Unravelling the triad of neuroinvasion, neurodissemination, and neuroinflammation of human immunodeficiency virus type 1 in the central nervous system

Since the identification of human immunodeficiency virus type 1 (HIV-1) in 1983, many improvements have been made to control viral replication in the peripheral blood and to treat opportunistic infections. This has increased life expectancy but also the incidence of age-related central nervous system (CNS) disorders and HIV-associated neurodegeneration/neurocognitive impairment and depression collectively referred to as HIV-associated neurocognitive disorders (HAND). HAND encompasses a spectrum of different clinical presentations ranging from milder forms such as asymptomatic neurocognitive impairment or mild neurocognitive disorder to a severe HIV-associated dementia (HAD). Although control of viral replication and suppression of plasma viral load with combination antiretroviral therapy has reduced the incidence of HAD, it has not reversed milder forms of HAND. The objective of this review, is to describe the mechanisms by which HIV-1 invades and disseminates in the CNS, a crucial event leading to HAND. The review will present the evidence that underlies the relationship between HIV infection and HAND. Additionally, recent findings explaining the role of neuroinflammation in the pathogenesis of HAND will be discussed, along with prospects for treatment and control.

HIV-Associated Neurocognitive Disorders: The First Longitudinal Follow-Up of a cART-Treated Cohort of Older People in Sub-Saharan Africa

BACKGROUND

HIV-associated neurocognitive disorders (HAND) are a highly prevalent chronic complication in older people living with HIV (PLWH) in high-income countries. Although sub-Saharan Africa has a newly emergent population of older combination antiretroviral therapy (cART)-treated PLWH, HAND have not been studied longitudinally. We assessed longitudinal prevalence of HAND and have identified possible modifiable factors in a population of PLWH aged 50 years or older, over 3 years of follow-up.

METHODS

Detailed neuropsychological and clinical assessment was completed annually in the period 2016-2019 in a systematic sample of cART-treated PLWH in Kilimanjaro, Tanzania. A consensus panel defined HAND using American Academy of Neurology criteria for asymptomatic neurocognitive impairment, mild neurocognitive disorder, and HIV-associated dementia. HIV disease severity and other factors associated with HAND progression, improvement, and stability were evaluated in individuals fully assessed at baseline and in 2019.

RESULTS

At baseline, 47% of the cohort (n = 253, 72.3% female individuals) met HAND criteria despite good HIV disease control [Y1 59.5% (n = 185), Y2 61.7% (n = 162), and Y3 57.9% (n = 121)]. Of participants fully assessed at baseline and year 3 (n = 121), HAND remained stable in 54% (n = 57), improved in 15% (n = 16), and declined in 31% (n = 33). Older age and lower education level significantly predicted HAND progression, whereas HIV-specific factors did not. Male sex and shorter cART duration were associated with improvement.

CONCLUSIONS

In this first longitudinal study characterizing clinical course of HAND in older cART-treated PLWH in sub-Saharan Africa, HAND was highly prevalent with variable progression and reversibility. Progression may be more related to cognitive reserve than HIV disease in cART-treated PLWH.

Contemporary trends in HIV-associated neurocognitive disorders in Ghana

BACKGROUND

Widespread introduction of early combination antiretroviral therapy (cART) for People Living with HIV (PLWH) will influence the burden, profile, and trajectory of HIV-associated neurocognitive disorders (HAND) in the 21st century.

OBJECTIVES

To assess the prevalence and trajectory of HAND among PLWH in a Ghanaian tertiary medical center.

METHODS

We analyzed the dataset of a study involving PLWH established on cART (n = 256) and PLWH not initially on cART (n = 244). HIV-negative individuals (n = 246) served as normative controls for neurocognitive assessments. HAND was defined according to the Frascati criteria into asymptomatic neurocognitive impairment (ANI), mild neurocognitive disorder (MND) and HIV-associated dementia (HAD) at enrollment and at month 12. Multivariate logistic regression models were fitted to identify factors associated with HAND.

RESULTS

Among PLWH on cART, 21.5%, 3.5% and 0.0% had ANI, MND and HAD respectively compared with 20.1%, 9.8% and 2.0% among PLWH cART naïve, p < 0.0001. Overall, 71.6%, 20.8%, 6.6% and 1.0% had no cognitive impairment, ANI, MND and HAD at baseline. Among participants who completed month 12 follow-up, 55.2% had no cognitive impairment, 43.5%, 1.2%, 0.0% had ANI, MND and HAD respectively, p < 0.0001. Adjusted odds ratio (95% CI) of six independent predictors of HAND at month 12 were no education (3.29;1.81-6.00), stage 4 disease (4.64;1.37-15.69), hypertension (2.28;1.10-4.73), nevirapine use (2.05;1.04-4.05), baseline viral load (0.66;0.56-0.77), and cigarette use (0.10; 0.03-0.42).

CONCLUSION

Most Ghanaian patients in the post-cART era with HAND had mild neurocognitive impairments. The impact of hypertension on progression of HAND warrants further evaluation in our settings.

Asymptomatic neurocognitive impairment is a risk for symptomatic decline over a 3-year study period

OBJECTIVE

To examine whether persons with asymptomatic neurocognitive impairment (ANI) were more likely to show progression to mild neurocognitive disorder or HIV-associated dementia than those who were neuropsychologically normal (NP-N).

DESIGN

Longitudinal observational cohort study.

METHODS

Study sample included 720 HIV-1 seropositive persons (317 with ANI and 403 NP-N) receiving care in Toronto, Canada [83% were on antiretroviral treatment; 71% had undetectable (<50 copies/ml) plasma HIVRNA]. Neuropsychological assessments were conducted at 12 months intervals for a median follow-up time of 34 months. Neuropsychological data were corrected for age, education, sex, and race/ethnicity, and corrected for practice effect at follow-ups. Progression to mild neurocognitive disorder and HIV-associated dementia at each time point was determined using the Global Deficit Score and presence of cognitive symptoms.

RESULTS

Over the follow-up period, 170 individuals (24%) progressed to symptomatic HIV-associated neurocognitive disorders (HAND). Persons with ANI were more likely to progress to symptomatic HAND than persons with NP-N after adjusting for baseline and time-varying confounders (adjusted hazards ratio: 1.88; 95% confidence interval: 1.37-2.60; P < 0.001). Female sex, depression, and cigarette smoking were associated with higher risk of progression to symptomatic HAND, but traditional HIV markers and antiretroviral treatment were not.

CONCLUSION

ANI is associated with a two-fold increased risk of progression to symptomatic HAND in a cohort with universal healthcare access. This represents the largest replication of comparable US results. Reproducibility of these findings indicate that routine monitoring of persons with ANI and exploration of clinical interventions to prevent or delay progression to symptomatic HAND are imperative.

SEARCH TERMS

HIV, HAND, HIV-associated dementia, cohort study, replicability, reproducibility.

