Gert J. Geurtsen

Increased brain-predicted aging in treated HIV disease

Objective: To establish whether HIV disease is associated with abnormal levels of age-related brain atrophy, by estimating apparent brain age using neuroimaging and exploring whether these estimates related to HIV status, age, cognitive performance, and HIV-related clinical parameters. Methods: A large sample of virologically suppressed HIV-positive adults (n = 162, age 45–82 years) and highly comparable HIV-negative controls (n = 105) were recruited as part of the Comorbidity in Relation to AIDS (COBRA) collaboration. Using T1-weighted MRI scans, a machine-learning model of healthy brain aging was defined in an independent cohort (n = 2,001, aged 18–90 years). Neuroimaging data from HIV-positive and HIV-negative individuals were then used to estimate brain-predicted age; then brain-predicted age difference (brain-PAD = brain-predicted brain age − chronological age) scores were calculated. Neuropsychological and clinical assessments were also carried out. Results: HIV-positive individuals had greater brain-PAD score (mean ± SD 2.15 ± 7.79 years) compared to HIV-negative individuals (−0.87 ± 8.40 years; b = 3.48, p < 0.01). Increased brain-PAD score was associated with decreased performance in multiple cognitive domains (information processing speed, executive function, memory) and general cognitive performance across all participants. Brain-PAD score was not associated with age, duration of HIV infection, or other HIV-related measures. Conclusion: Increased apparent brain aging, predicted using neuroimaging, was observed in HIV-positive adults, despite effective viral suppression. Furthermore, the magnitude of increased apparent brain aging related to cognitive deficits. However, predicted brain age difference did not correlate with chronological age or duration of HIV infection, suggesting that HIV disease may accentuate rather than accelerate brain aging.

α-synuclein genetic variability: A biomarker for dementia in Parkinson disease

The relationship between Parkinson disease (PD), PD with dementia (PDD), and dementia with Lewy bodies (DLB) has long been debated. Although PD is primarily considered a motor disorder, cognitive impairment is often present at diagnosis, and only ∼20% of patients remain cognitively intact in the long term. Alpha‐synuclein (SNCA) was first implicated in the pathogenesis of the disease when point mutations and locus multiplications were identified in familial parkinsonism with dementia. In worldwide populations, SNCA genetic variability remains the most reproducible risk factor for idiopathic PD. However, few investigators have looked at SNCA variability in terms of cognitive outcomes.

Poorer cognitive performance in perinatally HIV-infected children versus healthy socioeconomically matched controls

BACKGROUND Despite the declining incidence of severe neurological complications such as HIV encephalopathy, human immunodeficiency virus (HIV) infection in children is still associated with a range of cognitive problems. Although most HIV-infected children in industrialized countries are immigrants with a relatively low socioeconomic status (SES), cognitive studies comparing HIV-infected children to SES-matched controls are lacking. METHODS This cross-sectional study included perinatally HIV-infected children and controls matched for age, sex, ethnicity, and SES, who completed a neuropsychological assessment evaluating intelligence, information processing speed, attention, memory, executive function, and visual-motor function. Multivariate normative comparison was used to assess the prevalence of cognitive impairment in the HIV-infected group. Multivariable regression analyses were performed to identify HIV- and combination antiretroviral therapy-related factors associated with cognitive performance. RESULTS In total, 35 perinatally HIV-infected children (median age, 13.8 years; median CD4 count, 770 × 10(6) cells/L; 83% with undetectable HIV RNA) and 37 healthy children (median age, 12.1 years) were included. HIV-infected children scored lower than the healthy controls on all cognitive domains (eg, intelligence quotient [IQ], 76 [standard deviation {SD}, 15.7] vs 87.5 [SD, 13.6] for HIV-infected vs healthy children; P = .002). Cognitive impairment was found in 6 HIV-infected children (17%). The Centers for Disease Control and Prevention (CDC) clinical category at HIV diagnosis was inversely associated with verbal IQ (CDC clinical category C: coefficient -22.98; P = .010). CONCLUSIONS Our results show that cognitive performance of HIV-infected children is poor compared with that of SES-matched healthy controls. Gaining insight into these cognitive deficits is essential, as subtle impairments may progress to more pronounced complications that will influence future intellectual performance, job opportunities, and community participation of HIV-infected children.

Multivariate normative comparison, a novel method for more reliably detecting cognitive impairment in HIV infection.

