Alpha EEG activity and subcortical pathology in HIV infection

Quantitative electroencephalographic (QEEG) investigations of patients with HIV-1-infections were made to detect early signs of HIV brain involvement. QEEG data were recorded in a prospective controlled cohort study together with standardised clinical, immunological and neuropsychological tests. Subject groups were HIV-seronegative controls, HIV-seropositive subjects with asymptomatic infection, and HIV-seropositive subjects with symptomatic infection exclusing AIDS defining illnesses. Marked increase in background alpha amplitude preceded cognitive and neurological impairment in the symptomatic stage of infection. Elevation of alpha amplitude was also associated with change in psychiatric status. Antiretroviral medication suppressed this alpha elevation, supporting the usefulness of QEEG in monitoring drug CNS effects. In the context of clinical, neuropathological and brain imaging data it is suggested that these changes in the alpha rhythm are the earliest, albeit unspecific, signs of HIV brain involvement, reflecting the predominantly subcortical prominence of the pathological process.