HIV Neuropathogenesis in the Presence of a Disrupted Dopamine System

Antiretroviral therapy (ART) has transformed HIV into a chronic condition, lengthening and improving the lives of individuals living with this virus. Despite successful suppression of HIV replication, people living with HIV (PLWH) are susceptible to a growing number of comorbidities, including neuroHIV that results from infection of the central nervous system (CNS). Alterations in the dopaminergic system have long been associated with HIV infection of the CNS. Studies indicate that changes in dopamine concentrations not only alter neurotransmission, but also significantly impact the function of immune cells, contributing to neuroinflammation and neuronal dysfunction. Monocytes/macrophages, which are a major target for HIV in the CNS, are responsive to dopamine. Therefore, defining more precisely the mechanisms by which dopamine acts on these cells, and the changes in cellular function elicited by this neurotransmitter are necessary to develop therapeutic strategies to treat neuroHIV. This is especially important for vulnerable populations of PLWH with chemically altered dopamine concentrations, such as individuals with substance use disorder (SUD), or aging individuals using dopamine-altering medications. The specific neuropathologic and neurocognitive consequences of increased CNS dopamine remain unclear. This is due to the complex nature of HIV neuropathogenesis, and logistical and technical challenges that contribute to inconsistencies among cohort studies, animal models and in vitro studies, as well as lack of demographic data and access to human CNS samples and cells. This review summarizes current understanding of the impact of dopamine on HIV neuropathogenesis, and proposes new experimental approaches to examine the role of dopamine in CNS HIV infection. Graphical abstract HIV Neuropathogenesis in the Presence of a Disrupted Dopamine System. Both substance abuse disorders and the use of dopaminergic medications for age-related diseases are associated with changes in CNS dopamine concentrations and dopaminergic neurotransmission. These changes can lead to aberrant immune function, particularly in myeloid cells, which contributes to the neuroinflammation, neuropathology and dysfunctional neurotransmission observed in dopamine-rich regions in HIV+ individuals. These changes, which are seen despite the use antiretroviral therapy (ART), in turn lead to further dysregulation of the dopamine system. Thus, in individuals with elevated dopamine, the bi-directional interaction between aberrant dopaminergic neurotransmission and HIV infection creates a feedback loop contributing to HIV associated neurocognitive dysfunction and neuroHIV. However, the distinct contributions and interactions made by HIV infection, inflammatory mediators, ART, drugs of abuse, and age-related therapeutics are poorly understood. Defining more precisely the mechanisms by which these factors influence the development of neurological disease is critical to addressing the continued presence of neuroHIV in vulnerable populations, such as HIV-infected older adults or drug abusers. Due to the complexity of this system, understanding these effects will require a combination of novel experimental modalities in the context of ART. These will include more rigorous epidemiological studies, relevant animal models, and in vitro cellular and molecular mechanistic analysis.

Unraveling neuroHIV in the Presence of Substance Use Disorders

This special issue contains 10 invited review papers that highlighted and extended the presentations at the NIDA-sponsored workshop "Unraveling NeuroAIDS in the Presence of Substance Use Disorders" at the 25th Society on NeuroImmune Pharmacology conference in 2019. The topics covered by these papers focused on the interactive, additive or synergistic effects of substance use disorders (SUD) with HIV infection on the immune system and on neuropathogenesis. These papers reviewed four categories of substances of abuse (opioids, tobacco, stimulants, and cannabis) and how comorbid HIV infection (including models with HIV proteins, HIV transgenic rodent models and SIV) might further impact the dysregulated dopaminergic and immune systems, and the subsequent neuropathogenesis and behavioral disorders known as HIV-associated neurological disorders (HAND). These reviews provided detailed background knowledge regarding how each of these addictive substances and HIV individually or collectively affected the immune system at the cellular, molecular and system levels, and the subsequent clinical and behavioral outcomes. The authors also identified gaps, confounds or constraints in the current disease models and approaches, and proposed future research directions.

DSM-IV mental disorders and neurological complications in children and adolescents with human immunodeficiency virus type 1 infection (HIV-1)

Aim

To study the types of psychiatric problem encountered in children infected with the human immunodeficiency virus (HIV) and their relationship to central nervous system disorder and the severity of infection.

Methods

17 HIV-infected children presenting with psychiatric problems were included. Mental disorders were evaluated according to DSM-IV criteria. Neurological disorders and progressive encephalopathy (presence or absence) diagnosis were evaluated by clinical and radiological examination. The severity of infection was assessed by the percentage of CD4 lymphocytes.

Results

The most frequent diagnoses were major depression (MDD: 47%) and attention deficit hyperactivity disorder (ADHD: 29%). Major depression diagnosis was significantly associated with neuroimaging or clinical neurological abnormalities (p < 0.01). In contrast, no association was found between hyperactivity diagnosed according to DSM-IV criteria and central nervous system disorder. Percentage of CD4 lymphocytes were close to 0 for more than 80% of children presenting with psychiatric complications.

Conclusion

The very low % of CD4 lymphocytes of these children suggest that the appearance of a psychiatric complication should be regarded as a factor indicating severe HIV infection. Depressive disorders may be a clinical form of encephalopathy.

Are Fungal Pathogens Manipulating Human Behavior?

Many pathogens, especially fungi, have evolved the capacity to manipulate host behavior, usually to improve their chances of spreading to other hosts. Such manipulation is difficult to observe in long-lived hosts, like humans. First, much time may separate cause from effect in the case of an infection that develops over a human life span. Second, the host-pathogen relationship may initially be commensal: the host becomes a vector for infection of other humans, and in exchange the pathogen remains discreet and does as little harm as possible. Commensalism breaks down with increasing age because the host is no longer a useful vector, being less socially active and at higher risk of death. Certain neurodegenerative diseases may therefore be the terminal stage of a longer-lasting relationship in which the host helps the pathogen infect other hosts, largely via sexual relations. Strains from the Candida genus are particularly suspect. Such pathogens seem to have co-evolved not only with their host population but also with the local social environment. Different social environments may have thus favored different pathogenic strategies for manipulation of human behavior.

Differential Contribution of HIV-1 Subtypes B and C to Neurological Disorders: Mechanisms and Possible Treatments

With the introduction of combinatory antiretroviral therapy, patients infected with human immunodeficiency virus type 1 (HIV-1) can live much longer than before. However, the identification of HIV-associated neurocognitive disorder (HAND), especially HIV-associated dementia in 15-20% of patients infected with HIV-1, indicates additional complexity. These disorders turn out to be subtype dependent. Recently, many studies are ongoing trying to understand how the virus induces neuronal injury which could lead to neurological dysfunction. Most of these studies are focusing on the HIV-1 release of proteins such as Tat. However, the exact role of these proteins and their involvement in neuronal degeneration remains unidentified; this is especially true since viral proteins from different HIV-1 subtypes differ in their ability to cause neuronal damage. This review describes the role of different HIV-1 subtypes, identifies probable pathways involved in neuronal damage, the contribution of different HIV-1 subtypes to the progression of HAND, and potential treatments for HAND.

Longitudinal brain atrophy patterns and neuropsychological performance in older adults with HIV-associated neurocognitive disorder compared with early Alzheimer's disease

Older HIV-infected patients are at risk for both HIV-associated neurocognitive disorder (HAND) and Alzheimer's disease. We investigated neuroimaging and neuropsychological performance of 61 virally suppressed older adults with HAND (mean (SD) age 64.3 (3.9) years), 53 demographically matched individuals with mild cognitive impairment of the Alzheimer's type (MCI-AD; 65.0 [4.8]), and 89 healthy controls (65.0 [4.3]) cross-sectionally and over 20 months. At the baseline, both disease groups exhibited lower volumes in multiple cortical and subcortical regions compared with controls. Hippocampal volume differentiated MCI-AD from HAND. Cognitively, MCI-AD performed worse on memory and language compared with HAND. Adjusted longitudinal models revealed greater diffuse brain atrophy in MCI-AD compared with controls, whereas HAND showed greater atrophy in frontal gray matter and cerebellum compared with controls. Comparing HAND with MCI-AD showed similar atrophy rates in all brain regions explored, with no significant findings. MCI-AD exhibited more pronounced language decline compared with HAND. These findings reveal the need for further work on unique cognitive phenotypes and neuroimaging signatures of HAND compared with early AD, providing preliminary clinical insight for differential diagnosis of age-related brain dysfunction in geriatric neuroHIV.

