Verbal working memory in HIV-seropositive drug users

Attention/Working Memory, Learning and Memory in Adult Cameroonians: Normative Data, Effects of HIV Infection and Viral Genotype

OBJECTIVE

There is lack of Cameroonian adult neuropsychological (NP) norms, limited knowledge concerning HIV-associated neurocognitive disorders in Sub-Saharan Africa, and evidence of differential inflammation and disease progression based on viral subtypes. In this study, we developed demographically corrected norms and assessed HIV and viral genotypes effects on attention/working memory (WM), learning, and memory.

METHOD

We administered two tests of attention/WM [Paced Auditory Serial Addition Test (PASAT)-50, Wechsler Memory Scale (WMS)-III Spatial Span] and two tests of learning and memory [Brief Visuospatial Memory Test-Revised (BVMT-R), Hopkins Verbal Learning Test-Revised (HVLT-R)] to 347 HIV+ and 395 seronegative adult Cameroonians. We assessed the effects of viral factors on neurocognitive performance.

RESULTS

Compared to controls, people living with HIV (PLWH) had significantly lower T-scores on PASAT-50 and attention/WM summary scores, on HVLT-R total learning and learning summary scores, on HVLT-R delayed recall, BVMT-R delayed recall and memory summary scores. More PLWH had impairment in attention/WM, learning, and memory. Antiretroviral therapy (ART) and current immune status had no effect on T-scores. Compared to untreated cases with detectable viremia, untreated cases with undetectable viremia had significantly lower (worse) T-scores on BVMT-R total learning, BVMT-R delayed recall, and memory composite scores. Compared to PLWH infected with other subtypes (41.83%), those infected with HIV-1 CRF02_AG (58.17%) had higher (better) attention/WM T-scores.

CONCLUSIONS

PLWH in Cameroon have impaired attention/WM, learning, and memory and those infected with CRF02_AG viruses showed reduced deficits in attention/WM. The first adult normative standards for assessing attention/WM, learning, and memory described, with equations for computing demographically adjusted T-scores, will facilitate future studies of diseases affecting cognitive function in Cameroonians.

Effectiveness of an Intervention for Improving Treatment Adherence, Service Utilization and Viral Load Among HIV-Positive Adult Alcohol Users

This study evaluates whether a group intervention that included cognitive remediation improved ART adherence, service utilization, and viral load among HIV-positive adults with a history of alcohol abuse. HIV-seropositive adults (n = 243), recruited from community-based organizations were randomized to the Holistic Health Recovery Program (HHRP-A) or a comparison condition. Both conditions included eight group sessions; outcomes (adherence, service utilization, and viral load) and processes (social support and stress) were measured. Data were collected at baseline, immediately post-intervention, 3 months, and 6 months follow-up. Participants were ≥ 18 and ≤ 60 ([Formula: see text] years old), 71% male, and 79.6% black. Participants randomized to HHRP-A were more likely to report adequate ART adherence and to report an undetectable viral load at 6 months post-intervention. Participants in the HHRP-A condition showed significantly greater improvement in social support than the comparison group. Providing comprehensive health promotion interventions that incorporate cognitive remediation strategies, could improve health outcomes for HIV-positive substance users.

Comorbid HIV infection and alcohol use disorders: Converging glutamatergic and dopaminergic mechanisms underlying neurocognitive dysfunction

Alcohol use disorders (AUDs) are highly comorbid with human immunodeficiency virus (HIV) infection, occurring at nearly twice the rate in HIV positive individuals as in the general population. Individuals with HIV who consume alcohol show worse long-term prognoses and may be at elevated risk for the development of HIV-associated neurocognitive disorders. The direction of this relationship is unclear, and likely multifactorial. Chronic alcohol exposure and HIV infection independently promote cognitive dysfunction and further may interact to exacerbate neurocognitive deficits through effects on common targets, including corticostriatal glutamate and dopamine neurotransmission. Additionally, drug and alcohol use is likely to reduce treatment adherence, potentially resulting in accelerated disease progression and subsequent neurocognitive impairment. The development of neurocognitive impairments may further reduce cognitive control over behavior, resulting in escalating alcohol use. This review will examine the complex relationship between HIV infection and alcohol use, highlighting impacts on dopamine and glutamate systems by which alcohol use and HIV act independently and in tandem to alter corticostriatal circuit structure and function to dysregulate cognitive function.

Verbal and spatial working memory among drug-using HIV-infected men and women

Working memory (WM) is a critical component of many neurocognitive functions. The literature has demonstrated consistently that WM impairment is more frequent and severe among substance-dependent individuals (SDIs) infected with HIV compared with uninfected SDIs; however, the SDIs who participated in these previous studies were primarily male. There are few published data on WM performance among HIV+ women with or without substance use disorders, and essentially no direct comparisons of WM performance between HIV+ men and women, regardless of substance use. We investigated potential sex and serostatus effects on WM among a sample of 360 SDIs (114 with HIV; 66% female) verified abstinent from alcohol and drugs of abuse at testing and generally comparable on substance use and comorbid characteristics. Participants were tested with the n-back task, a well-established WM measure that is sensitive to HIV-associated cognitive impairment. HIV+ men and women performed spatial and verbal versions of the n-back significantly less accurately compared with HIV- participants. Women showed slower response times compared with men on both versions, regardless of HIV serostatus. Individuals dependent on cocaine showed faster RTs compared with non-dependent users, but this effect was not apparent among opioid- or alcohol-dependent groups. Findings on n-back accuracy are consistent with our previous proposal that WM impairment represents a signature deficit among HIV+ SDIs; however, WM impairment appears less common among HIV+ women without a substance use history. The pattern of sex differences in response speed but serostatus effects on response accuracy is comparable to a recent report by our group of sex differences in learning speed but serostatus effects on delayed recall.

