Reaction times are faster in HIV-seropositive patients on antiretroviral therapy: A preliminary report

Assessment and Diagnosis of HIV-Associated Dementia

The modern combined antiretroviral treatment (cART) for human immunodeficiency virus (HIV) infection has substantially lowered the incidence of HIV-associated dementia (HAD). The dominant clinical features include deficits in cognitive processing speed, concentration, attention, and memory. As people living with HIV become older, with high rates of comorbidities and concomitant treatments, the prevalence and complexity of cognitive impairment are expected to increase. Currently, the management of HAD and milder forms of HAND is grounded on the best clinical practice, as there is no specific, evidence-based, proven intervention for managing cognitive impairment. The present article acknowledges the multifactorial nature of the cognitive impairments found in HIV patients, outlining the current concepts in the field of HAD. Major areas of interest include neuropsychological testing and neuroimaging to evaluate CNS status, focusing on greater reliability in the exclusion of associated diseases and allowing for earlier diagnosis. Additionally, we considered the evidence for neurological involvement in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the impact of the coronavirus (COVID-19) pandemic, with wider consequences to population health than can be attributed to the virus itself. The indirect effects of COVID-19, including the increased adoption of telehealth, decreased access to community resources, and social isolation, represent a significant health burden, disproportionately affecting older adults with dementia who have limited social networks and increased functional dependence on the community and health system. This synopsis reviews these aspects in greater detail, identifying key gaps and opportunities for researchers and clinicians; we provide an overview of the current concepts in the field of HAD, with suggestions for diagnosing and managing this important neurological complication, which is intended to be applicable across diverse populations, in line with clinical observations, and closely representative of HIV brain pathology.

Behavioral and Physical Activity Interventions for HAND

Approximately 30-50% of persons living with HIV manifest some degree of neurocognitive impairment. Even mild-to-moderate forms of HIV-associated neurocognitive disorders (HAND) can result in difficulties with everyday functioning, such as suboptimal medication adherence and impaired driving. Despite the pervasive presence and consequences of HAND, there is a significant unmet need to develop effective behavioral strategies to reduce the incidence and consequences of HAND. Although there is an absence of evidence-based behavioral interventions specific to HAND, the literature reviewed in this chapter suggest the following modifiable lifestyle factors as intervention targets: physical activity, diet, sleep, and antiretroviral medication adherence. Adoption and maintenance of these healthy lifestyle factors may reduce inflammation and oxidative stress, which, in turn, may reduce the incidence and/or severity of HAND.

Neural response to working memory demand predicts neurocognitive deficits in HIV

Human immunodeficiency virus (HIV) continues to have adverse effects on cognition and the brain in many infected people, despite a reduced incidence of HIV-associated dementia with combined antiretroviral therapy (cART). Working memory is often affected, along with attention, executive control, and cognitive processing speed. Verbal working memory (VWM) requires the interaction of each of the cognitive component processes along with a phonological loop for verbal repetition and rehearsal. HIV-related functional brain response abnormalities during VWM are evident in functional MRI (fMRI), though the neural substrate underlying these neurocognitive deficits is not well understood. The current study addressed this by comparing 24 HIV+ to 27 demographically matched HIV-seronegative (HIV-) adults with respect to fMRI activation on a VWM paradigm (n-back) relative to performance on two standardized tests of executive control, attention and processing speed (Stroop and Trail Making A-B). As expected, the HIV+ group had deficits on these neurocognitive tests compared to HIV- controls, and also differed in neural response on fMRI relative to neuropsychological performance. Reduced activation in VWM task-related brain regions on the 2-back was associated with Stroop interference deficits in HIV+ but not with either Trail Making A or B performance. Activation of the posterior cingulate cortex (PCC) of the default mode network during rest was associated with Hopkins Verbal Learning Test-2 (HVLT-2) learning in HIV+. These effects were not observed in the HIV- controls. Reduced dynamic range of neural response was also evident in HIV+ adults when activation on the 2-back condition was compared to the extent of activation of the default mode network during periods of rest. Neural dynamic range was associated with both Stroop and HVLT-2 performance. These findings provide evidence that HIV-associated alterations in neural activation induced by VWM demands and during rest differentially predict executive-attention and verbal learning deficits. That the Stroop, but not Trail Making was associated with VWM activation suggests that attentional regulation difficulties in suppressing interference and/or conflict regulation are a component of working memory deficits in HIV+ adults. Alterations in neural dynamic range may be a useful index of the impact of HIV on functional brain response and as a fMRI metric in predicting cognitive outcomes.