Pathogenesis of age-related HIV neurodegeneration

People over the age of 50 are the fastest growing segment of the HIV-infected population in the USA. Although antiretroviral therapy has remarkable success controlling the systemic HIV infection, HIV-associated neurocognitive disorder (HAND) prevalence has increased or remained the same among this group, and cognitive deficits appear more severe in aged patients with HIV. The mechanisms of HAND in the aged population are not completely understood; a leading hypothesis is that aged individuals with HIV might be at higher risk of developing Alzheimer's disease (AD) or one of the AD-related dementias (ADRD). There are a number of mechanisms through which chronic HIV disease alone or in combination with antiretroviral therapy and other comorbidities (e.g., drug use, hepatitis C virus (HCV)) might be contributing to HAND in individuals over the age of 50 years, including (1) overlapping pathogenic mechanisms between HIV and aging (e.g., decreased proteostasis, DNA damage, chronic inflammation, epigenetics, vascular), which could lead to accelerated cellular aging and neurodegeneration and/or (2) by promoting pathways involved in AD/ADRD neuropathogenesis (e.g., triggering amyloid β, Tau, or α-synuclein accumulation). In this manuscript, we will review some of the potential common mechanisms involved and evidence in favor and against a role of AD/ADRD in HAND.

Clinical and neuroimaging correlates of cognition in HIV

This study investigated whether HIV-positive participants, stable on combined antiretroviral therapy (cART), showed cognitive impairments relative to HIV-negative controls; and whether clinical and neuroimaging factors correlated with cognitive function in the HIV-positive participants. One hundred and twenty-six white men who have sex with men, of whom 78 were HIV-positive and stable on cART and 48 were HIV negative, were recruited to this cross-sectional study. The median age of HIV-positive participants in this study was 47. They underwent clinical and neuropsychological evaluation and magnetic resonance imaging of the brain, including diffusion tensor imaging (DTI). Cognitive scores for both groups were compared, and regression models were run to explore the influence of clinical, psychiatric, lifestyle, and neuroimaging variables on cognition. The prevalence of neurocognitive impairment, using the multivariate normative comparison criteria, was 28% in HIV-positive participants and 5% in HIV-negative participants. After covarying for age, years of education, and non-English speaking background, there were significant differences between the HIV group and the controls across four cognitive domains. The HIV group showed significantly higher mean diffusivity (MD) and lower fractional anisotropy (FA) than the control group on DTI. Although anxiety levels were clinically low, anxiety and DTI measures were the only variables to show significant correlations with cognitive function. In the HIV group, poorer cognitive performance was associated with higher MD and lower FA on DTI and higher (albeit clinically mild) levels of anxiety. Our findings suggest that white matter changes and subtle anxiety levels contribute independently to cognitive impairment in HIV.

High prevalence of neurocognitive disorders observed among adult people living with HIV/AIDS in Southern Ethiopia: A cross-sectional study

BACKGROUND

Comprehensive care given to people living with HIV/AIDS is improving over time; however, their concurrent cognitive illness is still ignored, under screened and treated particularly in developing countries. And this problem is also striking in Ethiopia. Therefore, the objective of this study was to assess HIV-associated neurocognitive disorders and associated factors among adult people living with HIV/AIDS.

METHODS

An institution based cross sectional study was conducted from April to May, 2017 at Gamo Gofa zone public Hospitals. International HIV Dementia Scale was used to screen HIV associated neurocognitive disorders. Logistic regression analysis was used to assess predictors of neurocognitive disorders.

RESULT

A total of 684 study participants were included in this study with a response rate of 98%. Among them, 56% were females while 44% were males. The mean (±SD) age of the participants was 38.8±8.8years. The screening prevalence of HIV-associated neurocognitive disorder was 67.1% (95% CI; 63.6, 70.5). Body mass index 16 kg/m2 (AOR 4.389 (1.603-12.016)), being married (AOR 0.377 (0.213-0.666), unemployment status (AOR 3.181 (1.752-5.777) and being in WHO clinical stage T3 category/advancing stages of the disease (AOR 3.558 (1.406-9.006) were the key predictors of HIV-associated neurocognitive disorders among people living with HIV/AIDS.

CONCLUSION

In this study the screening prevalence of HIV-associated neurocognitive disorder is higher than the earlier reports in Ethiopia and Africa. This indicates that early screening strategies and policies for cognitive health in people living with HIV/AIDS should be given a top priority.

Association Between Cognitive Tests and Antiretroviral Medication Adherence in Older Adults With HIV

BACKGROUND

One of the fastest growing populations living with HIV is older adults especially those 65 years of age or older. Current antiretroviral therapy (ART) has prolonged life expectancy of persons with HIV. However, for therapy to be effective, patients need to be adherent. Over time, older persons with HIV may experience HIV-associated neurocognitive disorders or other factors that could affect ART adherence. The use of expedient cognitive tests that help measure medication adherence may be useful for the optimal care of these patients.

OBJECTIVE

To investigate the association between cognitive tests and ART adherence.

METHODS

This was a prospective study evaluating patients 65 years of age or older with HIV. Cognitive tests used included the Executive Clock-Drawing Task (CLOX) 1 and 2, Trail Making Test parts A and B, and Grooved Pegboard Test (GPB). The medication event monitoring system cap over 1 month was used as the primary measure for adherence.

RESULTS

CLOX 1 and GPB were significantly related to adherence ( P < 0.05). Comparison of the magnitude of each measure's relation to adherence suggests that the GPB is a better indicator of ability to adhere ( R = 0.514 vs R = 0.381). Conclusion and Relevance: CLOX 1 and GPB demonstrated an association with adherence in patients 65 years of age or older with HIV. Although the use of these tests to measure adherence in older persons with HIV seems promising, more research is needed to ascertain their ultimate utility.

Association Between Frailty and HIV-Associated Neurodegenerative Disorders Among Older Adults Living with HIV

The population of aging adults living with human immunodeficiency virus (HIV) is growing worldwide and evidence suggests that frailty occurs prematurely among them. In turn, frailty has been associated with cognitive decline. It is unknown, however, if people with both frailty and HIV infection have a higher risk of cognitive impairment compared with nonfrail HIV-infected persons. Therefore, the main objective of this study was to determine the association between the phenotype of frailty and HIV-associated neurocognitive disorders (HAND) among adults aged 50 years or older living with HIV/AIDS. A cross-sectional study was conducted on 206 adults living with HIV receiving care in a university-affiliated tertiary care hospital in Mexico City. Frailty was defined as per the Fried criteria. The presence of HAND was established according to the Antinori criteria: HIV-associated asymptomatic neurocognitive impairment (ANI), HIV-associated mild neurocognitive disorder (MND), or cognitively nonimpaired. Multinomial logistic regression models were used to test the independent association between frailty and HAND adjusting for potential confounders. Mean age of participants was 60.5 ± 6.3 years and 84.9% were male. Prevalence of HAND and frailty phenotype was 66.0% and 2.9%, respectively. The unadjusted analysis showed that both prefrail and frail statuses were associated with MND but not with ANI. However, after adjustment, the association with MND remained significant only among prefrail participants and no longer for frail persons (risk ratio [RR] = 5.7, 95% confidence intervals [CI] 1.09-29.82; p = .039 and RR = 18.3, 95% CI 0.93-362.6; p = .056, respectively). Prefrailty is associated with symptomatic neurocognitive disorders in older adults living with HIV. The spectrum of the frailty phenotype in this already vulnerable population should serve as an indicator of concomitant cognitive decline.

