Cognitive reserve and neuropsychological functioning in older HIV-infected people

Biopsychosocial phenotypes in people with HIV in the CHARTER cohort

Neuropsychiatric complications such as neurocognitive impairment and depression are common in people with HIV despite viral suppression on antiretroviral therapy, but these conditions are heterogeneous in their clinical presentations and associated disability. Identifying novel biopsychosocial phenotypes that account for neurocognitive performance and depressive and functional symptoms will better reflect the complexities encountered in clinical practice and may have pathological and therapeutic implications. We classified 1580 people with HIV based on 17 features, including 7 cognitive domains, 4 subscales of the Beck depression inventory-II, 5 components of the patient's assessment of own functioning inventory, and dependence in instrumental and basic activities of daily living. A two-stage clustering procedure consisting of dimension reduction with self-organizing maps and Mahalanobis distance-based k-means clustering algorithms was applied to cross-sectional data. Baseline demographic and clinical characteristics were compared between the phenotypes, and their prediction on the biopsychosocial phenotypes was evaluated using multinomial logistic regression. Four distinct phenotypes were identified. Participants in Phenotype 1 overall did well in all domains. Phenotype 2 had mild-to-moderate depressive symptoms and the most substance use disorders. Phenotype 3 had mild-to-moderate cognitive impairment, moderate depressive symptoms, and the worst daily functioning; they also had the highest proportion of females and non-HIV conditions that could affect cognition. Phenotype 4 had mild-to-moderate cognitive impairment but with relatively good mood, and daily functioning. Multivariable analysis showed that demographic characteristics, medical conditions, lifetime cocaine use disorder, triglycerides, and non-antiretroviral therapy medications were important variables associated with biopsychosocial phenotype. We found complex, multidimensional biopsychosocial profiles in people with HIV that were associated with different risk patterns. Future longitudinal work should determine the stability of these phenotypes, assess factors that influence transitions from one phenotype to another, and characterize their biological associations.

The utility of the Cognitive Reserve Index questionnaire in chronic traumatic brain injury

Objective: This study examined the relationship between cognitive reserve measured with the Cognitive Reserve Index questionnaire (CRIq) and cognitive and functional outcomes in a chronic traumatic brain injury (TBI) cohort compared to a non-TBI cohort. The utility of the CRIq was compared to common proxies of cognitive reserve (premorbid IQ and years of education) in TBI and non-TBI cohorts. Method: Participants were 105 individuals with moderate-severe TBI (10-33 years post injury) and 91 participants without TBI. Cognitive outcome was examined across four cognitive factors; verbal memory, visual ability and memory, executive attention, and episodic memory. Functional outcome was measured using the Glasgow Outcome Scale Extended. The CRIq total score and three subscale scores (education, work, leisure) were examined. Results: In the TBI cohort, associations were identified between two CRIq subscales and cognitive factors (CRIq education and verbal memory; CRIq work and executive attention). There were no associations between CRIq leisure and cognitive outcomes, or between CRIq and functional outcome. Model selection statistics suggested premorbid IQ and years of education provided a better fit than the CRIq for the relationship between cognitive reserve with two cognitive factors and functional outcome, with neither model providing an improved fit for the remaining two cognitive factors. This finding was broadly consistent in the non-TBI cohort. Conclusion: Cognitive reserve contributes significantly to long-term clinical outcomes following moderate-severe TBI. The relationship between cognitive reserve and long-term cognitive and functional outcomes following TBI is best characterised with traditional proxies of cognitive reserve, mainly premorbid IQ, rather than the CRIq.

The relationship between synaptodendritic neuropathology and HIV-associated neurocognitive disorders is moderated by cognitive reserve

We examined whether cognitive reserve moderated the relationship between neurodegeneration and cognition in 67 postmortem persons with HIV (PWH) who were cognitively assessed within 1 year of death. Cognitive reserve was measured via the Wide Range Achievement Test-4 reading subtest (WRAT4). Synaptodendritic neurodegeneration was based on densities of synaptophysin and microtubule-associated protein 2 immunohistochemical reactivity in frontal cortex, and categorized as minimal, moderate, or severe (tertile-split). T-Scores from 15 cognitive tests were averaged into a global cognitive T-score. Among those with low cognitive reserve (based on WRAT4 median split), the moderate neurodegeneration group showed cognition that was poorer than the minimal neurodegeneration group and comparable to the severe neurodegeneration group. Among those with high cognitive reserve, the moderate neurodegeneration group showed cognition comparable to the minimal neurodegeneration group and better than the severe neurodegeneration group. High cognitive reserve may buffer against cognitive impairment among PWH with moderate, but not severe, neurodegeneration.

