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In the US, HIV dementia occurs in 10-15% of HIV-positive individuals with advanced infection. The prevalence of HIV dementia in sub-Saharan countries, where the vast majority of individuals with HIV reside, is largely unknown. This Review will summarize our current understanding of HIV-associated cognitive impairment in resource-limited settings, focusing specifically on the countries of sub-Saharan Africa. We will describe the frequency of HIV dementia and HIV-associated cognitive impairment from several case series in the sub-Saharan region. We will then summarize recent studies from Uganda and Ethiopia that included detailed neuropsychological assessments. The potential influence of clade diversity on HIV-associated cognitive impairment will be discussed. Differences between the results of the studies in Uganda and in Ethiopia raise the possibility that HIV subtypes might have different biological properties with respect to their capacity to cause HIV-associated cognitive impairment. Further studies are needed to determine the true prevalence of HIV dementia in sub-Saharan Africa and to establish whether specific clade subtypes might influence the presentation of neurological complications.

Background: Few studies have examined cognitive functioning of HIV positive patients in sub-Saharan Africa. It cannot be assumed that HIV positive patients in Africa exhibit the same declines as patients in high-resource settings, since there are differences that may influence cognitive functioning including nutrition, history of concomitant disease, and varying HIV strains, among other possibilities. Part of the difficulty of specifying abnormalities in neuropsychological functioning among African HIV positive patients is that there are no readily available African normative databases. The purpose of the current study was to evaluate the pattern of neuropsychological performance in a sample of HIV positive patients in comparison to HIV negative control subjects in Uganda., Methods: The neuropsychological test scores of 110 HIV positive patients (WHO Stage 2, n = 21; WHO Stage 3, n = 69; WHO Stage 4, n = 20) were contrasted with those of 100 control subjects on measures of attention/concentration, mental flexibility, learning/memory, and motor functioning., Results: Analysis of covariance (ANCOVA) revealed significant group differences on measures of verbal learning and memory, speed of processing, attention and executive functioning between HIV seropositive and seronegative subjects., Conclusion: Ugandan patients with HIV demonstrated relative deficits on measures of verbal learning and memory, speed of processing, attention, and executive functioning compared to HIV negative controls. These results from a resource limited region where clades A and D are prevalent are consistent with previous findings in the developed world where clade B predominates.

Objective: HIV dementia is an important neurological complication of advanced HIV infection. The use of a cross-cultural screening test to detect HIV dementia within the international community is critical for diagnosing this condition. The objective of this study was to evaluate the sensitivity and specificity of a new screening test for HIV dementia, the International HIV Dementia Scale (IHDS) in cohorts from the US and Uganda., Design: Two cross-sectional cohort studies designed to evaluate for the presence of HIV dementia., Methods: Sixty-six HIV-positive individuals in the US and 81 HIV-positive individuals in Uganda received the IHDS and full standardized neurological and neuropsychological assessments. The sensitivity and specificity of varying cut-off scores of the IHDS were evaluated in the two cohorts., Results: In the US cohort, the mean IHDS score for HIV-positive individuals without dementia and with dementia were 10.6 and 9.3 respectively (P < 0.001). Using the cut-off of < or = 10, the sensitivity and specificity for HIV dementia with the IHDS were 80% and 57% respectively in the US cohort, and 80% and 55% respectively in the Uganda cohort., Conclusions: The IHDS may be a useful screening test to identify individuals at risk for HIV dementia in both the industrialized world and the developing world. Full neuropsychological testing should then be performed to confirm a diagnosis of HIV dementia.