Antiretroviral therapy effects on sources of cortical rhythms in HIV subjects: Responders vs. Mild Responders

EEG event related potentials in sustained, focused and divided attention tasks: Potential biomarkers for cognitive impairment in HIV patients

OBJECTIVES

The objective of this study was to assess the usability of event-related-potentials (ERPs) during sustained, focused, and divided attention tasks as biomarkers for cognitive decline in HIV patients.

METHODS

EEG was acquired using a mobile/wireless 9-channel system in 39 persons with HIV, with well-controlled immune function and 63 healthy control participants (HCs) during three ERP tasks: sustained attention, focused attention, and divided attention.

RESULTS

The HIV-group evidenced smaller late positive potential (LPP) and larger P200 amplitudes across the tasks compared to the HC group. P200 amplitude was correlated (r = 0.56) with the estimated duration of infection. Both groups showed higher P200 and LPP amplitudes in response to infrequent stimuli; this effect was not significantly different between groups. In the sustained attention task, the HIV-group showed significantly slower reaction time than controls while maintaining the same level of accuracy. In the divided attention task, the HIV-group showed a trend towards faster/less accurate responses.

CONCLUSIONS

HIV seropositive participants receiving anti-retroviral treatment (ART) demonstrated significantly larger P200 amplitude during three different attention tasks. This may reflect attentional deficits characterized by over-attending to non-target/distracting stimuli.

SIGNIFICANCE

These findings demonstrate the potential benefits of EEG-ERP metrics derived from attention tasks as neurocognitive biomarkers for HIV. This approach may reveal underlying causes of attentional deficits in HIV patients.

Cortical sources of resting state electroencephalographic rhythms probe brain function in naïve HIV individuals

OBJECTIVE

Here we evaluated the hypothesis that resting state electroencephalographic (EEG) cortical sources correlated with cognitive functions and discriminated asymptomatic treatment-naïve HIV subjects (no AIDS).

METHODS

EEG, clinical, and neuropsychological data were collected in 103 treatment-naïve HIV subjects (88 males; mean age 39.8 years ± 1.1 standard error of the mean, SE). An age-matched group of 70 cognitively normal and HIV-negative (Healthy; 56 males; 39.0 years ± 2.0 SE) subjects, selected from a local university archive, was used for control purposes. LORETA freeware was used for EEG source estimation in fronto-central, temporal, and parieto-occipital regions of interest.

RESULTS

Widespread sources of delta (<4 Hz) and alpha (8-12 Hz) rhythms were abnormal in the treatment-naïve HIV group. Fronto-central delta source activity showed a slight but significant (p < 0.05, corrected) negative correlation with verbal and semantic test scores. So did parieto-occipital delta/alpha source ratio with memory and composite cognitive scores. These sources allowed a moderate classification accuracy between HIV and control individuals (area under the ROC curves of 70-75%).

CONCLUSIONS

Regional EEG abnormalities in quiet wakefulness characterized treatment-naïve HIV subjects at the individual level.

SIGNIFICANCE

This EEG approach may contribute to the management of treatment-naïve HIV subjects at risk of cognitive deficits.

The electrophysiology of neuroHIV: A systematic review of EEG and MEG studies in people with HIV infection since the advent of highly-active antiretroviral therapy

OBJECTIVE

The Human Immunodeficiency Virus (HIV) has an impact on the brain, even when the infection is well-controlled with modern highly-active antiretroviral therapy (HAART). While dementia is rare in those on HAART, milder cognitive impairment is common. The causes, patterns, and evolution of brain dysfunction in people living with HIV remain uncertain. We evaluate whether electrophysiological methods provide informative measures of brain dysfunction in this population.

METHODS

A systematic literature search identified studies that used EEG or MEG to evaluate persons living with HIV published between 1996 (when HAART became available) and 2016.

RESULTS

Twenty-eight studies were identified. Most involved small samples, and all but four were cross-sectional. Reduced amplitude of Event Related Potentials and decreased power in the alpha band at rest were the most frequent differences between people with and without HIV infection. Of the 16 studies that also assessed cognitive ability, 13 found a significant relationship between cognition and electrophysiological changes in the HIV+ groups. Five of those studies also reported a significant relationship with current immunosuppression, suggesting a direct effect of HIV on the brain. There were few longitudinal studies; whether these electrophysiological changes progress over time, or respond to treatment, remains unclear.

CONCLUSIONS

EEG and MEG can provide useful information about brain dysfunction in people with HIV infection, but more consistent assessments of both cognition and EEG patterns, as well as longitudinal studies with larger, better characterized samples are needed.

SIGNIFICANCE

This is the first systematic review of electrophysiological findings in HIV since the availability of HAART. EEG and MEG measures are sensitive to brain dysfunction in this population, and could complement other approaches in improving the assessment, understanding and treatment of neurocognitive disorders in HIV.