Cognitive reserve attenuates the association between HIV serostatus and cognitive performance in adults living in the deep South

Cognitive reserve has shown evidence of mitigating HIV-related effects on cognition in people living with HIV (PWH). In a sample of adults residing in the Deep South, an underrepresented subgroup in the neuroAIDS literature, we assessed the association between HIV serostatus and age on processing speed, visual attention, executive function, and episodic memory and the attenuating effect of cognitive reserve. Adults (n = 138; 72 PWH; M age = 58.7 years, SD = 7.9 years; 75% nonwhite race) were recruited from a university clinic and the community. Verbal abilities served as a proxy for cognitive reserve. Regressions accounting for race, alcohol usage, and depressive symptoms were conducted for each cognitive outcome. Indirect effects were tested using the PROCESS macro. Being HIV seropositive was associated with worse executive function (b = -1.04, SE = 0.38, p = .007) and episodic memory (b = -39.94, SE = 12.54, p = .002) performance. Every year of age above the mean and nonwhite race was associated with worse cognitive performance (ps < .05). The addition of cognitive reserve to the model attenuated the HIV serostatus associations with executive function (BC 95% CI -0.770, -0.001) along with most associations between race and cognitive outcomes. Age associations remained for all cognitive outcomes (ps < .05). Findings highlight the importance of including verbal ability proxies of cognitive reserve when assessing cognition in PWH. Highlighting modifiable cognitive processes, such as cognitive reserve, will further the development of targeted cognitive interventions in this at-risk population.

Difference in the neurocognitive functions of WLWH and MLWH in an Italian cohort of people living with HIV

Based on the available literature, women living with HIV (WLWH) seem to show greater cognitive and emotional disadvantages than men living with HIV (MLWH). Our aim was to compare the cognitive performance of MLWH and WLWH in an Italian cohort of People Living With HIV (PLWH) and to analyse factors potentially contributing to sex differences in cognitive function. We ran a retrospective, cross-sectional analysis of a monocentric dataset of PLWH who were administered a standardized neuropsychological test battery (SNB) during routine clinical care. We enrolled 161 Italian PLWH who are on combined antiretroviral therapy (cART): 114 (70.8%) MLWH and 47 (29.2%) WLWH.

Global cognitive performance (composite z score) (GCP) was significantly higher in MLWH than WLWH [mean 0.19 (SD 0.85) vs − 0.13 (SD 0.96); p = 0.039]. Moreover, WLWH obtained significantly higher scores on the Zung Depression Scale than MLWH [mean 41.8 (SD 10.9) vs 36.7 (SD 9.2); p = 0.003]. However, there was no statistically significant direct effect between male sex and better GCP (p = 0.692) in the context of a mediation model. On the contrary, the associations between male sex and better GCP were mediated by higher level of education (a*b =  + 0.15, Bootstrap CI95 = 0.05 and 0.27) and a lower Zung depression score (a*b =  + 0.10, Bootstrap CI95 = 0.02 and 0.21).

In conclusion, the global cognitive performance of WLWH is lower than that of MLWH. However, other demographic and clinical factors besides sex might help explain differences in their neurocognitive functions and make it possible for us to monitor them and identify those patients most in need.

Machine Learning Quantifies Accelerated White-Matter Aging in Persons With HIV

BACKGROUND

Persons with HIV (PWH) undergo white matter changes, which can be quantified using the brain-age gap (BAG), the difference between chronological age and neuroimaging-based brain-predicted age. Accumulation of microstructural damage may be accelerated in PWH, especially with detectable viral load (VL).

METHODS

In total, 290 PWH (85% with undetectable VL) and 165 HIV-negative controls participated in neuroimaging and cognitive testing. BAG was measured using a Gaussian process regression model trained to predict age from diffusion magnetic resonance imaging in publicly available normative controls. To test for accelerated aging, BAG was modeled as an age × VL interaction. The relationship between BAG and global neuropsychological performance was examined. Other potential predictors of pathological aging were investigated in an exploratory analysis.

RESULTS

Age and detectable VL had a significant interactive effect: PWH with detectable VL accumulated +1.5 years BAG/decade versus HIV-negative controls (P = .018). PWH with undetectable VL accumulated +0.86 years BAG/decade, although this did not reach statistical significance (P = .052). BAG was associated with poorer global cognition only in PWH with detectable VL (P < .001). Exploratory analysis identified Framingham cardiovascular risk as an additional predictor of pathological aging (P = .027).

CONCLUSIONS

Aging with detectable HIV and cardiovascular disease may lead to white matter pathology and contribute to cognitive impairment.

Development and Validation of a Cognitive Reserve Index in HIV

OBJECTIVES

In the neuroHIV literature, cognitive reserve has most often been operationalized using education, occupation, and IQ. The effects of other cognitively stimulating activities that might be more amenable to interventions have been little studied. The purpose of this study was to develop an index of cognitive reserve in people with HIV, combining multiple indicators of cognitively stimulating lifetime experiences into a single value.

METHODS

The data set was obtained from a Canadian longitudinal study (N = 856). Potential indicators of cognitive reserve captured at the study entry included education, occupation, engagement in six cognitively stimulating activities, number of languages spoken, and social resources. Cognitive performance was measured using a computerized test battery. A cognitive reserve index was formulated using logistic regression weights. For the evidence on concurrent and predictive validity of the index, the measures of cognition and self-reported everyday functioning were each regressed on the index scores at study entry and at the last follow-up [mean duration: 25.9 months (SD 7.2)], respectively. Corresponding regression coefficients and 95% confidence intervals (CIs) were computed.

RESULTS

Professional sports [odds ratio (OR): 2.9; 95% CI 0.59-14.7], visual and performance arts (any level of engagement), professional/amateur music, complex video gaming and competitive games, and travel outside North America were associated with higher cognitive functioning. The effects of cognitive reserve on the outcomes at the last follow-up visit were closely similar to those at study entry.

