Comparison of scales to evaluate the progression of HIV-associated neurocognitive disorder

Brain computed tomography perfusion analysis in HIV-seropositive adults with and without neurocognitive impairment in Nigeria: outcomes and challenges of a pilot study

Introduction

the significance of cerebrovascular disease in HIV-associated neurocognitive disorder (HAND) in a homogeneous black population has not yet been determined. This incident case-control study used CT perfusion imaging to quantify and compare regional cerebral blood flow parameters in neuro-cognitively impaired and unimpaired HIV+ participants of the Ibadan Cohort on Neuro AIDS (ICON) in Nigeria.

Methods

this was an incident case-control study consisting of twenty-seven HIV+ adults, classified based on Frascati criteria into neurocognitive impaired (n=18) and unimpaired (n=9) groups, who had brain computed tomographic perfusion (CTP) with a 64-slice Toshiba T scanner. The standard deviation (SD) of regional mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume (CBV) values were calculated for bilateral basal ganglia (BG), frontal, parietal, temporal, and occipital regions from CT perfusion maps. The regional mean values and variability (SD) in the CTP measures were compared in the groups using an independent student t-test.

Results

differentially higher variability in the bilateral CBF measures in the parietal (right; OR = 1.14, x̄ =5.61, p=0.041, CI=0.27-11.35/left; OR = 1.16, x̄=7.01, p=0.03, CI=5.6-13.47) and time to peak (TTP) measures in the basal ganglia (right; OR = 3.78, x̄=0.88, p=0.032, CI=0.081-1.67/left; OR = 2.44, x̄=1.48, p=0.020, CI=0.26-2.71) and occipital (right; OR = 2.18, x̄=1.32, p=0.018, CI=0.25-2.38/left; OR = 1.93, x̄=1.08, p=0.034, CI=0.086-2.06) regions were observed in the cognitively impaired group compared to the unimpaired group.

Conclusion

the study evidence suggests that alterations in cerebral perfusion implicated in HIV-associated neurocognitive disorder may be possibly demonstrated using CTP, a readily available resource in most African countries saddled with the highest burden of HIV.

Abundance of Nef and p-Tau217 in Brains of Individuals Diagnosed with HIV-Associated Neurocognitive Disorders Correlate with Disease Severance

HIV-associated neurocognitive disorders (HAND) is a term used to describe a variety of neurological impairments observed in HIV-infected individuals. The pathogenic mechanisms of HAND and of its connection to HIV infection remain unknown, but one of the considered hypotheses suggests that HIV infection accelerates the development of Alzheimer’s disease. Previous studies suggested that HIV-1 Nef may contribute to HAND by inhibiting cholesterol efflux, increasing the abundance of lipid rafts, and affecting their functionality. Our comparative analysis of postmortem brain samples demonstrated a trend toward the decreased abundance of cholesterol transporter ABCA1 in samples from HIV-infected ART-treated individuals relative to samples from uninfected controls, and a reverse correlation between ABCA1 and flotillin 1, a marker for lipid rafts, in all analyzed samples. The brain samples from HIV-infected individuals, both with and without HAND, were characterized by the increased abundance of p-Tau217 peptide, which correlated with the abundance of flotillin 1. HIV-1 Nef was analyzed in samples from HAND-affected individuals by Western blot with 4 different antibodies and by LC–MS/MS, producing a Nef-positivity score. A significant correlation was found between this score and the abundance of flotillin 1, the abundance of p-Tau217, and the severity of HAND. These results highlight the contribution of Nef and Nef-dependent impairment of cholesterol efflux to HAND pathogenesis and support a connection between the pathogenesis of HAND and Alzheimer’s disease.

Fixel-Based Analysis and Free Water Corrected DTI Evaluation of HIV-Associated Neurocognitive Disorders

Background: White matter (WM) damage is a consistent finding in HIV-infected (HIV+) individuals. Previous studies have evaluated WM fiber tract-specific brain regions in HIV-associated neurocognitive disorders (HAND) using diffusion tensor imaging (DTI). However, DTI might lack an accurate biological interpretation, and the technique suffers from several limitations. Fixel-based analysis (FBA) and free water corrected DTI (fwcDTI) have recently emerged as useful techniques to quantify abnormalities in WM. Here, we sought to evaluate FBA and fwcDTI metrics between HIV+ and healthy controls (HIV−) individuals. Using machine learning classifiers, we compared the specificity of both FBA and fwcDTI metrics in their ability to distinguish between individuals with and without cognitive impairment in HIV+ individuals.

