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Inhibition of prepotent responding and attentional flexibility in treated phenylketonuria

Stephan Huijbregts1, Leo de Sonneville, Rob Licht

  • 1Department of Clinical Neuropsychology, Free University of Amsterdam, The Netherlands. scj.huijbregts@psy.vu.nl

Developmental Neuropsychology
|January 23, 2003
PubMed

Insights

Phenylketonuria (PKU) patients show deficits in inhibitory control and attentional flexibility. High phenylalanine levels in early childhood significantly impact executive functions, underscoring the need for strict dietary management.

Area of Science:

  • Neuroscience
  • Developmental Psychology
  • Metabolic Disorders

Background:

  • Phenylketonuria (PKU) is a genetic disorder requiring strict phenylalanine restriction.
  • Executive functions, including inhibitory control and attentional flexibility, develop significantly in early childhood.
  • The impact of phenylalanine levels on these developing executive functions in PKU patients requires further investigation.

Purpose of the Study:

  • To assess inhibitory control and attentional flexibility in early and continuously treated PKU patients compared to controls.
  • To investigate the association between plasma phenylalanine (phe) levels and executive function performance.
  • To determine the optimal phenylalanine (phe) management strategy for cognitive development in PKU.

Main Methods:

  • A computerized task assessed inhibition of prepotent responding and attentional flexibility in 58 PKU patients and 69 controls (ages 7-14).
  • Error rates were analyzed to compare performance between groups and correlate with concurrent and lifetime phenylalanine (phe) levels.

Main Results:

  • PKU patients exhibited poorer inhibitory control and attentional flexibility than controls.
  • Attentional flexibility deficits were primarily observed in younger PKU patients with phe levels > 360 micromol/L.
  • Performance was strongly associated with phe levels during critical developmental periods (ages 2-7 and age 9).

Conclusions:

  • High phenylalanine (phe) levels during early childhood can impede the development of inhibitory control and attentional flexibility in PKU patients.
  • Strict dietary management is crucial throughout the first decade of life.
  • Maintaining phe levels below 360 micromol/L through early adolescence is recommended for optimal executive function development.

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