in some reading conditions and visuo-motor coordination tasks; and (b) a more conservative decision mechanism that slowed down returning an answer across domains. These results suggest that the impairments in executive functions seen in AwPKUs are not the consequence of a generalized speed deficit. They also suggest that processing speed is linked to the efficiency of a particular cognitive component and cannot be considered a general function spanning domains. Similarities with patterns in ageing are discussed.



Original languageEnglish
JournalCognitive Neuropsychology
Volumein press
Early online date20 Jun 2017
Publication statusE-pub ahead of print - 20 Jun 2017

Bibliographic note

This is an Accepted Manuscript of an article published by Taylor & Francis in Cognitive Neuropsychology on 20/6/17, available online: http://www.tandfonline.com/10.1080/02643294.2017.1320278


  • ageing, executive functions, feature vs. conjunction search, Phenylketonuria, serial vs. parallel search, speed of processing

Download statistics

No data available

Employable Graduates; Exploitable Research

Copy the text from this field...