Cognitive function in women with HIV: findings from the Women's Interagency HIV Study

Reliability of White Matter Microstructural Changes in HIV Infection: Meta-Analysis and Confirmation

BACKGROUND

Diffusion tensor imaging has been widely used to measure HIV effects on white matter microarchitecture. While many authors have reported reduced fractional anisotropy and increased mean diffusivity in HIV, quantitative inconsistencies across studies are numerous.

PURPOSE

Our aim was to evaluate the consistency across studies of HIV effects on DTI measures and then examine the DTI reliability in a longitudinal seropositive cohort.

DATA SOURCES

Published studies and investigators.

STUDY SELECTION

The meta-analysis included 16 cross-sectional studies reporting fractional anisotropy and 12 studies reporting mean diffusivity in the corpus callosum.

DATA ANALYSIS

Random-effects meta-analysis was used to estimate study standardized mean differences and heterogeneity. DTI longitudinal reliability was estimated in seropositive participants studied before and 3 and 6 months after beginning treatment.

DATA SYNTHESIS

Meta-analysis revealed lower fractional anisotropy (standardized mean difference, -0.43; P < .001) and higher mean diffusivity (standardized mean difference, 0.44; P < .003) in seropositive participants. Nevertheless, between-study heterogeneity accounted for 58% and 66% of the observed variance (P < .01). In contrast, the longitudinal cohort fractional anisotropy was higher and mean diffusivity was lower in seropositive participants (both, P < .001), and fractional anisotropy and mean diffusivity measures were very stable during 6 months, with intraclass correlation coefficients all >0.96.

LIMITATIONS

Many studies pooled participants with varying treatments, ages, and disease durations.

CONCLUSIONS

HIV effects on WM microstructure had substantial variations that could result from acquisition, processing, or cohort-selection differences. When acquisition parameters and processing were carefully controlled, the resulting DTI measures did not show high temporal variation. HIV effects on WM microstructure may be age-dependent. The high longitudinal reliability of DTI WM microstructure measures makes them promising disease-activity markers.

Changes in cognitive function in women with HIV infection and early life stress

INTRODUCTION

HIV is frequently associated with deficits in brain function, including memory, psychomotor speed, executive function and attention. Early life stress (ELS) has also been shown to have a direct influence on neurocognitive performance. However, little is known about the combined impact of ELS and HIV on neurocognitive function over time. The aim of the present study was to follow a cohort of affected women, allowing us to assess the effects of HIV and childhood trauma on cognition and the change in cognition over time.

METHOD

A battery of neurocognitive tests was administered to 117 women at baseline and then a year later. The sample included a total of 67 HIV+ and 50 HIV- women, 71 with ELS and 46 without ELS. Controlling for age, education and antiretroviral therapy (ART) at baseline and 12-month follow-up, raw scores were compared across groups using a repeated-measures analysis of covariance.

RESULTS

More women were on ART at follow-up compared to baseline. Results revealed a significant combined HIV and childhood trauma effect over time on the Wisconsin Card Sorting Test (p = .003) and Category Fluency Test (p = .006). A significant individual HIV effect over time was evident on the WAIS-III Digit Symbol Test (p = .03) and the Controlled Oral Word Association Test (p = .003).

CONCLUSION

Findings suggest better performance in abstract reasoning, speed of information processing and verbal fluency over time. While all groups showed improvements that may correspond to practice effects, effects of HIV and childhood trauma remained evident at 12-month follow-up despite greater ART uptake and improved HIV disease status. This is the first study to assess the combined impact of HIV and trauma on neurocognitive function over time in an all-female cohort with more advanced disease.

Impairments in Component Processes of Executive Function and Episodic Memory in Alcoholism, HIV Infection, and HIV Infection with Alcoholism Comorbidity

BACKGROUND

Executive functioning and episodic memory impairment occur in HIV infection (HIV) and chronic alcoholism (ALC). Comorbidity of these conditions (HIV + ALC) is prevalent and heightens risk of vulnerability to separate and compounded deficits. Age and disease-related variables can also serve as mediators of cognitive impairment and should be considered, given the extended longevity of HIV-infected individuals in this era of improved pharmacological therapy.