Does antiretroviral therapy improve HIV-associated cognitive impairment? A quantitative review of the literature

The development of antiretroviral therapy (ART) has dramatically improved survival for those living with human immunodeficiency virus (HIV), but whether ART improves cognitive functioning remains unclear. The aim of the present review was to examine systematically the extent to which ART improves cognition among individuals with HIV using meta-analytic methods. Twenty-three studies were included in the quantitative review. ART was associated with modest improvements in attention (mean d = .17; p < .001; 95% confidence interval [CI], .09/.25), executive function (mean d = .18; p < .001; 95% CI, .10/.26), and motor function (mean d = .24; p < .001; 95% CI, .16/.32). ART did not improve language, verbal memory, visual memory or visuospatial function. The extent to which cognition improved was correlated with the change in CD4 cell count following ART, suggesting a link between cognitive outcome and immune system integrity. Together, the present findings indicate that the neuropsychological test performance of most HIV patients taking ART is comparable to those not taking ART. Development of pharmaceutical treatments and rehabilitation strategies that target the cognitive effects of HIV infection is needed.

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.

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.

Functional consequences of HIV-associated neuropsychological impairment

This review focuses on the "real world" implications of infection with HIV/AIDS from a neuropsychological perspective. Relevant literature is reviewed which examines the relationships between HIV-associated neuropsychological impairment and employment, driving, medication adherence, mood, fatigue, and interpersonal functioning. Specifically, the relative contributions of medical, cognitive, psychosocial, and psychiatric issues on whether someone with HIV/AIDS will be able to return to work, adhere to a complicated medication regimen, or safely drive a vehicle will be discussed. Methodological issues that arise in the context of measuring medication adherence or driving capacity are also explored. Finally, the impact of HIV/AIDS on mood state, fatigue, and interpersonal relationships are addressed, with particular emphasis on how these variables interact with cognition and independent functioning. The purpose of this review is to integrate neuropsychological findings with their real world correlates of functional behavior in the HIV/AIDS population.

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.

Aging, neurocognition, and medication adherence in HIV infection

OBJECTIVE

To evaluate the hypothesis that poor adherence to highly active antiretroviral treatment (HAART) would be more strongly related to cognitive impairment among older than among younger HIV-seropositive adults.

SETTING AND PARTICIPANTS

A volunteer sample of 431 HIV-infected adult patients prescribed self-administered HAART was recruited from community agencies and university-affiliated infectious disease clinics in the Los Angeles area.

MEASUREMENTS

Neurocognitive measures included tests of attention, information processing speed, learning/memory, verbal fluency, motor functioning, and executive functioning. Medication adherence was measured using microchip-embedded pill bottle caps (Medication Event Monitoring System) and self-report. Latent/structural analysis techniques were used to evaluate factor models of cognition and adherence.

RESULTS

Mean adherence rates were higher among older (>or=50 years) than younger (<50 years) HIV-positive adults. However, latent/structural modeling demonstrated that neurocognitive impairment was associated with poorer medication adherence among older participants only. When cognitive subdomains were examined individually, executive functioning, motor functioning, and processing speed were most strongly related to adherence in this age group. CD4 count and drug problems were also more strongly associated with adherence among older than younger adults.

