Prospective associations between lateralised brain function and immune status in HIV infection: analysis of EEG, cognition and mood over 30 months

Parietal resting-state EEG alpha source connectivity is associated with subcortical white matter lesions in HIV-positive people

OBJECTIVE

Parietal resting-state electroencephalographic (rsEEG) alpha (8-10 Hz) source connectivity is abnormal in HIV-positive persons. Here we tested whether this abnormality may be associated with subcortical white matter vascular lesions in the cerebral hemispheres.

METHODS

Clinical, rsEEG, and magnetic resonance imaging (MRI) datasets in 38 HIV-positive persons and clinical and rsEEG datasets in 13 healthy controls were analyzed. Radiologists visually evaluated the subcortical white matter hyperintensities from T2-weighted FLAIR MRIs (i.e., Fazekas scale). In parallel, neurophysiologists estimated the eLORETA rsEEG source lagged linear connectivity from parietal cortical regions of interest.

RESULTS

Compared to the HIV participants with no/negligible subcortical white matter hyperintensities, the HIV participants with mild/moderate subcortical white matter hyperintensities showed lower parietal interhemispheric rsEEG alpha lagged linear connectivity. This effect was also observed in HIV-positive persons with unimpaired cognition. This rsEEG marker allowed good discrimination (area under the receiver operating characteristic curve > 0.80) between the HIV-positive individuals with different amounts of subcortical white matter hyperintensities.

CONCLUSIONS

The parietal rsEEG alpha source connectivity is associated with subcortical white matter vascular lesions in HIV-positive persons, even without neurocognitive disorders.

SIGNIFICANCE

Those MRI-rsEEG markers may be used to screen HIV-positive persons at risk of neurocognitive disorders.

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.

Frontal brain asymmetry, childhood maltreatment, and low-grade inflammation at midlife

Frontal EEG asymmetry is thought to reflect variations in affective style, such that greater relative right frontal activity at rest predicts enhanced emotional responding to threatening or negative stimuli, and risk of depression and anxiety disorders. A diathesis-stress model has been proposed to explain how this neuro-affective style might predispose to psychopathology, with greater right frontal activity being a vulnerability factor especially under stressful conditions. Less is known about the extent to which greater relative right frontal activity at rest might be associated with or be a diathesis for deleterious physical health outcomes. The present study examined the association between resting frontal EEG asymmetry and systemic, low-grade inflammation and tested the diathesis-stress model by examining whether childhood maltreatment exposure interacts with resting frontal asymmetry in explaining inflammation. Resting EEG, serum inflammatory biomarkers (interleukin-6, C-reactive protein, and fibrinogen) and self-reported psychological measures were available for 314 middle-aged adults (age M=55.3years, SD=11.2, 55.7% female). Analyses supported the diathesis-stress model and revealed that resting frontal EEG asymmetry was significantly associated with inflammation, but only in individuals who had experienced moderate to severe levels of childhood maltreatment. These findings suggest that, in the context of severe adversity, a trait-like tendency towards greater relative right prefrontal activity may predispose to low-grade inflammation, a risk factor for conditions with inflammatory underpinnings such as coronary heart disease.

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.

Interhemispheric Asymmetries and Theta Activity in the Rostral Anterior Cingulate Cortex as EEG Signature of HIV-Related Depression: Gender Matters

