The generalizability of neurocognitive test/retest data derived from a nonclinical sample for detecting change among two HIV+ cohorts

A 2-year longitudinal randomized controlled trial examining the transfer of speed of processing training to secondary cognitive domains in middle-aged and older adults with HIV-associated neurocognitive disorder: Results of the think fast study

OBJECTIVE

As people with HIV (PWH) age, they are at-risk of developing cognitive impairments compared to their seronegative counterparts. Although speed of processing (SOP) training may help improve this cognitive ability, less work has examined transfer to other cognitive domains. This study examined the effect of SOP training has on secondary cognitive domains in PWH aged 40+ years.

METHOD

In this 3-group 2-year longitudinal study, 216 PWH with HIV-associated neurocognitive disorder (HAND) or borderline HAND were randomized to either: (1) 10 h of SOP training (n = 70); (2) 20 h of SOP training (n = 73); or (3) 10 h of an active control training (n = 73). Participants completed a comprehensive cognitive battery at baseline, immediately after training, and at 1 and 2 years. This battery yielded global and domain specific T-scores as well as a cognitive impairment variable. Generalized linear mixed-effect models were fitted to estimate between-group mean differences at the follow-up time-points adjusted for baseline.

RESULTS

No clinically or statistically significant improvements in any of the cognitive outcomes were observed. A sensitivity analysis was conducted; conclusions replicated those of the main analysis, with two exceptions: Global Function T and Psychomotor Speed T showed relevant training improvements among the intervention groups over the control group at the immediate post time point.

CONCLUSIONS

Although SOP training has been shown to improve cognitive abilities that correspond to driving and mobility, such training has limited therapeutic utility in improving cognition in other domains in PWH with HAND.

Studying the neuropsychological sequelae of SARS-CoV-2: lessons learned from 35 years of neuroHIV research

The virology of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and the human immune response to the virus are under vigorous investigation. There are now several reports describing neurological symptoms in individuals who develop coronavirus disease 2019 (COVID-19), the syndrome associated with SARS-CoV-2 infection. The prevalence, incidence, and clinical course of these symptoms will become clearer in the coming months and years through epidemiological studies. However, the long-term neurological and cognitive consequence of SARS-CoV-2 infection will remain conjectural for some time and will likely require the creation of cohort studies that include uninfected individuals. Considering the early evidence for neurological involvement in COVID-19 it may prove helpful to compare SARS-CoV-2 with another endemic and neurovirulent virus, human immunodeficiency virus-1 (HIV-1), when designing such cohort studies and when making predictions about neuropsychological outcomes. In this paper, similarities and differences between SARS-CoV-2 and HIV-1 are reviewed, including routes of neuroinvasion, putative mechanisms of neurovirulence, and factors involved in possible long-term neuropsychological sequelae. Application of the knowledge gained from over three decades of neuroHIV research is discussed, with a focus on alerting researchers and clinicians to the challenges in determining the cause of neurocognitive deficits among long-term survivors.

External validation of change formulae in neuropsychology with neuroimaging biomarkers: A methodological recommendation and preliminary clinical data

OBJECTIVE

Within neuropsychology, a number of mathematical formulae (e.g. reliable change index, standardized regression based) have been used to determine if change across time has reliably occurred. When these formulae have been compared, they often produce different results, but 'different' results do not necessarily indicate which formulae are 'best.' The current study sought to further our understanding of change formulae by comparing them to clinically relevant external criteria (amyloid deposition and hippocampal volume).

METHOD

In a sample of 25 older adults with varying levels of cognitive intactness, participants were tested twice across one week with a brief cognitive battery. Seven different change scores were calculated for each participant. An amyloid PET scan (to get a composite of amyloid deposition) and an MRI (to get hippocampal volume) were also obtained.

RESULTS

Deviation-based change formulae (e.g. simple discrepancy score, reliable change index with or without correction for practice effects) were all identical in their relationship to the two neuroimaging biomarkers, and all were non-significant. Conversely, regression-based change formulae (e.g. simple and complex indices) showed stronger relationships to amyloid deposition and hippocampal volume.

CONCLUSIONS

These results highlight the need for external validation of the various change formulae used by neuropsychologists in clinical settings and research projects. The findings also preliminarily suggest that regression-based change formulae may be more relevant than deviation-based change formulae in this context.

Effects of handcuffs on neuropsychological testing: Implications for criminal forensic evaluations

Neuropsychological evaluations are increasingly performed in forensic contexts, including in criminal settings where security sometimes cannot be compromised to facilitate evaluation according to standardized procedures. Interpretation of nonstandardized assessment results poses significant challenges for the neuropsychologist. Research is limited in regard to the validation of neuropsychological test accommodation and modification practices that deviate from standard test administration; there is no published research regarding the effects of hand restraints upon neuropsychological evaluation results. This study provides preliminary results regarding the impact of restraints on motor functioning and common neuropsychological tests with a motor component. When restrained, performance on nearly all tests utilized was significantly impacted, including Trail Making Test A/B, a coding test, and several tests of motor functioning. Significant performance decline was observed in both raw scores and normative scores. Regression models are also provided in order to help forensic neuropsychologists adjust for the effect of hand restraints on raw scores of these tests, as the hand restraints also resulted in significant differences in normative scores; in the most striking case there was nearly a full standard deviation of discrepancy.