Methods: Forty-two HIV+ and 52 HIV– participants underwent MRI exam, clinical, and neuropsychological assessments. FBA metrics included fiber density (FD), fiber bundle cross section (FC), and fiber density and cross section (FDC). We also obtained fwcDTI metrics such as fractional anisotropy (FA_T) and mean diffusivity (MD_T). Tract-based spatial statistics (TBSS) was performed on FA_T and MD_T. We evaluated the correlations between MRI metrics with cognitive performance and blood markers, such as neurofilament light chain (NfL), and Tau protein. Four different binary classifiers were used to show the specificity of the MRI metrics for classifying cognitive impairment in HIV+ individuals.

Results: Whole-brain FBA showed significant reductions (up to 15%) in various fiber bundles, specifically the cerebral peduncle, posterior limb of internal capsule, middle cerebellar peduncle, and superior corona radiata. TBSS of fwcDTI metrics revealed decreased FA_T in HIV+ individuals compared to HIV– individuals in areas consistent with those observed in FBA, but these were not significant. Machine learning classifiers were consistently better able to distinguish between cognitively normal patients and those with cognitive impairment when using fixel-based metrics as input features as compared to fwcDTI metrics.

Conclusion: Our findings lend support that FBA may serve as a potential in vivo biomarker for evaluating and monitoring axonal degeneration in HIV+ patients at risk for neurocognitive impairment.

Meta-analysis of factors affecting prevalence estimates of HIV-associated neurocognitive disorder in sub-Saharan Africa

Successful treatment of HIV with anti-retroviral therapy (ART) is resulting in more people living with HIV-associated neurocognitive disorder (HAND). In sub-Saharan Africa, this calls for strategic planning and judicious allocation of scarce resources, which requires an accurate estimate of the prevalence of HAND. Estimates of the prevalence of HAND in sub-Saharan Africa vary greatly, between 18.8% and 88.3%. This variability may be explained by factors such as different diagnostic approach, neuromedical examination, ART status, sampling method, substance abuse, assessors’ qualification, depression and outcome measure. Different methods of diagnosing HAND, different outcome measures and non-random sampling techniques make it almost impossible to accurately estimate the prevalence of HAND in sub- Saharan Africa, often resulting in overestimation of the burden of disease. Consumers of health research should consider certain study characteristics and exercise appropriate caution when interpreting burden of disease in sub-Saharan Africa, especially when pursuing policy shift. Underestimating the prevalence of HAND will certainly affect the capacity and speed of containment, while overestimating will draw unnecessary attention and result in the misallocation of scarce resources.

Prevalence and 1-year incidence of HIV-associated neurocognitive disorder (HAND) in adults aged ≥50 years attending standard HIV clinical care in Kilimanjaro, Tanzania

OBJECTIVES

HIV-associated neurocognitive disorders (HANDs) are prevalent in older people living with HIV (PLWH) worldwide. HAND prevalence and incidence studies of the newly emergent population of combination antiretroviral therapy (cART)-treated older PLWH in sub-Saharan Africa are currently lacking. We aimed to estimate HAND prevalence and incidence using robust measures in stable, cART-treated older adults under long-term follow-up in Tanzania and report cognitive comorbidities.

DESIGN

Longitudinal study.

PARTICIPANTS

A systematic sample of consenting HIV-positive adults aged ≥50 years attending routine clinical care at an HIV Care and Treatment Centre during March-May 2016 and followed up March-May 2017.

MEASUREMENTS

HAND by consensus panel Frascati criteria based on detailed locally normed low-literacy neuropsychological battery, structured neuropsychiatric clinical assessment, and collateral history. Demographic and etiological factors by self-report and clinical records.

RESULTS

In this cohort (n = 253, 72.3% female, median age 57), HAND prevalence was 47.0% (95% CI 40.9-53.2, n = 119) despite well-managed HIV disease (Mn CD4 516 (98-1719), 95.5% on cART). Of these, 64 (25.3%) were asymptomatic neurocognitive impairment, 46 (18.2%) mild neurocognitive disorder, and 9 (3.6%) HIV-associated dementia. One-year incidence was high (37.2%, 95% CI 25.9 to 51.8), but some reversibility (17.6%, 95% CI 10.0-28.6 n = 16) was observed.

CONCLUSIONS

HAND appear highly prevalent in older PLWH in this setting, where demographic profile differs markedly to high-income cohorts, and comorbidities are frequent. Incidence and reversibility also appear high. Future studies should focus on etiologies and potentially reversible factors in this setting.

Prevalence and Predictors of Neurocognitive Impairment in Ethiopian Population Living with HIV

BACKGROUND

Modern antiretroviral therapy has extended the life expectancies of people living with HIV; however, the prevention and treatment of their associated neurocognitive decline have remained a challenge. Consequently, it is desirable to investigate the prevalence and predictors of neurocognitive impairment to help in targeted screening and disease prevention.