Resting EEGs of 40 people living with HIV (PLWH) on long-term antiretroviral treatment were examined for z-scored deviations from a healthy control (normative database) to examine the main and interaction effects of depression and gender. Regions of interest were frontal (alpha) and central (all bands) for interhemispheric asymmetries in quantitative EEGs and theta in the rostral anterior cingulate cortex (rACC) in low-resolution electromagnetic tomography (LORETA). Z-scored normed deviations of depressed PLWH, compared with nondepressed, showed right-dominant interhemispheric asymmetries in all regions. However, after adjusting for multiple testing, significance remained only central for theta, alpha, and beta. Reversed (left-dominant) frontal alpha asymmetry is a potential EEG marker of depression in the HIV negative population that was not reversed in depressive PLWH; however, corresponding with extant literature, gender had an effect on the size of frontal alpha asymmetry. The LORETA analysis revealed a trending interactional effect of depression and gender on theta activity in the rACC in Brodmann area 32. We found that compared to men, women had greater right-dominant frontal alpha-asymmetry and elevated theta activity in voxels of the rACC, which may indicate less likelihood of depression and a higher likelihood of response to antidepressants. In conclusion, subtle EEG deviations, such as right-dominant central theta, alpha, and beta asymmetries and theta activity in the rACC may mark HIV-related depressive symptoms and may predict the likelihood of response to antidepressants but gender effects need to be taken into account. Although this study introduced the use of LORETA to examine the neurophysiological correlates of negative affect in PLWH, further research is needed to assess the utility of this tool in diagnostics and treatment monitoring of depression in PLWH.

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.

Prospective relationship between hemispheric lateralisation and CD4+ T cells in human immunodeficiency virus type 1

OBJECTIVES

Neuromodulation of the immune system has been proposed to be influenced by hemispheric lateralisation (HL). The present study tested whether HL predicted CD4+ levels, statistically controlling for confounders.

METHODS

Employing two assessments of HL, 68 human immunodeficiency virus (HIV)-1+ patients were followed prospectively. Numerous exclusion criteria and confounder assessments were employed (e.g. age/medication).

RESULTS

Left HL significantly positively predicted CD4+ levels at follow-up, and this was qualified by medication (HAART) status: only in HAART-naïve patients did HL predict CD4 levels. Furthermore, HL significantly predicted whether patients had clinically significantly high/low CD4+ counts.

CONCLUSIONS

Using a more rigorous methodology than a previous study, the present work partly corroborated the theory of HL influences on immunity, extended it to HIV immunity and identified a possible moderator: HAART medication. Implications for future research and treatments are provided.

Left-sided brain injury associated with more hospital-acquired infections during inpatient rehabilitation

OBJECTIVE

To test the hypothesis that a left-dominant brain immune network (LD-BIN) might affect the occurrence of infection during inpatient rehabilitation of stroke and traumatic brain injury (TBI).

DESIGN

A retrospective analysis was performed on electronic medical records between January 2009 and December 2010. All patients with left- or right-sided stroke or TBI were included into the study. The LD-BIN hypothesis was tested by comparing HAI rates depending on whether patients had left- or right-sided brain lesions.

SETTING

A large inpatient rehabilitation hospital.

PARTICIPANTS

Among the patients (N=2236) with stroke or TBI who had either a left- or right-sided brain lesion, 163 patients were identified with HAIs.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURE

Frequency of HAIs.

RESULTS

In the 163 patients identified with HAIs with a diagnosis of stroke or TBI, chi-square analysis revealed a significantly higher proportion of HAIs among patients with left-sided (n=98; 60.1%) relative to right-sided (n=65; 39.9%) brain injuries (χ(2)=6.68, P<.01). These effects could not be attributed to either clinical or demographic factors.

CONCLUSIONS

Our findings are consistent with the hypothesis that an LD-BIN may mediate vulnerability to infection during rehabilitation of patients with stroke or TBI. Further translational research investigating novel means of managing patients based on brain lesion location, and modulating the LD-BIN via behavioral and physiologic interventions, may result in neuroscience-based methods to improve infection resistance in brain-injured patients.

