Antiretroviral therapy effects on sources of cortical rhythms in HIV subjects: responders vs. mild responders.

Objective: We tested the hypothesis that 5months of combined anti-retroviral therapy (cART) affect cortical sources of resting state cortical electroencephalographic (EEG) rhythms in naïve HIV subjects.

Methods: Eyes-closed resting state EEG data were recorded at baseline (i.e. pre-treatment; T0), T1 (after 4weeks of cART), T2 (after 8weeks of cART), and T5 (after 5months of cART) in 38 naïve HIV subjects. EEG data were also recorded in 40 age-matched cognitively normal subjects for control purposes. EEG rhythms of interest were delta (2-4Hz), theta (4-8Hz), alpha 1 (8-10.5Hz), alpha 2 (10.5-13Hz), beta 1 (13-20Hz), and beta 2 (20-30Hz). Cortical EEG sources were estimated by LORETA software.

Results: Compared to the control group, the HIV group at T0 showed greater delta sources and lower widespread alpha sources. cART induced a global improvement of biological (viral load, CD4 count) and EEG (delta, alpha) markers, remarkable even after 4weeks. Compared to HIV Responders (>100cells/μl at 5-month follow up), the HIV Mild Responders (<100cells/μl) showed greater parietal delta sources at baseline and lower occipital alpha sources at 5-month follow up.

Conclusions: In naïve HIV subjects, 5months of successful cART affect brain synchronization mechanisms at the basis of the generation of delta and alpha rhythms.

Significance: The present EEG markers may be useful secondary neurophysiological end points for pharmacological clinical trials in naïve HIV subjects.