Multicenter European Prevalence Study of Neurocognitive Impairment and Associated Factors in HIV Positive Patients

We conducted a cross-sectional study in 448 HIV positive patients attending five European outpatient clinics to determine prevalence of and factors associated with neurocognitive impairment (NCI) using computerized and pen-and-paper neuropsychological tests. NCI was defined as a normalized Z score ≤-1 in at least 2 out of 5 cognitive domains. Participants' mean age was 45.8 years; 84% male; 87% white; 56% university educated; median CD4 count 550 cells/mm³; 89% on antiretroviral therapy. 156 (35%) participants had NCI, among whom 26 (17%; 5.8% overall) reported a decline in activities of daily living. Prevalence of NCI was lower in those always able to afford basic needs (adjusted prevalence ratio [aPR] 0.71, 95% confidence interval [CI] 0.54-0.94) or with a university education (aPR 0.72, 95% CI 0.54-0.97) and higher in those with severe depressive symptoms (aPR 1.53, 95% CI 1.09-2.14) or a significant comorbid condition (aPR 1.40, 95% CI 1.03-1.90).

Imaging studies of the HIV-infected brain

Human immunodeficiency virus (HIV) enters the brain early after infecting humans and may remain in the central nervous system despite successful antiretroviral treatment. Many neuroimaging techniques were used to study HIV+ patients with or without opportunistic infections. These techniques assessed abnormalities in brain structures (using computed tomography, structural magnetic resonance imaging (MRI), diffusion MRI) and function (using functional MRI at rest or during a task, and perfusion MRI with or without a contrast agent). In addition, single-photon emission computed tomography with various tracers (e.g., thallium-201, Tc99-HMPAO) and positron emission tomography with various agents (e.g., [18F]-dexoyglucose, [11C]-PiB, and [11C]-TSPO tracers), were applied to study opportunistic infections or HIV-associated neurocognitive disorders. Neuroimaging provides diagnoses and biomarkers to quantitate the severity of brain injury or to monitor treatment effects, and may yield insights into the pathophysiology of HIV infection. As the majority of antiretroviral-stable HIV+ patients are living longer, age-related comorbid disorders (e.g., additional neuroinflammation, cerebrovascular disorders, or other dementias) will need to be considered. Other highly prevalent conditions, such as substance use disorders, psychiatric illnesses, and the long-term effects of combined antiretroviral therapy, all may lead to additional brain injury. Neuroimaging studies could provide knowledge regarding how these comorbid conditions impact the HIV-infected brain. Lastly, specific molecular imaging agents may be needed to assess the central nervous system viral reservoir.

NeuroAIDS in children

The human immunodeficiency virus-1 (HIV-1) enters the central nervous system compartment within the first few weeks of systemic HIV infection and may cause a spectrum of neurologic complications. Without combination antiretroviral therapy (cART), 50-90% of all HIV-infected infants and children develop some form of neuroAIDS. Of the estimated 2.3 million children less than 15 years of age who were living in sub-Saharan Africa at the end of 2014, only 30% were receiving cART, suggesting that there is a large burden of neuroAIDS among HIV-infected children in sub-Saharan Africa. There is complex interplay between the disease process itself, the child's immune reaction to the disease, the secondary complications, the side-effects of antiretroviral drugs, and inadequate antiretroviral drug uptake into the central nervous system. In addition there is the layering effect from the multiple socioeconomic challenges for children living in low- and middle-income countries. Adolescents may manifest with a range of neurocognitive sequelae from mild neurocognitive disorder through to severe neurocognitive impairment. Neuroimaging studies on white-matter tracts have identified dysfunction, especially in the frontostriatal networks needed for executive function. Psychiatric symptoms of depression, attention deficit hyperactivity disorder, and behavioral problems are also commonly reported in this age group. Antiretroviral drugs may cause treatment-limiting neurologic and neuropsychiatric adverse reactions. The following chapter addresses the neurologic complications known to be, and suspected of being, associated with HIV infection in children and adolescents.

HIV-1-associated neurocognitive disorder: epidemiology, pathogenesis, diagnosis, and treatment

The modern antiretroviral treatment of human immunodeficiency virus (HIV-1) infection has considerably lowered the incidence of opportunistic infections. With the exception of the most severe dementia manifestations, the incidence and prevalence of HIV-associated neurocognitive disorders (HAND) have not decreased, and HAND continues to be relevant in daily clinical practice. Now, HAND occurs in earlier stages of HIV infection, and the clinical course differs from that before the widespread use of combination antiretroviral treatment (cART). The predominant clinical feature is a subcortical dementia with deficits in the domains concentration, attention, and memory. Motor signs such as gait disturbance and impaired manual dexterity have become less prominent. Prior to the advent of cART, the cerebral dysfunction could at least partially be explained by the viral load and by virus-associated histopathological findings. In subjects where cART has led to undetectable or at least very low viral load, the pathogenic virus-brain interaction is less direct, and an array of poorly understood immunological and probably toxic phenomena are discussed. This paper gives an overview of the current concepts in the field of HAND and provides suggestions for the diagnostic and therapeutic management.

Neurological involvement in patients with acute/recent HIV-1 infection. A case-control study

Primary HIV-1 infection is a relevant period for its virological and epidemiological consequences. Most patients present a symptomatic disease that can be potentially serious, but neurological involvement during primary HIV-1 infection has been poorly studied. The aim of this study was to describe the characteristics and outcomes of primary HIV-1 infection patients presenting neurological symptoms and to compare them with primary HIV-1 infection patients without neurological involvement. Retrospective case-control study (1:3) comparing primary HIV-1 infection patients with and without neurological involvement enrolled in the Acute/Recent Hospital Clinic PHI Cohort between 1997 and 2016. Matching criteria included age (±10 years), gender, year of diagnosis (±4 years), and Fiebig stage. The conditional logit model was used for comparisons. Fourteen out of 463 patients (3.02%) enrolled in the Acute/Recent Hospital Clinic PHI Cohort between 1997 and 2016 presented neurological symptoms. 28.5% of cases presented as meningitis and 71.5% as meningoencephalitis. Cerebrospinal fluid showed non-specific findings, including pleocytosis with lymphocyte predominance and increased protein levels. All cases required hospitalisation, whereas only 19% of the controls did. No other pathogen was identified in any case, but five patients initiated empirically antimicrobial treatment for other aetiologies until diagnosis was confirmed. CD4/CD8 ratio was significantly lower (p = 0.039) and plasmatic viral load significantly higher in the case group, compared to controls (p = 0.028). Risk factors, HIV-1 tropism, subtype distribution, and prescribed ART regimens were comparable between cases and controls. After 6 months on ART, 92% of cases had undetectable viral load, similar to controls, and CD4/CD8 ratio became also comparable between groups. All cases recovered rapidly with ART and were discharged without sequels. Neurological involvement during primary HIV-1 infection is unusual but serious, always requiring hospitalisation. Diagnosis is difficult because of the wide range of symptoms and similarities with other viral aetiologies. Neurological manifestations during primary HIV-1 infection are associated with a lower CD4/CD8 ratio and with a higher viral load than controls. Immediate ART initiation and rapid viral load decrease are required, allowing complete clinical recovery.

Validation of the International HIV Dementia Scale as a Screening Tool for HIV-Associated Neurocognitive Disorders in a German-Speaking HIV Outpatient Clinic

Background

HIV-associated neurocognitive disorders (HAND) are widely present among people living with HIV. Especially its milder forms, asymptomatic neurocognitive impairment (ANI) and mild neurocognitive disorder (MND), remain highly prevalent worldwide. Diagnosing these conditions is subject to a time and resource consuming neuropsychological assessment. Selecting patients at a higher risk of cognitive impairment by using a simple but effective screening tool helps to organise access to further neuropsychological diagnosis. The International HIV Dementia Scale (IHDS) has until now been a well-established screening tool in African and American countries, however these populations’ demographics defer significantly from ours, so using the same parameters could be ineffective.

Objectives

To calculate the prevalence of this condition among people attending an HIV outpatient clinic in Berlin and to validate the use of the IHDS as a screening tool for HAND in a German-speaking population.

