Determining optimal impairment rating methodology for a new HIV-associated neurocognitive disorder screening procedure

HIV associated neurocognitive disorder screening and diagnosis pathways in Australia: a scoping review and international implications

Symptomatic HIV-associated neurocognitive disorder (HAND) is a complication of HIV (cognitive impairment, difficulties with everyday functioning). If detected early, interventions assist with optimizing care, avoiding rapid decline and enhancing coping. There remains inconsistency surrounding screening/diagnosis information within Australian healthcare professionals and community settings. A scoping review of academic literature, government policies and non-government organisations (NGOs) was conducted to map existing screening/diagnosis information using the guidelines of Joanna Briggs Institute. A literature search of EBSCOhost and Medline (dates: 2015-2021), the Australian government NGO web domains, Google and unpublished academic works was conducted (July 2021) and updated (December 2022) to identify Australian items (past 5 years). Seventeen items met the inclusion criteria. No government guidelines were identified. Various HIV-related organisations proposed different diagnostic guidelines. Most HAND research originated in Sydney. The most accessible information was from Dementia Australia, with some inaccuracies noted. There is scant Australian research/information on HAND screening/diagnosis. HAND translational research and screening/diagnosis standards are urgently needed to inform best practices. The Australian context is used to discuss international implications regarding higher-income countries with similar patterns/healthcare.

The kynurenine pathway relates to post-acute COVID-19 objective cognitive impairment and PASC

OBJECTIVE

To determine the prevalence and natural history of post-acute COVID-19 objective cognitive impairment and function, and their relationship to demographic, clinical factors, post-acute sequelae of COVID-19 (PASC), and biomarkers.

METHODS

A total of 128 post-acute COVID-19 patients (age = 46 ± 15; 42% women, acute disease severity: not hospitalized: 38.6% mild: 0-1 symptoms, 52% 2+ symptoms; 9.4% hospitalized) completed standard cognition, olfaction, and mental health examinations 2-, 4-, and 12-month post diagnosis. Over the same time frame, WHO-defined PASC was determined. Blood cytokines, peripheral neurobiomarkers, and kynurenine pathway (KP) metabolites were measured. Objective cognitive function was demographically/practice corrected, and impairment prevalence was determined using the evidence-based Global Deficit Score method to detect at least mild cognitive impairment (GDS > 0.5). Linear mixed effect regression models with time effect (month post diagnosis) evaluated the relationships to cognition.

RESULTS

Across the 12-month study period, mild to moderate cognitive impairment ranged from 16% to 26%, and 46.5% were impaired at least once. Impairment associated with poorer work capacity (p < 0.05), and 2-month objectively tested anosmia (p < 0.05). PASC with (p = 0.01) and without disability (p < 0.03) associated with acute COVID-19 severity. KP measures showed prolonged activation (2 to 8 months) (p < 0.0001) linked to IFN-beta in those with PASC. Of the blood analytes, only the KP metabolites (elevated quinolinic acid, 3-hydroxyanthranilic acid, kynurenine, the kynurenine/tryptophan ratio) associated (p < 0.001) with poorer cognitive performance and greater likelihood of impairment. PASC, independent of disability associated with abnormal kynurenine/tryptophan (p < 0.03).

INTERPRETATION

The kynurenine pathway relates to post-acute COVID-19 objective cognitive impairment and PASC, thereby enabling biomarker and therapeutic possibilities.

Meaningful cognitive decline is uncommon in virally suppressed HIV, but sustained impairment, subtle decline and abnormal cognitive aging are not

Background

High antiretroviral therapy (ART) coverage and viral suppression among people with HIV (PWH) in Australia provide a unique context to study individual cognitive trajectories, cognitive aging and factors associated with longitudinal cognitive function during chronic and stable HIV disease.

