The HNRC 500--neuropsychology of HIV infection at different disease stages. HIV Neurobehavioral Research Center

Clinical contributors to cerebral white matter integrity in HIV-infected individuals

HIV-infected people frequently exhibit brain dysfunction characterized by preferential damage to the cerebral white matter. Despite suppressed viral load and reconstituted immune function afforded by combination antiretroviral therapy (CART), brain dysfunction continues to be observed even in medically stable individuals. To provide insight into the etiology of HIV-associated brain dysfunction in the CART era, we examined the effects of HIV disease markers, antiretroviral treatment, hepatitis C (HCV) coinfection, and age on DTI measures of white matter integrity in a cohort of 85 individuals aged 23 to 65 years with chronic HIV infection. Fractional anisotropy and mean diffusivity were derived from 29 cerebral white matter regions, which were segmented on each individual brain using a high-resolution T1-weighted image and registered to diffusion images. Significant effects of clinical variables were found on white matter abnormalities in nearly all brain regions examined. Most notably, HCV coinfection and older age were associated with decreased anisotropy or increased diffusivity in the majority of brain regions. Individuals with higher current CD4 levels exhibited higher anisotropy in parietal lobe regions, while those undergoing antiretroviral treatment exhibited higher anisotropy in temporal lobe regions. The observed diffuse pattern of white matter injury suggests that future neuroimaging studies should employ methodologies that are not limited to circumscribed regions of interest. The current findings underline the multifactorial nature of HIV-associated brain dysfunction in the CART era, and the importance of examining the effects of HIV disease in the context of other comorbidities, in particular HCV coinfection and aging.

Neurocognitive impact of substance use in HIV infection

BACKGROUND

: To determine how serious a confound substance use (SU) might be in studies on HIV-associated neurocognitive disorder (HAND), we examined the relationship of SU history to neurocognitive impairment (NCI) in participants enrolled in the Central Nervous System HIV Antiretroviral Therapy Effects Research study.

METHODS

: After excluding cases with behavioral evidence of acute intoxication and histories of factors that independently could account for NCI (eg, stroke), baseline demographic, medical, SU, and neurocognitive data were analyzed from 399 participants. Potential SU risk for NCI was determined by the following criteria: lifetime SU Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnosis, self-report of marked lifetime SU, or positive urine toxicology. Participants were divided into 3 groups as follows: no SU (n = 134), nonsyndromic SU (n = 131), syndromic SU (n = 134) and matched on literacy level, nadir CD4, and depressive symptoms.

RESULTS

: Although approximately 50% of the participants were diagnosed with HAND, a multivariate analysis of covariance of neurocogntive summary scores, covarying for urine toxicology, revealed no significant effect of SU status. Correlational analyses indicated weak associations between lifetime heroin dosage and poor recall and working memory and between cannabis and cocaine use and better verbal fluency.

CONCLUSIONS

: These data indicate that HIV neurocognitive effects are seen at about the same frequency in those with and without historic substance abuse in cases that are equated on other factors that might contribute to NCI. Therefore, studies on neuroAIDS and its treatment need not exclude such cases. However, the effects of acute SU and current SU disorders on HAND require further study.

Relationship of ethnicity, age, education, and reading level to speed and executive function among HIV+ and HIV- women: the Women's Interagency HIV Study (WIHS) Neurocognitive Substudy

Use of neuropsychological tests to identify HIV-associated neurocognitive dysfunction must involve normative standards that are well suited to the population of interest. Norms should be based on a population of HIV-uninfected individuals as closely matched to the HIV-infected group as possible and must include examination of the potential effects of demographic factors on test performance. This is the first study to determine the normal range of scores on measures of psychomotor speed and executive function among a large group of ethnically and educationally diverse HIV-uninfected, high-risk women, as well as their HIV-infected counterparts. Participants (n = 1,653) were administered the Trail Making Test Parts A and B (Trails A and Trails B), the Symbol Digit Modalities Test (SDMT), and the Wide Range Achievement Test-3 (WRAT-3). Among HIV-uninfected women, race/ethnicity accounted for almost 5% of the variance in cognitive test performance. The proportions ofvariance in cognitive test performance accounted for by age (13.8%), years of school (4.1%), and WRAT-3 score (11.5%) were each significant, but did not completely account for the effect of race (3%). HIV-infected women obtained lower scores than HIV-uninfected women on time to complete Trails A and B, SDMT total correct, and SDMT incidental recall score, but after adjustment for age, years of education, racial/ethnic classification, and reading level, only the difference on SDMT total correct remained significant. Results highlight the need to adjust for demographic variables when diagnosing cognitive impairment in HIV-infected women. Advantages of demographically adjusted regression equations developed using data from HIV-uninfected women are discussed.

The relationship between Gulf War illness, brain N-acetylaspartate, and post-traumatic stress disorder

A previous study (Haley RW, Marshall WW, McDonald GG, Daugherty MA, Petty F, Fleckenstein JL: Brain abnormalities in Gulf War syndrome: evaluation with 1H MR spectroscopy. Radiology 2000; 215: 807-817) suggested that individuals with Gulf War Illness (GWI) had reduced quantities of the neuronal marker N-acetylaspartate (NAA) in the basal ganglia and pons. This study aimed to determine whether NAA is reduced in these regions and to investigate correlations with other possible causes of GWI, such as psychological response to stress in a large cohort of Gulf War veterans. Individuals underwent tests to determine their physical and psychological health and to identify veterans with (n=81) and without (n=97) GWI. When concentrations of NAA and ratios of NAA to creatine- and choline-containing metabolites were measured in the basal ganglia and pons, no significant differences were found between veterans with or without GWI, suggesting that GWI is not associated with reduced NAA in these regions. Veterans with GWI had significantly higher rates of post-traumatic stress disorder, supporting the idea that GWI symptoms are stress related.

Factors contributing to impaired self-awareness of cognitive functioning in an HIV positive and at-risk population

PURPOSE

To examine the association between self-awareness of cognitive impairment and age, selected mood disorders, and type and severity of cognitive impairment in a sample of individuals with HIV/AIDS and at risk for HIV.

METHOD

75 subjects, 52 HIV+ and 23 at risk for HIV completed a psychosocial interview, the Patient's Assessment of Own Functioning (PAOF) questionnaire, and a battery of neuropsychological tests. Based upon the differences between their clinical impairment and self-reported impairment, subjects were classified as being "Underestimators", "Good Awareness", or "Impaired Awareness" with regard to self-awareness.

RESULTS

Those with more severe cognitive impairment were less aware than those with normal or borderline cognitive impairment. A one-way ANOVA suggested that the Impaired Awareness group differed significantly from the Underestimators on the Rey Figure Immediate and Delayed Recall tasks, and from both the Underestimators and Good Awarenesss groups on the Digit Symbol Substitution Task. There were significant differences among all awareness groups on the test of Simple Reaction Time. Furthermore there is some suggestion that age may contribute to impaired self-awareness. The role of HIV in self-awareness remains unclear, as both, individuals with HIV and at risk, demonstrated impaired self-awareness.

CONCLUSIONS

Overall, impaired awareness was associated with poorer test performance, suggesting a relationship between awareness and sustained complex attention and visual spatial processing. This research has implications for understanding factors contributing to poor awareness among individuals with cognitive impairment.