MATERIALS AND METHODS

Two hundred and forty-four people living with HIV were interviewed in a study using a cross-sectional design and the International HIV Dementia Scale (IHDS). Additionally, the sociodemographic, clinical, and psychosocial characteristics of the patients were recorded. Chi-square and binary logistic regression analysis were used to determine the level of significance among the independent risk factors and probable neurocognitive impairment.

RESULTS

The point prevalence of neurocognitive impairment was found to be 39.3%. Participants' characteristics of being older than 40 years (AOR= 2.81 (95% CI; 1.11-7.15)), having a history of recreational drug use (AOR= 13.67 (95% CI; 6.42-29.13)), and being non-compliant with prescribed medications (AOR= 2.99 (95% CI; 1.01-8.87)) were independent risk factors for neurocognitive impairment.

CONCLUSION

The identification of predictors, in the Ethiopian people living with HIV, may help in the targeted screening of vulnerable groups during cART follow-up visits. This may greatly help in strategizing and implementation of the prevention program, more so, because (i) HIV-associated neurocognitive impairment is an asymptomatic condition for considerable durations, and (ii) clinical trials on neurocognitive impairment therapies have been unsuccessful.

Female sex is strongly associated with cognitive impairment in HIV infection

BACKGROUND

Neurocognitive disorders remain frequent despite highly active antiretroviral treatment (HAART). The CNS is known as the sanctuary of HIV infection, where persistent neuroinflammation occurs regardless of viral suppression. Moreover, opportunistic infections, neurovascular damage and HAART neurotoxicity contribute to neurocognitive impairment. Therefore, detailed epidemiological studies might help to elucidate those complex mechanisms.

OBJECTIVE

To investigate the prevalence of cognitive impairment and the associated sociodemographic, clinical and neuropsychological variables among HIV-infected patients admitted to a tertiary centre, in southern Brazil.

METHODS

An observational, cross-sectional and analytic study was conducted between February 2019 and March 2020, in Hospital Nereu Ramos (HNR), with148 HIV-infected patients. They were interviewed, submitted to the International HIV Dementia Scale (IHDS) and had their medical data analysed.

RESULTS

The prevalence of cognitive impairment was 69.6%. It was higher among women (OR = 3.5; 95% CI 1.5-8; p < 0.01), independently of depression, educational status and age. Full years of schooling were strongly associated with IHDS scores (p < 0.01). Patient Health Questionnaire-9 (PHQ-9) scores for depression (p = 0.8), time since HIV diagnosis (p = 0.2), CD4⁺ cell counts (p = 0.8) and viral load (p = 0.8) were not associated with IHDS scale.

CONCLUSION

A high prevalence of cognitive impairment in HIV-infected patients was identified, independently associated with the female sex and fewer years of schooling. Further studies are needed to clarify the differences in the pathophysiology between sexes and the role of cognitive reserve in prevention of cognitive impairment in HIV infection.

Identifying Sleep Biomarkers to Evaluate Cognition in HIV

Sleep disturbance and cognitive impairment represent two of the most common and debilitating conditions facing seropositive (HIV+) individuals who are otherwise well controlled with antiretroviral therapy. Sleep-assessment-based biomarkers represent an important step towards improving our understanding of the unique mechanistic features that may link sleep disruption and cognition in HIV+ individuals, ultimately leading to advancements in treatment and management options. In this study, a risk score was computed via a generalized linear model (GLM), which optimally combines polysomnography (PSG) features extracted from EEG, EMG, and EOG signals, to distinguish 18 HIV+ Black male individuals with and without cognitive impairment. The optimal set of features was identified via the least absolute shrinkage and selection operator (LASSO) approach, and the risk separation between the two groups, i.e., cognitively normal and cognitive impaired, was significant (and has a P-value < .001). The optimal set of predictive features were all EEG derived and sleep stage-specific. These preliminary findings suggest that sleep-based EEG features may be used as both diagnostic and prognostic biomarkers for cognition in HIV+ subjects.

HIV, Depression, and Cognitive Impairment in the Era of Effective Antiretroviral Therapy

PURPOSE OF REVIEW

Mental health disorders, especially depression, are prevalent among people living with HIV (PLWH) and are associated with cognitive impairment (CI) among HIV-uninfected (HIV-) individuals. We conducted a comprehensive review of the link between depression and cognition among PLWH.