CONCLUSION

This work contributes evidence toward the relative benefit of engaging in specific cognitively stimulating life experiences in HIV.

Evidence for neuropsychological health disparities in Black Americans with HIV disease

OBJECTIVE

Black Americans are at high risk for HIV disease and associated morbidity. The impact and clinical correlates of HIV-associated neurocognitive impairment among Black Americans is not fully understood. The current study uses a full factorial design to examine the independent and combined effects of race and HIV disease on neurocognitive functioning, including its associations with everyday functioning and clinical disease markers in Black and White persons with HIV (PWH).

METHOD

Participants included 40 Black PWH, 83 White PWH, 28 Black HIV- and 64 White HIV- individuals. Neurocognition was measured by raw sample-based z-scores from a clinical battery. Everyday functioning was assessed using self- and clinician-rated measures of cognitive symptoms and activities of daily living. HIV-associated neurocognitive disorders were also classified using demographically adjusted normative standards and the Frascati criteria.

RESULTS

We observed a significant three-way interaction between HIV, race, and domain on raw neurocognitive z-scores. This omnibus effect was driven by medium and large effect size decrements in processing speed and semantic memory, respectively, in Black PWH compared to other study groups. Black PWH also demonstrated higher frequencies of HIV-associated neurocognitive disorders as compared to White PWH. Unexpectedly, global neurocognitive performance was negatively related to everyday functioning impairments for White PWH, but not for Black PWH.

CONCLUSIONS

Systemic disadvantages for Black Americans may combine with HIV disease to compound some neurocognitive impairments in this under-served population. Prospective studies are needed to identify better ways to prevent, measure, diagnose, and manage HIV-associated neurocognitive disorders among Black Americans.

Genome-wide association study detected novel susceptibility genes for social cognition impairment in people with schizophrenia

OBJECTIVES

People with schizophrenia (SCZ) present serious and generalised deficits in social cognition (SC), which affect negatively patients' functioning and treatment outcomes. The genetic background of SC has been investigated in disorders other than SCZ providing weak and sparse results. Thus, our aim was to explore possible genetic correlates of SC dysfunctions in SCZ patients with a genome-wide study (GWAS) approach.

METHODS

We performed a GWAS meta-analysis of data coming from two cohorts made of 242 and 160 SCZ patients, respectively. SC was assessed with different tools in order to cover its different domains.

RESULTS

We found GWAS significant association between the TMEM74 gene and the patients' ability in social inference as assessed by The Awareness of Social Inference Test; this association was confirmed by both SNP-based analysis (lead SNP rs3019332 p-value = 5.24 × 10^-9) and gene-based analysis (p-value = 1.09 × 10^-7). Moreover, suggestive associations of other genes with different dimensions of SC were also found.

CONCLUSIONS

Our study shows for the first time GWAS significant or suggestive associations of some gene variants with SC domains in people with SCZ. These findings should stimulate further studies to characterise the genetic underpinning of SC dysfunctions in SCZ.

The Turkish translation study of the Cognitive Reserve Index Questionnaire (CRIq)

BACKGROUND

Cognitive reserve (CR) is defined as the ability of individuals to use their brain in a flexible way to cope with brain pathologies and find alternative cognitive strategies.

AIM

The aim of this study was to adapt Cognitive Reserve Index Questionnaire (CRIq) for Turkish population.

METHODS

The CRIq was administered to 178 healthy participants from 18 to 80 years old.

RESULTS

The mean score of total CRI was found to be 97.7 indicating a medium level of CR. In line with the mean score, 68.6% of participants (n = 120) were found to have a medium level of CRI. The elderly group showed lowest total CRI as well as CRI-education, CRI-work, and CRI-leisure scores compared to young and middle-aged groups (p < .05, for all scores).

CONCLUSIONS

This study provided the first translated measure to assess CR in Turkish population.

The Impact of Antiretroviral Therapy on Neurocognitive Outcomes Among People Living with HIV in Low- and Middle-Income Countries (LMICs): A Systematic Review

Low and middle-income countries (LMICs) are the epicenter of the HIV epidemic. The scale-up of antiretroviral therapy (ART) has reduced mortality, but HIV-associated neurocognitive impairment (HANI) remains prevalent, which impacts functional performance, medication adherence, and quality of life. We aimed to evaluate the effect of ART on neurocognitive outcomes among people living with HIV/AIDS in LMICs and to identify determinants of these outcomes. We searched electronic databases and reference lists for studies published between 1996 and 2019. Two reviewers screened the primary studies for inclusion and performed the critical appraisal. Results were synthesized using the 'Synthesis without meta-analysis' approach through simple vote counting. We identified 31 studies conducted across four regions (Africa, Asia, South America, and Eastern Europe). Nine studies were cross-sectional, 15 were prospective, and seven were randomized controlled trials. The majority of the articles showed improved neurocognitive performance with ART use but found no association with treatment duration, regimen, central penetrating effectiveness, and conventional biomarkers. Despite the lack of appropriate norms and not accounting for practice effect in most studies, the evidence suggests ART is useful in the treatment of HIV-associated neurocognitive impairment (HANI) but limited in addressing legacy effects, and peripheral, and central viral reservoirs. Improved early ART treatment programs, viral reservoir eradication strategies, and identification of novel biomarkers will be critical in efforts to minimize HIV-associated neurocognitive impairment. PROSPERO registration: CRD42020152908.