Recent clinical history and cognitive dysfunction for attention and executive function among human immunodeficiency virus-infected patients

This study examined the association between recent trends in CD4 and viral loads and cognitive test performance with the expectation that recent history could predict cognitive performance. Eighty-three human immunodeficiency virus (HIV)-infected patients with a mean CD4 count of 428 copies/ml were examined in this study (62% with undetectable plasma viral load [PVL]). We investigated the relationships between nadir CD4 cell count, 1-year trends in immunologic function/PVLs, and cognitive performance across several domains using linear regression models. Nadir CD4 cell count was predictive of current executive function (p = .004). One year clinical history for CD4 cell counts and/or PVLs were predictive of executive function, attention/working memory, and learning/memory measures (p < .05). Models that combined recent clinical history trends and nadir CD4 cell counts suggested that recent clinical trends were more important in predicting current cognitive performance for all domains except executive function. This research suggests that recent CD4 and viral load history is an important predictor of current cognitive function across several cognitive domains. If validated, clinical variables and cognitive dysfunction models may improve our understanding of the dynamic relationships between disease evolution and progression and CNS involvement.

Neurocognitive consequences of HIV infection in older adults: an evaluation of the "cortical" hypothesis

The incidence and prevalence of older adults living with HIV infection is increasing. Recent reports of increased neuropathologic and metabolic alterations in older HIV+ samples, including increased cortical beta-amyloid, have led some researchers to suggest that aging with HIV may produce a neuropsychological profile akin to that which is observed in “cortical” dementias (e.g., impairment in memory consolidation). To evaluate this possibility, we examined four groups classified by HIV serostatus and age (i.e., younger ≤40 years and older ≥50 years): (1) Younger HIV− (n = 24); (2) Younger HIV+ (n = 24); (3) Older HIV− (n = 20); and (4) Older HIV+ (n = 48). Main effects of aging were observed on episodic learning and memory, executive functions, and visuoconstruction, and main effects of HIV were observed on measures of verbal learning and memory. The interaction of age and HIV was observed on a measure of verbal recognition memory, which post hoc analyses showed to be exclusively attributed to the superior performance of the younger HIV seronegative group. Thus, in this sample of older HIV-infected individuals, the combined effects of HIV and aging do not appear to result in a “cortical” pattern of cognitive deficits.

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.

Impact of HIV and a history of marijuana dependence on procedural learning among individuals with a history of substance dependence

Marijuana (MJ) use and HIV infection are both associated with neurocognitive deficits, yet there is little research to date examining their interactions, specifically how they pertain to procedural learning (PL). We examined a sample of 86 individuals with a history of dependence for multiple substances who underwent a comprehensive evaluation including measures of mental health, substance use history, and three measures of PL: the photoelectric Rotary Pursuit Task (RPT), the Star Mirror Tracing Task (SMT), and the Weather Prediction Task (WPT). We found that a positive HIV serostatus and a history of marijuana dependence were both independently associated with overall poorer performance on the SMT and RPT in this sample of individuals with a history of dependence for multiple substances. Rate of improvement across trial blocks did not differ as a function of HIV serostatus or history of marijuana dependence. Although we found no significant HIV × MJ interaction for any of the PL tasks, we did observe evidence of additive negative effects from HIV and a history of marijuana dependence on overall performance on the SMT and RPT, but not the WPT. The findings suggest that complex motor skills are adversely affected among abstinent polysubstance users with a history of marijuana dependence and that such deficits are compounded by HIV.

Impact of social support on cognitive symptom burden in HIV/AIDS

As many as 50% of people living with HIV/AIDS report cognitive difficulties, which can be associated with objective neuropsychological impairments and depression. A number of studies have demonstrated an association between higher social support and lower rates of depression. Using a cross-sectional design, we examined the role social support may play in attenuating the effects of both neuropsychological status and depression on cognitive difficulties. A total of 357 participants completed a battery of neuropsychological tests, questionnaires about cognitive difficulties and depression, and an interview that included an assessment of perceived level of social support. A multivariate linear regression analysis revealed that higher levels of cognitive symptom burden were significantly associated with depression (P<0.05) while lower levels of cognitive symptom burden were significantly associated with greater social support (P<0.01) and higher level of education (P<0.05). There was a significant interaction between neuropsychological status and depression (P<0.001); the presence of neuropsychological impairment with depression was associated with higher levels of cognitive symptom burden. There was also a significant interaction between social support and depression (P<0.05). Interestingly, social support was also associated with a lower cognitive symptom burden for non-depressed individuals living with HIV/AIDS. These findings have important clinical implications for promoting psychological well-being in persons living with HIV/AIDS. To improve quality of life, it is important to screen for and identify individuals with HIV/AIDS who may be depressed and to intervene appropriately. Further research should examine the potential role of social support interventions in modifying the effects of both depression and neuropsychological status on cognitive symptom burden.

Expression of mannose binding lectin in HIV-1-infected brain: implications for HIV-related neuronal damage and neuroAIDS

Mannose binding lectin (MBL) activates complement pathway that leads to pathogen opsonization and phagocytosis. MBL deficiency is linked to HIV transmission and disease progression. We sought to determine the role of MBL in HIV encephalitis (HIVE) by evaluating its presence and distribution in the HIV-1-infected brain and by assessing its association with monocyte chemoattractant protein-1 (MCP-1) expression. This retrospective study utilized archived post-mortem brain tissues obtained from 35 individuals enrolled in a longitudinal study as part of the California NeuroAIDS Tissue Network. MBL, MCP-1 and brain cell markers in post-mortem brain tissues with or without HIVE were evaluated using immunocytochemistry, immunofluorescence, confocal microscopy, and western blots. MBL was expressed in neurons, astrocytes, microglia, and oligodendrocytes of the frontal cortex of the HIV-1-infected brain. Overall, there were 30% to 40% more MBL-positive brain cells in HIVE vs non-HIVE cases (P = 0.01, paired t-test). Specifically, there was an increased MBL expression in the neuronal axons of HIVE cases. Also, western blots showed 3- to 4-fold higher levels of 78 kD MBL trimers in HIVE vs non-HIVE cases. This MBL-HIVE link was further confirmed by MBL associated higher MCP-1 expression in HIVE vs non-HIVE cases. HIV negative healthy individuals and normal or the gp120 transgenic mice did not show any differential MBL expression. Increased MBL expression in the major brain cell types, specifically in the neuronal axons of HIVE brain, and MBL associated higher MCP-1 expression in HIVE suggest that MBL could cause neuroinflammation and neuronal injury through MBL complement activation pathway.