Chronic Tobacco-Smoking on Psychopathological Symptoms, Impulsivity and Cognitive Deficits in HIV-Infected Individuals

HIV-infected individuals (HIV+) has 2-3 times the rate of tobacco smoking than the general population, and whether smoking may lead to greater psychiatric symptoms or cognitive deficits remains unclear. We evaluated the independent and combined effects of being HIV+ and chronic tobacco-smoking on impulsivity, psychopathological symptoms and cognition. 104 participants [27 seronegative (SN)-non-Smokers, 26 SN-Smokers, 29 HIV+ non-Smokers, 22 HIV+ Smokers] were assessed for psychopathology symptoms (Symptom Checklist-90, SCL-90), depressive symptoms (Center for Epidemiologic Studies-Depression Scale, CES-D), impulsivity (Barratt Impulsiveness Scale, BIS), decision-making (The Iowa Gambling Task, IGT, and Wisconsin Card Sorting Test, WCST), and cognition (seven neurocognitive domains). Both HIV+ and Smoker groups had higher SCL-90 and CES-D scores, with highest scores in HIV+ Smokers. On BIS, both HIV+ and Smokers had higher Total Impulsiveness scores, with higher behavioral impulsivity in Smokers, highest in HIV+ Smokers. Furthermore, across the four groups, HIV+ Smokers lost most money and made fewest advantageous choices on the IGT, and had highest percent errors on WCST. Lastly, HIV+ had lower z-scores on all cognitive domains, with the lowest scores in HIV+ Smokers. These findings suggest that HIV-infection and chronic tobacco smoking may lead to additive deleterious effects on impulsivity, psychopathological (especially depressive) symptoms and cognitive dysfunction. Although greater impulsivity may be premorbid in HIV+ and Smokers, the lack of benefits of nicotine in chronic Smokers on attention and psychopathology, especially those with HIV-infection, may be due to the negative effects of chronic smoking on dopaminergic and cardio-neurovascular systems. Tobacco smoking may contribute to psychopathology and neurocognitive disorders in HIV+ individuals.

Sex differences in HIV effects on visual memory among substance-dependent individuals

HIV's effects on episodic memory have not been compared systematically between male and female substance-dependent individuals. We administered the Brief Visuospatial Memory Test-Revised (BVMT-R) to 280 substance-dependent HIV+ and HIV- men and women. Groups were comparable on demographic, substance use, and comorbid characteristics. There were no significant main effects of sex or HIV serostatus on BVMT-R performance, but HIV+ women performed significantly more poorly on delayed recall. This effect was most prominent among cocaine-dependent HIV+ women. Our findings are consistent with recent speculation that memory impairment may be more common among HIV+ women, particularly those with a history of cocaine dependence.

HIV-associated executive dysfunction in the era of modern antiretroviral therapy: A systematic review and meta-analysis

OBJECTIVE

While some reports suggest that HIV+ individuals continue to display executive function (EF) impairment in the era of cART, findings have been contradictory and appear to differ based on the aspect of EF being measured. To improve the understanding of how discrete executive abilities may be differentially affected or spared in the context of HIV infection, we conducted a systematic review and meta-analysis to (a) determine whether and to what extent HIV+ adults experience deficits in EFs, and (b) understand how demographic and clinical characteristics may modify the associations between HIV infection and executive abilities.

METHOD

Studies comparing HIV+ and HIV-uninfected groups on measures of working memory, set-shifting, inhibition, decision-making, and apathy between 2000 and 2017 were identified from three databases. Effect sizes (Cohen's d) were calculated using inverse variance weighted random effects models. Meta-regression was used to examine the moderating effect of demographic and clinical variables.

RESULTS

Thirty-seven studies (n = 3935 HIV+; n = 2483 HIV-uninfected) were included in the meta-analysis. Pooled effect sizes for deficits associated with HIV infection were small for domains of set-shifting (d = -0.34, 95% CI [-0.47, -0.20]) and inhibition (d = -0.31, 95% CI [-0.40, -0.21]), somewhat larger for measures of decision-making (d = -0.41, 95% CI [-0.53, -0.28]) and working memory (d = -0.42, 95% CI [-0.59, -0.29]), and largest for apathy (d = -0.87, 95% CI [-1.09, -0.66]). Meta-regression demonstrated that age, sex, education, current CD4 count, and substance dependence differentially moderated the effects of HIV infection on specific EFs. However, lower nadir CD4 count was the only variable associated with greater deficits in nearly all EF domains.

CONCLUSIONS

Our results suggest that discrete domains of EF may be differentially affected by HIV infection and moderating demographic and clinical variables. These findings have implications for the development of targeted cognitive remediation strategies.

Working Memory Profiles in HIV-Exposed, Uninfected and HIV-Infected Children: A Comparison with Neurotypical Controls

This study compared the working memory profiles of three groups of children, namely HIV-infected (HIV-I; n = 95), HIV-exposed, uninfected (HIV-EU; n = 86) and an HIV-unexposed, uninfected, (HIV-UU; n = 92) neurotypical control group. Working memory, an executive function, plays an important role in frontal lobe-controlled behaviors, such as motivation, planning, decision making, and social interaction, and is a strong predictor of academic success in school children. Memory impairments have been identified in HIV-I children, particularly in visuospatial processing. Verbal working memory has not been commonly investigated in this population, while it is unknown how the working memory profiles of HIV-EU children compare to their HIV-I and HIV-UU peers. Of interest was whether the working memory profiles of the HIV-EU children would be more similar to the HIV-I group or to the uninfected control group. The results revealed no significant differences in working memory performance between the HIV-I and HIV-EU groups. However, this does not mean that the etiology of the working memory deficits is the same in the two groups, as these groups showed important differences when compared to the control group. In comparison to the controls, the HIV-I group experienced difficulties with processing tasks irrespective of whether they drew on a verbal or visuospatial modality. This appears to stem from a generalized executive function deficit that also interferes with working memory. In the HIV-EU group, difficulties occurred with verbally based tasks, irrespective of whether they required storage or processing. For this group, the dual demands of complex processing and using a second language seem to result in demand exceeding capacity on verbal tasks. Both groups experienced the greatest difficulties with verbal processing tasks for these different reasons. Thus, disruption of different cognitive abilities could result in similar working memory profiles, as evidenced in this study. This has implications for the underlying developmental neurobiology of HIV-I and HIV-EU children, as well the choice of appropriate measures to assist affected children.