METHODS

HIV, ALC, HIV + ALC, and normal controls (NC) were administered traditional and computerized tests of executive function and episodic memory. Test scores were expressed as age- and education-corrected Z-scores; selective tests were averaged to compute Executive Function and Episodic Memory Composite scores. Efficiency scores were calculated for tests with accuracy and response times.

RESULTS

HIV, ALC, and HIV + ALC had lower scores than NC on Executive Function and Episodic Memory Composites, with HIV + ALC even lower than ALC and HIV on the Episodic Memory Composite. Impairments in planning and free recall of visuospatial material were observed in ALC, whereas impairments in psychomotor speed, sequencing, narrative free recall, and pattern recognition were observed in HIV. Lower decision-making efficiency scores than NC occurred in all 3 clinical groups. In ALC, age and lifetime alcohol consumption were each unique predictors of Executive Function and Episodic Memory Composite scores. In HIV + ALC, age was a unique predictor of Episodic Memory Composite score.

CONCLUSIONS

Disease-specific and disease-overlapping patterns of impairment in HIV, ALC, and HIV + ALC have implications regarding brain systems disrupted by each disease and clinical ramifications regarding the complexities and compounded damping of cognitive functioning associated with dual diagnosis that may be exacerbated with aging.

Sex and HIV serostatus differences in decision making under risk among substance-dependent individuals

HIV+ individuals with and without substance use disorders make significantly poorer decisions when information about the probability and magnitude of wins and losses is not available. We administered the Game of Dice Task, a measure of decision making under risk that provides this information explicitly, to 92 HIV+ and 134 HIV- substance-dependent men and women. HIV+ participants made significantly poorer decisions than HIV- participants, but this deficit appeared more prominent among HIV+ women. These data indicate that decision making under risk is impaired among HIV+ substance-dependent individuals (SDIs). Potential factors for the HIV+ women's relatively greater impairment are discussed.

Monocyte Activation Is Associated With Worse Cognitive Performance in HIV-Infected Women With Virologic Suppression

BACKGROUND

 Cognitive impairment persists despite suppression of plasma human immunodeficiency virus (HIV) RNA. Monocyte-related immune activation is a likely mechanism. We examined immune activation and cognition in a cohort of HIV-infected and uninfected women from the Women's Interagency HIV Study (WIHS).

METHODS

 Blood levels of activation markers, soluble CD163 (sCD163), soluble CD14 (sCD14), CRP, IL-6, and a gut microbial translocation marker (intestinal fatty acid binding protein (I-FABP)) were measured in 253 women (73% HIV-infected). Markers were compared to concurrent (within ± one semiannual visit) neuropsychological testing performance.

RESULTS

 Higher sCD163 levels were associated with worse overall performance and worse verbal learning, verbal memory, executive function, psychomotor speed, and fine motor skills (P < .05 for all comparisons). Higher sCD14 levels were associated with worse verbal learning, verbal memory, executive function, and psychomotor speed (P < .05 for all comparisons). Among women with virological suppression, sCD163 remained associated with overall performance, verbal memory, psychomotor speed, and fine motor skills, and sCD164 remained associated with executive function (P < .05 for all comparisons). CRP, IL-6, and I-FABP were not associated with worse cognitive performance.

CONCLUSIONS

 Monocyte activation was associated with worse cognitive performance, and associations persisted despite viral suppression. Persistent inflammatory mechanisms related to monocytes correlate to clinically pertinent brain outcomes.

