The relationship between pediatric HIV infection, CD4 percentage, HAART, and WISC-III performance

Although the introduction of antiretroviral treatments such as Highly Active Antiretroviral Therapy Treatment (HAART) has improved overall cognitive functioning of children with human immunodeficiency virus (HIV) over the last decade, subtle cognitive weaknesses may persist and symptomatic children may continue to present with encephalopathy. As the HAART cohort of children move through their school-age years, ecologically valid measures of cognitive functioning will continue to play an important role in planning for their educational needs. The current study investigated differences in cognitive profile between school-aged children infected with HIV and non-infected participants as measured by the Wechsler Intelligence Scale for Children---Third Edition (WISC-III), a test with high ecological validity. Participants were 77 HIV positive children and 78 HIV negative children born to HIV positive mothers drawn from two clinics serving families in the Bronx, NY. Archival data for analysis included: (1) Independent Variables: HIV Status, CD4% (as a measure of HIV severity in the HIV positive group), HAART treatment duration, and (2) Dependent Variables: WISC-III test scores. Specific WISC-III index and subtest scores were selected based on prior research on cognitive impairments and CNS abnormalities associated with HIV infection. Results indicated that HIV-infected children with higher CD4% performed similarly to HIV negative children on the WISC-III in this sample. Lower CD4%'s were associated with lower overall cognitive functioning, as well as lower scores on WISC-III subtest measures of vocabulary knowledge, math reasoning, visual processing, and psychomotor processing speed. Differential effects of HIV on WISC-III verbal versus nonverbal domain scores were also found, with significant differences obtained for verbal index scores. These results suggest dichotomizing groups into HIV positive and HIV negative may have less clinical utility than creating subgroups based on CD4%. CD4% data may be useful when considering the higher incidence of continued cognitive weaknesses in some samples of HIV children versus others, and for guiding assessment in school and hospital settings. The results also suggest that there may be more pervasive differences in language functioning than in nonverbal performance in the post-HAART pediatric population. Additional implications of the results for assessment, academic functioning, and research are discussed.