Nicholas S. Thaler

Neuroimaging abnormalities, neurocognitive function, and fatigue in patients with hepatitis C

Objective: This study examined neurologic abnormalities (as measured by proton magnetic resonance spectroscopy imaging and diffusion tensor imaging), neurocognitive performance, and fatigue among a sample of adults with hepatitis C virus (HCV). We hypothesized that HCV+ individuals would demonstrate structural brain abnormalities and neurocognitive compromise consistent with frontostriatal dysfunction as well as increased fatigue compared to controls. Method: Participants were 76 individuals diagnosed with HCV and 20 controls who underwent a comprehensive neurocognitive evaluation and clinical assessments. A subset of the HCV+ participants (n = 29) and all controls underwent MRI. Results: Individuals diagnosed with chronic HCV infection demonstrated greater fractional anisotropy in the striatum as well as greater mean diffusivity in the fronto-occiptal fasciculus and external capsule compared to HCV− controls. HCV+ participants also demonstrated lower levels of N-acetylaspartate in bilateral parietal white matter and elevations in myo-inosital (mI) in bilateral frontal white matter compared to HCV− controls (all p values < 0.05). HCV+ participants also demonstrated significantly poorer neuropsychological performance, particularly in processing speed and verbal fluency. HCV+ patients reported higher levels of fatigue than controls, and fatigue was significantly correlated with diffusivity in the superior fronto-occipital fasciculus, elevations in mI in frontal white matter, and overall cognitive performance. Conclusions: Our results suggest that HCV-associated neurologic complications disrupt frontostriatal structures, which may result in increased fatigue and poorer cognitive performance, particularly in those cognitive domains regulated by frontostriatal regions.

Increased neurocognitive intra-individual variability is associated with declines in medication adherence in HIV-infected adults.

OBJECTIVEnThere is cross-sectional evidence that neurocognitive intra-individual variability (IIV), or dispersion, is elevated in human immunodeficiency virus (HIV) disease and is associated with declines in activities of daily living, including medication adherence.nnnMETHODSnThis longitudinal study extends this literature by examining whether increased neurocognitive IIV in HIV-positive persons over time predicts declines in medication adherence above and beyond changes in mean level of performance over a 6-month observation.nnnRESULTSnAfter controlling for drug use, declines in mean performance, and changes in depressive symptoms, results confirmed that increases in IIV were associated with overall poorer antiretroviral medication adherence. HIV-positive individuals with the greatest increases in dispersion demonstrated marked reductions in adherence by the third month that exceeded what was observed in less variable individuals.nnnCONCLUSIONSnOur results indicate that increases in dispersion are associated with poorer declines in medication adherence in HIV disease, which may have implications for the early detection and remediation of suboptimal antiretroviral adherence.

Interactive effects of neurocognitive impairment and substance use on antiretroviral non-adherence in HIV disease.

While numerous studies have established the adverse independent effects of clinical conditions including neurocognitive dysfunction, psychiatric illness, and substance abuse/dependence on medication adherence among HIV-infected adults, fewer have studied their interactive effects. The current study examined this issue among 204 HIV-infected participants based upon current neurocognitive functioning and DSM-IV-diagnosed psychiatric illness and current substance abuse or dependence. Results confirmed that participants with any of these risk factors demonstrated poorer adherence than individuals with no risk factors. A neurocognitive status × substance abuse/dependence interaction was also identified such that participants with impaired neurocognition and a co-occurring substance abuse/dependence diagnosis demonstrated the poorest adherence. Results confirm the deleterious impact of these risk factors in isolation and also identify a specific interactive effect for individuals with comorbid neurocognitive impairment and a substance abuse/dependence disorder. Findings highlight the need for interventions that simultaneously address these problems.

Quality of Education Predicts Performance on the Wide Range Achievement Test-4th Edition Word Reading Subtest

The current study examined whether self-rated education quality predicts Wide Range Achievement Test-4th Edition (WRAT-4) Word Reading subtest and neurocognitive performance, and aimed to establish this subtests construct validity as an educational quality measure. In a community-based adult sample (N = 106), we tested whether education quality both increased the prediction of Word Reading scores beyond demographic variables and predicted global neurocognitive functioning after adjusting for WRAT-4. As expected, race/ethnicity and education predicted WRAT-4 reading performance. Hierarchical regression revealed that when including education quality, the amount of WRAT-4s explained variance increased significantly, with race/ethnicity and both education quality and years as significant predictors. Finally, WRAT-4 scores, but not education quality, predicted neurocognitive performance. Results support WRAT-4 Word Reading as a valid proxy measure for education quality and a key predictor of neurocognitive performance. Future research should examine these findings in larger, more diverse samples to determine their robust nature.

Comparing the unmatched count technique and direct self-report for sensitive health-risk behaviors in HIV+ adults.

ABSTRACT Researchers often rely on self-report measures to assess sensitive health-risk behaviors in HIV+ individuals, yet the accuracy of self-report has been questioned, particularly when inquiring about behaviors that may be embarrassing, risky, and/or taboo. We compared an anonymous reporting method – the unmatched count technique (UCT) – to direct self-report (DSR) in order to assess reporting differences for several health-risk behaviors related to medication adherence and sexual risk. Contrary to hypotheses, the UCT only produced a significantly higher estimated base rate for one sensitive behavior: reporting medication adherence to ones physician, which may have been contextually primed by our study design. Our results suggest that anonymous reporting methods may not increase disclosure compared to DSR when assessing several health-risk behaviors in HIV+ research volunteers. However, our results also suggest that contextual factors should be considered and investigated further, as they may influence perception of sensitive behavior.