Dopamine receptor D3 genetic polymorphism (rs6280TC) is associated with rates of cognitive impairment in methamphetamine-dependent men with HIV: preliminary findings

Macrophages are one of HIV-1's principal targets and chiefly responsible for translocating HIV into the central nervous system (CNS). Previous research suggested an increase in macrophages being infected by HIV in the presence of methamphetamine (METH) or increased extracellular dopamine (DA). Experimental studies indicate that this is mediated by DA receptors, including DA receptor D3 (DRD3), which is expressed in macrophages. A single nucleotide polymorphism (SNP) of the DRD3 gene (rs6280TC) modulates its dopamine binding affinity, resulting in the possibility that inheriting a variant of this SNP increases macrophage susceptibility to HIV infection in the presence of METH and DA, particularly in the CNS where METH is sequestered, leading to cognitive impairment (CI). Thus, we conducted a retrospective clinical investigation to evaluate whether rs6280TC is associated with CI among HIV-positive METH users. We stratified 310 males by HIV serostatus (HIV-positive, -negative) and METH dependence (METH-positive, -negative) and then by rs6280TC genotype (CC, CT, and TT). Genotypic groups within each of four HIV/METH groups were compared for rates of CI. We hypothesized that only HIV-positive/METH-positive carriers of the C allele, which increases the DRD3's binding to DA, would be more likely to develop CI. Cochran-Armitage test for trends in proportions yielded significant (p < 0.05) association between three genotypes and impairment rates in the hypothesized order, but only among HIV-positive/METH-positive subjects. The results also confirmed that C allele carriers (CC and CT, 53.3%) in this group had higher impairment rates (p = 0.05) than TT carriers (33.3%). These findings support the theory that rs6280TC influences the frequency of CI in HIV-positive/METH-positive males.

Plasma cytokine concentrations associated with HIV/hepatitis C coinfection are related to attention, executive and psychomotor functioning

Cytokine disturbances have been linked to brain dysfunction among HIV-infected people. Past studies have not simultaneously examined a large set of cytokine measures and their relationships to HIV-associated neurocognitive deficits. We hypothesized that performance on measures of attention and executive and psychomotor functions would be associated with plasma cytokine concentrations in HIV-infected individuals. Plasma samples drawn from 30 HIV-infected and 37 HIV seronegative individuals were analyzed via xMAP multiplexed bead array immunoassay to determine concentrations of 13 cytokines. Performance on Trail Making A/B, Stroop Test, Letter-Number Sequencing, Digit Symbol Coding, Symbol Search, and Grooved Pegboard tests was assessed. Statistical analyses were performed to examine group differences in cytokine concentrations, and associations between cytokine and HIV clinical variables and neurocognitive performance. Significant HIV effects were found on 7 of the 13 cytokines, primarily with respect to interleukins. HIV clinical factors (CD4 and HIV RNA levels, duration of illness, antiretroviral treatment) and hepatitis C status were associated with specific plasma cytokine concentrations. Neurocognitive measures were associated with cytokine concentrations, most consistently among the interleukins and IP-10. Generally, cytokine concentrations were among the strongest predictors of neurocognitive function relative to other clinical factors, which reinforces their potential importance in examining the neuropathological processes of HIV. The findings also point to the potential value of simultaneously examining a panel of biomarkers. The current results suggest that a complex relationship likely exists among cytokines [how?] and that these relationships are mediated not only by HIV infection but also by antiretroviral treatment and other comorbid conditions.

Pontocerebellar contribution to postural instability and psychomotor slowing in HIV infection without dementia

Postural instability occurs in HIV infection, but quantitative balance tests in conjunction with neuroimaging are lacking. We examined whether infratentorial brain tissue volume would be deficient in nondemented HIV-infected individuals and whether selective tissue deficits would be related to postural stability and psychomotor speed performance. The 123 participants included 28 men and 12 women with HIV infection without dementia or alcohol use disorders, and 40 men and 43 women without medical or psychiatric conditions. Participants completed quantitative balance testing, Digit Symbol test, and a test of finger movement speed and dexterity. An infratentorial brain region, supratentorial ventricular system, and corpus callosum were quantified with MRI-derived atlas-based parcellation, and together with archival DTI-derived fiber tracking of pontocerebellar and internal and external capsule fiber systems, brain measures were correlated with test performance. The tissue ratio of the infratentorium was ~3% smaller in the HIV than control group. The HIV group exhibited performance deficits in balancing on one foot, walking toe-to-heel, Digit Symbol substitution task, and time to complete all Digit Symbol grid boxes. Total infratentorial tissue ratio was a significant predictor of balance and Digit Symbol scores. Balance scores did not correlate significantly with ventricular volumes, callosal size, or internal or external capsule fiber integrity but did so with indices of pontocerebellar tract integrity. HIV-infected individuals specifically recruited to be without complications from alcohol use disorders had pontocerebellar tissue volume deficits with functional ramifications. Postural stability and psychomotor speed were impaired and attributable, at least in part, to compromised infratentorial brain systems.

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.

HIV-associated neurocognitive disorders persist in the era of potent antiretroviral therapy: CHARTER Study

OBJECTIVES

This is a cross-sectional, observational study to determine the frequency and associated features of HIV-associated neurocognitive disorders (HAND) in a large, diverse sample of infected individuals in the era of combination antiretroviral therapy (CART).

METHODS

A total of 1,555 HIV-infected adults were recruited from 6 university clinics across the United States, with minimal exclusions. We used standardized neuromedical, psychiatric, and neuropsychological (NP) examinations, and recently published criteria for diagnosing HAND and classifying 3 levels of comorbidity (minimal to severe non-HIV risks for NP impairment).

RESULTS

Fifty-two percent of the total sample had NP impairment, with higher rates in groups with greater comorbidity burden (40%, 59%, and 83%). Prevalence estimates for specific HAND diagnoses (excluding severely confounded cases) were 33% for asymptomatic neurocognitive impairment, 12% for mild neurocognitive disorder, and only 2% for HIV-associated dementia (HAD). Among participants with minimal comorbidities (n = 843), history of low nadir CD4 was a strong predictor of impairment, and the lowest impairment rate on CART occurred in the subset with suppressed plasma viral loads and nadir CD4 ≥200 cells/mm(3) (30% vs 47% in remaining subgroups).

CONCLUSIONS

The most severe HAND diagnosis (HAD) was rare, but milder forms of impairment remained common, even among those receiving CART who had minimal comorbidities. Future studies should clarify whether early disease events (e.g., profound CD4 decline) may trigger chronic CNS changes, and whether early CART prevents or reverses these changes.

Family history of dementia predicts worse neuropsychological functioning among HIV-infected persons

HIV-negative individuals with a family history of dementia (FHD) are more likely to develop dementia than those without FHD. Whether FHD increases risk for neuropsychological (NP) impairment in HIV+ persons is unknown. As part of a multisite study into HIV-associated neurocognitive disorders (HAND), the authors captured FHD with a free-response, self-report question, and assessed NP performance with a comprehensive battery of tests. The authors examined HIV+ persons with (N=190) and without (N=916) self-reported FHD. Despite the fact that the FHD group had factors typically associated with better NP performance (e.g., higher CD4 counts and estimated verbal IQ), persons with FHD had significantly worse NP ability than those without FHD as measured by a Global Deficit Score. Thus, FHD appears to be a risk factor for HAND; the mechanism(s) underlying how FHD contributes to NP impairment among HIV+ persons warrants study.

HIV-associated neurocognitive disorders: a changing pattern

Combination antiretroviral therapy has dramatically decreased the incidence of HIV-related mortality and serious opportunistic diseases, among which is HIV-associated dementia. However, minor forms of cognitive dysfunction have not disappeared and may even have increased in frequency. Aging of HIV+ patients, insufficient penetration of antiretroviral drugs into the brain with continuous low-grade viral production and inflammation may play a role. A putative neurotoxicity of combination antiretroviral therapy is controversial. In this article, we will discuss these aspects, as well as clinical and pathophysiological features shared by HIV-associated neurocognitive disorders and other neurodegenerative diseases, especially Alzheimer’s disease. This article will briefly summarize the current clinical trials on neuroprotective agents, and the management of patients with neurocognitive disorders will be discussed.

