Inhibitory control in children with phenylketonuria.

Department of Psychological Sciences, University of Missouri-Columbia, Department of Psychology, Washington University, St. Louis, MO 65211, USA.
Developmental Neuropsychology (Impact Factor: 2.67). 02/2006; 30(3):845-64. DOI: 10.1207/s15326942dn3003_5
Source: PubMed

ABSTRACT Past studies have reported impairments in children with early-treated phenylketonuria (PKU) in executive abilities such as strategic processing and working memory. Findings have been inconsistent in terms of the integrity of inhibitory control, another executive ability. This study administered 4 inhibitory tasks (flanker, Stroop, go/no-go, antisaccade) to 26 children with PKU and 25 typically developing control children. Children with PKU performed more poorly than typically developing children on the 2 inhibitory tasks with the strongest experimental manipulations (go/no-go and antisaccade) between control and inhibitory conditions. Findings suggest that the inhibitory deficit associated with PKU is subtle and that inconsistent findings in past studies may be largely due to the insensitivity of experimental manipulations in some tasks.

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    ABSTRACT: Sapropterin dihydrochloride effectively lowers plasma phenylalanine (Phe) for at least a third of phenylketonuria (PKU) patients, with potential for increased dietary Phe tolerance and decreased medical food requirement. To investigate long-term quality of life (QOL) in patients with phenylketonuria (PKU) who took sapropterin (BH4, Kuvan(R)) for up to one year. 37 PKU patients, ages 10-49 years, were asked to complete a PKU-specific self-report QOL questionnaire (QOLQ) at baseline, 1, 4, 8, and 12 months. Questions were scored on a 5-point Likert scale under 5 sub-sections measuring Impact, Worries, Satisfaction, Support, and General wellbeing in relation to PKU. Responders with a plasma Phe decrease >= 15% after 1 month on sapropterin remained on the drug; Nonresponders ceased sapropterin after the trial month. Responders able to relax medical diet and maintain plasma Phe control were classified as Definitive; Responders unable to relax medical diet were classified as Provisional. All patients were routinely monitored by a registered dietitian. Data was analyzed in SPSS 19.0 using regression techniques. Of 17 Responders, 11 could maintain adequate Phe control on a less restrictive diet. One year mean Impact sub-score trends improved significantly for all sapropterin response groups, with greatest improvement among Definitive Responders (p < 0.0001). Satisfaction sub-scores also improved for Definitive Responders (p = 0.001). Trends for Total QOL score improved significantly over time for both Definitive (p = 0.001) and Provisional Responders (p = 0.028). Improvements in Definitive Responder scores were associated with increased Phe tolerance (Impact: p < 0.0001, Satisfaction: p = 0.022, Total QOL: p = 0.005) and MF adjustment (Satisfaction: p = 0.014, Total QOL: p = 0.026). Other sub-section scores remained steady, unaffected by sapropterin response or diet modification. Increased Phe tolerance and reduced MF requirement in sapropterin Definitive Responders improves QOL perception across one year, specifically for life impact and satisfaction.
    Health and Quality of Life Outcomes 12/2013; 11(1):218. DOI:10.1186/1477-7525-11-218 · 2.10 Impact Factor
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    ABSTRACT: BACKGROUND: phenylketonuria is manifested by partial or total deficiency of the hepatic enzyme phenylalanine hydroxylase that, in excess, has a toxic effect on the central nervous system functions, reflecting in the individual's global development. PURPOSE: to submit the alterations in the development verified in scientific studies with individuals with phenylketonuria, and to contemplate the abilities related to language development. CONCLUSION: individuals with phenylketonuria are risky for alterations in the cognitive, linguistics, motor and social-behavior functions. Deficits in the executive functions and neuropsychological abilities are common and imply in discrepancies as for language abilities development. The findings justify the proposal forwarding to the Ministry of Health with views to contracting a Speech and Language Pathologist in the accredited Neonatal Screening Programs.
    Revista CEFAC 04/2010; 12(2):326-330.
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    ABSTRACT: Phenylketonuria (PKU) is a well-defined metabolic disorder arising from a mutation that disrupts phenylalanine metabolism and so produces a variety of neural changes indirectly. Severe cognitive impairment can be prevented by dietary treatment; however, residual symptoms may be reported. These residual symptoms appear to overlap a more prevalent childhood disorder: Attention Deficit/Hyperactivity Disorder (ADHD). However, the aetiology of ADHD is a vast contrast to PKU: it seems to arise from a complex combination of genes; and it has a substantial environmental component. We ask whether these two disorders result from two vastly different genotypes that converge on a specific core phenotype that includes similar dysfunctions of Gray's (Gray, 1982) Behavioural Inhibition System (BIS), coupled with other disorder-specific dysfunctions. If so, we believe comparison of the commonalities will allow greater understanding of the neuropsychology of both disorders. We review in detail the aetiology, treatment, neural pathology, cognitive deficits and electrophysiological abnormalities of PKU; and compare this with selected directly matching aspects of ADHD. The biochemical and neural pathologies of PKU and ADHD are quite distinct in their causes and detail; but they result in the disorder in the brain of large amino acid levels, dopamine and white matter that are very similar and could explain the overlap of symptoms within and between the PKU and ADHD spectra. The common deficits affect visual function, motor function, attention, working memory, planning, and inhibition. For each of PKU and ADHD separately, a subset of deficits has been attributed to a primary dysfunction of behavioural inhibition. In the case of ADHD (excluding the inattentive subtype) this has been proposed to involve a specific failure of the BIS; and we suggest that this is also true of PKU. This accounts for a substantial proportion of the parallels in the superficial symptoms of both disorders and we see this as linked to prefrontal, rather than more general, dysfunction of the BIS.
    Brain research bulletin 10/2013; DOI:10.1016/j.brainresbull.2013.10.003 · 2.97 Impact Factor

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