Methods

Participants from the Predictors of Adherence to Antiretroviral Therapy study (n = 457, recruited between September 2013 and November 2015, median age = 52 years, and all with HIV RNA <50 copies mL) completed a cognitive assessment with CogState Computerized Battery (CCB) at baseline, Month-12, and Month-24. Demographics, psycho-social and socioeconomic factors, healthcare seeking behaviors, HIV disease characteristics and comorbidities were assessed. The CCB data were corrected for age, sex and practice effect and averaged into a global z-score (GZS). Cognitive impairment was defined with the global deficit score method (GDS>0.5). Meaningful cognitive change was statistically defined (decline or improvement versus stability, i.e., 90% CI, that is p < 0.05, 2-tailed) using a novel evidence-based change score: the linear mixed-effect regression (LMER)-based GZS change score. A separate LMER model with a top-down variable selection approach identified the independent effects of age and other demographic, HIV disease characteristics, socioeconomic and health-related factors on the demographically corrected GZS. The combined definitions of change and cross-sectional impairment enabled the identification of cognitive trajectories.

Findings

At Month-12 and Month-24, 6% and 7% showed meaningful cognitive decline and 4% and 3% improved respectively. Only 1% showed sustained decline. Incident impairment due to subtle cognitive decline (i.e., below the threshold of meaningful cognitive decline) was 31% and 25% at Month-12 and Month-24, while 14% showed sustained impairment (i.e., cognitively impaired at all study visits). Older age (≥50 years) and time interaction was associated with lower demographically corrected GZS (β = -0.31, p < 0.001). Having a regular relationship, excellent English proficiency, and perceived stigma (avoidance) were associated with higher GZS (all p < 0.05). Relying on government subsidy, severe depression, and lower belief in ART necessity and higher concerns were associated with lower GZS (all p < 0.05). No HIV disease characteristics had a significant effect.

Interpretations

Meaningful cognitive decline was not different from normal expectation in chronic stable HIV disease. Despite this, subtle cognitive decline, sustained cognitive impairment, and greater than normative-age cognitive aging were evident.

Funding

Funding for the PAART study was provided in part by unrestricted educational grants from Gilead Sciences (www.gilead.com) (Grant Number: IN-AU-264- 0131), the Balnaves Foundation (www.balnavesfoundation.com), the Victorian Department of Health and Human Services (Australia) (www.dhs.vic.gov.au/home), Western Australia Health (www.health.wa.gov.au), the ACT Ministry of Health (Australia) (www.health.act.gov.au), and in-kind support from the Queensland Department of Health (Australia) (www.health.qld.gov.au), and NHMRC Partnership grant APP1058474 (PI: Carr, Andrew).

Low incidence of advanced neurological burden but high incidence of age-related conditions that are dementia risk factors in aging people living with HIV: a data-linkage 10-year follow-up study

Although increasing research is focusing on age-related comorbidities (ARC) among people living with HIV (PLHIV), no studies have concomitantly assessed non-HIV age-related neurological disorders (e.g., Alzheimer’s dementia). A total of 254 PLHIV and 69 HIV-negative controls completed baseline medical history and cognitive testing. ARC data were collected from medical records over the subsequent 9-10 years and included all types of strokes, all types of dementia, mild cognitive impairment, Parkinson's disease, motor neuron disease (grouped into a non-HIV age-related neurological category), cardiovascular disease, chronic kidney disease, chronic liver disease, chronic lung disease, non-AIDS cancers, osteoporosis, and diabetes. Kaplan–Meier curves assessed differences in the incident rates (per 1000 person year) of groups of ARC as defined above and combined ARC (i.e., development of any of the ARC) among younger (baseline age < 50) and older (baseline age ≥ 50) PLHIV and younger and older controls. Cox-proportional hazard models assessed the individual and interaction effects of HIV status and chronological age, in addition to a range of demographic and clinical variables including historical and baseline HIV brain involvement on the risk of developing combined ARC. Older PLHIV had a higher incidence of cardiovascular disease, osteoporosis, and combined ARC compared to other groups (p < 0.05). Incident rate of non-HIV age-related neurological disorders was 2.3 [0.93, 4.79] per 1000 person year. While this incident rate was higher in older PLHIV (5.37 [1.97, 11.92]) than older HIV-negative participants (3.58 [0.18-17.67]), this was not significant. In multivariate analyses, HIV status and chronological age, but not their interaction, and smoking were associated with higher risk of combined ARC (p < 0.05). In analyses focusing on PLHIV, older age and taking abacavir/efavirenz/atazanavir/darunavir containing antiretroviral treatments at the time of diagnosis were associated with greater ARC (p < 0.05). Non-HIV age-related neurological disorders are uncommon in older PLHIV, where the majority were < 70 years of age at the end of follow-up. However, the greater burden of ARC among older PLHIV, most of which are established dementia risk factors, warrants the establishment of commensurate prevention strategies and greater attention to neurocognitive screening.