RECENT FINDINGS

Studies examining depression and cognition in PLWH report high rates of current (median = 24%) and lifetime depression (42%). There is reliable evidence that depression is associated with overall CI among PLWH, and in the cognitive domains of processing speed, executive function, learning and memory, and motor function. Although few studies have examined the interaction between HIV serostatus and depression on CI, there is no evidence of a stronger association between CI and depression in PLWH compared with HIV- controls. Depression is prevalent and reliably associated with CI in PLWH, with an overall pattern of domain-specific associations similar to that of HIV- individuals.

Neuropsychological and Syntactic Deficits in HIV Seropositive Males

Objective:

Given the underlying frontal-basal ganglia circuit neuropathogenesis of HIV-infected individuals, it is surprising that little is reported about potential language deficits as part of their higher cognitive dysfunctional profile. This study aims to elucidate whether HIV-positive individuals have linguistic impairments that may originate from or be intensified by deficits in cognitive functions. The research questions address (i) quantitative differences in sentence repetition abilities involving complex syntactic phenomena between adults with HIV and non-HIV healthy controls (ii) correlations of sentence repetition scores with neurocognitive measures and (iii) correlation of sentence repetition performance with duration and severity of HIV.

Methods:

A battery of neuropsychological tests were administered to 40 HIV - seropositive males and 40 demographically matched healthy controls to assess verbal learning/episodic memory, psychomotor speed, executive functions and visuospatial abilities. Language abilities were evaluated using a repetition task that screened specific complex syntactic operations at the sentence-level.

Results:

A significant difference was noted between the two groups regarding correct repetition of the sentence repetition task with the control group outperforming the HIV-seropositive group. For the HIV group, significant correlations were found for correct sentence repetition with years of education, duration of illness, Mini-Mental State Examination, semantic and phonemic fluency, symbol digit modality test scores, and the Trail Making Test (parts A and B).

Conclusion:

Speech-language pathologists and neuropsychologists should screen for language deficits associated with the different clinical syndromes in HIV patients as part of their routine clinical care.

Human Immunodeficiency Virus and the Nervous System

In the era of combination antiretroviral therapy, the diagnosis and management of HIV-associated neurocognitive disorders (HANDs) has arisen. Traditionally, severe HAND was seen in those with untreated HIV infection and had a guarded prognosis. Antiretroviral therapy has provided longevity and viral control to many living with the disease, revealing an increase in prevalence of less severe forms of HAND. Despite peripheral blood and cerebrospinal fluid viral suppression, cognitive impairment occurs and progresses for reasons that are unclear at present. This article provides a review of current theories behind the development of HAND, clinical and pathologic findings, recent developments, and future research opportunities.

Can computerized cognitive training reverse the diagnosis of HIV-associated neurocognitive disorder? A research protocol

Nearly 50% of adults with HIV have some form of HIV-associated neurocognitive disorder (HAND), ranging from subtle to symptoms that interfere with everyday functioning and quality of life. HAND is diagnosed when a person performs more than 1 standard deviation below his or her normative mean on standardized measures in two or more cognitive domains (e.g., attention, speed of processing, verbal memory, executive functioning). As adults age with HIV, they are more likely to develop comorbidities such as cardiovascular disease, hypertension, and insulin resistance that may further contribute to poorer cognitive functioning and HAND. Certain computerized cognitive training programs may be able to improve specific cognitive domains in those with HIV. Such programs may be effective in changing the diagnosis of HAND in cognitively vulnerable adults. In this article, we describe the design and methods of TOPS-the Training On Purpose Study. In this on-going experimental study, 146 older adults (50+) with HAND are randomized to either: (i) an Individualized-Targeted Cognitive Training group, or (ii) a no-contact control group. This study targets those cognitive domains in which participants experience a deficit and trains participants with the corresponding computerized cognitive training program for that domain. An Individualized Targeted Cognitive Training approach using cognitive-domain-specific cognitive training programs may offer symptom relief to those individuals diagnosed with HAND, which may actually reverse this diagnosis. Given that these cognitive training programs are commercially available, this approach represents a potential paradigm shift in how HAND is considered and treated.

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.