Affective differences in Iowa Gambling Task performance associated with sexual risk taking and substance use among HIV-positive and HIV-negative men who have sex with men

We investigated the relationship between emotional distress and decision making in sexual risk and substance use behavior among 174 (ages 25 to 50 years, 53% black) men who have sex with men (MSM), a population at increased risk for HIV. The sample was stratified by HIV status. Measures of affective decision making, depression, anxiety, sex acts, and substance use during the past 60 days were collected at our research center. Negative binomial regression models were used to examine the relationship between age, HIV status, anxiety, depression, and IGT performance in the prediction of number of risky sex acts and substance use days. Among those without anxiety or depression, both number of risky sex acts and drug use days decreased with better performance during risky trials (i.e., last two blocks) of the IGT. For those with higher rates of anxiety, but not depression, IGT risk trial performance and risky sex acts increased concomitantly. Anxiety also interacted with IGT performance across all trials to predict substance use, such that anxiety was associated with greater substance use among those with better IGT performance. The opposite was true for those with depression, but only during risk trials. HIV-positive participants reported fewer substance use days than HIV-negative participants, but there was no difference in association between behavior and IGT performance by HIV status. Our findings suggest that anxiety may exacerbate risk-taking behavior when affective decision-making ability is intact. The relationship between affective decision making and risk taking may be sensitive to different profiles of emotional distress, as well as behavioral context. Investigations of affective decision making in sexual risk taking and substance use should examine different distress profiles separately, with implications for HIV prevention efforts.

Progression of temporal processing deficits in the HIV-1 transgenic rat

The HIV-1 transgenic (Tg) rat, which expresses 7 of the 9 HIV-1 genes, was used to investigate the effect(s) of long-term HIV-1 viral protein exposure on chronic neurocognitive deficits observed in pediatric HIV-1 (PHIV). A longitudinal experimental design was used to assess the progression of temporal processing deficits, a potential underlying dimension of neurocognitive impairment in HIV-1. Gap prepulse inhibition (gap-PPI), a translational experimental paradigm, was conducted every thirty days from postnatal day (PD) 30 to PD 180. HIV-1 Tg animals, regardless of sex, displayed profound alterations in the development of temporal processing, assessed using prepulse inhibition. A differential sensitivity to the manipulation of interstimulus interval was observed in HIV-1 Tg animals in comparison to control animals. Moreover, presence of the HIV-1 transgene was diagnosed with 90.8% accuracy using measures of prepulse inhibition and temporal sensitivity. Progression of temporal processing deficits in the HIV-1 Tg rat affords a relatively untapped opportunity to increase our mechanistic understanding of the role of long-term exposure to HIV-1 viral proteins, observed in pediatric HIV-1, in the development of chronic neurological impairment, as well as suggesting an innovative clinical diagnostic screening tool.

Increased subcortical neural activity among HIV+ individuals during a lexical retrieval task

BACKGROUND

Deficits in lexical retrieval, present in approximately 40% of HIV+ patients, are thought to reflect disruptions to frontal-striatal functions and may worsen with immunosuppression. Coupling frontal-striatal tasks such as lexical retrieval with functional neuroimaging may help delineate the pathophysiologic mechanisms underlying HIV-associated neurological dysfunction.

OBJECTIVE

We examined whether HIV infection confers brain functional changes during lexical access and retrieval. It was expected that HIV+ individuals would demonstrate greater brain activity in frontal-subcortical regions despite minimal differences between groups on neuropsychological testing. Within the HIV+ sample, we examined associations between indices of immunosuppression (recent and nadir CD4+ count) and task-related signal change in frontostriatal structures. Method16 HIV+ participants and 12 HIV- controls underwent fMRI while engaged in phonemic/letter and semantic fluency tasks. Participants also completed standardized measures of verbal fluency

RESULTS

HIV status groups performed similarly on phonemic and semantic fluency tasks prior to being scanned. fMRI results demonstrated activation differences during the phonemic fluency task as a function of HIV status, with HIV+ individuals demonstrating significantly greater activation in BG structures than HIV- individuals. There were no significant differences in frontal brain activation between HIV status groups during the phonemic fluency task, nor were there significant brain activation differences during the semantic fluency task. Within the HIV+ group, current CD4+ count, though not nadir, was positively correlated with increased activity in the inferior frontal gyrus and basal ganglia.

CONCLUSION

During phonemic fluency performance, HIV+ patients recruit subcortical structures to a greater degree than HIV- controls despite similar task performances suggesting that fMRI may be sensitive to neurocompromise before overt cognitive declines can be detected. Among HIV+ individuals, reduced activity in the frontal-subcortical structures was associated with lower CD4+ count.