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

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

An Update of the Review of Neuropsychological Consequences of HIV and Substance Abuse: A Literature Review and Implications for Treatment and Future Research

Neuropyschological dysfunction, ranging from mild cerebral indicators to dementia has been a consistent part of the medical picture of HIV/AIDS. However, advances in medical supervision, particularly as a result of antiretroviral (ARV) treatment, have resulted in some mitigation of the neuropsychological effects of HIV and necessitate re-evaluation of the pattern and nature of HIV-related cognitive or mental deficits. The associated enhancements in morbidity and mortality that have occurred as a result of ARV medication have led to a need for interventions and programs that maintain behaviors that are healthy and stop the resurgence of the risk of HIV transmission. Risk factors such as mental illness and substance use that may have contributed to the initial infection with HIV still need consideration. These risk factors may also increase neuropsychological dysfunction and impact observance of prevention for treatment and recommendations. Explicitly, a better comprehension of the role of substance use on the progression of HIV-related mental decline can enlighten management and evaluation of persons living with HIV with concurrent disorders of substance use. This review provides a summary of the neurophyschology of substance use and HIV and the existing research that has looked at the effects of both substance use and HIV disease on neurophyscological function and suggestions for future research and treatment.

Neural correlates of working memory training in HIV patients: study protocol for a randomized controlled trial

Background

Potent combined antiretroviral therapy decreased the incidence and severity of HIV-associated neurocognitive disorders (HAND); however, no specific effective pharmacotherapy exists for HAND. Patients with HIV commonly have deficits in working memory and attention, which may negatively impact many other cognitive domains, leading to HAND. Since HAND may lead to loss of independence in activities of daily living and negative emotional well-being, and incur a high economic burden, effective treatments for HAND are urgently needed. This study aims to determine whether adaptive working memory training might improve cognitive functions and neural network efficiency and possibly decrease neuroinflammation. This study also aims to assess whether subjects with the LMX1A-rs4657412 TT(AA) genotype show greater training effects from working memory training than TC(AG) or CC(GG)-carriers.

Methods/Design

60 HIV-infected and 60 seronegative control participants will be randomized to a double-blind active-controlled study, using adaptive versus non-adaptive Cogmed Working Memory Training® (CWMT), 20–25 sessions over 5–8 weeks. Each subject will be assessed with near- and far-transfer cognitive tasks, self-reported mood and executive function questionnaires, and blood-oxygenation level-dependent functional MRI during working memory (n-back) and visual attention (ball tracking) tasks, at baseline, 1-month, and 6-months after CWMT. Furthermore, genotyping for LMX1A-rs4657412 will be performed to identify whether subjects with the TT(AA)-genotype show greater gain or neural efficiency after CWMT than those with other genotypes. Lastly, cerebrospinal fluid will be obtained before and after CWMT to explore changes in levels of inflammatory proteins (cytokines and chemokines) and monoamines.

Discussion

Improving working memory in HIV patients, using CWMT, might slow the progression or delay the onset of HAND. Observation of decreased brain activation or normalized neural networks, using fMRI, after CWMT would lead to a better understanding of how neural networks are modulated by CWMT. Moreover, validating the greater training gain in subjects with the LMX1A-TT(AA) genotype could lead to a personalized approach for future working memory training studies. Demonstrating and understanding the neural correlates of the efficacy of CWMT in HIV patients could lead to a safe adjunctive therapy for HAND, and possibly other brain disorders.

Trial registration

ClinicalTrial.gov, NCT02602418.

Genetic predictor of working memory and prefrontal function in women with HIV

The Val158Met (rs4680) single-nucleotide polymorphism (SNP) of the catechol-O-methyltransferase gene (COMT) influences executive function and prefrontal function through its effect on dopamine (DA) metabolism. Both HIV and the Val allele of the Val158Met SNP are associated with compromised executive function and inefficient prefrontal function. The present study used behavioral and neuroimaging techniques to determine independent and interactive associations between HIV serostatus and COMT genotype on working memory and prefrontal function in women. For the behavioral study, 54 HIV-infected and 33 HIV-uninfected women completed the 0-, 1-, and 2-back conditions of the verbal N-back, a working memory test. For the imaging study, 36 women (23 HIV-infected, 13 HIV-uninfected) underwent functional magnetic resonance imaging (fMRI) assessments while completing the N-back task. HIV-infected women demonstrated significantly worse N-back performance compared with HIV-uninfected women (p < 0.05). A significant serostatus by genotype interaction (p < 0.01) revealed that, among Val/Val, but not Met allele carriers, HIV-infected women performed significantly worse than HIV-uninfected controls across N-back conditions (p < 0.01). Analogous to behavioral findings, a serostatus by genotype interaction revealed that HIV-infected Val/Val carriers showed significantly greater prefrontal activation compared with HIV-uninfected Val/Val carriers (p < 0.01). Conversely, HIV-uninfected Met allele carriers demonstrated significantly greater prefrontal activation compared with HIV-infected Met allele carriers. Findings suggest that the combination of HIV infection and the Val/Val COMT genotype leads to working memory deficits and altered prefrontal function in HIV-infected individuals.