Impairments of Motor Function While Multitasking in HIV

Human immunodeficiency virus (HIV) became a treatable illness with the introduction of combination antiretroviral therapy (CART). As a result, patients with regular access to CART are expected to live decades with HIV. Long-term HIV infection presents unique challenges, including neurocognitive impairments defined by three major stages of HIV-associated neurocognitive disorders (HAND). The current investigation aimed to study cognitive and motor impairments in HIV using a novel multitasking paradigm. Unlike current standard measures of cognitive and motor performance in HIV, multitasking increases real-world validity by mimicking the dual motor and cognitive demands that are part of daily professional and personal settings (e.g., driving, typing and writing). Moreover, multitask assessments can unmask compensatory mechanisms, normally used under single task conditions, to maintain performance. This investigation revealed that HIV+ participants were impaired on the motor component of the multitask, while cognitive performance was spared. A patient-specific positive interaction between motor performance and working memory recall was driven by poor HIV+ multitaskers. Surprisingly, HAND stage did not correspond with multitask performance and a variety of commonly used assessments indicated normal motor function among HIV+ participants with poor motor performance during the experimental task. These results support the use of multitasks to reveal otherwise hidden impairment in chronic HIV by expanding the sensitivity of clinical assessments used to determine HAND stage. Future studies should examine the capability of multitasks to predict performance in personal, professional and health-related behaviors and prognosis of patients living with chronic HIV.

Testing a Computerized Cognitive Training Protocol in Adults Aging With HIV-Associated Neurocognitive Disorders: Randomized Controlled Trial Rationale and Protocol

Background

HIV-associated neurocognitive disorders occur in nearly 50% of adults with HIV. Such disorders can interfere with everyday functioning such as driving and medication adherence. Therefore, cognitive interventions are needed to address such neurocognitive disorders as well as improve everyday functioning, especially as people age with HIV.

Objective

This article reports and discusses the overall rationale and development of speed of processing training, a computerized Internet cognitive training program, to improve this specific neurocognitive ability as well as everyday functioning and quality of life in adults aging with HIV. Although this protocol has been shown to improve speed of processing, everyday functioning, and quality of life in healthy, community-dwelling older adults in the advanced cognitive training in vital elderly (ACTIVE) study, its efficacy in adults aging with HIV has not been established. Nevertheless, such a cognitive intervention is particularly germane as 52%-59% of adults with HIV experience HIV-associated neurocognitive disorders (HAND), and both the frequency and severity of such disorders may increase with advancing age.

Methods

The description of this longitudinal randomized controlled trial covers the following: (1) rationale for speed of processing training in this clinical population, (2) overview of overall study design, (3) eligibility criteria and HAND, (4) intervention dosage, (5) assessment battery, and (6) examination of biomarkers.

Results

The project was funded in April 2016 and enrolment is on-going. The first results are expected to be submitted for publication in 2020.

Conclusions

Similar novel cognitive intervention approaches are suggested as they may be of value to those with HAND and may utilize similar features of this current randomized controlled trial (RCT) protocol to examine their therapeutic efficacy.

Trial Registration

ClinicalTrials.gov NCT02758093; https://clinicaltrials.gov/ct2/show/NCT02758093 (Archived by Webcite at http://www.webcitation.org/6p8C5fBCX)

Serotonin-Related Gene Polymorphisms and Asymptomatic Neurocognitive Impairment in HIV-Infected Alcohol Abusers

HIV-infected individuals continue to experience neurocognitive deterioration despite virologically successful treatments. While the cause remains unclear, evidence suggests that HIV-associated neurocognitive disorders (HAND) may be associated with neurobehavioral dysfunction. Genetic variants have been explored to identify risk markers to determine neuropathogenesis of neurocognitive deterioration. Memory deficits and executive dysfunction are highly prevalent among HIV-infected adults. These conditions can affect their quality of life and HIV risk-taking behaviors. Single nucleotide polymorphisms in the SLC6A4, TPH2, and GALM genes may affect the activity of serotonin and increase the risk of HAND. The present study explored the relationship between SLC6A4, TPH2, and GALM genes and neurocognitive impairment in HIV-infected alcohol abusers. A total of 267 individuals were genotyped for polymorphisms in SLC6A4 5-HTTLPR, TPH2 rs4570625, and GALM rs6741892. To assess neurocognitive functions, the Short Category and the Auditory Verbal Learning Tests were used. TPH2 SNP rs4570625 showed a significant association with executive function in African American males (odds ratio 4.8, 95% CI, 1.5–14.8; P = 0.005). Similarly, GALM SNP rs6741892 showed an increased risk with African American males (odds ratio 2.4, 95% CI, 1.2–4.9; P = 0.02). This study suggests that TPH2 rs4570625 and GALM rs6741892 polymorphisms may be risk factors for HAND.