Neurological disorders in HIV: Hope despite challenges

Introduction

Human Immunodeficiency virus (HIV) is a virus that causes several diseases by attacking the human immune system. It is transmitted by contact with certain bodily fluids of an infected person, most commonly during unprotected sex, through sharing needles, or from mother to baby during pregnancy, birth or breastfeeding. The central nervous system is not spared from this virus, as HIV has been shown to induce several neurological disorders. However most neurological pathologies (such as dementia, infections, meningitis, and neuropathy) rarely show until late stages, in this case, after the patients develop acquired immunodeficiency syndrome (AIDS). This article aims to review the neurological disorders in the HIV population and the attempts initiated to limit the disease.

Methodology

Data were collected from medical journals published on PubMed, Ovid MEDLINE, Science Direct and Embase bibliographical databases with a predefined search strategy. All articles considering neurological disorders associated with HIV were considered.

Results

To date, the pathogenesis of HIV‐associated neurological complications remains poorly elucidated; thus, imposing a hindrance and limitations on the treatment options. Nevertheless, some studies have reported alterations in dendritic spine as the causative agent for developing brain damage.

Conclusion

HIV remains one of the most serious global health challenges, with neurological manifestations imposing a major concern among patients with HIV. Despite the availability and efficacy of antiretroviral therapies, yet, the risk of developing neurological complications remains relatively high among patients with HIV. Thus, the 2030 HIV vision must focus on further preventive measures to protect HIV patients from developing such neurological complications.

Validity of Digital Assessments in Screening for HIV-Related Cognitive Impairment: a Review

PURPOSE OF REVIEW

While traditional neuropsychological tests are the gold standard in screening for HIV-related cognitive impairment, computerized neuropsychological assessment devices (CNADs) offer an alternative to these time- and resource-intensive batteries and may prove to be particularly useful for remote assessments or longitudinal monitoring. This review seeks to describe the benefits, limitations, and validity of CNADs in the evaluation of HIV-associated neurocognitive disorder (HAND).

RECENT FINDINGS

We identified eight CNADs that have undergone validity testing for cognitive impairment in the setting of HIV. Included among these are batteries that have been modeled after the traditional neuropsychological exam, as well as others that implement new technologies, such as simulated reality and daily ecological assessments in their testing. Currently, these digital batteries do not yet have the ability to supplant gold standard neuropsychological tests in screening for HAND. However, many have the potential to become effective clinical screening tools.

Screening for HIV-Associated Neurocognitive Disorders: Sensitivity and Specificity

HIV-associated neurocognitive disorder (HAND) remains prevalent among people living with HIV (PLWH), especially the mild forms, even those with well-controlled HIV. Recommendations from the literature suggest routine and regular screening for HAND to detect it early and manage it effectively and adjust treatments, if warranted, when present. However, screening for HAND is not routinely done, as there are no current guidelines on when to screen and which test or tests to use. Furthermore, many of the available screening tools for HAND often cannot accurately detect the mild forms of HAND and require highly trained healthcare professionals to administer and score the tests, a requirement that is not feasible for those low- and middle-income countries with the highest HIV incidence and prevalence rates. The purpose of this chapter was to review recent research on screening tests to detect HAND and report on the strengths, limitations, and psychometric properties of those tests to detect HAND.