[Role of hypnosis and hypno-suggestions methods in the complex therapy of tumor patients]

Besides more conventional tumor risks, depression and negative life events are significant risk factors in cancer here in Hungary, therefore oncopsychology is increasingly important. We discuss traumatizing effects of the diagnosis and invasive diagnostic and therapeutic procedures from the viewpoint of altered state of consciousness. During stress and hypnosis brain functioning is altered in a similar way, which can be seen both in the patient's symptoms and his/her physiological and neuroimaging findings. In trance state patients part from reality, they no longer communicate conventionally or maturely. Hypnosis is characterized not only by physical and mental changes, but important unique social interactions as well. These interactions affect the endocrine and immune system and the mental state of the patient, they strengthen and synchronize resources and help posttraumatic growth. Since in the stress induced spontaneous altered state of consciousness the susceptibility to suggestions is increased, suggestive communication can be used effectively and it can even result in formal hypnosis induction. Under the strong time and mental pressure characterizing the work of the oncologic departments, it might help the staff to improve the cooperation with the patient if staff members, physicians and nurses as well, are aware of the nature and the neurophysiologic background of the spontaneous trance state induced by the life-threatening diagnosis of cancer.

Cognitive functioning predicts survival in the elderly

Prior studies of aging have identified a number of predictors of survival, including performances on some cognitive-functioning tests. However, few studies have used a multidomain test battery to identify which specific cognitive abilities predict death. The current study examined the 12 subtests of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to see which subtests predicted death in a sample of 796 older, primary care patients. After 4 years, 98 individuals died, and 698 individuals remained alive. The individuals who died performed more poorly at baseline on 9 of the 12 RBANS subtests (p < .05) than did their peers who remained alive. In a multivariate analysis, however, only the RBANS Coding subtest independently predicted death (p < .001), along with male gender and greater initial medical comorbidity. Although the mechanism of poorer cognition and impending death remains unclear, some possibilities are discussed (e.g., brain dysfunction, poor medical compliance, impaired cellular immunity).

Anterior EEG asymmetries and opponent process theory

The opponent process theory of emotion [Solomon, R.L., and Corbit, J.D. (1974). An opponent-process theory of motivation: I. Temporal dynamics of affect. Psychological Review, 81, 119-143.] predicts a temporary reversal of emotional valence during the recovery from emotional stimulation. We hypothesized that this affective contrast would be apparent in asymmetrical activity patterns in the frontal lobes, and would be more apparent for left frontally active individuals. The present study tested this prediction by examining EEG asymmetries during and after blocked presentations of aversive pictures selected from the International Affective Picture System (IAPS). 12 neutral images, 12 aversive images, and 24 neutral images were presented in blocks. Participants who were right frontally active at baseline did not show changes in EEG asymmetry while viewing aversive slides or after cessation. Participants left frontally active at baseline, however, exhibited greater relative left frontal activity after aversive stimulation than before stimulation. Asymmetrical activity patterns in the frontal lobes may relate to affect regulatory processes, including contrasting opponent after-reactions to aversive stimuli.

An investigation into asymmetrical cortical regulation of salivary S-IgA in conscious man using transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS) can activate discrete areas of the cerebral cortex through the intact skull of healthy conscious volunteers. A magnetic coil generates a brief and focused magnetic field that penetrates the skull to activate the specific area of cerebral cortex beneath. This non-invasive procedure is painless, well tolerated by participants and now widely used to explore brain function. We used TMS to investigate asymmetrical cortical regulatory influences on one aspect of immune function: secretion of the antibody immunoglobulin A (S-IgA) into saliva. The right and left temporo-parietal-occipital cortex of 16 healthy, conscious subjects was stimulated on two different occasions, at least 1 week apart. There was an immediate increase in S-IgA concentration following both right and left stimulation. Saliva volume was reduced immediately post-right but not left stimulation. When secretion (microg/min) of S-IgA was calculated (controlling for changing saliva volume) an increase was apparent following left but not right hemisphere stimulation. Furthermore, a significant difference between the relationship between S-IgA concentration and volume of saliva post-left and right stimulation was observed. We conclude that TMS can be used as a tool to investigate cortical regulation of autonomic and immune function in healthy, conscious human subjects and that secretion of saliva and S-IgA is differentially affected by stimulation of the left and right cerebral cortex.