Effect of AIDS on women who have sex-determined health issues

Worldwide, women account for a growing percentage of human immunodeficiency virus (HIV)-infected patients and more than half of all HIV infections. For many years, morphologic imaging methods were the main approaches employed to investigate HIV and its complications. However, during the past decade, advancements in PET and SPECT imaging technologies opened new possibilities for improved understanding of the pathophysiological processes in HIV. Diagnosis of early HIV-associated neurocognitive disorders (HAND) is important, as many of its symptoms can be caused by other conditions common to people with HIV/AIDS. Presently, there are no PET and SPECT tracers or combination of markers for HAND, hence novel HAND-specific tracers are needed if nuclear medicine is to play a role in solving the problem of the HAND "epidemic." As both highly active antiretroviral therapy (HAART)-induced lipoatrophy and cardiovascular diseases are characterized by ongoing inflammation, FDG-PET/CT imaging may represent an important imaging technique for better understanding the metabolic risk in HIV-infected women on HAART. HIV-infected women are at increased risk for the development of human papilloma virus-associated neoplasms such as cervical and anal carcinomas; these aggressive tumors could be treated better with integration of FDG-PET as part of the standard pretreatment workup. A similar value of FDG-PET may be realized in women with HIV-associated Kaposi sarcoma, as they have more extensive cutaneous disease than men do. In the era of HAART, the incidence and local invasiveness of breast cancer may change, thus creating a need to redefine the pathophysiology of breast cancer in HIV-positive women. Finally, mammary tuberculosis, occasionally the presenting symptom in HIV-infected women, may present with nonspecific clinical, radiological, and histologic findings. In these women, FDG-PET can be of value to detect the lesion for a representative biopsy, staging to exclude pulmonary and other extrapulmonary lesions, and also for therapy monitoring.

Cognitive impairment in patients with AIDS - prevalence and severity

The advent of highly active antiretroviral therapy has prolonged the life expectancy of HIV patients and decreased the number of adults who progress to AIDS and HIV-associated dementia. However, neurocognitive deficits remain a pronounced consequence of HIV/AIDS. HIV-1 infection targets the central nervous system in subcortical brain areas and leads to high rates of delirium, depression, opportunistic central nervous system infections, and dementia. Long-term HIV replication in the brain occurs in astrocytes and microglia, allowing the virus to hide from antiviral medication and later compromise neuronal function. The associated cognitive disturbance is linked to both viral activity and inflammatory and other mediators from these immune cells that lead to the damage associated with HIV-associated neurocognitive disorders, a general term given for these disturbances. We review the severity and prevalence of the neuropsychiatric complications of HIV including delirium, neurobehavioral impairments (depression), minor cognitive-motor dysfunction, and HIV-associated dementia.

Factors related to HIV-associated neurocognitive impairment differ with age

Over 50% of HIV-infected (HIV+) persons are expected to be over age 50 by 2015. The pathogenic effects of HIV, particularly in cases of long-term infection, may intersect with those of age-related illnesses and prolonged exposure to combined antiretroviral therapy (cART). One potential outcome is an increased prevalence of neurocognitive impairment in older HIV+ individuals, as well as an altered presentation of HIV-associated neurocognitive disorders (HANDs). In this study, we employed stepwise regression to examine 24 features sometimes associated with HAND in 40 older (55-73 years of age) and 30 younger (32-50 years of age) HIV+, cART-treated participants without significant central nervous system confounds. The features most effective in generating a true assessment of the likelihood of HAND diagnosis differed between older and younger cohorts, with the younger cohort containing features associated with drug abuse that were correlated to HAND and the older cohort containing features that were associated with lipid disorders mildly associated with HAND. As the HIV-infected population grows and the demographics of the epidemic change, it is increasingly important to re-evaluate features associated with neurocognitive impairment. Here, we have identified features, routinely collected in primary care settings, that provide more accurate diagnostic value than a neurocognitive screening measure among younger and older HIV individuals.

Neuronal ferritin heavy chain and drug abuse affect HIV-associated cognitive dysfunction

Interaction of the chemokine CXCL12 with its receptor CXCR4 promotes neuronal function and survival during embryonic development and throughout adulthood. Previous studies indicated that μ-opioid agonists specifically elevate neuronal levels of the protein ferritin heavy chain (FHC), which negatively regulates CXCR4 signaling and affects the neuroprotective function of the CXCL12/CXCR4 axis. Here, we determined that CXCL12/CXCR4 activity increased dendritic spine density, and also examined FHC expression and CXCR4 status in opiate abusers and patients with HIV-associated neurocognitive disorders (HAND), which is typically exacerbated by illicit drug use. Drug abusers and HIV patients with HAND had increased levels of FHC, which correlated with reduced CXCR4 activation, within cortical neurons. We confirmed these findings in a nonhuman primate model of SIV infection with morphine administration. Transfection of a CXCR4-expressing human cell line with an iron-deficient FHC mutant confirmed that increased FHC expression deregulated CXCR4 signaling and that this function of FHC was independent of iron binding. Furthermore, examination of morphine-treated rodents and isolated neurons expressing FHC shRNA revealed that FHC contributed to morphine-induced dendritic spine loss. Together, these data implicate FHC-dependent deregulation of CXCL12/CXCR4 as a contributing factor to cognitive dysfunction in neuroAIDS.