The Relationship Between Central Auditory Tests and Neurocognitive Domains in Adults Living With HIV

Objective: Tests requiring central auditory processing, such as speech perception-in-noise, are simple, time efficient, and correlate with cognitive processing. These tests may be useful for tracking brain function. Doing this effectively requires information on which tests correlate with overall cognitive function and specific cognitive domains. This study evaluated the relationship between selected central auditory focused tests and cognitive domains in a cohort of normal hearing adults living with HIV and HIV- controls. The long-term aim is determining the relationships between auditory processing and neurocognitive domains and applying this to analyzing cognitive function in HIV and other neurocognitive disorders longitudinally. Method: Subjects were recruited from an ongoing study in Dar es Salaam, Tanzania. Central auditory measures included the Gap Detection Test (Gap), Hearing in Noise Test (HINT), and Triple Digit Test (TDT). Cognitive measures included variables from the Test of Variables of Attention (TOVA), Cogstate neurocognitive battery, and Kiswahili Montreal Cognitive Assessment (MoCA). The measures represented three cognitive domains: processing speed, learning, and working memory. Bootstrap resampling was used to calculate the mean and standard deviation of the proportion of variance explained by the individual central auditory tests for each cognitive measure. The association of cognitive measures with central auditory variables taking HIV status and age into account was determined using regression models. Results: Hearing in Noise Tests and TDT were significantly associated with Cogstate learning and working memory tests. Gap was not significantly associated with any cognitive measure with age in the model. TDT explained the largest mean proportion of variance and had the strongest relationship to the MoCA and Cogstate tasks. With age in the model, HIV status did not affect the relationship between central auditory tests and cognitive measures. Age was strongly associated with multiple cognitive tests. Conclusion: Central auditory tests were associated with measures of learning and working memory. Compared to the other central auditory tests, TDT was most strongly related to cognitive function. These findings expand on the association between auditory processing and cognitive domains seen in other studies and support evaluating these tests for tracking brain health in HIV and other neurocognitive disorders.

Rates of cognitive impairment in a South African cohort of people with HIV: variation by definitional criteria and lack of association with neuroimaging biomarkers

There is wide variation in the reported prevalence of cognitive impairment in people with HIV (PWH). Part of this variation may be attributable to different studies using different methods of combining neuropsychological test scores to classify participants as either cognitively impaired or unimpaired. Our aim was to determine, in a South African cohort of PWH (N = 148), (a) how much variation in reported rates was due to method used to define cognitive impairment and (b) which method correlated best with MRI biomarkers of HIV-related brain pathology. Participants completed detailed neuropsychological assessment and underwent 3 T structural MRI and diffusion tensor imaging (DTI). We used the neuropsychological data to investigate 20 different methods of determining HIV-associated cognitive impairment. We used the neuroimaging data to obtain volumes for cortical and subcortical grey matter and total white matter and DTI metrics for several white matter tracts. Applying each of the 20 methods to the cognitive dataset resulted in a wide variation (20-97%) in estimated rates of impairment. Logistic regression models showed no method was associated with HIV-related neuroimaging abnormalities as measured by structural volumes or DTI metrics. We conclude that for the population from which this sample was drawn, much of the variation in reported rates of cognitive impairment in PWH is due to the method of classification used, and that none of these methods accurately reflects biological effects of HIV in the brain. We suggest that defining HIV-associated cognitive impairment using neuropsychological test performance only is insufficient; pre-morbid functioning, co-morbidities, cognitive symptoms, and functional impairment should always be considered.