Brain and cognitive functions in two groups of naïve HIV patients selected for a different plan of antiretroviral therapy: A qEEG study

OBJECTIVE

Cortical sources of electroencephalographic (EEG) rhythms were investigated in two sub-populations of naïve HIV subjects, grouped based on clinical criteria to receive different combination anti-retroviral therapies (cARTs). These EEG sources were hypothesized to reflect beneficial effects of both regimes.

METHODS

Eyes-closed resting state EEG data were collected in 19 (Group A) and 39 (Group B) naïve HIV subjects at baseline (i.e. pre-treatment; T0) and after 5months of cART (T5). Compared with the Group A, the Group B was characterized by slightly worse serological parameters and higher cardiovascular risk. At T0, mean viral load (VL) and CD4 count were 87,694copies/ml and 435cells/μl in the Group A and 187,370copies/ml and 331cells/μl in the Group B. The EEG data were also collected in 50 matched control HIV-negative subjects. Cortical EEG sources were assessed by LORETA software.

RESULTS

Compared to the Control Group, the HIV Groups showed lower alpha (8-12Hz) source activity at T0 while the Group B also exhibited higher delta source activity. The treatment partially normalized alpha and delta source activity in the Group A and B, respectively, in association with improved VL, CD4, and cognitive functions.

CONCLUSIONS

Different cART regimens induced diverse beneficial effects in delta or alpha source activity in the two naïve HIV Groups.

SIGNIFICANCE

These sources might unveil different neurophysiological effects of diverse cART on brain function in naïve HIV Groups as a function of clinical status and/or therapeutic compounds.

Antiretroviral therapy affects the z-score index of deviant cortical EEG rhythms in naïve HIV individuals

OBJECTIVE

Here we tested the effect of combined antiretroviral therapy (cART) on deviant electroencephalographic (EEG) source activity in treatment-naïve HIV individuals.

METHODS

Resting state eyes-closed EEG data were recorded before and after 5 months of cART in 48 male HIV subjects, who were naïve at the study start. The EEG data were also recorded in 59 age- and sex-matched healthy subjects as a control group. Frequency bands of interest included delta, theta, alpha1, alpha2 and alpha3, based on alpha frequency peak specific to each individual. They also included beta1 (13-20 Hz) and beta2 (20-30 Hz). Low-resolution brain electromagnetic tomography (LORETA) estimated EEG cortical source activity in frontal, central, temporal, parietal, and occipital regions.

RESULTS

Before the therapy, the HIV group showed greater parietal delta source activity and lower spatially diffuse alpha source activity compared to the control group. Thus, the ratio of parietal delta and alpha3 source activity served as an EEG marker. The z-score showed a statistically deviant EEG marker (EEG +) in 50% of the HIV individuals before therapy (p < 0.05). After 5 months of cART, delta source activity decreased, and alpha3 source activity increased in the HIV subjects with EEG + (about 50% of them showed a normalized EEG marker).

CONCLUSIONS

This procedure detected a deviant EEG marker before therapy and its post-therapy normalization in naïve HIV single individuals.

SIGNIFICANCE

The parietal delta/alpha3 EEG marker may be used to monitor cART effects on brain function in such individuals.

Abnormal cortical sources of resting state electroencephalographic rhythms in single treatment-naïve HIV individuals: A statistical z-score index

OBJECTIVE

This study tested a simple statistical procedure to recognize single treatment-naïve HIV individuals having abnormal cortical sources of resting state delta (<4 Hz) and alpha (8-13 Hz) electroencephalographic (EEG) rhythms with reference to a control group of sex-, age-, and education-matched healthy individuals. Compared to the HIV individuals with a statistically normal EEG marker, those with abnormal values were expected to show worse cognitive status.

METHODS

Resting state eyes-closed EEG data were recorded in 82 treatment-naïve HIV (39.8 ys.±1.2 standard error mean, SE) and 59 age-matched cognitively healthy subjects (39 ys.±2.2 SE). Low-resolution brain electromagnetic tomography (LORETA) estimated delta and alpha sources in frontal, central, temporal, parietal, and occipital cortical regions.

RESULTS

Ratio of the activity of parietal delta and high-frequency alpha sources (EEG marker) showed the maximum difference between the healthy and the treatment-naïve HIV group. Z-score of the EEG marker was statistically abnormal in 47.6% of treatment-naïve HIV individuals with reference to the healthy group (p<0.05). Compared to the HIV individuals with a statistically normal EEG marker, those with abnormal values exhibited lower mini mental state evaluation (MMSE) score, higher CD4 count, and lower viral load (p<0.05).

CONCLUSIONS

This statistical procedure permitted for the first time to identify single treatment-naïve HIV individuals having abnormal EEG activity.

SIGNIFICANCE

This procedure might enrich the detection and monitoring of effects of HIV on brain function in single treatment-naïve HIV individuals.