Persisting inflammation and chronic immune activation but intact cognitive function in HIV-infected patients after long-term treatment with combination antiretroviral therapy

OBJECTIVES

Impaired cognitive function in HIV-infected patients has been suggested. Treatment with combination antiretroviral therapy (cART) restores CD4⁺ cell counts and suppresses viral replication, but immune activation and inflammation may persist. The aim of the study was to examine if cognitive function in HIV-infected patients was related to immune activation and inflammation.

METHODS

Sixty-one HIV-infected patients and 31 healthy controls were included. All patients were on treatment with cART, had suppressed viral replication, and had a mean CD4⁺ cell count of 522 cells/μL. Cognitive function was assessed using a test battery of neurocognitive tests. Plasma concentrations of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and β-2-microglobulin were measured. Immune activation (CD8⁺HLR-DR⁺CD38⁺ cells) was determined using flow cytometry. Multiple linear regression analysis was performed to identify relationship between cognitive scores and markers of inflammation and immune activation.

RESULTS

HIV-infected patients had intact cognitive function compared with healthy controls. Higher levels of TNF-α, β-2-microglobulin, and chronic activated CD8⁺ cells were found in HIV-infected patients (P = 0.0002, P < 0.0001, and P = 0.021, respectively). Weak negative correlations were found between chronic activated CD8⁺ cells (β-coefficient = -0.277, P = 0.044), IL-6 (β-coefficient = -0.280, P = 0.014), and memory and learning.

CONCLUSIONS

HIV-infected patients on cART with undetectable viral load had an increased level of inflammation and immune activation. However, intact cognitive function was found, and only weak correlations were found between cognitive function and markers of inflammation and immune activation, indicating that peripheral inflammation and immune activation are not major drivers of cognitive decay in HIV-infected patients.

Neurologic complications of HIV-1 infection and its treatment in the era of antiretroviral therapy

PURPOSE OF REVIEW

Neurologic complications of HIV infection are unfortunately common, even in the era of effective antiretroviral treatment (ART). The consulting neurologist is often asked to distinguish among neurologic deterioration due to opportunistic infection (OI), immune reconstitution, or the effect of the virus itself, and to comment on the role of immunomodulatory agents in patients with HIV infection. Additionally, as successful virologic control has extended the life span of patients with HIV infection, neurologists are called upon to manage long-term complications, such as neurocognitive disorders and peripheral neuropathy.

RECENT FINDINGS

Despite the use of ART, significant numbers of patients continue to be affected by HIV-associated neurocognitive disorders, although with milder forms compared to the pre-ART era. Regimens of ART have been ranked according to CNS penetration and are being studied with regard to neuropsychological outcomes. Nucleoside analogs with the greatest potential for peripheral neurotoxicity are no longer considered first-line agents for HIV treatment. Efavirenz, a non-nucleoside reverse transcriptase inhibitor, has the greatest frequency of neurologic side effects among newer ART regimens. The spectrum of clinical manifestations of immune reconstitution inflammatory syndrome (IRIS) continues to grow, including IRIS without underlying OI. A greater understanding of pathophysiology and risk factors has shown that while HIV should be treated early to prevent severe immunocompromise, delayed initiation of ART may be helpful while treating OIs.

SUMMARY

This article reviews the neurologic complications of HIV infection, or its treatment, most commonly encountered by neurologists.

Routine detection and management of neurocognitive impairment in HIV-positive patients in a UK centre

We estimated the burden of HIV-associated neurocognitive disorders (HAND) in a UK clinic. From a random sample, and referrals to specialist services over one year (neurology, clinical psychology, hospital admissions), we determined whether patients were diagnosed with HIV-associated dementia (HAD) and whether they reported symptoms suggesting neurocognitive impairment (NCI). In the first sample, 2/150 (prevalence 1.3%; 95% confidence interval [CI] 0.2–4.7%) had documented HAD. Eleven patients (7.3%; CI 3.7–12.7%) reported recent symptoms suggesting NCI; most of these individuals were diagnosed with a psychiatric or substance-use disorder. Among specialist referrals with symptoms suggesting NCI, 11 were diagnosed with HAD from a clinic population of 3129 individuals (annual incidence 0.4%; CI 0.2–0.6%). No patients with mildly symptomatic or asymptomatic HAND were identified in either sample, suggesting that such patients remain undetected in current clinical practice. Evidence-based screening for HAND in HIV clinics may be needed.

