Abstract #395  -  Characterizing Neurobehavioral Decline Among HIV Groups In Zimbabwe: Pilot Study
Authors:   Presenting Author:   Dr. Diana Echeverria - Battelle CPHRE
Additional Authors:  Dr D Kasprzyk D, Dr S Goldenkranz, Dr CE Ndhlovu, Dr K Mangwende, Dr T Mushove,
Aim: Abstract. The central nervous system is a critical target organ of HIV. There is little debate regarding the potential for cognitive decline resulting in dementia when diagnosed with stage C HIV. However, HIV may enter the CNS soon after infection and no consensus exists regarding differential sensitivity between basic domains associated with central and peripheral nervous system function. Questions also remain as to when cognitive and motor decline is initiated with respect to the mildly symptomatic and asymptomatic stages of HIV infection and whether the nature of decline is preventable or rapidly reversible in the presence of drug treatments. This is the first feasibility study to be conducted in Zimbabwe that used a comprehensive set of measures to more fully characterize potential neurobehavioral deficits with respect to CD4 counts. The goal was to determine whether deficits increased in magnitude as HIV progresses.
Method / Issue: Four groups of volunteer participants (n=36) were recruited from a community-based sample that lived in Harare Zimbabwe. Participants were either HIV-negative, had CD4 T-cell count >200, had CD4 T-cell count <200, or were on treatment with an Antiretroviral Therapy. Inclusion criteria required fluency in English and no consumption of alcohol within 12 hours of the assessment. Controls were group-matched on age, gender, and education. The 3-hour neurobehavioral test battery combined paper-and-pencil and computerized tests to ensure valid comparison with results from other international studies. Nine cognitive domains included: Visuomotor Processing, Attention, Selective Attention, Working Memory, Verbal Declarative Memory, Visual Declarative Memory, Cognitive Flexibility, Motor Speed and Coordination, and Hold Tests.
Results / Comments: MANOVA analyses examined evidence for a linear, quadratic, or cubic model of ‘exposure-effect’ that specified contrasts between Controls and the three HIV groups where the ARV use-group scores approach that of the controls. Outcomes were modeled using three and four group models in order to determine the shape of potential deficit between groups. Fixed models included Group (Fixed), Gender (Random), and Age and Years of Education (Covariate). Pre-morbid intelligence was measured using years of education as the expected hold test (National Adult Reading Test) improved in the ARV-use group. There was general consistency in directionality for 20 out of 37 measures in the expected direction for the domain of Verbal Declarative Memory (6 of 8 measures), Attention (3 of 3 measures), Working Memory (Digit Span Backward)), Visual Declarative Memory (1 of 2 measures), Cognitive Flexibility (4 of 5 measures), and Motor Speed and Coordination (4 of 4 clinical measures). Statistical significance was achieved for scores for Immediate and Delayed Recall (RAVLT), Digit Span (Forward and Backward),Trailmaking ATime. Controlled Oral Word Attention Test, Category Fluency (Animals), The Paced Auditory Serial Addition Test N Correct and Design Fluency N Unique Designs. Finger Tapping Dominant and Non-Dominant Hand and all four Grooved-Pegboard measures also achieved significance. We report on 37 measures, 21 of which met statistical significance. The probability of observing this by chance (binomial distribution with n=37, k=20 and p=.05) is 7x10-12. Only the Hopkins Verbal Learning Test Delayed Recognition N Correct was in the wrong direction.
Discussion: Overall, the results are consistent with that in the literature and support a seminal study in sub-Sahara Africa designed to characterize both protective and deleterious factors that alter trajectories of CNS/PNS decline across domains before and after serro-conversion
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