Methods

We screened 480 HIV-infected patients using the IHDS, 89% of them were on a stable antiretroviral treatment. Ninety of them completed a standardised neuropsychological battery of tests and a specific cognitive complaints questionnaire. The same procedure was applied to a control group of 30 HIV-negative participants. HAND diagnosis was established according to the Frascati criteria.

Results

The overall prevalence of HAND in our cohort was 43% (20% ANI, 17% MND and 6% HIV-associated dementia). The optimal cut-off on the IHDS for detecting HAND cases was set at 11 and achieved both a sensitivity and a specificity of 80%. When specifically screening for the more severe form of HAND, HIV-associated dementia, a cut-off value of 10 offered an increase in both sensitivity (94%) and specificity (86%). The Youden Index for diagnostic accuracy was 0.6 and 0.8, respectively.

Conclusions

The prevalence of HAND was comparable to the reported by recent studies performed in countries with a similar economic development. The study confirms the IHDS to be a useful HAND screening tool in primary care settings and establishes new recommendations for its use in German-speaking countries.

Depression and diagnosis of neurocognitive impairment in HIV-positive patients

Neurocognitive impairment (NCI) is frequently observed in patients infected with human immunodeficiency virus (HIV) and results from the compromise of subcortical brain structures by the virus. The manifestations of NCI range from asymptomatic impairment to dementia. In addition to cognitive impairment resulting from HIV infection, other factors such as depression are associated with the loss of cognitive functions. The aim of this study was to estimate the prevalence of NCI in HIV-positive patients in a city in southern Brazil and to establish possible associations for the prevalence of NCI with HIV-related and other risk factors. This cross-sectional study of HIV-positive outpatients was conducted in a specialized care service in the city of Pelotas in Southern Brazil. Sociodemographic data and HIV-related information were collected, and all patients underwent psychiatric and neurocognitive evaluations. The prevalence of NCI among the 392 patients was 54.1% when tracked using the IHDS (International HIV Dementia Scale) and 36.2% when the IHDS was associated with a battery of complementary tests. A bivariate analysis suggested an association of NCI with gender, age, educational level, depression, current CD4 count and lowest CD4 count. The association of NCI with depression remained in the Poisson regression (PR=1.96, 95%CI=1.12-3.42). The prevalence of cognitive impairment in HIV-positive patients estimated in this study is in accordance with international and Brazilian data. Of the factors analyzed, depression showed the greatest evidence of association with neurocognitive loss. Based on our findings, the inclusion of instruments to evaluate depression in our services for patients with HIV and acquired immunodeficiency syndrome (AIDS) is recommended.

Low levels of neurocognitive impairment detected in screening HIV-infected men who have sex with men: The MSM Neurocog Study

This study aimed to determine the prevalence of HIV neurocognitive impairment in HIV-infected men who have sex with men aged 18-50 years, using a simple battery of screening tests in routine clinical appointments. Those with suspected abnormalities were referred on for further assessment. The cohort was also followed up over time to look at evolving changes. HIV-infected participants were recruited at three clinical sites in London during from routine clinical visits. They could be clinician or self-referred and did not need to be symptomatic. They completed questionnaires on anxiety, depression, and memory. They were then screened using the Brief Neurocognitive Screen (BNCS) and International HIV Dementia Scale (IHDS). Two hundred and five HIV-infected subjects were recruited. Of these, 59 patients were excluded as having a mood disorder and two patients were excluded due to insufficient data, leaving 144 patients for analysis. One hundred and twenty-four (86.1%) had a normal composite z score (within 1 SD of mean) calculated for their scores on the three component tests of the BNCS. Twenty (13.9%) had an abnormal z score, of which seven (35%) were symptomatic and 13 (65%) asymptomatic. Current employment and previous educational level were significantly associated with BNCS scores. Of those referred onwards for diagnostic testing, only one participant was found to have impairment likely related to HIV infection. We were able to easily screen for mood disorders and cognitive impairment in routine clinical practice. We identified a high level of depression and anxiety in our cohort. Using simple screening tests in clinic and an onward referral process for further testing, we were not able to identify neurocognitive impairment in this cohort at levels consistent with published data.

Identifying Neurocognitive Decline at 36 Months among HIV-Positive Participants in the CHARTER Cohort Using Group-Based Trajectory Analysis

Introduction

While HIV-associated neurocognitive impairment remains common despite the widespread use of combined antiretroviral therapy (cART), there have been relatively few studies investigating the trajectories of neurocognitive change in longitudinal NeuroAIDS studies.

Objective

To estimate the magnitude and pattern of neurocognitive change over the first 3 years of follow-up using Group-Based Trajectory Analysis (GBTA) applied to participants in the longitudinal arm of the CHARTER cohort.

Method

The study population consisted of 701 CHARTER participants who underwent neuropsychological (NP) testing on at least 2 occasions. Raw test scores on 15 NP measures were modeled using GBTA. Each trajectory was categorized as stable, improved or declined, according to two different criteria for change (whether the magnitude of the estimated change at 36 months differed ≥ 0.5 standard deviations from baseline value or changed by > the standard error of measurement estimated at times 1 and 2). Individuals who declined on one or more NP measures were categorized as decliners.

Results

Overall, 111 individuals (15.8%) declined on at least one NP test over 36 months, with the vast majority showing decline on a single NP test (93/111-83.8%). The posterior probability of group assignment was high in most participants (71%) after only 2 sessions, and in the overwhelming majority of those with 3+ sessions. Heterogeneity of trajectories was the norm rather than the exception. Individuals who declined had, on average, worse baseline NP performance on every test, were older, had a longer duration of HIV infection and more follow-up sessions.

Conclusion

The present study identified heterogeneous trajectories over 3 years across 15 NP raw test scores using GBTA. Cognitive decline was observed in only a small subset of this study cohort. Decliners had demographics and HIV characteristics that have been previously associated with cognitive decline, suggesting clinical validity for the method.

CROI 2016: Neurologic Complications of HIV Infection

The brain remains a major target for HIV infection and a site of potential complications for HIV-infected individuals. Emerging data presented at the 2016 Conference on Retroviruses and Opportunistic Infections suggest that during the early stages of infection, activated CD4+ cells may traffic the virus into the central nervous system (CNS). HIV is detectable in cells and tissues of the CNS in some individuals despite suppressive antiretroviral treatment. A potential source of cerebrospinal fluid HIV escape may be compartmentalized HIV replication within macrophage lineage cells. Virally infected cells can traffic out of the CNS and may have the potential to reseed the systemic compartment. Additional modifiers of HIV-associated neurocognitive disorder (HAND) were identified, including female sex and hepatic dysfunction. Large epidemiologic studies reported an elevated risk of stroke among HIV-infected individuals, related to traditional vascular risk factors, history of recreational drug use, and HIV measures (lower CD4+ cell nadir and higher viral load). Brain imaging may provide a noninvasive means for detecting early changes in the brain associated with HIV infection and may assist in prognosis of HAND. Some potential adjunctive therapies to standard antiretroviral therapy for HIV-infected individuals were considered.

The validity of the Substance Abuse and Mental Illness Symptom Screener (SAMISS) in people living with HIV/AIDS in primary HIV care in Cape Town, South Africa

Given the high prevalence of HIV in South Africa and co-morbid mental disorders in people living with HIV/AIDs (PLWHA) we sought to validate a brief screening tool in primary HIV care.

METHODS

366 PLWHA were recruited prior to combination anti-retroviral treatment (CART) initiation from two primary health HIV clinics. A mental health nurse administered a socio-demographic questionnaire and the Mini Neuropsychiatric Interview (MINI) and a lay counsellor administered the Substance and Mental Illness Symptom Screener (SAMISS).