CONCLUSIONS

Older HIV-positive individuals with neurocognitive impairment or drug problems are at increased risk of suboptimal adherence to medication. Likewise, older adults may be especially vulnerable to immunological and neurocognitive dysfunction under conditions of suboptimal HAART adherence. These findings highlight the importance of optimizing medication adherence rates and evaluating neurocognition in the growing population of older HIV-infected patients.

Impairments in fine-motor coordination and speed of information processing predict declines in everyday functioning in hepatitis C infection

Research increasingly supports the neurovirulence of chronic infection with the hepatitis C virus (HCV). For example, HCV infection has been associated with neuropsychological impairment in several ability areas, including psychomotor skills. This study aimed to examine whether HCV-associated neuropsychological impairment is predictive of declines in the independent performance of physical (PADLs) and instrumental (IADLs) activities of daily living. A total of 106 volunteers with HCV infection completed a comprehensive neuropsychological, medical, and psychiatric research evaluation. As compared to 30 HCV-seronegative comparison participants, the HCV-infected group reported significantly greater declines in both PADLs and IADLs. Within the HCV cohort, individuals with impaired speed of information processing reported significantly greater IADL declines, whereas impaired fine-motor coordination was associated with declines in both IADLs and PADLs. In a series of regression analyses, impaired speed of information processing and depressive symptoms (as measured by the Beck Depression Inventory) were the only independent predictors of IADL declines, whereas general affective distress (as measured by the Profile of Mood States), sex, and fine-motor coordination impairment were predictive of declines in PADLs. Although the clinical assessment of HCV typically emphasizes both affective (e.g., depression) and physical factors, findings from the present study suggest that cognitive impairment is an important contributor to everyday functioning in persons living with HCV infection and therefore warrants consideration in clinical and research evaluations.

Influence of Major Antiepileptic Drugs on Attention, Reaction Time, and Speed of Information Processing: Results from a Randomized, Double-blind, Placebo-controlled Withdrawal Study of Seizure-free Epilepsy Patients Receiving Monotherapy

PURPOSE

All major antiepileptic drugs (AEDs) have been reported to be associated with cognitive side effects. Uncertainty exists regarding the degree of cognitive effects, primarily because many studies do not adhere to basic standards of methodology and design. The aim of this study was to assess the effect of discontinuation of AEDs in patients receiving monotherapy on measures of attention, reaction time, and speed of information processing.

METHODS

The 150 subjects who had been seizure free>2 years on drug monotherapy went through a randomized, double-blind, placebo-controlled study. Each patient was included for 12 months or until seizure relapse. Cognitive function was assessed with the California Computerized Assessment Package at baseline and 7 months after discontinuation.

RESULTS

The major finding in this study is that discontinuation of major AEDs significantly improved performance on tests that require complex cognitive processing under time pressure. The difference in speed of cognitive processing between the two groups on these tasks was between 24 to 43 ms. Simple tasks of attention and reaction time revealed no significant differences between the discontinuation group and the nondiscontinuation group. Most of the subjects in the study were medicated with carbamazepine (CBZ) and valproate (VPA). The outcome of discontinuation of CBZ was similar to the outcome for the total study population, whereas withdrawal of VPA revealed only a nonsignificant tendency in the same direction.

CONCLUSIONS

The results suggest that seizure-free epilepsy patients receiving monotherapy can obtain improvement in cognitive function if they discontinue AED treatment.

Co-occurring Hepatitis C, substance use, and psychiatric illness: treatment issues and developing integrated models of care