Clarifying Discrepancies in Responsiveness Between Reliable Change Indices

OBJECTIVE

Several reliable change indices (RCIs) exist to evaluate statistically significant individual change with repeated neuropsychological assessment. Yet there is little guidance on model selection and subsequent implications. Using existing test-retest norms, key parameters were systematically evaluated for influence on different RCI models.

METHOD

Normative test-retest data for selected Wechsler Memory Scale-IV subtests were chosen based on the direction and magnitude of differential practice (inequality of test and retest variance). The influence of individual relative position compared to the normative mean was systematically manipulated to evaluate for predictable differences in responsiveness for three RCI models.

RESULTS

With respect to negative change, RCI McSweeny was most responsive when individual baseline scores were below the normative mean, irrespective of differential practice. When an individual score was greater than the normative mean, RCI Chelune was most responsive with lower retest variance, and RCI Maassen most responsive with greater retest variance. This pattern of results can change when test-retest reliability is excellent and there is greater retest variability. Order of responsiveness is reversed if positive change is of interest.

CONCLUSION

RCI models tend to agree when the individual approximates the normative mean at baseline and test-retest variability is equal. However, no RCI model will be universally more or less responsive across all conditions, and model selection may influence subsequent interpretation of change. Given the systematic and predictable differences between models, a more rationale choice can now be made. While a consensus on RCI model preference does not exist, we prefer the regression-based model for several reasons outlined.

The Effects of Aging, Malingering, and Traumatic Brain Injury on Computerized Trail-Making Test Performance

The trail making test (TMT) is widely used to assess speed of processing and executive function. However, normative data sets gathered at different sites show significant inconsistencies. Here, we describe a computerized version of the TMT (C-TMT) that increases the precision and replicability of the TMT by permitting a segment-by-segment analysis of performance and separate analyses of dwell-time, move-time, and error time. Experiment 1 examined 165 subjects of various ages and found that completion times on both the C-TMT-A (where subjects connect successively numbered circles) and the C-TMT-B (where subjects connect circles containing alternating letters and numbers) were strongly influenced by age. Experiment 2 examined 50 subjects who underwent three test sessions. The results of the first test session were well fit by the normative data gathered in Experiment 1. Sessions 2 and 3 demonstrated significant learning effects, particularly on the C-TMT-B, and showed good test-retest reliability. Experiment 3 examined performance in subjects instructed to feign symptoms of traumatic brain injury: 44% of subjects produced abnormal completion times on the C-TMT-A, and 18% on the C-TMT-B. Malingering subjects could be distinguished from abnormally slow controls based on (1) disproportionate increases in dwell-time on the C-TMT-A, and (2) greater deficits on the C-TMT-A than on the C-TMT-B. Experiment 4 examined the performance of 28 patients with traumatic brain injury: C-TMT-B completion times were slowed, and TBI patients showed reduced movement velocities on both tests. The C-TMT improves the reliability and sensitivity of the trail making test of processing speed and executive function.

Select neurocognitive impairment in HIV-infected women: associations with HIV viral load, hepatitis C virus, and depression, but not leukocyte telomere length

BACKGROUND

Through implementation of combination antiretroviral therapy (cART) remarkable gains have been achieved in the management of HIV infection; nonetheless, the neurocognitive consequences of infection remain a pivotal concern in the cART era. Research has often employed norm-referenced neuropsychological scores, derived from healthy populations (excluding many seronegative individuals at high risk for HIV infection), to characterize impairments in predominately male HIV-infected populations.

METHODS

Using matched-group methodology, we assessed 81 HIV-seropositive (HIV+) women with established neuropsychological measures validated for detection of HIV-related impairments, as well as additional detailed tests of executive function and decision-making from the Cambridge Neuropsychological Test Automated Battery (CANTAB).

RESULTS

On validated tests, the HIV+ women exhibited impairments that were limited to significantly slower information processing speed when compared with 45 HIV-seronegative (HIV-) women with very similar demographic backgrounds and illness comorbidities. Additionally, select executive impairments in shifting attention (i.e., reversal learning) and in decision-making quality were revealed in HIV+ participants. Modifiers of neurocognition in HIV-infected women included detectable HIV plasma viral load, active hepatitis C virus co-infection, and self-reported depression symptoms. In contrast, leukocyte telomere length (LTL), a marker of cellular aging, did not significantly differ between HIV+ and HIV- women, nor was LTL associated with overall neurocognition in the HIV+ group.