RESULTS

Using the MINI, 17 % of participants were identified with either depression, anxiety disorders or adjustment disorder and 18 % with substance or alcohol abuse/dependence. The sensitivity and specificity of the SAMISS was 94 % (95 % CI: 88-98 %) and 58 % (95 % CI: 52-65 %) respectively, with the alcohol component (sensitivity: 94 %; specificity: 85 %) performing better than the mental illness component of the SAMISS (sensitivity: 97 %; specificity: 60 %). The specificity of the tool improved when the cut-off for the mental illness component was increased.

CONCLUSION

The SAMISS may provide a useful first tier screening tool for common mental disorders in primary care for PLWHA.

HIV subtype is not associated with dementia among individuals with moderate and advanced immunosuppression in Kampala, Uganda

HIV-associated neurocognitive disorders (HAND) are a common neurological manifestation of HIV infection. A previous study suggested that HIV dementia may be more common among patients with subtype D virus than among those with subtype A virus among HIV+ individuals with advanced immunosuppression. We conducted a study to evaluate the frequency of HIV dementia, and the association of HIV dementia with HIV subtype and compartmentalization among HIV+ individuals with moderate and advanced immunosuppression (CD4 lymphocyte count >150 cells/μL and <250 cells/μL). The study enrolled 117 antiretroviral naïve HIV+ individuals in Kampala, Uganda. HIV+ individuals received neurological, neuropsychological testing, and functional assessments, and gag and gp41 regions were subtyped. Subjects were considered infected with a specific subtype if both regions analyzed were from the same subtype. 41% of the HIV+ individuals had HIV dementia (mean CD4 lymphocyte count = 233 cells/μL). 67 individuals had subtype A, 25 individuals had subtype D, 24 individuals were classified as A/D recombinants, and one individual had subtype C. There was no difference in the frequency of HIV dementia when stratified by HIV subtype A and D and no association with compartmentalization between the cerebrospinal fluid and peripheral blood. These results suggest that HIV dementia is common in HIV+ individuals in Uganda. There was no association between HIV subtype and dementia among HIV+ individuals with moderate and advanced immunosuppression. Future studies should be performed to confirm these results.

CROI 2014: Neurologic complications of HIV infection

A shift in focus in the field of neuroHIV was clearly manifest at the 2014 Conference on Retroviruses and Opportunistic Infections (CROI), where a major emphasis was on the milder forms of neurologic morbidity, including cognitive impairment, seen in well-treated patients. Mechanisms of this persistent abnormality were investigated, including extensive analysis of the prevalence and associations of persistent HIV detection in cerebrospinal fluid (CSF) and characterization of persistent CNS immune activation. Another key emphasis was the early establishment of HIV replication and inflammation within the central nervous system (CNS) and the potentially salutary effect of very early HIV diagnosis and treatment in protecting the CNS from HIV-related injury. Mitochondrial function was identified as a potential mediator of a number of aspects of HIV-associated CNS dysfunction, including neurotoxicity associated with efavirenz, host genetic determinants of HIV-associated neurocognitive disorders (HAND), associations with direct measures of mitochondria in CSF, and metabolomic screening of CSF in HIV-infected subjects and those with HAND. Many studies employed laboratory rather than neuropsychologic end points, with a major focus on CSF biomarkers. Overall, neuroHIV presentations at CROI 2014 provided new insights into pathogenesis and treatment of the CNS, raising new challenges for researchers and practitioners aiming to optimize the status of the brain in people living with HIV infection.

HIV-associated neurocognitive disorder in Australia: a case of a high-functioning and optimally treated cohort and implications for international neuroHIV research

The Australian HIV-infected (HIV+) population is largely comprised of high-functioning men who have sex with men (MSM). Like other English-speaking countries, Australia mostly relies on US neuropsychological normative standards to detect and determine the prevalence of neurological disorders. Whether the US neuropsychological (NP) normative standards are appropriate in Australian HIV+ MSM has not been established. Ninety virally suppressed HIV+ and 49 HIV-uninfected (HIV-) men (respectively 86 and 85 % self-reported MSM; mean age 54 and 56 years, mean premorbid verbal IQ estimate 110 and 111) undertook standard NP testing. The raw neuropsychological data were transformed using the following: (1) US standards as uncorrected scaled scores and demographically corrected T scores (US norms); and (2) z scores (without demographic corrections) derived from Australian comparison group scaled scores (local norms). To determine HIV-associated neurocognitive disorder prevalence, we used a standard definition of impairment based upon a battery-wide summary score: the global deficit score (GDS). Impairment classification (GDS ≥ 0.5) based on the local norms was best at discriminating between the two groups (HIV- = 14.3 % vs. HIV+ = 53.3 %; p < 0.0001). This definition was significantly associated with age. Impairment classification based on the US norms yielded much lower impairment rate regardless of the HIV status (HIV- = 4.1 % vs. HIV+ = 14.7 %; p = 0.05), but was associated with historical AIDS, and not age. Both types of summary scores were associated with reduced independence in activities of daily living (p ≤ 0.03). Accurate neuropsychological classifications of high (or low) functioning individuals may need country-specific norms that correct for performance-based (e.g., reading) estimates of premorbid cognition in addition to the traditional demographic factors.

The veterans aging cohort study index is associated with concurrent risk for neurocognitive impairment

OBJECTIVE

The Veterans Aging Cohort Study (VACS) Index is predictive of mortality and combines age, traditional HIV biomarkers (HIV-1 plasma RNA and current CD4 count), and non-HIV biomarkers (indicators of renal and liver function, anemia, and hepatitis C coinfection). We examined the association between the VACS Index and HIV-associated neurocognitive impairment (NCI).

DESIGN AND METHODS

Participants included 601 HIV-infected adults enrolled in cohort studies at the University of California, San Diego, HIV Neurobehavioral Research Program (ages: 18-76 years; 88% male; 63% white; median current CD4 = 364 cells/mm; 63% on antiretroviral therapy; AIDS = 64%). Biomarkers used in calculating the VACS Index were measured in prospectively collected blood samples using conventional laboratory methods. NCI was defined using global and seven domain deficit scores.

RESULTS

Higher VACS Index scores were associated with concurrent risk for global NCI [P < 0.001; odds ratio = 1.21, confidence interval (CI): 1.12 to 1.32], even when adjusting for psychiatric comorbidities. This relation was statistically significant for most cognitive domains in adjusted models. Furthermore, the VACS Index predicted concurrent NCI beyond nadir CD4 and estimated duration of infection. Older age, lower hemoglobin, and lower CD4 counts were the VACS components most strongly linked to NCI.

CONCLUSIONS

The findings extend previous research on the potential usefulness of the VACS Index in predicting HIV-associated outcomes to include NCI. Although the effect size was relatively small, our findings suggest that demographic information, HIV-disease factors, and common comorbidities might each play important roles in the clinical manifestation of cognitive impairment among HIV-infected individuals. Additional research is needed to determine if a more sensitive and specific index can be developed.

HIV, aging, and cognition: emerging issues

The prevalence of HIV-associated neurocognitive disorder has not changed from the pre- to the potent antiretroviral therapy era, remaining at approximately 50%. In research settings, mild neurocognitive disorder (MND) and so-called asymptomatic neurocognitive impairment (ANI) are now more common than HIV-associated dementia. The diagnosis of ANI is misleading because functional deficits, when tested in a laboratory, and degree of neuropsychologic testing abnormalities are often comparable in patients with ANI and those with symptomatic MND. Age-related comorbidities increase the risk of cognitive impairment in HIV infection. In a cohort of patients aged 60 years or older with excellent antiretroviral therapy adherence, correlates to cognitive impairment were apolipoprotein (Apo) E4 genotype and a novel measure of the effectiveness of antiretroviral drugs in monocytes, the monocyte efficacy (ME) score, with trend associations for diabetes and nadir CD4+ cell count. Management of impairment includes ensuring that patients are on and adhere to antiretroviral therapy and addressing comorbidities. Switching from effective and well-tolerated antiretroviral therapy for patients with mild cognitive impairment is not routinely recommended, but this must still be addressed on a case-by-case basis. This article summarizes a presentation by Victor G. Valcour, MD, at the IAS-USA continuing education program held in Atlanta, Georgia, in April 2013.