Exploring Substance Use and HIV Treatment Factors Associated with Neurocognitive Impairment among People Living with HIV/AIDS

Neurocognitive (NC) impairment remains prevalent among people living with HIV (PLWH) and may be exacerbated by alcohol and drug use. This cross-sectional study assesses the degree to which alcohol and other drug use, time from HIV diagnosis to treatment, and years living with HIV affect three areas of NC functioning among HIV-seropositive adults. NC functioning in 370 PLWH living in Miami, FL was assessed using the Auditory Verbal Learning Test, the Short Category Test, Booklet Format, and the Color Trails Test 2 (CTT2). Participants reported the number of days using alcohol, marijuana, and cocaine over the previous 3 months, the number of known years living with HIV and length of time from HIV diagnosis to seeking care. Bivariate linear regression and multivariate linear regression were used to test associations between independent and dependent variables. Mean scores on NC measures were significantly lower than published norms; 39% of participants scored ≥1 standard deviation below normative sample means on >2 NC tests. No significant associations were found between alcohol or cocaine use and any NC measure. Years living with HIV was associated with CTT2 in the bivariate analysis (β = 1.031; p = 0.007). In multivariate analysis, each day of marijuana use and years living with HIV were associated with a 0.32 (p = 0.05) point and 1.18 (p = 0.03) points poorer performance score on the CTT2, respectively. Results suggest that both marijuana use and duration of HIV infection may affect cognitive functioning among PLWH in ways that may impair their ability to follow important treatment guidance.

Cognitive Performance in Men and Women Infected with HIV-1

Introduction. Very few studies have examined the neuropsychological performance of HIV-positive women, and even fewer have attempted a comparison of cognitive functioning by gender. The aim of this study was to describe the nature of the neuropsychological performance of HIV seropositive patients by gender. Methods. A clinical sample made up of 151 subjects was recruited to participate in this study. All of the subjects underwent the same assessment process, consisting of a neuropsychological evaluation and an interview to gather sociodemographic, toxicological, and clinical data. Results and Discussion. Despite the fact that men obtained higher scores in visual memory, attention/psychomotor speed, and abstract reasoning/verbal intelligence, these differences were not statistically significant. In contrast, significant differences were found depending on subjects' serological status. Seropositive participants' neuropsychological performance was significantly lower than that of the seronegative participants in all of the areas assessed as follows: (1) visual memory; (2) attention/psychomotor speed; (3) abstract reasoning/verbal intelligence; (4) verbal memory for texts; (5) verbal memory for digits and words. Conclusions. The results from this study reveal no significant gender differences in the cognitive performance of patients infected with HIV-1.

Neurological function, information-motivation-behavioral skills factors, and risk behaviors among HIV-positive alcohol users

The purpose of this study was to examine neurological impairment in combination with information-motivation-behavioral skills (IMB) variables. The study tests the role of IMB variables as mediators of antecedent variables of demographics, life stress, social support, and neurological impairment with outcome measures of HIV preventive and risk behaviors in a sample of HIV-positive, alcohol-using adults (n = 250) with a history of alcohol abuse/dependence. Neurological impairment was measured with the Color Trails Test (CTT). Average performance on the CTT by the sample was substantially worse than established norms. In a directional latent variable model, neurological impairment directly predicted lower transmission knowledge scores and poorer performance on an observational condom skills assessment. Greater neurological impairment was significantly associated with greater age. Future interventions geared toward HIV+ adults who use alcohol should take into consideration HIV-related and age-related neurological functioning which may impede the facilitation of safe sex behaviors.

Substance Abuse, Hepatitis C, and Aging in HIV: Common Cofactors that Contribute to Neurobehavioral Disturbances

Although the prevalence of neurocognitive disturbances among individuals with HIV has decreased in recent years, rates of impairment still remain high. This review presents findings from comorbid conditions that may contribute to further neurocognitive impairments in this already vulnerable population. We will focus on three co-factors that have received substantial attention in the neuroAIDS literature: drug use, hepatitis C co-infection (HCV), and aging. All three conditions commonly co-occur with HIV and likely interact with HIV in complex ways. Collectively, the extant literature suggests that drug use, HCV, and aging serve to worsen the neurocognitive profile of HIV through several overlapping mechanisms. A better understanding of how specific comorbidities interact with HIV may reveal specific phenotypes of HIV-associated neurocognitive disorder that may aid in the development of more targeted behavioral and pharmacological treatment efforts.

fMRI brain activation during a delay discounting task in HIV-positive adults with and without cocaine dependence

Cocaine use is associated with poorer HIV clinical outcomes and may contribute to neurobiological impairments associated with impulsive decision making. This study examined the effect of cocaine dependence on brain activation during a delay discounting task involving choices between smaller immediate rewards and larger delayed ones. Participants were 39 HIV-positive adults on antiretroviral therapy who had current cocaine dependence ("active," n=15), past cocaine dependence ("recovered," n=13), or no lifetime substance dependence ("naïve," n=11). Based on responses on a traditional delay discounting task, three types of choices were individualized for presentation during functional magnetic resonance imaging: hard (similarly valued), easy (disparately valued), and no (single option). Active participants had significantly smaller increases in activation than naïve participants during hard versus easy choices bilaterally in the precentral gyrus and anterior cingulate cortex and in the right frontal pole (including dorsolateral, ventrolateral, and orbitofrontal cortex). During hard and easy choices relative to no choices, active participants had smaller increases in activation compared to naïve participants in frontoparietal cortical regions. These deficits in the executive network during delay discounting choices may contribute to impulsive decision making among HIV-positive cocaine users, with implications for risk behaviors associated with disease transmission and progression.

