Neurocognitive function profile in HIV-infected school-age children.

OBJECTIVES: Evaluation of neurocognitive function of school-age children with HIV. DESIGN: Cross-sectional observational study. METHODS: Twenty-two children (median age 9.46 years) with perinatally acquired HIV infection were administered a global intelligence test and tests from the Amsterdam Neuropsychological Tasks (ANT) program. The relationship between various patient-, disease- and treatment factors and neurocognitive outcome variables was examined. RESULTS: Compared with age-appropriate norms, mean IQ of the HIV-infected children was in the average range. However, the HIV-infected children performed poorer on several neuropsychological tests compared with age-appropriate norms. Executive function (attentional flexibility, visuospatial working memory) and processing speed emerged as the most sensitive cognitive measures in relation to HIV disease. The correlational analyses resulted in only two significant outcomes, showing that higher CD4% at initiation of highly active antiretroviral therapy (HAART) and longer treatment duration were associated with better working memory function and attentional control, respectively. CONCLUSIONS: These exploratory data suggest that subtle neurocognitive impairments may exist in HIV-infected school-age children, in particular characterized by compromised executive function and slowed information processing. Further research with larger sample sizes is needed to confirm these findings.

Inhibition of prepotent responding and attentional flexibility in treated phenylketonuria.

Inhibition of prepotent responding and attentional flexibility were assessed in 58 early and continuously treated phenylketonuria (PKU) patients and 69 controls, age 7 to 14 years. A computerized task was used requiring participants to process consecutive stimuli according to various attentional sets. Analysis of error rate suggested poorer inhibition of prepotent responding in PKU patients compared with controls. No influence of concurrent plasma phenylalanine (phe) was shown, neither in the younger (age < 11 years) nor in the older participants (age > or = 11 years). Analysis of error rate provided strong evidence for poorer attentional flexibility in PKU patients compared with controls. The difference between attentional flexibility in controls and PKU patients could mainly be attributed to younger PKU patients, with concurrent phe levels higher than 360 micromol/L. Younger PKU patients with phe levels below 360 micromol/L performed at the same level as age-matched controls. Performance of PKU patients was strongly associated with phe levels in age periods during the first 10 years of life, which are characterized by a strong development of executive functioning (ages 2-7 and age 9). High phe levels during these age periods could delay development of inhibitory control and attentional flexibility. With regard to treatment, analyses with lifetime and concurrent phe levels support strict dietary control throughout the first decade of life, after which the phe-restricted diet can be relaxed. However, based on the evidence that development of specific executive functions continues until approximately age 12, it is recommended to maintain phe levels below 360 micromol/L throughout early adolescence.