Antiretroviral adherence and the nature of HIV-associated verbal memory impairment

The authors investigated the relationship between antiretroviral adherence and HIV-associated verbal memory impairment. HIV-positive participants demonstrated poorer verbal memory than HIV-negative participants. Both good (≥90%) and poor (<90%) adherers displayed encoding deficits as compared with controls, but only poor adherers exhibited retrieval deficits. Encoding deficits primarily accounted for reduced delayed recall in good adherers, but both encoding and retrieval deficits accounted for reduced delayed recall in poor adherers. The retrieval difference between the adherence groups might be explained by a neuroprotective effect of good antiretroviral adherence or preexisting HIV-related retrieval deficits that result in poorer adherence.

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.

Neurocognitive functioning in acute or early HIV infection

We examined neurocognitive functioning among persons with acute or early HIV infection (AEH) and hypothesized that the neurocognitive performance of AEH individuals would be intermediate between HIV seronegatives (HIV−) and those with chronic HIV infection. Comprehensive neurocognitive testing was accomplished with 39 AEH, 63 chronically HIV infected, and 38 HIV− participants. All AEH participants were HIV infected for less than 1 year. Average domain deficit scores were calculated in seven neurocognitive domains. HIV−, AEH, and chronically HIV infected groups were ranked from best (rank of 1) to worst (rank of 3) in each domain. All participants received detailed substance use, neuromedical, and psychiatric evaluations and HIV infected persons provided information on antiretroviral treatment and completed laboratory evaluations including plasma and CSF viral loads. A nonparametric test of ordered alternatives (Page test), and the appropriate nonparametric follow-up test, was used to evaluate level of neuropsychological (NP) functioning across and between groups. The median duration of infection for the AEH group was 16 weeks [interquartile range, IQR: 10.3–40.7] as compared to 4.9 years [2.8–11.1] in the chronic HIV group. A Page test using ranks of average scores in the seven neurocognitive domains showed a significant monotonic trend with the best neurocognitive functioning in the HIV− group (mean rank = 1.43), intermediate neurocognitive functioning in the AEH group (mean rank = 1.71), and the worst in the chronically HIV infected (mean rank = 2.86; L statistic = 94, p < 0.01); however, post-hoc testing comparing neurocognitive impairment of each group against each of the other groups showed that the chronically infected group was significantly different from both the HIV− and AEH groups on neurocognitive performance; the AEH group was statistically indistinguishable from the HIV− group. Regression models among HIV infected participants were unable to identify significant predictors of neurocognitive performance. Neurocognitive functioning was worst among persons with chronic HIV infection. Although a significant monotonic trend existed and patterns of the data suggest the AEH individuals may fall intermediate to HIV− and chronic participants, we were not able to statistically confirm this hypothesis.

Human immunodeficiency virus infection in the CNS and decreased dopamine availability: relationship with neuropsychological performance

Human immunodeficiency virus (HIV-1) infection in the central nervous system (CNS) is associated with a wide range of neurological, cognitive, and behavioral problems. HIV-1 enters the brain soon after the initial infection and is distributed in varying concentrations in different regions with specific affinity to the subcortical regions, particularly the basal ganglia, causing neurodegeneration of dopaminergic regions and resulting in the decreased availability of dopamine (DA) in the CNS. Although there are numerous reports on HIV-1-associated neuropsychological (NP) impairment, there is a paucity of studies showing a direct relationship between the decreased availability of dopamine in different regions of postmortem brains of HIV-1-infected individuals and the level of performance in different NP functions during life. Dopamine is the key neurotransmitter in the brain and plays a regulatory role for motor and limbic functions. The purpose of the present study was to investigate the relationship between the decreased availability of dopamine found in the postmortem brain regions (fronto-cortical regions, basal ganglia, caudate, putamen, globus pallidus, and substantia nigra) of individuals with HIV/AIDS and the antemortem level of performance (assessed as T scores) in different NP functions. The relationship between HIV-1 RNA levels in different brain regions and the level of performance in different NP domains was also investigated. We found that although DA concentrations were 2-53% lower in the brain regions of HIV-1-infected, HAART-treated individuals, compared with HIV-negative controls, a 45% decrease in DA levels in the substantia nigra (SN) of HIV-1-infected individuals was significantly correlated with the low level of performance (T scores) in the speed of information processing, learning, memory, verbal fluency, and average T scores across domains. In case of homovanillic acid (HVA), the variable changes in different regions, including the substantia nigra, basal ganglia, caudate, and putamen (compared to that in the HIV-negative individuals), were significantly correlated with the level of performance (T scores) in motor functions, speed of information processing, and attention/working memory. HIVRNA levels in the frontal cortex, caudate, and GP were significantly inversely correlated with abstract/executive function, motor, learning, verbal fluency, and attention/working memory. No significant correlations were found between HIVRNA in other brain regions and NP performance. These findings suggest that the decreased availability of dopamine in the SN (the main site of DA synthesis in the CNS), and changes in the levels of HVA in different brain regions are, in part, related with the lower level of performance in some of the NP functions in individuals with HIV/AIDS.

Peripheral biomarkers do not correlate with cognitive impairment in highly active antiretroviral therapy-treated subjects with human immunodeficiency virus type 1 infection

Neuropsychological (NP) impairments in human immunodeficiency virus (HIV)-infected individuals remain high despite the introduction of highly active antiretroviral therapy (HAART). We sought to determine whether or not a monocyte gene expression profile along with other peripheral factors would correlate with neuropsychological impairment among HIV-infected individuals. Forty-four HIV-1-seropositive subjects (HIV+) on HAART and 11 HIV-1-seronegative controls (HIV-) had NP testing and blood drawn for monocyte gene expression analysis. All HIV+ subjects were assessed for CD4 counts, apolipoprotein E (ApoE) genotype, viral load, and plasma lipopolysaccharide (LPS) and soluble CD14 (sCD14). NP scores were normalized to age, gender, and education. Twenty-five percent of HIV+ individuals showed abnormal NP testing results (> 1.5 SD below normal in two domains). HIV+ individuals had deficits in attention/working memory, verbal learning, and information processing speed compared to HIV- controls. There was no correlation between overall NP impairment and plasma viral load, level of education, age, ethnic diversity, sCD14, plasma LPS, CD4 cell count, ApoE genotype, or years of infection. However, greater years of infection had worse visual learning performance. sCD14 and CD4 nadir positively correlated with information processing speed and fine motor skills, respectively. LPS correlated with viral load but not cognitive impairment. Monocyte gene expression confirmed a chronic inflammatory profile that correlated with viral load but not cognition. No blood index or profile was associated with overall NP impairment.

