Goodman, Galya;
(2002)
Selective impairment in executive functions: A test of the selective executive deficit hypothesis in adults with treatment-discontinued phenylketonuria.
Doctoral thesis (D.Clin.Psy), UCL (University College London).
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Abstract
Executive functions are processes involved in the everyday control of thoughts and actions and have been linked to the prefrontal cortex. Recent models of cognitive functioning in Phenylketonuria (PKU) have linked it to selective impairment in executive functions due to depleted dopamine levels in the prefrontal cortex. This is caused, in part, by elevated levels of Phenylalanine in the blood. Dopamine is thought to play a central role in functions linked with the lateral prefrontal cortex and associated pathways. The selective executive deficit hypothesis of PKU suggests that measures that place high demands on active working memory and sustained attention are likely to be sensitive to any impairments mediated by dopamine depletion. These functions have been linked to the dorsolateral prefrontal cortex, which is particularly sensitive to fluctuations in dopamine in the brain. This study compared performance of a group of treatment-discontinued adults with PKU to a group of healthy controls matched for age, sex, IQ and educational background on tasks sensitive to dorsolateral prefrontal cortex functioning, in comparison to another test of executive functioning, reward-based learning, and a control task, considered to make minimal demands on executive functions. Adults with PKU were shown to be selectively impaired on tasks requiring monitoring of information in the context of processing of higher working memory loads, but not on the alternative executive task or the control task, in comparison to healthy control participants.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | D.Clin.Psy |
| Title: | Selective impairment in executive functions: A test of the selective executive deficit hypothesis in adults with treatment-discontinued phenylketonuria |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Thesis digitised by ProQuest. |
| Keywords: | Psychology; Executive functioning |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10099571 |
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