Association between education level and HIV-associated neurocognitive disorder: a systematic review and meta-analysis

In the era of antiretroviral treatment, human immunodeficiency virus (HIV)-associated neurocognitive disorder (HAND) is common in HIV-positive (HIV+) patients, with an incidence of 30-50%. The relationship between education level and HAND has been evaluated in some studies, however, the results were inconsistent. The aim of this meta-analysis was to provide compelling evidence on the association between education level and the risk of HAND. Reports were searched for in the databases of Medline, Embase and PsyclNFO. Studies evaluating the relationship between education level and HAND in adult HIV+ patients were included. The pooled odds ratio/risk ratio was analysed by using the random-effects model. Two subgroup analyses were performed according to the adjustment of educational level in the neurocognitive impairment assessment and the income level. In total, 18 studies were included. Six studies and 12 studies reported education level as the continuous variable and categorical variable, respectively. The methods used for the assessment of neurocognitive impairment in included studies were neuropsychological battery tests (n = 10), HIV Dementia Scale (n = 1), the International HIV Dementia Scale (n = 6) and the Chinese version of the Montreal Cognitive Assessment (n = 1). The result showed that the risk of HAND in HIV+ patients who have lower education attainment was significantly higher than that in HIV+ patients who have higher education attainment. In conclusion, this meta-analysis demonstrated that HIV+ patients who have low education attainment carry higher risk of developing HAND compared with HIV+ patients who have high education attainment. This study highlighted the importance of early neurological screening for HIV+ patients who have low education level.

Daily Activities Related to Mobile Cognitive Performance in Middle-Aged and Older Adults: An Ecological Momentary Cognitive Assessment Study

Background

Daily activities have been associated with neurocognitive performance. However, much of this research has used in-person neuropsychological testing that requires participants to travel to a laboratory or clinic, which may not always be feasible and does not allow for the examination of real-time relationships between cognition and behavior. Thus, there is a need to understand the real-time relationship between activities in the real world and neurocognitive functioning to improve tracking of symptoms or disease states and aid in the early identification of neurocognitive deficits among at-risk individuals.

Objective

We used a smartphone-based ecological momentary cognitive assessment (EMCA) platform to examine real-time relationships between daily activities and neurocognitive performance (executive functioning and verbal learning) in the everyday environment of middle-aged and older adults with and without HIV.

Methods

A total of 103 adults aged 50-74 years (67 persons with HIV; mean age 59 years, SD 6.4) were recruited from the University of California, San Diego HIV Neurobehavioral Research Program and the San Diego community. Participants completed our EMCA protocol for 14 days. Participants reported their current daily activities 4 times per day; following 2 of the 4 daily ecological momentary assessment (EMA) surveys, participants were administered the mobile Color-Word Interference Test (mCWIT) and mobile Verbal Learning Test (mVLT), each once per day. Activities were categorized into cognitively stimulating activities, passive leisure activities, and instrumental activities of daily living (IADLs). We used multilevel modeling to examine the same-survey and lagged within-person and between-person effects of each activity type on mobile cognitive performance.

Results

On average, participants completed 91% of the EMA surveys, 85% of the mCWIT trials, and 80% of the mVLT trials, and they reported engaging in cognitively stimulating activities on 17% of surveys, passive leisure activities on 33% of surveys, and IADLs on 20% of surveys. Adherence and activity percentages did not differ by HIV status. Within-persons, engagement in cognitively stimulating activities was associated with better mCWIT performance (β=−1.12; P=.007), whereas engagement in passive leisure activities was associated with worse mCWIT performance (β=.94; P=.005). There were no lagged associations. At the aggregate between-person level, a greater percentage of time spent in cognitively stimulating activities was associated with better mean mVLT performance (β=.07; P=.02), whereas a greater percentage of time spent in passive leisure activities was associated with worse mean mVLT performance (β=−.07; P=.01). IADLs were not associated with mCWIT or mVLT performance.

Conclusions

Smartphones present unique opportunities for assessing neurocognitive performance and behavior in middle-aged and older adults’ own environment. Measurement of cognition and daily functioning outside of clinical settings may generate novel insights on the dynamic association of daily behaviors and neurocognitive performance and may add new dimensions to understanding the complexity of human behavior.