Methamphetamine and lentivirus interactions: reciprocal enhancement of central nervous system disease

Use of methamphetamine is increasingly a significant factor for the spread of human immunodeficiency virus type 1, for in certain populations, there is a convergence of methamphetamine abuse with human immunodeficiency virus type 1 infection. Methamphetamine and human immunodeficiency virus type 1 are both individually neuropathogenic, and the neuropathology caused by these two agents occurs in overlapping brain regions. However, the biological interaction of methamphetamine with lentiviruses remains unknown. Here, we investigate the effects of simultaneous exposure of these two agents on disease progression using the feline immunodeficiency virus model. The study models the bingeing methamphetamine user with sequential and repeated episodes of use, which were interrupted by periods of abstinence. Methamphetamine exposure significantly accelerated and enhanced the severity of the feline immunodeficiency virus model-induced central nervous system functional pathology, as measured in delays in brainstem auditory evoked potentials. Reciprocally, feline immunodeficiency virus enhanced the severity of the methamphetamine-induced effects on brain monoamine neurotransmitter and dopamine transporter levels. The results of this study indicate that a dual potentiation occurred. That is, methamphetamine enhanced feline immunodeficiency virus model-induced central nervous system disease and feline immunodeficiency virus model enhanced the toxic effects of methamphetamine, heralding a significant concern for those individuals that are exposed to both agents.

Interactive role of human immunodeficiency virus type 1 (HIV-1) clade-specific Tat protein and cocaine in blood-brain barrier dysfunction: implications for HIV-1-associated neurocognitive disorder

In recent years, increasing interest has emerged to assess the human immunodeficiency virus type 1 (HIV-1) clade C viral pathogenesis due to its anticipated spread in the United States and other western countries. Previous studies suggest that clade C is less neuropathogenic than clade B; however, the underlying mechanism is poorly understood. Additionally, the interactive role of drugs of abuse such as cocaine on clade C-associated neuropathogenesis has not been reported. In the current study, we hypothesize that HIV-1 clade-specific Tat proteins exert differential effects on blood-brain barrier (BBB) integrity and cocaine further differentially aggravates the BBB dysfunction. We evaluated the effect of Tat B and Tat C and/or cocaine on the BBB integrity using an in vitro model constructed with primary human brain microvascular endothelial cells (HBMECs) and astrocytes. The BBB membrane integrity was measured by transendothelial electrical resistance (TEER) and paracellular permeability was measured by fluorescein isothiocyanate (FITC)-dextran transport assay and monocytes transmigration across the BBB. Results indicate that Tat B disrupts BBB integrity to a greater extent compared to Tat C and cocaine further differentially exacerbates the BBB dysfunction. This BBB dysfunction was associated with altered expression of tight junction proteins zona occuldens (ZO-1) and junctional adhesion molecule (JAM)-2. Thus, these results for the first time delineate the differential role of Tat B and Tat C and/or cocaine in BBB dysfunction, which may be correlated with the clade-specific differences observed in HIV-1-associated neurological disorders.

Homelessness and neuropsychological impairment: preliminary analysis of adults entering outpatient psychiatric treatment

Homelessness has been associated with neuropsychological (NP) impairment, but few studies have adequately controlled for factors known to affect NP performance. We performed brief NP testing examining learning, recall, processing speed, executive functioning, and verbal fluency in 50 ever- and 22 never-homeless persons entering outpatient psychiatric treatment. Groups were matched a priori on key demographic, substance use, psychiatric, and premorbid intelligence quotient characteristics. Rates of NP impairment were high among both groups (46%-54%). There were no significant differences in global NP impairment. There were trends toward better levels of processing speed and executive functioning among never-homeless relative to ever-homeless. Among the ever-homeless group, NP test performance was unrelated to number of homelessness episodes (median 3). Findings confirm high prevalence of NP impairment among homeless individuals but provide little evidence for broad NP differences between ever- and never-homeless persons matched for coexisting conditions that have confounded interpretation of previous results in the literature.

Preliminary evidence of motor impairment among polysubstance 3,4-methylenedioxymethamphetamine users with intact neuropsychological functioning

Neuropsychological disturbances have been reported in association with use of the recreational drug "ecstasy," or 3,4-methylenedioxymethamphetamine (MDMA), but findings have been inconsistent. We performed comprehensive neuropsychological testing examining seven ability domains in 21 MDMA users (MDMA+) and 21 matched control participants (MDMA-). Among MDMA+ participants, median [interquartile range] lifetime MDMA use was 186 [111, 516] doses, with 120 [35-365] days of abstinence. There were no significant group differences in neuropsychological performance, with the exception of the motor speed/dexterity domain in which 43% of MDMA+ were impaired compared with 5% of MDMA- participants (p = .004). Motor impairment differences were not explained by use of other substances and were unrelated to length of abstinence or lifetime number of MDMA doses. Findings provide limited evidence for neuropsychological differences between MDMA+ and MDMA- participants with the exception of motor impairments observed in the MDMA+ group. However, replication of this finding in a larger sample is warranted.

Neurobehavioral effects of human immunodeficiency virus infection among former plasma donors in rural China

The human immunodeficiency virus (HIV) epidemic in China has expanded rapidly in recent years, but little is known about the prevalence and features of HIV-associated neurocognitive disorders (HANDs) in this part of the world. We administered a comprehensive Western neuropsychological (NP) test battery to 203 HIV+ and 198 HIV- former plasma donors in the rural area of Anhui province. They found that 26% of the HIV- samples, and 46% of the HIV+ samples, were infected with hepatitis C virus (HCV), which can also have central nervous system (CNS) effects. To classify NP impairment, we developed demographically corrected test norms based upon individuals free of both infections (N=141). Using a global summary score, NP impairment was found in 34.2% of the HIV-monoinfected group and 39.7% of the coinfected group, as compared to 12.7% of the uninfected controls (P<.001). HIV+ participants with acquired immunodeficiency syndrome (AIDS) were more likely to be impaired (43%) than non-AIDS individuals (29%; P<.05). Lastly, when all infection groups were combined, participants with NP impairment reported more cognitive complaints (P<.01) and increased dependence in everyday functioning (P=.01). In sum, NP impairment in this large rural Chinese sample was associated with both HIV and HCV infections, and the impairment's prevalence, severity, and pattern were similar to those reported by Western studies. Clinical significance of NP impairment in this population is suggested by the participants' reports of reduced everyday functioning. These findings indicate that HAND is likely to be an important feature of HIV infection in developing countries, underscoring the need for international efforts to develop CNS-relevant treatments.

Cognitive changes in asymptomatic drug-naïve human immunodeficiency virus type 1 clade C infection

Asymptomatic human immunodeficiency virus (HIV) infection is associated with impaired cognitive functioning in both clade B and C infections. The nature of cognitive change longitudinally has not been studied in asymptomatic clade C infection. The present study evaluated changes in neuropsychological functioning over a 2(1/2)-year period in a cohort of HIV-1 clade C-infected asymptomatic individuals from South India. Participants with CD4 counts below 250 were started on highly active antiretroviral therapy (HAART) as per National AIDS Control Organisation NACO guidelines and hence excluded. The sample consisted of 68 patients (30 men and 38 women), with a mean age of 29.4 years (SD=5.6 years) and a mean education of 10.0 years (SD=2.7 years). A comprehensive neuropsychological assessment with 12 tests yielding 21 variables was used to examine cognitive functioning at baseline and subsequently at 6-monthly intervals for five follow-ups. Shift in CD4 and viral load categories measured by the McNemar's test indicated disease progression. Latent growth curve (LGC) modeling assessed the nature of change in cognition over the 2(1/2)-year study period. Ten variables representing attention, executive functions, and long-term memory fit the LGC model. Excepting visual working memory, the slope was nonsignificant for nine variables, indicating absence of deterioration in cognition over a 2(1/2)-year period. However, CD4 and viral load levels worsened, indicating disease progression. Asymptomatic individuals with HIV-1 clade C infection do not show any significant decline on individual neuropsychological functions over 2(1/2) years despite disease progression, as evidenced by immune suppression and viral loads.