Cognitive ageing is premature among a community sample of optimally treated people living with HIV

OBJECTIVES

Evidence of premature cognitive ageing amongst people living with HIV (PLHIV) remains controversial due to previous research limitations including underpowered studies, samples with suboptimal antiretroviral access, varying rate of virological control, high rate of AIDS, over-representation of non-community samples, and inclusion of inappropriate controls. The current study addresses these limitations, while also considering mental health and non-HIV comorbidity burden to determine whether PLHIV showed premature cognitive ageing compared with closely comparable HIV-negative controls.

METHODS

This study enrolled 254 PLHIV [92% on antiretroviral therapy; 84% with HIV RNA < 50 copies/mL; 15% with AIDS) and 72 HIV-negative gay and bisexual men [mean (SD) age = 49 (10.2) years] from a single primary care clinic in Sydney, Australia. Neurocognitive function was evaluated with the Cogstate Computerized Battery (CCB) at baseline and 6 months after. Linear mixed-effects (LME) models examined main and interaction effects of HIV status and chronological age on the CCB demographically uncorrected global neurocognitive z-score (GZS), adjusting for repeated testing, and then adjusting sequentially for HIV disease markers, mental health and comorbidities.

RESULTS

HIV status and age interacted with a lower GZS (β = -0.43, P < 0.05). Higher level of anxiety symptoms (β = -0.11, P < 0.01), historical AIDS (β = -0.12, P < 0.05) and historical HIV brain involvement (β = -0.12, P < 0.05) were associated with lower GZS.

CONCLUSIONS

We found a robust medium-sized premature ageing effect on cognition in a community sample with optimal HIV care. Our study supports routine screening of cognitive and mental health among PLHIV aged ≥ 50 years.

Central Auditory Tests to Track Cognitive Function in People With HIV: Longitudinal Cohort Study

Background

The development of neurocognitive deficits in people infected with HIV is a significant public health problem. Previous cross-sectional studies have shown that performance on central auditory tests (CATs) correlates with cognitive test results in those with HIV, but no longitudinal data exist for confirmation. We have been performing longitudinal assessments of central auditory and cognitive function on a cohort of HIV-positive and HIV-negative individuals in Dar es Salaam, Tanzania to understand how the central auditory system could be used to study and track the progress of central nervous system dysfunction.

Objective

The goal of the project was to determine if CATs can track the trajectory of cognitive function over time in people diagnosed with HIV.

Methods

Tests of peripheral and central auditory function as well as cognitive performance were performed on 382 individuals over the course of 3.5 years. Visits were scheduled every 6 months. CATs included tests of auditory temporal processing (gap detection) and speech perception in noise (Hearing in Noise Test and Triple Digit Test). Cognitive tests included the Montreal Cognitive Assessment (MoCA), Test of Variables of Attention (TOVA), and subtests from the Cogstate battery. HIV-positive subjects were divided into groups based on their CAT results at their final visit (bottom 20%, top 20%, middle 60%). Primary analyses focused on the comparison between HIV-positive individuals that performed worse on CATs (bottom 20%) and the overall HIV-positive group (middle 60%). Data were analyzed using linear mixed-effect models with time as the main fixed effect.

Results

The group with the worst (bottom 20%) CAT performance showed a difference in trajectory for the MoCA (P=.003), TOVA (P<.048), and Cogstate (P<.046) over the course of the study period compared to the overall HIV-positive group. A battery of three CATs showed a significant difference in cognitive trajectory over a relatively short study period of 3.5 years independent of age (bottom 20% vs HIV-positive group).

Conclusions

The results of this study support the ability for CATs to track cognitive function over time, suggesting that central auditory processing can provide a window into central nervous system performance. CATs can be simple to perform, and are relatively insensitive to education and socioeconomic status because they only require repeating sentences, numbers, or detecting gaps in noise. These tests could potentially provide a time-efficient, low-cost method to screen for and monitor cognitive decline in patients with HIV, making them a useful surveillance tool for this major public health problem.