Objective:The objective of this study is to assess whether multivariate normative comparison (MNC) improves detection of HIV-1-associated neurocognitive disorder (HAND) as compared with Frascati and Gisslén criteria. Methods:One-hundred and three HIV-1-infected men with suppressed viremia on combination antiretroviral therapy (cART) for at least 12 months and 74 HIV-uninfected male controls (comparable regarding age, ethnicity, sexual orientation, premorbid intelligence and educational level), aged at least 45 years, underwent neuropsychological assessment covering six cognitive domains (fluency, attention, information processing speed, executive function, memory, and motor function). Frascati and Gisslén criteria were applied to detect HAND. Next, MNC was performed to compare the cognitive scores of each HIV-positive individual against the cognitive scores of the control group. Results:HIV-infected men showed significantly worse performance on the cognitive domains of attention, information processing speed and executive function compared with HIV-uninfected controls. HAND by Frascati criteria was highly prevalent in HIV-infected [48%; 95% confidence interval (95% CI) 38–58] but nearly equally so in HIV-uninfected men (36%; 95% CI 26–48), confirming the low specificity of this method. Applying Gisslén criteria, HAND-prevalence was reduced to 5% (95% CI 1–9) in HIV-infected men and to 1% (95% CI 1–3) among HIV-uninfected controls, indicating better specificity but reduced sensitivity. MNC identified cognitive impairment in 17% (95% CI 10–24) of HIV-infected men and in 5% (95% CI 0–10) of the control group (P = 0.02, one-tailed), showing an optimal balance between sensitivity and specificity. Conclusion:Prevalence of cognitive impairment in HIV-1-infected men with suppressed viremia on cART estimated by MNC was much higher than that estimated by Gisslén criteria, while the false positive rate was greatly reduced compared with the Frascati criteria. Video abstract:http://links.lww.com/QAD/A633

White matter hyperintensities in relation to cognition in HIV-infected men with sustained suppressed viral load on combination antiretroviral therapy

Objectives:The objective of this study was to assess whether HIV-infected patients on long-term successful combination antiretroviral therapy (cART) have more extensive white matter hyperintensities (WMH) of presumed vascular origin compared with uninfected controls and whether these intensities are associated with cognitive impairment. Furthermore, we explored potential determinants of increased WMH load long-term suppressed HIV infection. Design:A cross-sectional comparison of WMH in an observational cohort. Methods:Clinical, cognitive, and MRI data were collected from 103 middle-aged, aviremic HIV-infected men on cART, and 70 HIV-uninfected, otherwise similar controls. In the MRI data, WMH load was quantified by automated approaches and qualitatively reviewed by an experienced neuroradiologist using the Fazekas scale. Results:HIV-infected men had an increased WMH load. Among HIV-infected patients, increased WMH load was independently associated with older age, higher DBP, higher D-dimer levels, and longer time spent with a CD4+ cell count below 500 cells/&mgr;l. HIV-associated cognitive deficits were associated with increased WMH load. Conclusions:WMH are more extensive and associated with cognitive deficits in middle-aged, aviremic cART-treated HIV-infected men. The extent of WMH load was associated with both cardiovascular risk factors and past immune deficiency. As cognitive impairment in these same patients is also associated with these risk factors, this may suggest that in the setting of HIV, WMH, and cognitive deficits share a common cause. This supports the importance of optimizing cardiovascular risk management, and early, effective treatment of HIV infection.

Parkinson's disease mild cognitive impairment: application and validation of the criteria

Dementia in Parkinsons disease (PD) is a serious health issue and a major concern for many patients. In most cases mild cognitive impairment (MCI) is considered a transitional stage between normal cognitive functioning and dementia which is of potential importance in the early identification of patients at risk for dementia. Recently, the Movement Disorder Society (MDS) proposed diagnostic criteria for MCI in PD (PD-MCI). These criteria comprise two operationalizations: Level I (based on an abbreviated assessment) and Level II (based on comprehensive neuropsychological evaluation permitting MCI subtyping). These criteria need to be validated. This paper describes a project aiming to validate the MDS PD-MCI criteria by pooling and analyzing cross-sectional and longitudinal neuropsychological databases comprising ≥5,500 PD patients and ≥1,700 controls. After applying the MDS PD-MCI Level I and Level II criteria, rates of conversion to PD-dementia and predictive variables for conversion to PD-dementia will be established. This study will also assist in identifying whether revisions of the PD-MCI criteria are required.

Mild Cognitive Impairment as a risk factor for Parkinson's disease dementia

The International Parkinson and Movement Disorder Society criteria for mild cognitive impairment in PD were recently formulated.

White matter structure alterations in HIV-1-infected men with sustained suppression of viraemia on treatment.