Neurocognitive impairment and medication adherence in HIV patients with and without cocaine dependence

Cocaine abuse among HIV patients is associated with faster disease progression and mortality. This study examined the relationship between neurocognitive functioning and medication adherence in HIV patients with (n = 25) and without (n = 39) current cocaine dependence. Active users had greater neurocognitive impairment (mean T-score = 35.16 vs. 40.97, p < .05) and worse medication adherence (mean z-score = -0.44 vs. 0.27, p < .001). In a multiple regression model, neurocognitive functioning (β = .33, p < .01) and cocaine dependence (β = -.36, p < .01) were predictive of poorer adherence. There was a significant indirect effect of cocaine dependence on medication adherence through neurocognitive impairment (estimate = -0.15, p < .05), suggesting that neurocognitive impairment partially mediated the relationship between cocaine dependence and poorer adherence. These results confirm that cocaine users are at high risk for poor HIV outcomes and underscore the importance of treating both neurocognitive impairment and cocaine dependence among HIV patients.

Utility of the Neuropsychological Assessment Battery in detecting cognitive impairment after unilateral stroke

This study evaluated the clinical utility of the Neuropsychological Assessment Battery (NAB) in a stroke sample by examining the NAB's ability to differentiate a chronic stroke group with radiologically confirmed unilateral damage (n = 42) and a demographically matched healthy control (HC) group (n = 36). The stroke group performed more poorly than the control group across NAB Total score and all five Domain scores. Receiver operator curves (ROC) were derived and area under the curve (AUC) showed moderate diagnostic effectiveness (AUC .70 to .90) for NAB Total score, all five Domain scores, a motor composite, and a Global Deficit Score (GDS) that has been shown to closely approximate clinical ratings of neuropsychological impairment. The NAB Total, GDS, and motor composite had comparable clinical utility, whereas the Attention and Executive domain scores demonstrated better classification utility compared with the Memory domain. Because 90.5% of our stroke sample had middle cerebral artery territory strokes, the comparison of motor and cognitive classification utility may be biased. However, follow-up analyses showed that the NAB accounted for additional variance even when motor composite was included in the model. Sensitivity, specificity, and odds ratios at various clinical cutoffs are provided. These results suggest that the NAB is a useful clinical tool for detection of cognitive deficits in individuals with chronic unilateral stroke, although lenient clinical cutoffs appear warranted to maximize sensitivity.

Cytochrome P450-2D6 extensive metabolizers are more vulnerable to methamphetamine-associated neurocognitive impairment: preliminary findings

While neuropsychological deficits are evident among methamphetamine (meth) addicts, they are often unrelated to meth exposure parameters such as lifetime consumption and length of abstinence. The notion that some meth users develop neuropsychological impairments while others with similar drug exposure do not, suggests that there may be individual differences in vulnerability to the neurotoxic effects of meth. One source of differential vulnerability could come from genotypic variability in metabolic clearance of meth, dependent on the activity of cytochrome P450-2D6 (CYP2D6). We compared neuropsychological performance in 52 individuals with a history of meth dependence according with their CYP2D6 phenotype. All were free of HIV or hepatitis C infection and did not meet dependence criteria for other substances. Extensive metabolizers showed worse overall neuropsychological performance and were three times as likely to be cognitively impaired as intermediate/poor metabolizers. Groups did not differ in their demographic or meth use characteristics, nor did they evidence differences in mood disorder or other substance use. This preliminary study is the first to suggest that efficient meth metabolism is associated with worse neurocognitive outcomes in humans, and implicates the products of oxidative metabolism of meth as a possible source of brain injury.

Reaction time variability in HIV-positive individuals

Progression of HIV/AIDS is frequently associated with frontal/subcortical dysfunction and mean reaction time (RT) slowing. Beyond group means, within-subject variability of RT has been found to be particularly sensitive to frontal/subcortical dysfunction in other populations. However, the possible relevance of RT variability to HIV/AIDS patients remains unknown. This study evaluated the relationships between RT variability and indicators such as neurocognitive, behavioral, and immunological status. A total of 46 HIV-positive adults on antiretroviral medication regimens were included in this study. Overall performance of this sample was poorer than normative means on measures of RT latency, RT variability, and traditional neurocognitive domains. Results demonstrated that the measures of RT variability were associated with global cognition, medication adherence rates, and peak immunological dysfunction, above and beyond the effects of RT latency. These preliminary findings suggest that measures of RT variability may provide enhanced sensitivity to neurocognitive disease burden in HIV/AIDS relative to more traditional measures of mean RT or cognitive function.

Verbal Fluency Component Analysis in Adults with HIV/AIDS

The present study examined the impact of HIV disease severity, depressed mood, and highly-active antiretroviral therapy (HAART) on verbal fluency components in a sample of adults with HIV-infection. Switching and clustering have been identified as dissociable components that contribute to performance on tests of phonemic and semantic verbal fluency. Advanced HIV-infection was predicted to differentially impair switching. Switching has been shown to be reduced in disorders affecting frontal-striatal systems (e.g., Parkinson's disease). Verbal fluency protocols (FAS and Animals) of 217 adults with HIV-infection were scored for total switches and average cluster size following the method of Troyer, et al. (1998). Component scores were compared to published norms. Analysis of variance (ANOVA) was used to examine the impact on switching and clustering performance of (1) HIV disease severity (presence of AIDS diagnosis) and depressed mood, and (2) AIDS diagnosis and medication status (current HAART therapy). FAS switching was more often impaired in participants with AIDS. Depressed mood did not affect switching. Neither AIDS diagnosis nor depressed mood was associated with clustering performance. Participants with an AIDS diagnosis who were receiving HAART showed better performance on FAS switching relative to participants with AIDS who were not taking antiretroviral medication. FAS switching appears to be sensitive to cognitive changes associated with advanced HIV-infection. Further research is needed to determine if switching is a specific marker of frontal-striatal dysfunction in this population.

Medication and finance management among HIV-infected adults: the impact of age and cognition

This study examined the effects of aging and cognitive impairment on medication and finance management in an HIV sample. We observed main effects of age (older < younger) and neuropsychological impairment on functional task performance. Interactions between age and cognition demonstrated that older impaired individuals performed significantly more poorly than all other comparison groups. There were no relationships between laboratory performance and self-reported medication and finance management. The interaction of advancing age and cognitive impairment may confer significant functional limitations for HIV individuals that may be better detected by performance-based measures of functional abilities rather than patient self-report.

HIV-associated neurocognitive disorders in sub-Saharan Africa: a pilot study in Cameroon

BACKGROUND

The disease burden of human immunodeficiency virus (HIV)--acquired immunodeficiency syndrome (AIDS) is highest in sub-Saharan Africa but there are few studies on the associated neurocognitive disorders in this region. The objectives of this study were to determine whether Western neuropsychological (NP) methods are appropriate for use in Cameroon, and to evaluate cognitive function in a sample of HIV-infected adults.

METHODS

We used a battery of 19 NP measures in a cross-sectional study with 44 HIV+ adults and 44 demographically matched HIV- controls, to explore the validity of these NP measures in Cameroon, and evaluate the effect of viral infection on seven cognitive ability domains.