Liver steatosis and nonalcoholic fatty liver disease with fibrosis are predictors of frailty in people living with HIV

OBJECTIVE

The aim was to investigate the contribution of liver steatosis and significant fibrosis alone and in association [nonalcoholic fatty liver disease (NAFLD) with fibrosis] to frailty as a measure of biological age in people living with HIV (PLWH).

DESIGN

This was a cross-sectional study of consecutive patients attending Modena HIV Metabolic Clinic in 2018-2019.

METHODS

Patients with hazardous alcohol intake and viral hepatitis coinfection were excluded. Liver steatosis was diagnosed by controlled attenuation parameter (CAP), while liver fibrosis was diagnosed by liver stiffness measurement (LSM). NAFLD was defined as presence of liver steatosis (CAP ≥248 dB/m), while significant liver fibrosis or cirrhosis (stage ≥F2) as LSM at least 7.1 kPa. Frailty was assessed using a 36-Item frailty index. Logistic regression was used to explore predictors of frailty using steatosis and fibrosis as covariates.

RESULTS

We analysed 707 PLWH (mean age 53.5 years, 76.2% men, median CD4 cell count 700 cells/μl, 98.7% with undetectable HIV RNA). NAFLD with fibrosis was present in 10.2%; 18.9 and 3.9% of patients were classified as frail and most-frail, respectively. Univariate analysis demonstrated that neurocognitive impairment [odds ratio (OR) = 5.1, 1.6-15], vitamin D insufficiency (OR = 1.94, 1.2-3.2), obesity (OR = 8.1, 4.4-14.6), diabetes (OR = 3.2, 1.9-5.6), metabolic syndrome (OR = 2.41, 1.47-3.95) and osteoporosis (OR = 0.37, 0.16-0.76) were significantly associated with NAFLD with fibrosis. Predictors of frailty index included steatosis (OR = 2.1, 1.3-3.5), fibrosis (OR = 2, 1-3.7), NAFLD with fibrosis (OR = 9.2, 5.2-16.8), diabetes (OR = 1.7, 1-2.7) and multimorbidity (OR = 2.5, 1.5-4).

CONCLUSION

Liver steatosis and NAFLD with fibrosis were associated with frailty. NAFLD with fibrosis exceeded multimorbidity in the prediction of frailty, suggesting the former as an indicator of metabolic age in PLWH.

An examination of reliable change methods for measuring cognitive change with the Cogstate Computerized Battery: Research and clinical implications

Objective

To compare the performance of four reliable change (RC) methods with respect to measuring cognitive change on the Cogstate Computerized Battery (CCB).

Method

We assessed cognitive change in 57 healthy, urban, well-educated males on the CCB at baseline and 6 months (Median age = 50, 65% university-educated). The study CCB version comprised seven measures covering attention, processing speed, verbal learning, and memory. Raw scores were z-score transformed using age-corrected Cogstate norms (CN) or the sample mean and standard deviation (internal standardization [IS]), and then averaged to create composite z-scores. Composite scores were entered into four RC formulae. RC was defined based on a 90% two-tailed confidence interval. Change scores were compared as continuous (z-scores) and ordinal variables (RC outcomes).

Results

CCB composite score reliability (rXY = .78–.79) was replicated in an age- and sex-matched Cogstate database sample of similar size. There was good overall agreement between the four RC methods (Bland–Altman Mdiff = .00; 95% limits of agreement with the mean—CN: z = ± .90; IS: z = ± .93), with each model adhering closely to the 10% rate of RC expected by chance alone (largest χ2 = .86, p = .99). Initial norming strategy (CN or IS) did not affect these outcomes.

Conclusions

Norming strategy and RC method choice did not significantly impact cognitive change predictions on CCB composite scores. A series of example case data are provided to practically demonstrate the steps involved in applying the longitudinal norms generated in this study. Research in more diverse normative samples is warranted.