Elevated stress is associated with prefrontal cortex dysfunction during a verbal memory task in women with HIV

HIV-infected women may be particularly vulnerable to verbal learning and memory deficits. One factor contributing to these deficits is high perceived stress, which is associated with prefrontal cortical (PFC) atrophy and memory outcomes sensitive to PFC function, including retrieval and semantic clustering. We examined the association between stress and PFC activation during a verbal memory task in 36 HIV-infected women from the Chicago Consortium of the Women's Interagency HIV Study (WIHS) to better understand the role of the PFC in this stress-related impairment. Participants completed standardized measures of verbal learning and memory and stress (perceived stress scale-10). We used functional magnetic resonance imaging to assess brain function while participants completed encoding and recognition phases of a verbal memory task. HIV-infected women with higher stress (scores in top tertile) performed worse on all verbal memory outcomes including strategic encoding (p < 0.05) compared to HIV-infected women with lower stress (scores in lower two tertiles). Patterns of brain activation during recognition (but not encoding) differed between women with higher vs. lower stress. During recognition, women with higher stress demonstrated greater deactivation in medial PFC and posterior cingulate cortex compared to women with lower stress (p < 0.05). Greater deactivation in medial PFC marginally related to less efficient strategic retrieval (p = 0.06). Similar results were found in analyses focusing on PTSD symptoms. Results suggest that stress might alter the function of the medial PFC in HIV-infected women resulting in less efficient strategic retrieval and deficits in verbal memory.

Maraviroc-intensified combined antiretroviral therapy improves cognition in virally suppressed HIV-associated neurocognitive disorder

OBJECTIVE

To investigate whether intensification of combined antiretroviral therapy (cART) with the CC chemokine receptor type 5 (CCR5) entry inhibitor maraviroc leads to improvement in global neurocognitive functioning in virally suppressed men with HIV-associated neurocognitive disorder (HAND).

DESIGN

Prospective, double observer-blinded, open-label pilot randomized-controlled trial. Participants were randomized to remain on their existing cART regimen (control arm; n = 8) or receive maraviroc-intensification (maraviroc arm; n = 9).

METHODS

Participants completed a five-domain neuropsychological battery at baseline, 6- and 12-month visits. Raw scores were transformed into age-corrected z-scores and averaged into a global z-score. Single voxel (H)-magnetic resonance spectroscopy (MRS) major cerebral metabolite concentrations were collected at baseline and 12 months in the basal ganglia and frontal white matter and quantified using jMRUI. Neuroinflammatory biomarkers cerebrospinal fluid neopterin and β2-microglobulin were also measured.

RESULTS

Fourteen of the 17 participants completed the study: nine maraviroc arm and five control. We found medium to large effect sizes in favour of improved global neurocognitive performance in the maraviroc arm over time {arm*time interaction: P < 0.05; 6 month: [β=-0.10, standard error (SE)= 0.04, 90% confidence interval (90%CI)= -0.18,.03; P < 0.03] yielding a large effect-size d = 0.77 (90%CI = -0.19,1.71); 12 month: [β=-0.01; SE = 0.05; 90%CI = -0.09, 0.06; P < 0.77] yielding a moderate effect-size d = 0.55 (90%CI = -0.47,1.55)}. No treatment-related changes were detected for H-MRS metabolites or cerebrospinal fluid biomarkers.

CONCLUSION

This pilot study provides feasibility, tolerability, proof-of-concept and preliminary evidence for clinically relevant neurocognitive improvement in cART enhancement with maraviroc in virally suppressed HAND patients. Lack of concomitant brain metabolite and biomarker change may be related to complex dynamics of brain repair.