The University of California San Diego performance-based skills assessment: a useful tool to detect mild everyday functioning difficulties in HIV-infected patients with very good immunological condition

Everyday functioning (EF) impairment is frequent in people living with HIV (PLWH). Our aim was to better explore EF and its association with PLWH cognition, by administering both the IADL scale, the most common functional scale, and a new and ecologic multi-domain (communication and financial skills) tool to measure EF as the University of California San Diego (UCSD) Performance-Based Skills Assessment-Brief Version (UPSA-B). Eighty-five PLWH on cART with very good immunological condition and 23 age- and education-matched healthy controls (HC) were enrolled. PLWH underwent a standardized neuropsychological battery plus IADL, and cognitive impairment was defined according to Frascati criteria. Both groups underwent the UPSA-B. Only 6 subjects (7%) were affected by cognitive impairment (asymptomatic profile). While IADL score was at ceiling for all patients, the UPSA-B total score was significantly worse in PLWH when compared with HC [mean 82.1 (SD 9.3) vs 89.2 (SD 6.2); p < 0.001]. At communication subtest, PLWH group and HC were significantly different (p = 0.002), while no difference emerged at financial skills (p = 0.096). Higher score at UPSA-B was independently associated with better global cognitive performance (composite Z-score) (β 7.79; p < 0.001). Also considering each single cognitive domain, UPSA-B performance (both total and at subtests) confirmed the association with neurocognitive performance. In conclusion, UPSA-B seems to better discriminate EF impairment than IADL in PLWH, and it was associated with cognitive functions, also in the absence of symptomatic cognitive impairment. Thus, it appears a promising tool in the context of HIV infection to avoid misdiagnosis and to better detect also mild EF.

Frequency and Predictors of HIV-Related Cognitive Impairment in East Africa: The Africa Cohort Study (AFRICOS)

BACKGROUND

Medication adherence is a critical issue in achieving viral suppression targets, particularly in resource-limited countries. As HIV-related cognitive impairment (CI) impacts adherence, we examined frequency and predictors of CI in the African Cohort Study.

SETTING

Cross-sectional examination of enrollment data from President's Emergency Plan for AIDS Relief supported clinic sites.

METHODS

In a 30-minute cognitive assessment, CI was defined as -1SD on 2 tests or -2SD on one, as compared with 429 controls. We performed univariable and multivariable logistic and linear models examining clinical and demographic factors associated with CI and global neuropsychological performance (NP-6).

RESULTS

Two thousand four hundred seventy-two HIV+ participants from Kenya (n = 1503), Tanzania (n = 469), and Uganda (n = 500). The mean (SD) age was 39.7 (10.7) years, and 1452 (59%) were women. The majority reported completing or partially completing primary school (n = 1584, 64%). Mean (SD) current and nadir CD4 count were 463 (249) and 204 (221) cells/mm, respectively; 1689 (68%) were on combination antiretroviral therapy. Nine hundred thirty-nine (38%) HIV+ versus 113 (26%) HIV- individuals showed CI: (P < 0.001). We found significant effects of literacy [odds ratio (OR): 0.3; 95% CI: 0.2 to 0.4; P < 0.001] and World Health Organization stage 4 (OR: 1.5; 95% CI: 1.0 to 2.q; P = 0.046) on CI. Tanzanians (OR: 3.2; 95% CI: 2.4 to 4.3; P < 0.001) and Kenyans (OR: 2.0; 95% CI: 1.6 to 2.6; P < 0.001) had higher risk of CI compared with Ugandans. Results were relatively unchanged in predictive models of NP-6, with the only difference being an additional significant effect of current CD4 cell count (coeff: 0.0; 95% CI: 0.0 to 0.0; P = 0.005).

CONCLUSIONS

Literacy, country, World Health Organization stage, and current CD4 cell count were associated with increased risk of cognitive dysfunction. Our findings help optimize care practices in Africa, illustrating the importance of strategies for early and effective viral-immunological control.

Considerations on nosology for HIV-associated neurocognitive disorders: it is time to update?

AIMS

The prognosis and the clinical manifestations of HIV infection have changed with the introduction of the potent combination antiretroviral therapy (cART); however, up to 50% of patients meet research criteria for "HIV-associated neurocognitive disorders" (HAND) according with current nosology. The majority of patients affected by HAND, especially in cohorts with suppressed plasma viremia, showed an Asymptomatic Neurocognitive Impairment (ANI), without any functional impairment. After more than 10 years from the introduction of the current so-called "Frascati criteria", this mini-review aimed to address the emerging limitations in current diagnosis procedures.

METHODS

We discussed the most relevant literature on HAND prevalence, etiology, and diagnosis.

RESULTS

We addressed three main emerging issues: (1) the unclear clinical relevance of ANI entity; (2) the evidences that Frascati criteria could produce a significant overestimation of HAND; (3) the need to better identify patients with a higher risk to develop HAND requiring routine neuropsychological examinations.

CONCLUSIONS

Frascati criteria should be updated to better respond to the present characteristics of HIV + cohorts and to help clinicians in their cognitive and global management.

The association of memory disorders and chronic HIV disease in the antiretroviral therapy era: a systematic literature review

OBJECTIVES

Despite recent pharmacological progress, memory impairment is still frequently reported in people living with HIV. We aimed to conduct a systematic literature review investigating the presence of impairment of (sub)components of memory function in patients prescribed highly active antiretroviral therapy (ART).

METHODS

We adopted a cognitive neuropsychological model of memory function as the theoretical framework, distinguishing between a short-term working memory component and a long-term component of memory, along with their specific (sub)components. We systematically searched for the presence of impairment of each (sub)component in the selected papers. Careful consideration was given to study design and methods and control of covariates.