Improved neuropsychological and neurological functioning across three antiretroviral regimens in diverse resource-limited settings: AIDS Clinical Trials Group study a5199, the International Neurological Study

BACKGROUND

AIDS Clinical Trials Group (ACTG) A5199 compared the neurological and neuropsychological (NP) effects of 3 antiretroviral regimens in participants infected with human immunodeficiency virus type 1 (HIV-1) in resource-limited settings.

METHODS

Participants from Brazil, India, Malawi, Peru, South Africa, Thailand, and Zimbabwe were randomized to 3 antiretroviral treatment arms: A (lamivudine-zidovudine plus efavirenz, n = 289), B (atazanavir, emtricitabine, and didanosine-EC, n = 293), and C (emtricitabine-tenofovir-disoproxil fumarate plus efavirenz, n = 278) as part of the ACTG PEARLS study (A5175). Standardized neurological and neuropsychological (NP) screening examinations (grooved pegboard, timed gait, semantic verbal fluency, and finger tapping) were administered every 24 weeks from February 2006 to May 2010. Associations with neurological and neuropsychological function were estimated from linear and logistic regression models using generalized estimating equations.

RESULTS

The median weeks on study was 168 (Q1 = 96, Q3 = 192) for the 860 participants. NP test scores improved (P < .05) with the exception of semantic verbal fluency. No differences in neurological and neuropsychological functioning between treatment regimens were detected (P > .10). Significant country effects were noted on all NP tests and neurological outcomes (P < .01).

CONCLUSIONS

The study detected no significant differences in neuropsychological and neurological outcomes between randomized ART regimens. Significant improvement occurred in neurocognitive and neurological functioning over time after initiation of ARTs. The etiology of these improvements is likely multifactorial, reflecting reduced central nervous system HIV infection, better general health, and practice effects. This study suggests that treatment with either of the World Health Organization -recommended first-line antiretroviral regimens in resource-limited settings will improve neuropsychological functioning and reduce neurological dysfunction.

CLINICAL TRIALS REGISTRATION

NCT00096824.

Neuropsychiatric complications of aging with HIV

Persons over age 50 are not only aging with human immunodeficiency virus (HIV) infection but also represent a high proportion of new HIV infections. Neuropsychiatric symptoms, including depression, cognitive impairment, and substance abuse, are very common in individuals infected with HIV. However, there is little understanding of the relationship between these HIV-related comorbid conditions in newly infected elderly patients compared to uninfected elderly and those who have survived after 20 years of HIV/AIDS. We summarize the current theories and research that link aging and HIV with psychiatric illnesses and identify emerging areas for improved research, treatment, and patient care.

Neurocognitive and motor deficits in HIV-infected Ugandan children with high CD4 cell counts

BACKGROUND

Human immunodeficiency virus (HIV) infection causes neurocognitive or motor function deficits in children with advanced disease, but it is unclear whether children with CD4 cell measures above the World Health Organization (WHO) thresholds for antiretroviral therapy (ART) initiation suffer significant impairment.

METHODS

The neurocognitive and motor functions of HIV-infected ART-naive Ugandan children aged 6-12 years with CD4 cell counts of >350 cells/μL and CD4 cell percentage of >15% were compared with those of HIV-uninfected children, using the Test of Variables of Attention (TOVA), the Kaufman Assessment Battery for Children, second edition (KABC-2), and the Bruininks-Oseretsky Test of Motor Proficiency, second edition (BOT-2).

RESULTS

Ninety-three HIV-infected children (median CD4 cell count, 655 cells/μL; plasma HIV RNA level, 4.7 log(10) copies/mL) were compared to 106 HIV-uninfected children. HIV-infected children performed worse on TOVA visual reaction times (multivariate analysis of covariance; P = .006); KABC-2 sequential processing (P = .005), simultaneous processing (P = .039), planning/reasoning (P = .023), and global performance (P = .024); and BOT-2 total motor proficiency (P = .003). High plasma HIV RNA level was associated with worse performance in 10 cognitive measures and 3 motor measures. In analysis of only WHO clinical stage 1 or 2 HIV-infected children (n = 68), significant differences between the HIV-infected and HIV-uninfected groups (P < .05) remained for KABC-2 sequential processing, KABC-2 planning/reasoning, and BOT-2 motor proficiency.

CONCLUSIONS

Significant motor and cognitive deficits were found in HIV-infected ART-naive Ugandan children with CD4 cell counts of ∼350 cells/μL and percentages of >15%. Study of whether early initiation of ART could prevent or reverse such deficits is needed.

HIV-1 effects on neuropsychological performance in a resource-limited country, Zambia

Zambia has substantially been affected by the HIV/AIDS epidemic with prevalence rates at 14% in a population estimated at 12 million. Yet, the extent of HIV-associated neurocognitive disorders (HAND) in this population remains to be clearly understood. A series of culturally appropriate neuropsychological (NP) assessments [International HIV Dementia Scale (IHDS), Color Trails Test 1 and 2, Grooved pegboard Test, and Time Gait Test] were used to test the effects of HIV on NP performance of HIV seropositive and seronegative individuals. Twenty-two percent HIV positive individuals ARV naïve met the criteria for IHDS-defined NP impairment. Gender significantly influenced the performance on NP tests with females performing more poorly compared to males. Larger studies that will accommodate gender differences and age are necessary to generate appropriate norms in Zambia in order to better assess the prevalence of HAND in the developing country setting.

HIV-associated neurocognitive disorders before and during the era of combination antiretroviral therapy: differences in rates, nature, and predictors

Combination antiretroviral therapy (CART) has greatly reduced medical morbidity and mortality with HIV infection, but high rates of HIV-associated neurocognitive disorders (HAND) continue to be reported. Because large HIV-infected (HIV+) and uninfected (HIV−) groups have not been studied with similar methods in the pre-CART and CART eras, it is unclear whether CART has changed the prevalence, nature, and clinical correlates of HAND. We used comparable methods of subject screening and assessments to classify neurocognitive impairment (NCI) in large groups of HIV + and HIV − participants from the pre-CART era (1988–1995; N = 857) and CART era (2000–2007; N = 937). Impairment rate increased with successive disease stages (CDC stages A, B, and C) in both eras: 25%, 42%, and 52% in pre-CART era and 36%, 40%, and 45% in CART era. In the medically asymptomatic stage (CDC-A), NCI was significantly more common in the CART era. Low nadir CD4 predicted NCI in both eras, whereas degree of current immunosuppression, estimated duration of infection, and viral suppression in CSF (on treatment) were related to impairment only pre-CART. Pattern of NCI also differed: pre-CART had more impairment in motor skills, cognitive speed, and verbal fluency, whereas CART era involved more memory (learning) and executive function impairment. High rates of mild NCI persist at all stages of HIV infection, despite improved viral suppression and immune reconstitution with CART. The consistent association of NCI with nadir CD4 across eras suggests that earlier treatment to prevent severe immunosuppression may also help prevent HAND. Clinical trials targeting HAND prevention should specifically examine timing of ART initiation.