Measurement of executive functioning with the National Institute of Health Toolbox and the association to anxiety/depressive symptomatology in childhood/adolescence

INTRODUCTION

Despite preliminary research, there remain inconsistent findings with regard to the role of executive functioning (EF) deficits in childhood anxiety and depression. This report examined the association of The National Institute of Health (NIH) Toolbox to clinical neuropsychological measures and to childhood, anxiety/depressive symptomatology. Methods: One-hundred eight children and adolescents completed the three EF measures from the NIH Toolbox (List Sorting Working Memory Test [LSWMT], Dimensional Change Card Sorting Test [DCCST], and Flanker Test of Attention and Inhibition [Flanker]) in an outpatient neuropsychology program. These tests were compared to established measures of EF in terms of linear correlations and detection of impairment. Heaton's Global Deficit Score (GDS) was utilized to calculate impairment. The Toolbox-EF measures were paired with parent-reported EF symptoms (Behavior Rating Inventory of Executive Function [BRIEF2]) to identify the role of EF in childhood anxiety/depressive symptomatology.

RESULTS

Toolbox-EF measures displayed medium sized correlations with their clinically comparable counterparts, and generally did not differ in their detection of impairment. Toolbox-GDS was associated with depression diagnosis and clinically significant child-reported anxiety and depressive symptoms. Together, Toolbox/BRIEF2 accounted for 26.8-30.9% of elevated depressive symptom variance, but only 13.2-14% of elevated anxiety symptom variance. Further, EF impairment was associated with depression across self report, parent report, and clinical diagnosis.

DISCUSSION

The NIH Toolbox-EF measures display comparable psychometric properties to clinically available EF measures in a pediatric (primarily psychiatric) neuropsychology setting. The Toolbox appears to display an appropriate ability to detect EF deficits secondary to self-reported depression in childhood.

Neurocognitive heterogeneity across the spectrum of psychopathology: need for improved approaches to deficit detection and intervention

Neurocognition is one of the strongest predictors of clinical and functional outcomes across the spectrum of psychopathology, yet there remains a dearth of unified neurocognitive nosology and available neurocognition-targeted interventions. Neurocognitive deficits manifest in a transdiagnostic manner, with no psychiatric disorder uniquely affiliated with one specific deficit. In fact, recent research has identified that essentially all investigated disorders are comprised of 3-4 neurocognitive profiles. This within-disorder neurocognitive heterogeneity has hampered the development of novel, neurocognition-targeted interventions, as only a portion of patients with any given disorder possess neurocognitive deficits that would warrant neurocognitive intervention. The development of criteria and terminology to characterize these neurocognitive deficit syndromes would provide clinicians with the opportunity to more systematically identify and treat their patients and provide researchers the opportunity to develop neurocognition-targeted interventions for patients. This perspective will summarize recent work and discuss possible approaches for neurocognition-focused diagnosis and treatment in psychiatry.

Measurement of Human Immunodeficiency Virus p24 Antigen in Human Cerebrospinal Fluid With Digital Enzyme-Linked Immunosorbent Assay and Association With Decreased Neuropsychological Performance

New tools are needed to understand human immunodeficiency virus central nervous system involvement. Testing 15 cerebrospinal fluid (CSF) samples for p24 antigen, using a high-sensitivity assay, we found a strong correlation trend between CSF p24 concentration and worse neuropsychological performance.