Cellular and humoral immunity, mood and exam stress: the influences of self-hypnosis and personality predictors

The effects of self-hypnosis training on immune function and mood were examined in medical students at exam time. Hypnosis involved relaxation and imagery directed at improved immune function and increased energy, alertness and concentration. Hypotheses were made about activated and withdrawn personality differences. Eight high and eight low hypnotically susceptible participants were given 10 sessions of hypnosis, one live and nine tape-recorded, and were compared with control subjects (N=12). CD3, CD4, CD8, CD19 and CD56 NK cells and blood cortisol were assayed. Life-style, activated vs. withdrawn temperament, arousal and anxiety questionnaires were administered. Self-hypnosis buffered the decline found in controls in NK (P<0.002) and CD8 cells (P<0.0.07) and CD8/CD4% (P<0.06) (45-35% order of magnitude differences) while there was an increase in cortisol (P<0.05). The change in NK cell counts correlated positively with changes in both CD8 cells and cortisol. Results were independent of changes in life-style. Energy ratings were higher after hypnosis (P<0.01), and increased calmness with hypnosis correlated with an increase in CD4 counts (P<0.01). The activated temperament, notably the cognitive subscale (speaking and thinking quickly), was predictive of exam levels of T and B lymphocytes (P&z.Lt;0.08-P<0.02), and reaching r=0.72 (P<0.001) in the non-intervention control group. The sizeable influences on cell-mediated immunity achieved by a relatively brief, low cost psychological intervention in the face of a compelling, but routine, stress in young, healthy adults have implications for illness prevention and for patients with compromised immunity.

Source localization of EEG activity during hypnotically induced anxiety and relaxation

The engagement of different brain regions which implement subjectively experienced emotional states in normals is not completely clarified. Emotional states can conveniently be induced by hypnosis-based suggestions. We studied brain electric activity during hypnotically induced anxiety and relaxation in 11 right-handed normals (5 males, 6 females, mean age 26.5+/-7.6 years). After induction of light hypnosis, anxiety and then relaxation was suggested using a standardized text (reverse sequence in half of the subjects). Nineteen-channel, eyes-closed EEG (20 artifact-free s/subject) was analyzed (source localization using FFT approximation and low resolution electromagnetic tomography, LORETA). Global tests revealed the strongest difference (P<0.005) between EEG source gravity center locations during the two emotional states in the excitatory beta-2 EEG frequency band (18.5-21 Hz). Post hoc tests showed that the sources were located more right during anxiety than during relaxation (P=0.01). LORETA specified that anxiety showed maximally stronger activity than relaxation in right Brodmann area 10, and relaxation showed maximally stronger activity than anxiety in left Brodmann area 22. Clearly, the two induced emotional states were associated with activity of different neural populations. Our results agree with reports on brain activity shifted to the right (especially fronto-temporal) during negative compared with positive emotions, and support the role of beta-2 EEG frequency in emotional states.

Immunological markers of frequently recurrent genital herpes simplex virus and their response to hypnotherapy: a pilot study

Patients were recruited for hypnotherapy from a clinic for patients with frequently recurrent genital herpes simplex virus (rgHSV). Psychological and immunological parameters were measured 6 weeks prior to hypnotherapy and 6 weeks afterwards, during which time each patient kept a diary of symptoms of rgHSV. Following hypnotherapy there was a significant overall reduction in the number of reported episodes of rgHSV, accompanied by an increase in the numbers of CD3 and CD8 lymphocytes, which may represent a non specific effect of hypnosis. The improvers showed significant rises in natural killer (NK) cell counts, HSV specific lymphokine activated killer (LAK) activity, and reduced levels of anxiety when compared to non-improvers. NK cell numbers and HSV specific LAK activity may therefore be important in the reduction in rgHSV following hypnotherapy.