RESULTS

Only the central executive component of working memory has been consistently reported to be impaired in HIV infection. The other two (sub)components, namely the phonological loop and the visuospatial sketchpad, were unimpaired. Discordant results have been obtained as to verbal and visual episodic memory, as some authors reported an association with HIV infection, whereas others did not. There is little evidence for semantic memory deficit in HIV infection, while there are suggestions that the neural substrate of implicit memory may be damaged by the effects of HIV infection and inflammation. Most studies in this area have been conducted in small samples and with poor control for covariates. Thus, conclusions regarding the association of memory dysfunction with HIV infection are hampered by methodological issues such as selection bias and unmeasured confounding.

CONCLUSIONS

The task remains for future research to ascertain the impact of HIV infection on memory function.

Measuring Cognitive Reserve (CR) - A systematic review of measurement properties of CR questionnaires for the adult population

Aim

The aim of this systematic review was to summarize and critically appraise the quality of published literature on measurement properties of questionnaires assessing Cognitive Reserve (CR) in adults (>18 years).

Methods

We systematically searched for published studies on MEDLINE, PsycINFO, and Web of Science through August 2018. We evaluated the methodological quality of the included studies and the results on measurement properties based on a consensus-based standard checklist.

Results

The search strategy identified 991 publications, of which 37 were selected evaluating the measurement properties of six different questionnaires. Construct validity of the Cognitive Reserve Index questionnaire was most extensively evaluated, while evaluation of the remaining measurement properties of this questionnaire was scarce. Measurement properties of the Cognitive Reserve Questionnaire and the Cognitive Reserve Scale were assessed more completely. While the Lifetime of Experience Questionnaire seems to be the most thorough instrument, a finale recommendation for one specific questionnaire cannot be drawn, since about half of the measurement properties for each questionnaire were poorly or not assessed at all.

Conclusions

There is a need of high quality methodological studies assessing measurement properties of CR questionnaires, especially regarding content validity, structural validity, and responsiveness.

Trial registration

PROSPERO Registration number CRD42018107766.

Association between cognitive reserve and cognitive performance in people with HIV: a systematic review and meta-analysis

Cognitive reserve is a potential explanation for the disparity between brain pathology and its clinical manifestations. The main objective of this study was to estimate, based on published studies, the strength of the association between cognitive reserve and cognitive performance in individuals with HIV. A systematic literature search using Ovid MEDLINE, PsychINFO, and EMBASE was performed to identify studies published between 1990 and 2016 that quantified the association between cognitive reserve and cognitive performance in HIV. A random-effects meta-analysis was used to compute a summary estimate (Cohen's d) with 95% confidence intervals (CI) and 95% prediction intervals (PI). The risk of bias and quality of reporting in the studies were indicated by the Appraisal tool for Cross-Sectional Studies (AXIS). Ten observational studies were deemed eligible. The pooled effect size was 0.9 (95% CI: 0.7-1.0; 95% PI: 0.4-1.4) with marked heterogeneity studies [Cochran's Q (df = 9) = 28.0, p = .0009; I² statistic = 67.4%]. Risk-of-bias appraisal showed that non-response bias was never addressed and the items associated with selection bias were only partially met. The association between cognitive reserve and cognitive performance suggests that building reserve through non-pharmacological interventions could be a potentially effective way of combating cognitive impairment in people with HIV.

Aging, comorbidities, and the importance of finding biomarkers for HIV-associated neurocognitive disorders

HIV-associated neurocognitive disorders (HAND) continue to affect a large proportion of persons living with HIV despite effective viral suppression with combined antiretroviral therapy (cART). Importantly, milder versions of HAND have become more prevalent. The pathogenesis of HAND in the era of cART appears to be multifactorial with contributions from central nervous system (CNS) damage that occur prior to starting cART, chronic immune activation, cART neurotoxicity, and various age-related comorbidities (i.e., cardiovascular and cerebrovascular disease, diabetes, hyperlipidemia). Individuals with HIV may experience premature aging, which could also contribute to cognitive impairment. Likewise, degenerative disorders aside from HAND increase with age and there is evidence of shared pathology between HAND and other neurodegenerative diseases, such as Alzheimer's disease, which can occur with or without co-existing HAND. Given the aforementioned complex interactions associated with HIV, cognitive impairment, and aging, it is important to consider an age-appropriate differential diagnosis for HAND as the HIV-positive population continues to grow older. These factors make the accuracy and reliability of the diagnosis of mild forms of HAND in an aging population of HIV-infected individuals challenging. The complexity of current diagnosis of mild HAND also highlights the need to develop reliable biomarkers. Ultimately, the identification of a set of specific biomarkers will be required to achieve early and accurate diagnosis, which will be necessary assuming specific treatments for HAND are developed.

Liver fibrosis is associated with cognitive impairment in people living with HIV

PURPOSE

Our aim was to better explore the association between liver fibrosis (LF) and neurocognitive impairment (NCI) in people living with HIV (PLWH).

METHODS

We performed a cross-sectional cohort study by consecutively enrolling PLWH at two clinical centers. All subjects underwent a comprehensive neuropsychological battery; NCI was defined as having a pathological performance (1.5 SD below the normative mean) on at least two cognitive domains. LF was explored using FIB4 index; in a subgroup of PLWH, LF was also assessed by transient elastography.