Machine learning models reveal neurocognitive impairment type and prevalence are associated with distinct variables in HIV/AIDS

Neurocognitive impairment (NCI) among HIV-infected patients is heterogeneous in its reported presentations and frequencies. To determine the prevalence of NCI and its associated subtypes as well as predictive variables, we investigated patients with HIV/AIDS receiving universal health care. Recruited adult HIV-infected subjects underwent a neuropsychological (NP) test battery with established normative (sex-, age-, and education-matched) values together with assessment of their demographic and clinical variables. Three patient groups were identified including neurocognitively normal (NN, n = 246), HIV-associated neurocognitive disorders (HAND, n = 78), and neurocognitively impaired-other disorders (NCI-OD, n = 46). Univariate, multiple logistic regression and machine learning analyses were applied. Univariate analyses showed variables differed significantly between groups including birth continent, quality of life, substance use, and PHQ-9. Multiple logistic regression models revealed groups again differed significantly for substance use, PHQ-9 score, VACS index, and head injury. Random forest (RF) models disclosed that classification algorithms distinguished HAND from NN and NCI-OD from NN with area under the curve (AUC) values of 0.87 and 0.77, respectively. Relative importance plots derived from the RF model exhibited distinct variable rankings that were predictive of NCI status for both NN versus HAND and NN versus NCI-OD comparisons. Thus, NCI was frequently detected (33.5%) although HAND prevalence (21%) was lower than in several earlier reports underscoring the potential contribution of other factors to NCI. Machine learning models uncovered variables related to individual NCI types that were not identified by univariate or multiple logistic regression analyses, highlighting the value of other approaches to understanding NCI in HIV/AIDS.

Neuropathogenesis of human immunodeficiency virus infection

Human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) remain a common end-organ manifestation of viral infection. Subclinical and mild symptoms lead to neurocognitive and behavioral abnormalities. These are associated, in part, with viral penetrance and persistence in the central nervous system. Infections of peripheral blood monocytes, macrophages, and microglia are the primary drivers of neuroinflammation and neuronal impairments. While current antiretroviral therapy (ART) has reduced the incidence of HIV-associated dementia, milder forms of HAND continue. Depression, comorbid conditions such as infectious liver disease, drugs of abuse, antiretroviral drugs themselves, age-related neurodegenerative diseases, gastrointestinal maladies, and concurrent social and economic issues can make accurate diagnosis of HAND challenging. Increased life expectancy as a result of ART clearly creates this variety of comorbid conditions that often blur the link between the virus and disease. With the discovery of novel biomarkers, neuropsychologic testing, and imaging techniques to better diagnose HAND, the emergence of brain-penetrant ART, adjunctive therapies, longer life expectancy, and better understanding of disease pathogenesis, disease elimination is perhaps a realistic possibility. This review focuses on HIV-associated disease pathobiology with an eye towards changing trends in the face of widespread availability of ART.

HIV-Associated Neurocognitive Disorders: A Global Perspective

The present review on HIV-associated neurocognitive disorders (HAND) provides a worldwide overview of studies that have investigated the rate and neuropsychological (NP) profile of HAND research since the inception of the 2007 HAND diagnostic nomenclature. In the first part, the review highlights some of the current controversies around HAND prevalence rates. In the second part, the review critically assesses some solutions to move the field forward. In the third part, we present the cross-sectional NP profile in non-Western HIV+ cohorts and in relation to Western cohorts' findings. The adopted global perspective highlights the successful expansion of NP studies in HIV infection to culturally diverse low- to medium-income countries with high HIV burden. These studies have produced interestingly similar rates of HAND whether patients were naïve or treated and/or virally suppressed compared to the rich income countries where the NP research in NeuroHIV has originated. The perspective also demonstrates that globally, the group which is the most representative of the HIV epidemic, and thus at risk for HAND are persons with chronic HIV infection and survivors of past immunosuppression, while in relative terms, those who have been treated early with long-term viral suppression represent a minority. In the last part, we present a review of the naturalistic longitudinal NP global studies in HIV+cohorts, discuss the role of longitudinal design in solving issues around the question of asymptomatic neurocognitive impairment, and the question of biomarker discovery. Finally, we conclude by calling for greater methods and data harmonization at a global level. (JINS, 2017, 23, 860-869).