Diagnostic utility of the HIV dementia scale and the international HIV dementia scale in screening for HIV-associated neurocognitive disorders among Spanish-speaking adults

ABSTRACT Given that neurocognitive impairment is a frequent complication of HIV-1 infection in Spanish-speaking adults, the limited number of studies assessing HIV-associated neurocognitive disorders (HAND) in this population raises serious clinical concern. In addition to being appropriately translated, instruments need to be modified, normed, and validated accordingly. The purpose of the current study was to examine the diagnostic utility of the HIV Dementia Scale (HDS) and International HIV Dementia Scale (IHDS) to screen for HAND in Spanish-speaking adults living with HIV infection. Participants were classified as either HAND (Nu2009=u200947) or No-HAND (Nu2009=u200953) after completing a comprehensive neuropsychological evaluation. Receiver operating characteristic analyses found the HDS (AUCu2009=u2009.706) was more sensitive to detecting HAND than the IHDS (AUCu2009=u2009.600). Optimal cutoff scores were 9.5 for the HDS (PPVu2009=u200965.2%, NPVu2009=u200971.4%) and 9.0 for the IHDS (PPVu2009=u200959.4%, NPVu2009=u200959.1%). Canonical Correlation Analysis found the HDS converged with attention and executive functioning. Findings suggest that while the IHDS may not be an appropriate screening instrument with this population, the HDS retains sufficient statistical validity and clinical utility to screen for HAND in Spanish-speaking adults as a time-efficient and cost-effective measure in clinical settings with limited resources.

Longitudinal stability of RBANS profiles in a geriatric community-dwelling sample

This investigation is an extension of a previous study that identified four neurocognitive RBANS groups via cluster analysis in a geriatric community-dwelling sample of 699 individuals who were at least 65 years of age. Groups were examined longitudinally over a 2-year interval to establish if they exhibited marked score changes over three assessment periods. Dropout rates, onset of medical pathology, and self-reported functioning were tracked at each evaluation. Results confirmed that cluster scores were generally stable over time although the Low Immediate Memory group’s Immediate Memory index score regressed upward toward the mean by the third assessment. Of interest, individuals in the Below Average group had substantial dropout between the first and third assessments. Results are interpreted through a clinical framework to explore how RBANS cluster profiles may have predictive value in general neurocognitive functioning over the observed time period and be potentially influenced by general health factors.

Medication adherence in HIV-positive African Americans: The roles of age, health beliefs, and sensation seeking

Abstract We examined how two critical constructs, health beliefs and sensation seeking, influence combination antiretroviral therapy adherence in HIV + African Americans, and whether these factors mediate the association between age and adherence. Two hundred and eighty-six HIV + African Americans participated in this observational study. Path analyses revealed that higher levels of a specific health belief, perceived utility of treatment, and lower levels of a sensation seeking component, Thrill and Adventure Seeking, directly predicted optimal adherence. The influence of age on adherence was partially mediated by lower Thrill and Adventure Seeking levels. Depression predicted adherence via perceived utility of treatment and Thrill and Adventure Seeking, whereas current substance abuse and dependence did via Thrill and Adventure Seeking. Poorer neurocognitive function had a direct, adverse effect on adherence. Our findings suggest that supporting the development of more positive perceptions about HIV treatment utility may help increase medication adherence among African Americans. This may be particularly relevant for those with higher levels of depression symptoms, which were directly associated with negative perceptions about treatment. Additionally, clinicians can assess sensation seeking tendencies to help identify HIV + African Americans at risk for suboptimal adherence. Compensatory strategies for medication management may help improve adherence among HIV + individuals with poorer neurocognitive function.

Cognitive and academic achievement changes associated with day hospital rehabilitation in children with acquired brain injury

ABSTRACT An evaluation was made of the outcome of a day hospital rehabilitation program for children who experienced an acquired neurological illness, mainly traumatic brain injury. Participants were administered neuropsychological and academic evaluations upon entry to the program, immediately upon discharge and several months after discharge Repeated measures ANOVA results for variables selected from the Reynolds Intellectual Assessment and the Delis-Kaplan Executive Function System found that comparisons showed significant (≥pu2009<u2009.01) improvement occurred between the first and second assessment, generally with large effect sizes. There were some nonsignificant decrements in performance between the discharge and follow-up assessments. A correlational analysis showed that while the association between cognitive function and academic achievement was robust, correlation coefficients did not differ in strength before and following rehabilitation. The study demonstrates significant improvement in children with acquired neurological disorders following rehabilitation.

HIV-transmission-related risk behavior in HIV+ African American men: Exploring biological, psychological, cognitive, and social factors

ABSTRACT This article seeks to identify factors associated with HIV-transmission-related risk behavior among HIV+ African American men. We examined biological, psychological, cognitive, and social factors and recent HIV-transmission-related risk behavior (i.e., needle sharing, unprotected sex, exchange sex) among a sample of HIV+ African American men. A binary logistic regression showed that individuals under age 50 (OR = 4.2), with clinically-elevated masochism scores (OR = 3.9) on the Millon Clinical Multiaxial Inventory-III (MCMI-III), current substance abuse/dependence (OR = 2.6), and higher sensation-seeking (OR = 1.3) were more likely to report recent risk behavior. We conclude that reducing substance use, addressing self-defeating attitudes, and improving self-control may be avenues for future prevention and intervention research among HIV+ African American men engaging in HIV-transmission-related risk behavior.