RESULTS

A total of 386 subjects were enrolled, of whom 17 (4.4%) had FIB4 > 3.25. In the subgroup of PLWH (N = 127) performing also liver transient elastography, 14 (11%) had liver stiffness > 14 kPa. Overall, 47 subjects (12%) were diagnosed with NCI. At multivariate regression analyses, participants with FIB4 > 1.45 showed a higher risk of NCI in comparison with those with lower values (aOR 3.04, p = 0.044), after adjusting for education (aOR 0.71, p < 0.001), past AIDS-defining events (aOR 2.91, p = 0.014), CD4 cell count, past injecting drug use (IDU), HIV-RNA < 50 copies/mL, and HCV co-infection. Also a liver stiffness > 14 kPa showed an independent association with a higher risk of NCI (aOR 10.13, p = 0.041). Analyzing any single cognitive domain, a higher risk of abnormal psychomotor speed was associated with a liver stiffness > 14 kPa (aOR 223.17, p = 0.019) after adjusting for education (aOR 0.57, p = 0.018), HIV-RNA < 50 copies/mL (aOR 0.01, p = 0.007), age, past IDU, and HCV co-infection.

CONCLUSIONS

In PLWH, increased LF, estimated through non-invasive methods, was associated to a higher risk of NCI independently from HCV status.

Sex differences in neurocognitive screening among adults living with HIV in China

HIV-infected (HIV+) women may be more vulnerable to neurocognitive impairment (NCI) due to psychological and physiological factors but previous studies show mixed findings. We investigated the neurocognitive performances in HIV+ versus HIV- women and men. This cross-sectional analysis included 669 HIV+ patients (223 women) and 1338 HIV-uninfected (HIV-) controls (446 women) which were frequency matched on sex, education, and 5-year age categories. NCI was screened using the Mini-mental State Examination. Psychomotor speed was assessed using timed alternating hand sequence test. Prevalence of NCI was higher among women versus men in the HIV+ group (16.1% vs 10.5%) but not the HIV- group (4.3% vs 3.5%). HIV+ women performed worse compared to men on psychomotor speed, orientation, attention, and calculation, whereas HIV- women performed worse compared to men on attention and calculation. Adjusted interaction effects of HIV status × sex (women vs men) were significant on orientation, attention, and calculation, and marginally significant on psychomotor speed (p = 0.053). In multivariable models, among both HIV+ women and men, less years of education and depressive symptoms were associated with NCI. Waist-to-hip ratio above the cut-off was strongly associated with NCI among HIV+ women. HIV+ women perform worse on cognitive measures compared to HIV+ men. The association of central obesity with NCI in HIV+ women should be noted.

Grit and Ambition are Associated with Better Neurocognitive and Everyday Functioning Among Adults Living with HIV

Grit and ambition are psychological factors that may protect neurocognitive function among persons living with HIV (PLWH). We examined associations between grit, ambition, premorbid verbal intellectual function, and current neurocognitive and everyday functioning among PLWH and persons without HIV (HIV-). 120 PLWH and 94 HIV- adults completed the Grit Scale (includes total score and consistency of interests and perseverance of effort subscales), ambition scale, and a comprehensive neurobehavioral battery. PLWH had lower grit scores than HIV- adults. The two groups did not differ on ambition. No relationship was observed between grit and cognition among HIV- adults. Among PLWH, however, higher perseverance of effort and more ambition was related to better global neurocognitive functioning, and higher grit, but not ambition, was related to independence in daily functioning. Longitudinal studies are needed to elucidate these relationships over time and examine whether grit or ambition have protective effects on cognitive outcomes among PLWH.

Development of reserves over the life course and onset of vulnerability in later life

This Review develops a theoretical framework for the development and onset of vulnerability in later life based on the concept of reserves. We stress the advantages of using the concept of reserves in interdisciplinary life-course studies, compared with related concepts such as resources and capital. We enrich the definition of vulnerability as a lack of reserves and a reduced capacity of an individual to restore reserves. Two dimensions of reserves, originating from lifespan psychology and gerontology, are of particular importance: their constitution and sustainability by behaviours and interaction with the environment (the 'use it or lose it' paradigm) and the presence of thresholds, below which functioning becomes highly challenging. This heuristic approach reveals the potential for a conceptualization of reserves and is exemplified in an empirical illustration. Further interdisciplinary research based on the concept is needed.

HIV-associated cognitive disorders in perinatally infected children and adolescents: a novel composite cognitive domains score