Untangling the Gordian knot of HIV, stress, and cognitive impairment

As individuals live longer with HIV, this "graying of the HIV epidemic" has introduced a new set of challenges including a growing number of age and inflammation-related diseases such as cardiovascular disease, type II diabetes, cancer, and dementia. The biological underpinnings of these complex and co-morbid diseases are not fully understood and become very difficult to disentangle in the context of HIV and aging. In the current review we examine the contributions and interactions of HIV, stress, and cognitive impairment and query the extent to which inflammation is the linchpin in these dynamic interactions. Given the inter-relatedness of stress, inflammatory mechanisms, HIV, and cognitive impairment, future work will either need to address multiple dimensions simultaneously or embrace the philosophy that breaking the aberrant cycle at any one point will subsequently remedy the other related systems and processes. Such a single-point intervention may be effective in early disease states, but after perpetuation of an aberrant cycle, adaptations in an attempt to internally resolve the issue will likely lead to the need for multifaceted interventions. Acknowledging that HIV, inflammation, and stress may interact with one another and collectively impact cognitive ability is an important step in fully understanding an individual's complete clinical picture and moving towards personalized medicine.

Post-traumatic stress is associated with verbal learning, memory, and psychomotor speed in HIV-infected and HIV-uninfected women

The prevalence of post-traumatic stress disorder (PTSD) is higher among HIV-infected (HIV+) women compared with HIV-uninfected (HIV-) women, and deficits in episodic memory are a common feature of both PTSD and HIV infection. We investigated the association between a probable PTSD diagnosis using the PTSD Checklist-Civilian (PCL-C) version and verbal learning and memory using the Hopkins Verbal Learning Test in 1004 HIV+ and 496 at-risk HIV- women. HIV infection was not associated with a probable PTSD diagnosis (17% HIV+, 16% HIV-; p = 0.49) but was associated with lower verbal learning (p < 0.01) and memory scores (p < 0.01). Irrespective of HIV status, a probable PTSD diagnosis was associated with poorer performance in verbal learning (p < 0.01) and memory (p < 0.01) and psychomotor speed (p < 0.001). The particular pattern of cognitive correlates of probable PTSD varied depending on exposure to sexual abuse and/or violence, with exposure to either being associated with a greater number of cognitive domains and a worse cognitive profile. A statistical interaction between HIV serostatus and PTSD was observed on the fine motor skills domain (p = 0.03). Among women with probable PTSD, HIV- women performed worse than HIV+ women on fine motor skills (p = 0.01), but among women without probable PTSD, there was no significant difference in performance between the groups (p = 0.59). These findings underscore the importance of considering mental health factors as correlates to cognitive deficits in women with HIV.

Human immunodeficiency virus has similar effects on brain volumetrics and cognition in males and females

Most studies that have examined neuropsychological impairments associated with human immunodeficiency virus (HIV) have focused on males, yet females represent one of the largest groups of newly infected patients. Further, few studies have examined neuropsychological performance and neuroimaging outcomes among females compared to males in the modern era of highly active anti-retroviral therapy (HAART). The present study investigated neuropsychological performance and brain volumetrics among HIV+ males (n = 93) and females (n = 44) on stable HAART compared to HIV seronegative (HIV-) males (n = 42) and females (n = 49). Results revealed a significant effect of HIV on neuropsychological performance and neuroimaging measures. An effect of gender, independent of HIV status, was also observed for neuroimaging measures but not neuropsychological performance. Additionally, no significant differences in neuropsychological performance or brain volumetrics were seen between HIV+ males and females. No significant interaction was observed between HIV and gender on either neuropsychological or neuroimaging indices. Our results suggest that both HIV+ males and females treated with HAART experience similar outcomes in terms of brain integrity.

HIV infection results in ventral-striatal reward system hypo-activation during cue processing

OBJECTIVE

Functional MRI has thus far demonstrated that HIV has an impact on frontal-striatal systems involved in executive functioning. The potential impact of HIV on frontal-striatal systems involved in reward processing has yet to be examined by functional MRI. This study therefore aims to investigate the effects of HIV infection on reward processing by examining the function of the ventral-striatal reward system during a monetary incentive delay task.

DESIGN

This is a cross-sectional case-control study.

METHODS

Eighteen combined antiretroviral therapy-naive HIV-positive (HIV+) participants, as well as 16 matched healthy controls, performed a monetary incentive delay task. This paradigm assesses behaviour as well as functional brain activity-associated reward anticipation and reward outcome.