Clinical correlates of HIV-associated neurocognitive disorders in South Africa

Human immunodeficiency virus-associated neurocognitive disorders (HAND) occurs globally and across different genetic clades of the virus. However, few studies have examined HAND in South Africa, despite the prevalence of HIV in this region of the world, and the predominance of clade C. The present study examined the relationship between a number of demographic and clinical variables in a sample of 536 patients attending HIV clinics in South Africa. HAND was present in 23.5% of the sample and was associated with older age, a low educational level among those with post-traumatic stress disorder (PTSD) and alcohol abuse among those with many months since diagnosis. These results suggest that HAND is common among patients in South Africa, and is associated with clinical variables such as PTSD and alcohol abuse. This underlines the impact of HIV on the nervous system and the importance of screening for co morbid mental health conditions.

Risk factors for HIV-associated neurocognitive disorders (HAND) in sub-Saharan Africa: the case of Yaoundé-Cameroon

BACKGROUND

The prevalence of HIV-associated neurocognitive disorders (HAND), especially HIV-associated dementia (HAD) is influenced by several risk factors. The prevalence as well as risk factors for HAD are not well known in sub-Saharan Africa (SSA). We have shown that the International HIV Dementia Scale (IHDS) is a useful screening tool for HAND in Yaoundé [Njamnshi AK, Djientcheu VdP, Fonsah JY, Yepnjio FN, Njamnshi DM, Muna WFT. The IHDS is a useful screening tool for HAD/Cognitive Impairment in HIV-infected adults in Yaoundé-Cameroon. Journal of Acquired Immune Deficiency Syndromes 2008;49(4):393-397], but no study in Cameroon has yet investigated the risk factors for HAND or HAD.

PATIENTS AND METHODS

A cross-sectional study was conducted in Yaoundé, the capital of Cameroon from September to December 2006. One hundred and eighty-five HIV-positive subjects were included. Diagnosis of HAND was done using the IHDS with a score < or = 10 considered as abnormal. Age, sex, level of education, IV drug use, body mass index (BMI), CDC clinical stage, CD4 counts, hemoglobin levels, administration of highly active antiretroviral therapy (HAART) and type of regimen used, were considered in univariate analysis, with level of significance set at P < or = 0.05. A binary logistic regression was used to determine independent risk factors.

RESULTS

The following factors were independent predictors of HAND: advanced clinical stage (OR=7.43, P=0.001), low CD4 count especially CD4 < or = 200 cells/microL (OR=4.88, P=0.045) and low hemoglobin concentration (OR=1.16, P=0.048).

CONCLUSION

This first study of the risk factors for HAND in Yaoundé-Cameroon shows findings similar to those described in other studies. These results call for rapid action by policy makers to include HAND prevention strategies such as providing early universal access to HAART based on these risk factors, in the management of HIV patients at risk of HAND in resource-limited settings of SSA like ours.

Cellular & molecular basis of HIV-associated neuropathogenesis

Although a plethora of molecules have been implicated in the development of HIV associated dementia (HAD), the identity of the indispensable ones is still elusive. The action of various molecules appears to follow a cascade path with one molecule activating another thereby regulating the expression and modulation of the regulatory machineries. Two pathways have been proposed leading to HIV-induced central nervous system (CNS) injury. First involving neurotoxic effect of viral proteins and second, with immunomodulatory substances secreted by the infected cells playing vital role. The viral transfer from infected cells (for example, cells representing macrophage-microglial lineage) to uninfected cells (such as same cell type or nerve cells) occurring perhaps via virological synapse is also not well documented. While the mechanism underlying transfer of HIV-1 through blood-brain barrier is not clearly understood, macrophage-microglial cell lineages are undisputedly predominant cell types that HIV uses for transmission in CNS. The present review describes existing knowledge of the modus operandi of HIV-induced neuropathogenesis gathered through research evidences. Mechanisms by which regulatory molecules exploit such cell types in promoting neuropathogenesis would provide key insights in intersecting pathway(s) for designing intervention strategies.

The comorbidity of HIV-associated neurocognitive disorders and Alzheimer's disease: a foreseeable medical challenge in post-HAART era

Although the introduction of highly active antiretroviral therapy (HAART) has led to a strong reduction of HIV-associated dementia (HAD) incidence, the prevalence of minor HIV-1-associated neurocognitive disorder (HAND) is rising among AIDS patients. HAART medication has shifted neuropathology from a subacute encephalitic condition to a subtle neurodegenerative process involving synaptic and dendritic degeneration, particularly of hippocampal neurons that are spared prior to HAART medication. Considerable neuroinflammation coupled with mononuclear phagocyte activation is present in HAART-medicated brains, particularly in the hippocampus. Accumulating evidence suggests that the resultant elevated secretion of pro-inflammatory cytokines such as interferon-gamma, tumor necrosis factor-alpha, and interleukin-1beta can increase amyloid-beta peptide (Abeta) generation and reduce Abeta clearance. Recent advancements in Alzheimer's disease (AD) research identified Abeta biogenesis and clearance venues that are potentially influenced by HIV viral infection, providing new insights into beta-amyloidosis segregation in HIV patients. Our study suggests enhanced beta-amyloidosis in ART-treated HAD and HIV-associated encephalitis brains and suppression of Abeta clearance by viral infection of human primary macrophages. A growing awareness of potential convergent mechanisms leading to neurodegeneration shared by HIV and Abeta points to a significant chance of comorbidity of AD and HAND in senile HIV patients, which calls for a need of basic studies.

Closing gaps in antiretroviral therapy access: human immunodeficiency virus-associated dementia screening instruments for non-physician healthcare workers

Human immunodeficiency virus-associated dementia (HIV-D) is an indication for antiretroviral therapy (ART), but HIV-D is not routinely screened for in ART clinics in sub-Saharan Africa. Given the dearth of physicians in sub-Saharan Africa, enabling non-physician healthcare workers to identify HIV-D is crucial for early treatment initiation and preventing chronic neurologic disability. Non-physician healthcare workers administered locally adapted screening instruments to 48 persons living with acquired immunodeficiency syndrome (PLWAs), and 15 healthy comparison persons provided normative data. Stage IV PLWAs performed worse than the comparison group on all tests. Overall, 24 (50%) of 48 PLWAs had significant cognitive impairment. Among HIV staging categories, 1 stage II (33%), 6 stage III (42%), and 17 stage IV (55%) patients were identified as cognitively impaired. Our pilot study indicates that screening instruments used by non-physician healthcare workers can identify cognitive impairment in PLWAs and may facilitate appropriate initiation of ART in resource-poor settings.

HIV and the brain

Right from the early years of the epidemic, researchers have recognized that HIV can affect the brain. Before effective antiretroviral therapy (ART), people with AIDS were susceptible to a variety of opportunistic infections of the brain, as well as HIV-related dementia. With the advent of effective combination ART in the mid-1990s, the prevalence of both conditions declined dramatically in areas with widespread access to treatment. Less severe neurocognitive impairment, however, remains common. In fact, some research indicates that the frequency of HIV-related neurological impairment is rising as people with HIV live longer.

Emerging issues in the neuropsychology of HIV infection

Neurocognitive compromise, a common sequela of HIV infection, ranges in severity from minor motor and information-processing speed decrements to severely incapacitating symptoms that affect functional independence. However, with the emergence of highly active antiretroviral therapy (HAART), neurocognitive phenotypes have become highly heterogeneous and increasingly fail to resemble pre-HAART presentations. This article provides an overview of our current knowledge of HIV-associated neuropsychological abnormalities, with an emphasis on the most recent attempts to classify cognitive impairment within Western and developing societies, the emergence of diverse cognitive presentations in the post-HAART era, factors that moderate the development or impact of HIV-related neurocognitive and functional deficits, and the neurophysiologic consequences of infection.