A systematic review of the screening accuracy of the HIV Dementia Scale and International HIV Dementia Scale

BACKGROUND

The HIV Dementia Scale (HDS) and International HIV Dementia Scale (IHDS) are brief tools that have been developed to screen for and aid diagnosis of HIV-associated dementia (HAD). They are increasingly being used in clinical practice for minor neurocognitive disorder (MND) as well as HAD, despite uncertainty about their accuracy.

METHODS AND FINDINGS

A systematic review of the accuracy of the HDS and IHDS was conducted. Studies were assessed on Standards for Reporting Diagnostic Accuracy criteria. Pooled sensitivity, specificity, likelihood ratios (LR) and diagnostic odds ratios (DOR) were calculated for each scale as a test for HAD or MND. We retrieved 15 studies of the HDS, 10 of the IHDS, and 1 of both scales. Thirteen studies of the HDS were conducted in North America, and 7 of the IHDS studies were conducted in sub-Saharan Africa. Estimates of accuracy were highly heterogeneous between studies for the HDS but less so for the IHDS. Pooled DOR for the HDS was 7.52 (95% confidence interval 3.75-15.11), sensitivity and specificity for HAD were estimated at 68.1% and 77.9%, and sensitivity and specificity for MND were estimated at 42.0% and 91.2%. Pooled DOR for the IHDS was 3.49 (2.12-5.73), sensitivity and specificity for HAD were 74.3% and 54.7%, and sensitivity and specificity for MND were 64.3% and 66.0%.

CONCLUSION

Both scales were low in accuracy. The literature is limited by the lack of a gold standard, and variation in estimates of accuracy is likely to be due to differences in reference standard. There is a lack of studies comparing both scales, and they have been studied in different populations, but the IHDS may be less specific than the HDS. These rapid tests are not recommended for diagnostic use, and further research is required to inform their use in asymptomatic screening.

Trail Making Test A improves performance characteristics of the International HIV Dementia Scale to identify symptomatic HAND

Although HIV-associated dementia (HAD) occurs in less than 5 % of individuals with access to combination antiretroviral therapy, rates of milder forms of HIV-associated neurocognitive disorder (HAND) are much higher. We sought to define an optimal cut point for the International HIV Dementia Scale (IHDS) in Thailand for the identification of symptomatic HAND, defined as both HAD and mild neurocognitive disorder. We then sought to determine if adding a simple test from a larger neuropsychological battery could improve the performance characteristics for identifying symptomatic HAND. In this study, subjects comprising 75 seropositive adults in Bangkok, Thailand, completed neuropsychological tests and underwent a full neurological assessment. HAND diagnoses were determined by consensus conference using the 2007 Frascati criteria, blinded to the IHDS results. The optimal IHDS cut point was determined by receiver operating characteristic analysis with cross-validation. Individual neuropsychological tests were then evaluated and combined with the IHDS to test performance characteristics. The IHDS was poor at detecting symptomatic HAND at the optimized cut point of ≤ 10 (sensitivity, 53.3 %; specificity, 89.8 %). Trail Making Test A was most effective in improving performance characteristics when combined with the IHDS, with net sensitivity of 86 % and specificity of 79 %. In this setting, the IHDS performed poorly in identifying symptomatic HAND, but was substantially improved by the addition of Trail Making Test A, which typically requires less than 2 min to complete. This combination should be validated in a larger setting since it may address the critical need for HAND screening instruments in international settings.

A comparison of performance-based measures of function in HIV-associated neurocognitive disorders

The objectives of this study are to compare the results of newer performance-based functional assessments in the study of HIV-associated neurocognitive disorders (HAND) and to correlate these functional assessments with specific levels of severity of HAND. One hundred fourteen HIV+ subjects in an existing cohort were evaluated with a medical history, neurological exam, neuropsychological test battery as well as subjective and novel objective measures of functional abilities. Self-reported measures of functional performance included the Karnofsky Performance Scale, a questionnaire for instrumental activities of daily living, and a questionnaire for physical quality of life measures. The newer objective functional performance assessments included the Columbia Medication Management and the San Diego Finances tests. These newer performance-based measures of function were assessed for their ability to predict level of HAND. The two objective measures of functional performance, The Columbia Medication Management Scale and the San Diego Finances Test, were both associated with levels of severity of HAND. The Karnofsky Performance Scale and the questionnaires for role and physical quality of life were subjective measures that were also associated with specific levels of HAND. Newer measures of functional performance can be used to objectively evaluate functional impairment in HAND and validate different levels of HAND.