Deficits in memory strategy use related to prefrontal dysfunction during early development: Evidence from children with phenylketonuria

The prefrontal cortex has been implicated in the mediation of executive pro cesses that facilitate learning and memory. The authors hypothesized that c hildren with prefrontal dysfunction related to phenylketonuria (PKU) would experience deficits in learning and memory because of impaired strategy use . They evaluated 23 children with PKU and 23 controls by using the Californ ia Verbal Learning Test-Children's Version (CVLT-C). General executive abil ities were tested using the Stroop Color and Word Test, the Wisconsin Card Sorting Test, and phonemic and category fluency, Children with PKU, especia lly older children, showed poorer learning across trials and less use of se mantic clustering on the CVLT-C but intact retention of previously encoded information. With the exception of phonemic fluency, deficits were not obse rved in general executive control. Results are discussed within the context of abnormalities in the prefrontal. cortex and white matter of the brain.