HIV-1 infection and alcohol abuse: neurocognitive impairment, mechanisms of neurodegeneration and therapeutic interventions

Clinical studies indicate that alcohol dependence has an additive effect on cognitive deficits associated with HIV-1 infection. Findings in humans and animal models suggest that alcohol, similar to HIV-1, induces inflammatory processes in the brain leading to neurodegeneration. The causes of HIV-1-associated neurotoxicity are comparable to those mediating alcohol-induced neuronal injury. This review aims to present the mechanisms of the combined effects of HIV-1 and alcohol abuse in the brain and to discuss neuroprotective therapies. Oxidative stress, overproduction of pro-inflammatory factors, impairment of blood-brain barrier and glutamate associated neurotoxicity appear to play important roles in alcohol driven neurodegeneration. Diminution of neuroinflammation constitutes a logical approach for prevention of HIV-1 and alcohol mediated neurodegeneration. Agonists of cannabinoid receptor 2 (CB₂) possess potent anti-inflammatory and neuroprotective properties. We address multifaceted beneficial effects of CB₂ activation in the setting of HIV-1 brain infection and alcohol abuse.

Remote semantic memory for public figures in HIV infection, alcoholism, and their comorbidity

BACKGROUND

Impairments in component processes of working and episodic memory mark both HIV infection and chronic alcoholism, with compounded deficits often observed in individuals comorbid for these conditions. Remote semantic memory processes, however, have only seldom been studied in these diagnostic groups. Examination of remote semantic memory could provide insight into the underlying processes associated with storage and retrieval of learned information over extended time periods while elucidating spared and impaired cognitive functions in these clinical groups.

METHODS

We examined component processes of remote semantic memory in HIV infection and chronic alcoholism in 4 subject groups (HIV, ALC, HIV + ALC, and age-matched healthy adults) using a modified version of the Presidents Test. Free recall, recognition, and sequencing of presidential candidates and election dates were assessed. In addition, component processes of working, episodic, and semantic memory were assessed with ancillary cognitive tests.

RESULTS

The comorbid group (HIV + ALC) was significantly impaired on sequencing of remote semantic information compared with age-matched healthy adults. Free recall of remote semantic information was also modestly impaired in the HIV + ALC group, but normal performance for recognition of this information was observed. Few differences were observed between the single diagnosis groups (HIV, ALC) and healthy adults, although examination of the component processes underlying remote semantic memory scores elicited differences between the HIV and ALC groups. Selective remote memory processes were related to lifetime alcohol consumption in the ALC group and to viral load and depression level in the HIV group. Hepatitis C diagnosis was associated with lower remote semantic memory scores in all 3 clinical groups. Education level did not account for group differences reported.

CONCLUSIONS

This study provides behavioral support for the existence of adverse effects associated with the comorbidity of HIV infection and chronic alcoholism on selective component processes of memory function, with untoward effects exacerbated by Hepatitis C infection. The pattern of remote semantic memory function in HIV + ALC is consistent with those observed in neurological conditions primarily affecting frontostriatal pathways and suggests that remote memory dysfunction in HIV + ALC may be a result of impaired retrieval processes rather than loss of remote semantic information per se.

Iowa Gambling Task performance and emotional distress interact to predict risky sexual behavior in individuals with dual substance and HIV diagnoses

HIV+ substance-dependent individuals (SDIs) show emotional distress and executive impairment, but in isolation these poorly predict sexual risk. We hypothesized that an executive measure sensitive to emotional aspects of judgment (Iowa Gambling Task; IGT) would identify HIV+ SDIs whose sexual risks were influenced by emotional distress. We assessed emotional distress and performance on several executive tasks in 190 HIV+ SDIs. IGT performance interacted significantly with emotional distress, such that only in better performers were distress and risk related. Our results are interpreted using the somatic marker hypothesis and indicate that the IGT identifies HIV+ SDIs for whom psychological distress influences HIV risk.

Working and episodic memory in HIV infection, alcoholism, and their comorbidity: baseline and 1-year follow-up examinations

BACKGROUND

Selective memory deficits occur in individuals with human immunodeficiency virus (HIV) infection and those with chronic alcoholism, but the potential compounded effect of these conditions is seldom considered, despite the high prevalence of alcohol use disorders in HIV infection.

METHODS

Here, we examined component processes of working and episodic memory in HIV infection and chronic alcoholism (ALC) in 4 subject groups (HIV, ALC, HIV + ALC, and normal controls) at baseline and 1-year follow-up. Accuracy scores, response times, and rate of information processing were assessed with subtests of the computerized neuropsychological test battery, the MicroCog.

RESULTS

Although individuals with either HIV infection or alcoholism generally performed at normal levels, individuals comorbid with HIV infection and alcoholism were impaired relative to controls and to the single diagnosis groups on selective memory processes. Immediate episodic memory was impaired, whereas working memory remained intact. Ability to retain information over time was not impaired in the clinical groups. Little performance change between groups was detected over 1 year. Results could not be explained by amount of alcohol consumed over a lifetime, CD4 cell count, AIDS diagnosis, or HAART medication.

CONCLUSIONS

This study provides behavioral support for adverse synergism of HIV infection and chronic alcoholism on brain function and is consistent with neuroimaging reports of compromised hippocampal and associated memory structures related to episodic memory processes in these 2 conditions.