Accurate assessment of HIV-associated cognitive disorders in perinatally infected children and adolescents is challenging. Assessments of general intellectual functioning, or global cognition, may not provide information regarding domain-specific strengths and weaknesses, and may therefore fail to detect, impaired trajectories of development within particular cognitive domains. We compare the efficacy of global cognitive scores to that of composite cognitive domain scores in detecting cognitive disorders in a sample of perinatally HIV-infected children, and a demographically matched HIV negative control group, drawn from the Cape Town Adolescent Antiretroviral Cohort (CTAAC) study. All children were administered a comprehensive neuropsychological test battery. Using data from that test battery, we created ten separate composite cognitive domains: general intellectual functioning, attention, working memory, visual memory, verbal memory, language, visual spatial ability, motor coordination, processing speed and executive function. Within each domain, each test bore a high level of association with each of the other tests in that domain (Cronbach's α ≥ .70 for all domains). We found that composite domain scores calculated on whole-sample data were significantly higher than those calculated using control-sample data. Our comparison of a global cognitive score to composite domain scores suggested that the latter provided more detailed information (regarding strengths, weaknesses, areas of impairment), and when compared to global scores, were more sensitive in detecting HIV-associated cognitive disorders, and were able to distinguish HIV-infected patients from uninfected controls. Hence, we recommend using this method of composite cognitive domains scores, rather than global aggregate scores, when assessing cognitive function in paediatric HIV. This method provides a convenient and relatively accurate assessment that might help with cross-cultural and cross-region comparisons as researchers try to detect cognitive impairment patterns in HIV-infected children and adolescents globally.

Differentiating HIV-Associated Neurocognitive Disorders From Alzheimer's Disease: an Emerging Issue in Geriatric NeuroHIV

PURPOSE OF REVIEW

The purpose of this review was to examine characteristics that may distinguish HIV-associated neurocognitive disorder (HAND) from early Alzheimer's disease (AD).

RECENT FINDINGS

Cerebrospinal fluid (CSF) AD biomarkers are perturbed in HIV, yet these alterations may be limited to settings of advanced dementia or unsuppressed plasma HIV RNA. Neuropsychological testing will require extensive batteries to maximize utility. Structural imaging is limited for early AD detection in the setting of HIV, but proper studies are absent. While positron-emission tomography (PET) amyloid imaging has altered the landscape of differential diagnosis for age-associated neurodegenerative disorders, costs are prohibitive. Risk for delayed AD diagnosis in the aging HIV-infected population is now among the most pressing issues in geriatric neuroHIV. While clinical, imaging, and biomarker characterizations of AD are extensively defined, fewer data define characteristics of HIV-associated neurocognitive disorder in the setting of suppressed plasma HIV RNA. Data needed to inform the phenotype of AD in the setting of HIV are equally few.

HIV-associated neurocognitive disorder

Human immunodeficiency virus (HIV)-associated neurocognitive disorder (HAND) affects roughly half the HIV-positive population. The symptoms of cognitive slowing, poor concentration, and memory problems can impact on everyday life. Its diagnosis is validated where possible by identifying deficits in two cognitive domains on neuropsychologic testing in patients either with or without symptoms. Corroborating evidence may be found on imaging, blood tests, and cerebrospinal fluid analysis, though sensitive and specific biomarkers are currently lacking. The introduction of combined antiretroviral therapy in the 1990s has generated a therapeutic paradox whereby the number of severe cases of HAND has fallen, yet milder forms continue to rise in prevalence. New emphasis has been placed on identifying the cause of apparent ongoing HIV infection and inflammation of the central nervous system (CNS) in the face of durable systemic viral suppression, and how this equates to the neuronal dysfunction underlying HAND. The interaction with aging and comorbidities is becoming increasingly common as the HIV-positive population enters older adulthood, with neurodegenerative, metabolic, and vascular causes of cognitive impairment combining and probably accelerating in the context of chronic HIV infection. Therapies targeted to the CNS, but without neurotoxic side-effects, are being investigated to attempt to reduce the likelihood of developing, and improving, HAND.

Effect of ageing on neurocognitive function by stage of HIV infection: evidence from the Multicenter AIDS Cohort Study

BACKGROUND

The demographics of the HIV epidemic in the USA have shifted towards older age. We aimed to establish the relationship between the processes of ageing and HIV infection in neurocognitive impairment.

METHODS

With longitudinal data from the Multicenter AIDS Cohort Study, a long-term prospective cohort study of the natural and treated history of HIV infection among men who have sex with men in the USA, we examined the effect of ageing, HIV infection (by disease stage), and their interaction on five neurocognitive domains: information processing speed, executive function, episodic memory, working memory, and motor function. We controlled for duration of serostatus in a subanalysis, as well as comorbidities and other factors that affect cognition. Analyses were by linear mixed models for longitudinal data.

FINDINGS

5086 participants (47 886 visits) were included in the analytic sample (2278 HIV-seropositive participants contributed 20 477 visits and 2808 HIV-seronegative control participants contributed 27 409 visits). In an a-priori multivariate analysis with control variables including comorbidities and time since seroconversion, significant, direct negative effects of ageing were noted on all neurocognitive domains (p<0·0001 for all). Similar effects were noted for late-stage HIV disease progression on information processing speed (p=0·002), executive function (p<0·0001), motor function (p<0·0001), and working memory (p=0·001). Deleterious interaction effects were also noted in the domains of episodic memory (p=0·03) and motor function (p=0·02).

INTERPRETATION

A greater than expected effect of ageing on episodic memory and motor function with advanced stages of HIV infection suggests that these two domains are most susceptible to the progression of neurocognitive impairment caused by ageing in individuals with HIV. This deficit pattern suggests differential damage to the hippocampus and basal ganglia (specifically nigrostriatal pathways). Older individuals with HIV infection should be targeted for regular screening for HIV-associate neurocognitive disorder, particularly with tests referable to the episodic memory and motor domains.

FUNDING

National Institute of Mental Health.