RESULTS

In this pilot study, the global mean z-score on the NP battery showed worse overall cognition in the HIV+ individuals. Significantly lower performance was seen in the HIV+ sample on tests of executive function, speed of information processing, working memory, and psychomotor speed. HIV+ participants with AIDS performed worse than those with less advanced HIV disease.

CONCLUSIONS

Similar to findings in Western cohorts, our results in Cameroon suggest that HIV infection, particularly in advanced stages, is associated with worse performance on standardized, Western neurocognitive tests. The tests used here appear to be promising for studying NeuroAIDS in sub-Saharan Africa.

APOE epsilon4 and MBL-2 O/O genotypes are associated with neurocognitive impairment in HIV-infected plasma donors

BACKGROUND

Host genetic factors are important determinants for risk of HIV-1 infection and disease progression. This study examined associations of host genetic variants and neurocognitive impairment in Chinese individuals infected through contaminated blood products.

METHODS

Two hundred and one HIV-infected patients from Anhui, China, had neuropsychological tests at baseline and 12 months. DNA was genotyped for APOE epsilon2, epsilon3 and epsilon4 alleles; MBL2-A/O; CCR5-wt/Delta32; CCR5-59029-G/A; CCR2-180-G/A; SDF-1-G/A; IL4-589-C/T; MCP-1-2518-A/G; CX3CR1-745-G/A; -849-C/T polymorphisms and CCL3L1 copy number variants using real-time PCR. Univariate and multivariate analyses were performed.

RESULTS

The cohort included 61% men, with mean education 5.5 years, AIDS diagnosis 113 (55%), on antiretrovirals 114 (56%), mean baseline CD4(+) cell count 349 cells/microl and mean log10 RNA 4.09. At baseline, 37% had global neuropsychological impairment increasing to 44% after 12 months. Of 43 patients with the APOE epsilon4 allele, 58% were cognitively impaired compared with 31% without the epsilon4 allele (P = 0.001, odds ratio 3.09, 95% confidence interval 1.54-6.18). The mean global deficit score (GDS) for epsilon4-positive participants on antiretrovirals for 12 months was 0.88 (0.55) compared with 0.63 (0.54) for epsilon4-negative participants (P = 0.053, 95% confidence interval -0.004 to 0.51). For MBL2, 52% of patients with the O/O genotype declined in cognitive function over 12 months compared with 23% with A/A (odds ratio 3.62, 95% confidence interval 1.46-9.03, P = 0.004). No associations were observed for the other genetic variants.

CONCLUSION

The APOE epsilon4 allele was associated with increased risk for cognitive deficits, whereas the MBL2 O/O genotype was associated with increased risk for progressive cognitive decline in Chinese individuals infected with HIV through contaminated blood products.

Cliniconeuropathologic correlates of human immunodeficiency virus in the era of antiretroviral therapy

The objective of this study was to examine the spectrum of human immunodeficiency virus (HIV) brain pathology and its clinical correlates in the antiretroviral era. We carried out a cross-sectional survey, analyzing prospective clinical and neuropathological data collected by the National NeuroAIDS Tissue Consortium (NNTC), comprising 589 brain samples from individuals with advanced HIV disease collected from 1999 onwards. We assessed gender, ethnicity/race, mode of transmission, age, year of death, nadir CD4, plasma viral load, last antiretroviral regimen, presence of parenchymal HIV brain pathology, HIV-associated neurocognitive disorder, and major depressive disorder. We compared cohort demographic variables with Centers for Disease Control and Prevention US HIV/AIDS statistics and examined associations of parenchymal HIV brain pathology with demographic, clinical, and HIV disease factors. With regard to Centers for Disease Control and Prevention US data, the NNTC was similar in age distribution, but had fewer females and African Americans and more Hispanics and men who have sex with men. Only 22% of the brains examined were neuropathologically normal. Opportunistic infections occurred in 1% to 5% of the cohort. Parenchymal HIV brain pathology was observed in 17.5% of the cohort and was associated with nadir CD4 and plasma viral load. Brains without parenchymal HIV brain pathology often had other noninfectious findings or minimal nondiagnostic abnormalities that were associated with HIV-associated neurocognitive disorder. Clinically, 60% of the cohort reported a lifetime episode of major depressive disorder and 88% had a HIV-associated neurocognitive disorder. No pathological finding correlated with major depressive disorder. Both antiretroviral treatment regimen and elevated plasma HIV viral load were associated with presence of parenchymal HIV brain pathology; however, multivariate analyses suggest a stronger association with plasma viral load. The frequency of HIV brain pathology was lower than previous pre-antiretroviral reports, and was predicted by lower nadir CD4 and higher plasma viral load. Noninfectious pathologies and minimal changes correlated with HIV-associated neurocognitive disorder, suggesting a shift in pathogenesis from florid HIV replication to other, diverse mechanisms.

HIV and SIV induce alterations in CNS CaMKII expression and activation: a potential mechanism for cognitive impairment

The molecular mechanisms underlying learning and memory impairment in patients with HIV-associated neurological disease have remained unclear. Calcium/calmodulin-dependent kinase II (CaMKII) has key roles in synaptic potentiation and memory storage in neurons and also may have immunomodulatory functions. To determine whether HIV and simian immunodeficiency virus (SIV) induce alterations in CaMKII expression and/or activation (autophosphorylation) in the brain, we measured CaMKII alterations by quantitative immunoblotting in both an in vitro HIV/neuronal culture model and in vivo in an SIV-infected macaque model of HIV-associated neurological damage. Using primary rat hippocampal neuronal cultures treated with culture supernatants harvested from HIV-1-infected human monocyte-derived macrophages (HIV/MDM), we found that CaMKII activation declined after exposure of neurons to HIV/MDM. Consistent with our in vitro measurements, a significant decrease in CaMKII activation was present in both the hippocampus and frontal cortex of SIV-infected macaques compared with uninfected animals. In SIV-infected animals, total CaMKII expression in the hippocampus correlated well with levels of synaptophysin. Furthermore, CaMKII expression in both the hippocampus and frontal cortex was inversely correlated with viral load in the brain. These findings suggest that alterations in CaMKII may compromise synaptic function in the early phases of chronic neurodegenerative processes induced by HIV.

Neurocognitive correlates of alexithymia in asymptomatic individuals with HIV

Alexithymia, an impairment of affective and cognitive emotional processing, is often associated with human immunodeficiency virus (HIV) and may reflect effects of the virus on brain areas that are also important for multiple cognitive functions, such as the prefrontal and anterior cingulate cortices. We hypothesized that there would be a correlation between extent of alexithymia and cognitive performance associated with these brain areas, including attention, executive function, and visuospatial processing. Thirty-four asymptomatic HIV+ participants and 34 matched healthy HIV- volunteers were administered the Toronto Alexithymia Scale, a series of neuropsychological tests, and measures of apathy, depression, and quality of life (QoL). The HIV+ participants had significantly higher levels of alexithymia, depression and apathy than the HIV- group. The extent of alexithymia and two of its processing components (Difficulty Describing Feelings [DDF] and Externally Oriented Thinking), but not depression, correlated with performance on measures of executive and visuospatial abilities, consistent with dysfunction of the frontostriatal circuits and their cortical projections. Apathy was related to alexithymia and two processing components (Difficulty Identifying Feelings and DDF) but to only one cognitive measure. The higher rate of alexithymia, as well as cognitive dysfunction, in HIV may be a consequence of the infection on the frontostriatal system and its cortical connections. Our findings also demonstrated a dissociation of apathy and alexithymia in HIV, pointing to overlapping but distinct neural substrates within frontostriatal circuits. Alexithymia correlated strongly with QoL ratings, underscoring the importance of assessment and treatment of HIV-associated emotional and cognitive processing deficits.