Drug abuse and hepatitis C infection as comorbid features of HIV associated neurocognitive disorder: neurocognitive and neuroimaging features

Substance abuse and co-infection with hepatitis C (HCV) are two highly relevant determinants of neurocognitive and neuroimaging abnormalities associated with HIV. Substance abuse and HCV are common in the HIV population and there is increasing evidence that the CNS is directly compromised by these comorbid conditions via additive or synergistic processes. In this article we review the current literature regarding mechanisms of neuronal injury as well as the neuropsychological and neuroimaging signatures associated with substance abuse and HCV status among HIV patients. We discuss specific methodological challenges and threats to validity associated with studies of HIV and comorbid substance use disorders or HCV and review potential strategies for minimizing their confounding effects. Efforts to understand the interactions between HIV, substance abuse and HCV co-infection will lead to more complete models of neuropathogenesis of HIV and a greater understanding of the variability in neuropsychological expression of HIV Associated Neurocognitive Disorder.

Cognitive neuropsychology of HIV-associated neurocognitive disorders

Advances in the treatment of the human immunodeficiency virus (HIV) have dramatically improved survival rates over the past 10 years, but HIV-associated neurocognitive disorders (HAND) remain highly prevalent and continue to represent a significant public health problem. This review provides an update on the nature, extent, and diagnosis of HAND. Particular emphasis is placed on critically evaluating research within the realm of cognitive neuropsychology that aims to elucidate the component processes of HAND across the domains of executive functions, motor skills, speeded information processing, episodic memory, attention/working memory, language, and visuoperception. In addition to clarifying the cognitive mechanisms of HAND (e.g., impaired cognitive control), the cognitive neuropsychology approach may enhance the ecological validity of neuroAIDS research and inform the development of much needed novel, targeted cognitive and behavioral therapies.

Deficits in complex motor functions, despite no evidence of procedural learning deficits, among HIV+ individuals with history of substance dependence

Human immunodeficiency virus (HIV) and drugs of abuse affect common neural systems underlying procedural memory, including the striatum. The authors compared performance of 48 HIV seropositive (HIV+) and 48 HIV seronegative (HIV-) participants with history of cocaine and/or heroin dependence across multiple Trial Blocks of three procedural learning (PL) tasks: Rotary Pursuit (RP), Mirror Star Tracing (MST), and Weather Prediction (WP). Groups were well matched on demographic, psychiatric, and substance use parameters, and all participants were verified abstinent from drugs. Mixed model analyses of variance revealed that the individuals in the HIV+ group performed more poorly across all tasks, with a significant main effect of HIV serostatus observed on the Mirror Star Tracing and a trend toward significance obtained for the Rotary Pursuit task. No significant differences were observed on the Weather Prediction task. Both groups demonstrated significant improvements in performance across all three procedural learning tasks. It is important to note that no significant Serostatus x Trial Block interactions were observed on any task. Thus, the individuals in the HIV+ group tended to perform worse than those in the HIV- group across all trial blocks of procedural learning tasks with motor demands, but showed no differences in their rate of improvement across all tasks. These findings are consistent with HIV--associated deficits in complex motor skills, but not in procedural learning.

Neuropsychological impairment and gender differences in HIV-1 infection

AIMS

Research into neuropsychological consequences of HIV has focused mainly on male subjects, and therefore very little is known about the disease in female subjects and, of course, about gender differences. The aim of the present research was therefore to investigate neuropsychological impairment rates and pattern in HIV male and female patients, with regard to the study of gender differences in tasks assessing attention, memory for texts, digits and words, psychomotor speed, verbal intelligence and abstract reasoning.

METHODS

A clinical sample was recruited consisting of 122 subjects, divided into four groups: (i) 57 HIV+ men; (ii) 31 HIV+ women; (iii) 18 HIV- men and (iv) 16 HIV- women. All the subjects had more than 18 years, being the average of age of 34.08 for men and 33.35 for women. The evaluation of each subject consisted of a semistructured interview investigating sociodemographic, clinical and toxicological aspects and a neuropsychological assessment, with a battery of tests specifically selected for this study and chosen for their validity and because they have been shown to be sensitive to neuropsychological impairment in HIV-infected patients in other studies.

RESULTS

None of HIV- male and female groups fulfilled impairment criteria. Regarding the HIV+ group, a rate of neuropsychological impairment of 51.9% was obtained for the men and 54.8% for the women, but there were no significant differences between groups. Nevertheless, were detected significant differences in neuropsychological impairment rates between HIV+ and HIV- women, and also between HIV+ and HIV- men. Although HIV+ women presented multiple factors that could increase their neuropsychological vulnerability to the effects of HIV, HIV+ men had the same probability of having neuropsychological impairment as HIV+ women.

CONCLUSIONS

A different neuropsychological impairment pattern was detected between genders: while HIV+ men had greater impairment in visual memory, attention, psychomotor speed and abstract reasoning, HIV+ women had greater impairment on attention, psychomotor speed and verbal memory for texts.

Co-factors in HIV neurobehavioural disturbances: substance abuse, hepatitis C and aging

Neurocognitive disturbances associated with HIV infection may be modulated or confounded by coexisting and comorbid conditions that reflect the changing populations affected by the disease. HIV infection is often accompanied by substance dependence and/or hepatitis C co-infection. Both of these cofactors that may lead to brain dysfunction on their own, and therefore can affect the nature and course neurocognitive functioning in HIV. Improvements in antiretroviral therapies translate into greater longevity for people infected with HIV, many of whom are now entering their 6th and 7th decade of life and beyond. The increasing proportion of older persons with HIV is also the result of new infections in this age group. As aging confers additional metabolic, neurologic, and neuropsychiatric vulnerability, it is important to understand how this constellation of changes affects neurocognitive functioning in the context of HIV.

Neurocognitive disturbances in HIV

HIV infection is associated with disturbances in brain function which reflect themselves in HIV associated neurocognitive disorder (HAND). Neurocognitive examination is a sensitive and relevant approach to detecting and monitoring HAND. The approaches to evaluating the various neurocognitive disturbances are reviewed, along with consideration of cofactors that may influence expression of these disorders.

