Cortical sources of resting-state EEG rhythms in "experienced" HIV subjects under antiretroviral therapy

Treatment-naïve patients with human immunodeficiency virus (HIV) are characterized by diffuse abnormalities of resting-state cortical electroencephalographic (EEG) rhythms (Babiloni et al., 2012a). Here, we tested the hypothesis that these EEG rhythms vary as a function of the systemic immune activity and antiretroviral therapy (ART) in HIV patients.

Resting-state eyes-closed EEG data were recorded in 68 ART-HIV patients (mini mental state evaluation (MMSE) of 27.5 ± 0.3 SEM), in 60 treatment-naïve HIV subjects (MMSE of 27.5 ± 0.4 SEM) and in 75 age-matched cognitively normal subjects (MMSE of 29.3 ± 0.1 SEM). Based on the CD4 lymphocytes' count, we divided ART-HIV subjects into two subgroups: those with CD4>500 cells/μl (ART-HIV+) and those with CD4<500 cells/μl (ART-HIV-). EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-12 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). Cortical EEG sources were estimated by LORETA software.

Widespread theta, alpha, and beta sources were lower in ART-HIV subjects than in control subjects. Furthermore, occipital and temporal alpha 1 sources were lower in treatment-naïve HIV than in ART-HIV subjects. Moreover, the opposite was true for widespread pathological delta sources. Finally, parietal, occipital, and temporal alpha 1 sources were lower in ART-HIV- than in ART-HIV+ subjects.

In ART-HIV subjects, cortical sources of resting-state alpha rhythms are related to systemic immune activity and cART.

This EEG procedure may produce biomarkers of treatment response in patients' brain compartments for longitudinal clinical studies.