Despite the advent of highly active antiretroviral therapy (HAART), the prevalence of neurocognitive impairment among HIV-infected patients continues to be an important issue. Although severe forms of AIDS-related dementia have diminished, milder forms of cognitive impairment have been noted among approximately 30% of asymptomatic HIV patients. Studies among HIV-infected U.S. military personnel regarding neurocognitive function have largely been limited to the early 1990s, before the advent of HAART. In these studies subtle neurobehavioral changes were noted among asymptomatic HIV-positive military personnel.

This study proposes to determine the prevalence of neurocognitive deficits among HIV-positive military beneficiaries during the era of HAART who are participants of the U.S. Military HIV Natural History Study. The prevalence ascertained in this study will be compared to HIV-negative military beneficiaries who are demographically similar to the HIV positive group. The sample size of the study is to have complete testing on 200 HIV positive and 50 HIV-negative participants; due to the possibility of attrition before study completion, the investigators will enroll up to 300 participants (240 HIV-positive and 60 HIV-negative) to achieve this sample size. The investigators' rates among HIV-positive patients found in this study will also be contextualized in the setting of the prevalence of prior neurocognitive deficits seen in a HIV positive U.S. military population studied in the 1990s, contemporary rates among civilian HIV-infected persons, and normative values in the general HIV-negative population. Compared to other data in the field of neuropsychology, this study is novel in that the HIV population studied is composed largely of HIV patients who have been diagnosed early in their HIV infection; have open, free access to antiretrovirals to begin therapy earlier than most other cohorts; and consists of highly-functioning, educated individuals.