RESULTS

HIV+ participants showed a general decrease in activation associated with both neutral as well as potentially rewarding cues in their ventral striatum. We found normal activity related to reward outcome in the orbito-frontal cortex. Despite HIV+ participants' reaction times being significantly slower when independently measured from the reward paradigm, this performance deficit normalized during the performance of the reward task.

CONCLUSION

HIV caused a decrease in activity during cue processing in the ventral striatum, with normal cortical functioning during reward outcome processing. Our results therefore suggest that HIV not only has an impact on fronto-striatal systems involved in executive functioning, but also has a direct impact on the function of the ventral-striatal reward system.

The association of perceived stress and verbal memory is greater in HIV-infected versus HIV-uninfected women

In contrast to findings from cohorts comprised primarily of HIV-infected men, verbal memory deficits are the largest cognitive deficit found in HIV-infected women from the Women's Interagency HIV Study (WIHS), and this deficit is not explained by depressive symptoms or substance abuse. HIV-infected women may be at greater risk for verbal memory deficits due to a higher prevalence of cognitive risk factors such as high psychosocial stress and lower socioeconomic status. Here, we investigate the association between perceived stress using the Perceived Stress Scale (PSS-10) and verbal memory performance using the Hopkins Verbal Learning Test (HVLT) in 1009 HIV-infected and 496 at-risk HIV-uninfected WIHS participants. Participants completed a comprehensive neuropsychological test battery which yielded seven cognitive domain scores, including a primary outcome of verbal memory. HIV infection was not associated with a higher prevalence of high perceived stress (i.e., PSS-10 score in the top tertile) but was associated with worse performance on verbal learning (p < 0.01) and memory (p < 0.001), as well as attention (p = 0.02). Regardless of HIV status, high stress was associated with poorer performance in those cognitive domains (p's < 0.05) as well as processing speed (p = 0.01) and executive function (p < 0.01). A significant HIV by stress interaction was found only for the verbal memory domain (p = 0.02); among HIV-infected women only, high stress was associated with lower performance (p's < 0.001). That association was driven by the delayed verbal memory measure in particular. These findings suggest that high levels of perceived stress contribute to the deficits in verbal memory observed in WIHS women.

Human immunodeficiency virus (HIV) modulates the associations between insulin resistance and cognition in the current combination antiretroviral therapy (cART) era: a study of the Women's Interagency HIV Study (WIHS)

Cognitive impairment (CI) remains common despite access to combination antiretroviral therapy (cART); it has been linked to HIV-specific, HIV-related, and HIV-unrelated factors. Insulin resistance (IR) was associated with CI in the early cART era, when antiretroviral medications had greater mitochondrial and metabolic toxicity. We sought to examine these relationships in the current cART era of reduced antiretroviral toxicities. This study examined IR among non-diabetics in relation to a 1-h neuropsychological test battery among 994 women (659 HIV-infected and 335 HIV-uninfected controls) assessed between 2009 and 2011. The mean (standard deviation (SD)) age of the sample was 45.1 (9.3) years. The HIV-infected sample had a median interquartile range (IQR) cluster of differentiation 4 (CD4) T-lymphocyte count of 502 (310-727) cells/μL, and 54 % had undetectable plasma HIV RNA levels. Among all, the homeostasis model assessment (HOMA) of IR ranged from 0.25 to 37.14. In adjusted models, increasing HOMA was significantly associated with reduced performance on Letter-Number Sequencing (LNS) attention task (β = -0.10, p < 0.01) and on Hopkins Verbal Learning Test (HVLT) recognition (β = -0.10, p < 0.01) with weaker but statistically significant associations on phonemic fluency (β = -0.09, p = 0.01). An HIV*HOMA interaction effect was identified on the LNS attention task and Stroop trials 1 and 2, with worse performance in HIV-infected vs. HIV-uninfected women. In separate analyses, cohort members who had diabetes mellitus (DM) performed worse on the grooved pegboard test of psychomotor speed and manual dexterity. These findings confirm associations between both IR and DM on some neuropsychological tests and identify an interaction between HIV status and IR.