Characteristics of prospective memory deficits in HIV-seropositive substance-dependent individuals: preliminary observations

The construct of "prospective memory" (PM) refers to a type of episodic memory for a future intention or "remembering what one must do." This function has been proposed as a candidate mechanism underlying behaviors of critical importance in HIV disease, including adherence with medication regimens and continued engagement in risk behavior. We administered tasks of time-based and event-based prospective memory and control tasks of retrospective and working memory to 31 HIV-seropositive and 35 HIV-seronegative substance-dependent individuals (SDIs). We found that compared with HIV- controls HIV+ participants showed deficits in time-based but not event-based PM. Retrospective, but not working, memory performance correlated significantly with time-based PM performance. In addition, performance on the time-based PM task was a significant predictor of scores on a self-report measure of risky sexual and injection practices. These preliminary data provide new and unique findings regarding the components of executive function mediated by prefrontal cortical systems that are impaired among HIV+ SDIs and their relevance to "real-world" behaviors.

Neuropsychological Impairment Among Asymptomatic HIV-Positive Former Intravenous Drug Users

OBJECTIVE

To evaluate the influence of human immunodeficiency virus (HIV) infection and situation of drug consumption on neuropsychological impairment in asymptomatic HIV-positive (HIV+) former intravenous drug users (IVDUs) of Spanish nationality.

BACKGROUND

Currently, we have no data about neuropsychological impairment in asymptomatic HIV+ IVDUs taking into account different situations of drug consumption.

METHOD

A neuropsychological evaluation was made of four groups of IVDUs: 33 abstinent HIV+ IVDUs, 21 methadone-maintained HIV+ IVDUs, 27 abstinent HIV-negative (HIV-) IVDUs, and 21 methadone-maintained HIV- IVDUs. Their neuropsychological impairment rates were determined taking as a reference the performance of 23 HIV- subjects without history of drug abuse.

RESULTS

The rate of neuropsychological impairment of methadone-maintained HIV+ patients (48%) and that of those in abstinence (24%) is greater than that of HIV- subjects in a similar condition (19% and 11%). The impairment rate of the methadone-maintained HIV+ group is significantly greater than that of the abstinent HIV+. Methadone-maintained HIV+ subjects with neuropsychological impairment have fewer education years than those not impaired; likewise, the percentages of subjects with significant immunodepression, detectable viral load, and without antiretroviral treatments are higher among methadone-maintained subjects with neuropsychological impairment.

CONCLUSIONS

This study emphasizes the association of asymptomatic HIV infection with neuropsychological impairment in IVDUs and reveals the importance of the drug consumption situation in relation to this risk, being methadone-maintained IVDUs more likely to suffer from it. This fact seems to be related to the worsening of the infection and its treatment and to educational level.

The stability of neurocognitive patterns in HIV infected men: classification considerations

For the neuropsychological impairment which takes place in HIV-1 infection, various classification systems, based on either neuropathological criteria, severity of the disorder or functional criteria, have been suggested in the literature. This study identifies the patterns of neurocognitive disorders in HIV-1 infection and investigates their stability at one-year follow-up. Two hundred and seventeen HIV-1-positive subjects in various stages of infection and 55 HIV-1-negative subjects were evaluated. Our results suggest that there is considerable diversity in the neuropsychological functioning of HIV patients but the patterns are relatively stable, functionally distinct, and differ with respect to the severity of the deficit. The overall pattern is consistent with existing neuropsychological knowledge on HIV infection. Comparison of the patterns identified in this study with other classification systems posed several problems, however, and these problems may have important implications for the theory and methodology of neuropsychological HIV research.

The influence of executive functions, sensation seeking, and HIV serostatus on the risky sexual practices of substance-dependent individuals

From a public health standpoint, identifying factors that contribute to risky sexual practices among substance-dependent individuals is critical, particularly in the context of HIV infection. This study examines the respective contributions of executive neurocognitive functions, sensation seeking, and HIV serostatus in predicting risky sexual practices among poly-substance users (with a history of dependence primarily for cocaine or cocaine/heroin). HIV+ (n=109) and HIV- (n=154) substance-dependent individuals were assessed using three neurocognitive tasks of executive functions: Stroop reaction time, delayed non-matching to sample, and the Iowa Gambling Task. Sensation seeking was assessed using the Sensation Seeking Scale-V. Greater sensation seeking was associated with more risky sexual practices among HIV+ participants, particularly among those who performed best on the Iowa Gambling Task. Our findings indicate that continued risk behavior among HIV+ drug users may be driven by sensation seeking (a personality trait common among drug users); however, the impact of executive functions is less clear.

HIV dementia: an evolving disease

Several advances have led to improvements in the care and prognosis of HIV+ individuals. The first is an understanding of the direct relationship between HIV replication and subsequent immunological and clinical progression, reinforcing the need to completely suppress HIV replication to control disease progression. The second is the wider availability of HAART which can provide effective suppression of HIV. The third major change is the ability to monitor HAART through the reliable and widespread measurement of plasma HIV RNA levels, which has become a routine part of clinical care. Since the introduction of highly active antiretroviral therapy (HAART) in the 1990s, there have been significant declines in the incidence rates of opportunistic infections in developed countries. HAART has clearly improved survival for individuals with HIV/AIDS, and has reduced the incidence of HIV-associated dementia (HIV-D) by 40-50% (Brodt et al., 2002). The prevalence of sensory neuropathies in advanced HIV/AIDS now exceeds 20% (Schifitto et al., 2002), and may rise further with prolonged exposure to neurotoxic HAART. HIV-D and HIV-related sensory neuropathies (HIV-SN) have a combined prevalence of about 30-50% in advanced HIV disease, suggesting that HAART does not provide complete protection against neurological damage (Bouwman et al., 1998). HIV-associated dementia (HIV-D) remains a common cause of dementia worldwide, and with HIV-related sensory neuropathies (HIV-SN) represents the commonest neurological disorders associated with AIDS. Furthermore, the temporal progression of HIV-D appears to have been altered by HAART, with most patients now showing an attenuated form of dementia, which with treatment is slowly progressive or static (Dougherty et al., 2002). This overview will review some of the outstanding questions relating to HIV-dementia, including: (a) are there differing phenotypes or temporal patterns of progression in HIV-dementia? (b) what determines these temporal patterns? and (c), what has been the impact of therapy on HIV dementia?