Objective:Cognitive impairment is highly prevalent in HIV-1-infected (HIV+) patients, despite adequate suppression of viral replication by combination antiretroviral therapy (cART). Cerebral white matter structure alterations are often associated with cognitive impairment and have commonly been reported in the natural course of HIV infection. However, the existence of these alterations in adequately treated HIV+ patients remains unknown, as well as its possible association with cognitive impairment. Design:We used diffusion tensor imaging (DTI) to investigate whether white matter structure alterations exist in HIV+ patients with sustained suppressed viral replication on cART, and if such alterations are related to HIV-associated cognitive deficits. Methods:We compared 100 aviraemic HIV+ men on cART with 70 HIV-uninfected, otherwise comparable men. Clinical and neuropsychological assessments were performed. From DTI data, white matter fractional anisotropy and mean diffusion were calculated. Subsequently, tract-based spatial statistics (TBSS) was performed, with and without masking out white matter lesions. Results:HIV+ patients showed diffuse white matter structure alterations as compared with HIV-uninfected controls, observed as widespread decreased fractional anisotropy and an increased mean diffusion. These white matter structure alterations were associated with the number of years spent with a CD4+ cell count below 500 cells/&mgr;l, but not with HIV-associated cognitive deficits. Conclusion:Cerebral white matter structure alterations are found in middle-aged HIV+ men with sustained suppression of viraemia on cART, and may result from periods with immune deficiency when viral toxicity and host-inflammatory responses were at their peak. These white matter structure alterations were not associated with the observed subtle HIV-associated cognitive deficits. Video abstract:https://youtu.be/Dg3AOLNxVVo

Determinants of reduced cognitive performance in HIV-1-infected middle-aged men on combination antiretroviral therapy

Objective:The spectrum of risk factors for HIV-associated cognitive impairment is likely very broad and includes not only HIV/antiretroviral therapy-specific factors but also other comorbid conditions. The purpose of this current study was to explore possible determinants for decreased cognitive performance. Design and methods:Neuropsychological assessment was performed on 103 HIV-1-infected men with suppressed viraemia on combination antiretroviral therapy for at least 12 months and 74 HIV-uninfected highly similar male controls, all aged at least 45 years. Cognitive impairment and cognitive performance were determined by multivariate normative comparison (MNC). Determinants of decreased cognitive performance and cognitive impairment were investigated by linear and logistic regression analysis, respectively. Results:Cognitive impairment as diagnosed by MNC was found in 17% of HIV-1-infected men. Determinants for decreased cognitive performance by MNC as a continuous variable included cannabis use, history of prior cardiovascular disease, impaired renal function, diabetes mellitus type 2, having an above normal waist-to-hip ratio, presence of depressive symptoms, and lower nadir CD4+ cell count. Determinants for cognitive impairment, as dichotomized by MNC, included cannabis use, prior cardiovascular disease, impaired renal function, and diabetes mellitus type 2. Conclusion:Decreased cognitive performance probably results from a multifactorial process, including not only HIV-associated factors, such as having experienced more severe immune deficiency, but also cardiovascular/metabolic factors, cannabis use, and depressive symptoms.

Gray and White Matter Abnormalities in Treated Human Immunodeficiency Virus Disease and Their Relationship to Cognitive Function

Background Long-term comorbidities such as cognitive impairment remain prevalent in otherwise effectively treated people living with human immunodeficiency virus (HIV). We investigate the relationship between cognitive impairment and brain structure in successfully treated patients using multimodal neuroimaging from the Comorbidity in Relation to AIDS (COBRA) cohort. Methods Cognitive function, brain tissue volumes, and white matter microstructure were assessed in 134 HIV-infected patients and 79 controls. All patients had suppressed plasma HIV RNA at cohort entry. In addition to comprehensive voxelwise analyses of volumetric and diffusion tensor imaging, we used an unsupervised machine learning approach to combine cognitive, diffusion, and volumetric data, taking advantage of the complementary information they provide. Results Compared to the highly comparable control group, cognitive function was impaired in 4 of the 6 cognitive domains tested (median global T-scores: 50.8 vs 54.2; P < .001). Patients had lower gray but not white matter volumes, observed principally in regions where structure generally did not correlate with cognitive function. Widespread abnormalities in white matter microstructure were also seen, including reduced fractional anisotropy with increased mean and radial diffusivity. In contrast to the gray matter, these diffusion abnormalities correlated with cognitive function. Multivariate neuroimaging analysis identified a neuroimaging phenotype associated with poorer cognitive function, HIV infection, and systemic immune activation. Conclusions Cognitive impairment, lower gray matter volume, and white matter microstructural abnormalities were evident in HIV-infected individuals despite fully suppressive antiretroviral therapy. White matter abnormalities appear to be a particularly important determinant of cognitive dysfunction seen in well-treated HIV-infected individuals.