Hepatitis C virus (HCV) infection is transmitted by injection drug use and associated with psychiatric conditions. Patients with drug use or significant psychiatric illness have typically been excluded from HCV treatment trials noting the 1997 National Institutes of Health Consensus Statement on HCV that indicated active drug use and major depressive illness were contraindications to treatment of HCV infection. However, the 2002 NIH Consensus Statement recognized that these patients could be effectively treated for HCV infection and recommended that treatment be considered on a case-by-case basis. Treating HCV infection in these patients is challenging, with drug use relapse possibly leading to psychosocial instability, poor adherence, and HCV reinfection. Interferon therapy may exacerbate preexisting psychiatric symptoms. Co-occurring human immunodeficiency virus or hepatitis B virus provide additional challenges, and access to ancillary medical and psychiatric services may be limited. Patients with co-occurring HCV infection, substance use, and psychiatric illness can complete interferon treatment with careful monitoring and aggressive intervention. Clinicians must integrate early interventions for psychiatric conditions and drug use into their treatment algorithm. Few programs or treatment models are designed to manage co-occurring substance use, psychiatric illness, and HCV infection and therapy. The National Institute on Drug Abuse convened a panel of experts to address the current status and the long-range needs through a 2-day workshop, Co-occurring Hepatitis C, Substance Abuse, and Psychiatric Illness: Addressing the Issues and Developing Integrated Models of Care. This conference report summarizes current data, medical management issues, and strategies discussed.

Neurocognitive effects of repetitive transcranial magnetic stimulation in severe major depression

OBJECTIVE

Repetitive transcranial magnetic stimulation (rTMS) is being investigated as a potential treatment for depression. Few studies have addressed the neurocognitive effects of a course of rTMS in severely depressed patients. We evaluated neurocognitive effects of a 1-4 week course (mean 3 weeks) of rTMS using an aggressive set of parameters, in 15 severely depressed subjects.

METHODS

A battery of neurocognitive tests relevant to attention, working memory-executive function, objective memory and motor speed were administered to 15 subjects with treatment-resistant major depression (unipolar and bipolar), before and after a course of rTMS. Mean z scores were computed for each of 4 cognitive domains and analyzed using repeated measures multivariate analysis of covariance. Significant interactions were further clarified using univariate analysis of variance.

RESULTS

There was no worsening of performance on any of the cognitive domains over the baseline-post rTMS period. On the contrary, evidence of modest but statistically significant improvement in performance was noted in working memory-executive function, objective memory and fine motor speed domains over the rTMS treatment period.

CONCLUSIONS

There was no evidence of adverse neurocognitive changes over the baseline-post rTMS period in 15 treatment-resistant depressed subjects undergoing a 3 week (mean) trial of rTMS. Significant improvements in several domains observed over the rTMS treatment period could not be explained by improved mood. Practice effects as well as other factors potentially contributing to these findings are discussed.

SIGNIFICANCE

rTMS is being increasingly studied as a neurophysiological probe as well as for its potential antidepressive effects. The effects on neuronal function raise appropriate questions of safety of its use at varying stimulus parameters and durations. This study contributes to the small body of evidence of the cognitive effects of rTMS in severely depressed patients.

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.

Medication adherence among HIV+ adults: effects of cognitive dysfunction and regimen complexity

BACKGROUND

Although the use of highly active antiretroviral therapy in the treatment of HIV infection has led to considerable improvement in morbidity and mortality, unless patients are adherent to their drug regimen (i.e., at least 90 to 95% of doses taken), viral replication may ensue and drug-resistant strains of the virus may emerge.

METHODS

The authors studied the extent to which neuropsychological compromise and medication regimen complexity are predictive of poor adherence in a convenience sample of 137 HIV-infected adults. Medication adherence was tracked through the use of electronic monitoring technology (MEMS caps).

RESULTS

Two-way analysis of variance revealed that neurocognitive compromise as well as complex medication regimens were associated with significantly lower adherence rates. Cognitively compromised participants on more complex regimens had the greatest difficulty with adherence. Deficits in executive function, memory, and attention were associated with poor adherence. Logistic regression analysis demonstrated that neuropsychological compromise was associated with a 2.3 times greater risk of adherence failure. Older age (>50 years) was also found to be associated with significantly better adherence.

CONCLUSIONS

HIV-infected adults with significant neurocognitive compromise are at risk for poor medication adherence, particularly if they have been prescribed a complex dosing regimen. As such, simpler dosing schedules for more cognitively impaired patients might improve adherence.