Cognitive impulsivity and HIV serostatus in substance dependent males

HIV-seropositive (HIV+) drug users show impaired performance on measures of integrity of prefrontal-subcortical systems. The Iowa Gambling Task (GT) is mediated primarily through ventromedial-prefrontal systems, and poor performance on this measure ("cognitive impulsivity") is common among substance dependent individuals (SDIs) as well as patients with disease involving prefrontal-subcortical systems (e.g., Huntington disease). We hypothesized that HIV+ SDIs might be more vulnerable to cognitive impulsivity when compared with HIV-seronegative (HIV-) SDIs because recent studies report evidence of additive effects of HIV serostatus and drug dependence on cognition. Further, working memory is considered a key component of GT performance and is reliably impaired among HIV+ SDIs compared to controls. We administered the GT to 46 HIV+ and 47 well-matched HIV- males with a past or current history of substance dependence. In addition, we evaluated correlations between subjects' scores on the GT and on a delayed nonmatch to sample (DNMS) task in order to test if working memory deficits accounted for cognitive impulsivity among the HIV+ subjects. The HIV+ subjects performed significantly more poorly on the GT compared to the HIV- group but this effect could not be explained by working memory deficits. Implications of these findings for future basic and applied studies of HIV and substance dependence are discussed.

Impaired Decision Making Related to Working Memory Deficits in Individuals With Substance Addictions

This study examined whether individuals with substance dependence (ISDs) show impairments in working memory and whether there is a relationship between their impairments in decision making as measured by the gambling task (GT) paradigm and working memory as measured by a delayed nonmatching to sample (DNMS) task. Using the GT, 11% of healthy control participants and 61% of ISDs opted for choices with high immediate gains in spite of higher future losses. For the ISDs and controls with equal GT impairments, the ISDs performed significantly lower than controls on the DNMS task. The nonimpaired ISDs on the GT also performed significantly worse than matched controls on the DNMS task. The DNMS task deficit in ISDs was across all delay times, suggesting the deficit may lie in the "executive" process of working memory, which supports earlier findings (E. M. Martin et al., 2003). The authors suggest that the prefrontal cortex hosts multiple distinct mechanisms of decision making and inhibitory control and that ISDs may be affected in any one or combination of them.

Delayed nonmatch-to-sample performance in HIV-seropositive and HIV-seronegative polydrug abusers

Working memory (WM) deficits are common in HIV-seropositive (HIV+) individuals and can be amplified by manipulating a variety of task parameters, such as increasing memory load or information complexity. The authors investigated the role of timing in HIV-associated WM defects by varying the amount of time required to maintain information online while holding memory load and information complexity constant. The authors studied 50 HIV+ and 35 HIV-seronegative (HIV-) polydrug abusers abstinent at testing and well-matched on demographic variables. The HIV- group outperformed the HIV+ group across all stimulus-response time delays. HIV-associated WM defects are not critically dependent on the amount of time stimulus representations must be maintained and might be attributed to impaired encoding or retrieval of stimulus representations.

Working memory performance predicts subjective cognitive complaints in HIV infection

The authors examined the contribution of working memory performance to subjective cognitive complaints in HIV infection beyond the influence of depressive symptoms. Thirty-six adults with HIV infection were administered neuropsychological (NP) tests of working memory, complex psychomotor efficiency, verbal learning, delayed recall, and questionnaires measuring depressive symptoms and cognitive complaints. Working memory performance, depression scores, and complex psychomotor efficiency were most strongly associated with self-reported cognitive complaints, whereas verbal learning scores and simple psychomotor efficiency showed more modest associations. Regression analyses revealed working memory performance to be the strongest NP predictor of self-reported cognitive complaints, comparable with depression scores in the amount of variance explained. These results suggest that working memory performance may be well suited to reflect how patients function in their everyday environment.

Factors affecting cognitive functioning in a sample of human immunodeficiency virus-positive injection drug users

Injection drug users represent a major vector of human immunodeficiency virus (HIV) infection in the nation's inner cities, and are an important population for harm reduction treatment interventions to target. However, there has been relatively little research examining the specific contribution of the multiple factors contributing to cognitive functioning among injection drug users that may affect engagement in, and response to, addiction and HIV-related interventions. The current study examined the independent contributions to neuropsychological (NP) test performance of premorbid educational attainment, medical and psychiatric history, long- and short-term drug use, assessed by laboratory, observation, and self-report measures, and HIV disease, assessed by plasma HIV-1 RNA viral load and CD4+ count, in a sample of 90 HIV-positive injection drug users dually addicted to heroin and cocaine. Fully 88% of the sample showed evidence of impairment (>1 standard deviation below the population mean) on an NP test battery selected to assess processes associated with successful engagement in the treatment of substance abuse and HIV, such as learning and memory of verbal information, capacity to solve new problems and deal with more than one stimulus at a time, visual-motor coordination, and visual tracking and cognitive flexibility. In addition to drug use, independent predictors of NP test performance were HIV viral load, educational attainment, and premorbid medical and psychiatric problems. Findings underscore the multiplicity of factors that contribute to cognitive impairment in HIV-positive drug-abusing individuals in addition to drug use. Clinical implications are discussed.