HIV-associated cognitive impairment in sub-Saharan Africa—the potential effect of clade diversity


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.

Key Points

  • HIV dementia is characterized by cognitive, behavioral and motor dysfunction

  • HIV-1 subtypes in the US and Europe differ from subtypes seen elsewhere in the world

  • The frequency of HIV dementia in sub-Saharan Africa is largely unknown, but one study in Uganda suggests that 31% of HIV-positive individuals with advanced infection could have dementia

  • Differences in HIV-1 subtype could cause differences in HIV-associated neurological disease

  • HIV dementia might be among the most common forms of dementia worldwide, along with Alzheimer's disease and vascular dementia

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Figure 1: Global distribution of HIV-1 viral subtypes


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The authors thank Alice Namudde and Fred Sebuuma for their work as research assistants for the Ugandan studies, and Marie Sonderman for providing administrative support.

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Correspondence to Ned Sacktor.

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Sacktor, N., Nakasujja, N., Robertson, K. et al. HIV-associated cognitive impairment in sub-Saharan Africa—the potential effect of clade diversity. Nat Rev Neurol 3, 436–443 (2007).

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