Reciprocal prediction of medication adherence and neurocognition in HIV/AIDS

BACKGROUND

Antiretroviral medications have been shown to benefit neurocognition in HIV/AIDS, and neurocognitive deficits are a risk factor for poor adherence to these medications. However, little is known about the predictive pathways linking medication adherence with cognitive ability.

METHODS

In the current 6-month cohort study, antiretroviral medication adherence was tracked prospectively among 91 HIV-positive adults using electronic monitoring. Comprehensive neuropsychological evaluations were performed at baseline and 6 months.

RESULTS

Multivariate path analyses provided evidence that antiretroviral adherence and cognitive ability are reciprocally related, although the neurocognitive pathways of this relationship appear to vary by predictive direction. Executive function and learning/memory were most strongly predictive of levels of medication adherence achieved, whereas higher levels of adherence were predictive of relative improvements in a wide range of frontostriatal brain functions including processing speed, attention, executive functions, and motor functioning.

CONCLUSIONS

These data provide evidence that cognition and adherence are reciprocally related in HIV/AIDS. In particular, executive dysfunction may play a key role in this relationship. Interventions aimed at improving or preserving executive functions could hold promise for interrupting progressive declines in adherence and neurocognitive ability in HIV/AIDS.

Neurological disease: the effects of HIV and antiretroviral therapy and the implications for early antiretroviral therapy initiation

PURPOSE OF REVIEW

The purpose of this review is to examine the literature regarding HIV-associated neurocognitive disorders, early HIV infection of the central nervous system (CNS), the role of the peripheral immune system in controlling HIV infection and disease within the brain and the potential role that early antiretroviral treatment may play in the preservation of neurocognitive health in patients with more than 500 CD4+ cells/microl.

RECENT FINDINGS

In the post highly active antiretroviral therapy (HAART) era, HIV-associated neurocognitive disorders remain prevalent and even mild-moderate immunosuppression carries a risk for the development of HIV-associated dementia. HIV infection of the CNS occurs early in the illness, and data suggest that a robust peripheral immune system is key to the long-term control of CNS HIV infection. HAART results in clinical, neuropsychological and neuroradiological improvement in patients with HIV-associated neurocognitive disorders, and the prescription of HAART regimens with good cerebrospinal fluid penetration appears to be preferable in this setting. There is little evidence that HAART causes CNS toxicity. The benefits and risks of HAART in the preservation or enhancement of neurocognitive function in well, HIV-infected patients with more than 500 CD4+ cells/microl are unknown.

SUMMARY

The prescription of HAART in well, HIV-infected patients with high CD4+ cell counts may afford enhanced control of CNS HIV infection as a result of the benefits of HAART upon peripheral immune function. In turn, this may result in superior or preserved neurocognitive performance in comparison to the current practice of commencing HAART when CD4+ cells reach 350 cells/microl or lower. This hypothesis will be tested in an upcoming randomized clinical trial.

Neurocognitive functioning in HIV-1 infection: effects of cerebrovascular risk factors and age

This study examined the interactive effects of cerebrovascular risks, advancing age, and HIV infection on neurocognition, and explored whether pharmacological treatment of cerebrovascular risk factors attenuated neurocognitive dysfunction. Participants included 98 HIV-seropositive adults (cerebrovascular risk: 23.5%; age > 50: 27.6%). Cerebrovascular risk was associated with slower processing speed even after controlling for age effects (b = -2.071; p =.04), and the interaction of age and cerebrovascular risk was associated with poorer verbal fluency (b = 1.276, p =.002). Participants with pharmacologically untreated cerebrovascular risk demonstrated reduced processing speed, learning/memory, and executive functioning relative to those on medication. Poor cerebrovascular health confers significant risk for HIV+ individuals, and this effect may be of greater consequence than advancing age. The cognitive impact of risk appears to be more pronounced in the absence of adequate pharmacological treatment.

Subcortical profile of memory compromise among HIV-1-infected individuals

OBJECTIVE

To examine the hypothesis of subcortical pathologic impairment in HIV/AIDS.

METHOD

The study included 22 HIV+, 22 HIV- controls, 22 learning disordered (LD) HIV-, and 22 depressive HIV-. The groups were compared on eight WMS-III Indices.

RESULTS

Analyses revealed significantly lower scores (p < .05) in HIV+ on visual immediate memory, immediate memory, visual delayed memory, auditory delayed memory, working memory, and general memory. For all cases, HIV+ participants scored below the control group only.

CONCLUSIONS

WMS-III indices discriminated HIV+ participants from normal comparisons. Inability to find differences between HIV+ and depressive and LD groups reflects the isolation of the subcortical effect to the HIV+ group.

Methamphetamine use parameters do not predict neuropsychological impairment in currently abstinent dependent adults

Methamphetamine (meth) abuse is increasingly of public health concern and has been associated with neurocognitive dysfunction. Some previous studies have been hampered by background differences between meth users and comparison subjects, as well as unknown HIV and hepatitis C (HCV) status, which can also affect brain functioning. We compared the neurocognitive functioning of 54 meth dependent (METH+) study participants who had been abstinent for an average of 129 days, to that of 46 demographically comparable control subjects (METH-) with similar level of education and reading ability. All participants were free of HIV and HCV infection. The METH+ group exhibited higher rates of neuropsychological impairment in most areas tested. Among meth users, neuropsychologically normal (n=32) and impaired (n=22) subjects did not differ with respect to self-reported age at first use, total years of use, route of consumption, or length of abstinence. Those with motor impairment had significantly greater meth use in the past year, but impairment in cognitive domains was unrelated to meth exposure. The apparent lack of correspondence between substance use parameters and cognitive impairment suggests the need for further study of individual differences in vulnerability to the neurotoxic effects of methamphetamine.

COMT Val158Met Polymorphism, Executive Dysfunction, and Sexual Risk Behavior in the Context of HIV Infection and Methamphetamine Dependence

Catechol-O-methyltransferease (COMT) metabolizes prefrontal cortex dopamine (DA), a neurotransmitter involved in executive behavior; the Val158Met genotype has been linked to executive dysfunction, which might increase sexual risk behaviors favoring HIV transmission. Main and interaction effects of COMT genotype and executive functioning on sexual risk behavior were examined. 192 sexually active nonmonogamous men completed a sexual behavior questionnaire, executive functioning tests, and were genotyped using blood-derived DNA. Main effects for executive dysfunction but not COMT on number of sexual partners were observed. A COMT x executive dysfunction interaction was found for number of sexual partners and insertive anal sex, significant for carriers of the Met/Met and to a lesser extent Val/Met genotypes but not Val/Val carriers. In the context of HIV and methamphetamine dependence, dopaminergic overactivity in prefrontal cortex conferred by the Met/Met genotype appears to result in a liability for executive dysfunction and potentially associated risky sexual behavior.