CONCLUSIONS

The findings suggest that well-managed HIV infection may entail a more circumscribed neurocognitive deficit pattern than that reported in many norm-referenced studies, and that common comorbidities make a secondary contribution to HIV-related neurocognitive impairments.

A brief and feasible paper-based method to screen for neurocognitive impairment in HIV-infected patients: the NEU screen

OBJECTIVE

Practical screening methods are necessary to detect neurocognitive impairment (NCI) in HIV-infected patients. We aimed to find a brief and feasible paper-based tool to facilitate the diagnosis of an HIV-associated neurocognitive disorder.

METHODS

A total of 106 HIV-infected outpatients with variable clinical characteristics were recruited in a multicenter investigation. NCI was diagnosed using a standardized neuropsychological tests battery (7 areas, 21 measures, ∼2 hours). Multiple score combinations were compared to find a paper-based method that took ≤10 minutes to apply. The presence of NCI was considered the gold standard for comparisons, and the sensitivity and specificity were calculated.

RESULTS

Subjects were mostly middle-aged (median, 44 years) men (87%) on antiretroviral treatment. NCI was detected in 51 individuals (48%) and was associated with lower nadir CD4 count (P < 0.001), receiving antiretroviral therapy (P = 0.004), fewer years of education (P = 0.009), and presence of comorbidities (P < 0.001). The score combination that showed the highest sensitivity (74.5%) and specificity (81.8%) detecting NCI included 3 measures of attention/working memory, executive functioning, and verbal fluency (part A of Trail Making Test, part B of Trail Making Test, and Controlled Oral Word Association Test scores). A broader paper-based selection of measures covering 7 areas indicated a sensitivity of 100% and a specificity of 96.3% (7 measures, ∼35 minutes).

CONCLUSIONS

The combination of the 3 measures presented in this study seems to be a rapid and feasible screening mean for NCI in HIV-infected patients. This approach, combined with screening for potential comorbidities and daily functioning interference, could help in the initial stages of a HIV-associated neurocognitive disorder diagnosis and in settings with limited access to neuropsychological resources.

Evidence-based indicators of neuropsychological change in the individual patient: relevant concepts and methods

Repeated assessments are a relatively common occurrence in clinical neuropsychology. The current paper will review some of the relevant concepts (e.g., reliability, practice effects, alternate forms) and methods (e.g., reliable change index, standardized based regression) that are used in repeated neuropsychological evaluations. The focus will be on the understanding and application of these concepts and methods in the evaluation of the individual patient through examples. Finally, some future directions for assessing change will be described.

Relationship of ethnicity, age, education, and reading level to speed and executive function among HIV+ and HIV- women: the Women's Interagency HIV Study (WIHS) Neurocognitive Substudy

Use of neuropsychological tests to identify HIV-associated neurocognitive dysfunction must involve normative standards that are well suited to the population of interest. Norms should be based on a population of HIV-uninfected individuals as closely matched to the HIV-infected group as possible and must include examination of the potential effects of demographic factors on test performance. This is the first study to determine the normal range of scores on measures of psychomotor speed and executive function among a large group of ethnically and educationally diverse HIV-uninfected, high-risk women, as well as their HIV-infected counterparts. Participants (n = 1,653) were administered the Trail Making Test Parts A and B (Trails A and Trails B), the Symbol Digit Modalities Test (SDMT), and the Wide Range Achievement Test-3 (WRAT-3). Among HIV-uninfected women, race/ethnicity accounted for almost 5% of the variance in cognitive test performance. The proportions ofvariance in cognitive test performance accounted for by age (13.8%), years of school (4.1%), and WRAT-3 score (11.5%) were each significant, but did not completely account for the effect of race (3%). HIV-infected women obtained lower scores than HIV-uninfected women on time to complete Trails A and B, SDMT total correct, and SDMT incidental recall score, but after adjustment for age, years of education, racial/ethnic classification, and reading level, only the difference on SDMT total correct remained significant. Results highlight the need to adjust for demographic variables when diagnosing cognitive impairment in HIV-infected women. Advantages of demographically adjusted regression equations developed using data from HIV-uninfected women are discussed.

Regulation of neural specification from human embryonic stem cells by BMP and FGF

Inhibition of bone morphogenetic protein (BMP) signaling is required for vertebrate neural induction, and fibroblast growth factors (FGFs) may affect neural induction through phosphorylation at the linker region of Smad1, thus regulating BMP signaling. Here we show that human embryonic stem cells efficiently convert to neuroepithelial cells in the absence of BMP antagonists, or even when exposed to high concentrations of exogenous BMP4. Molecular and functional analyses revealed multiple levels of endogenous BMP signaling inhibition that may account for the efficient neural differentiation. Blocking FGF signaling inhibited neural induction, but did not alter the phosphorylation of the linker region of Smad1, suggesting that FGF enhances human neural specification independently of BMP signaling.

Screening for Neurocognitive Impairment in Pediatric Cancer Long-Term Survivors

Purpose

Recent studies suggest that up to 40% of childhood cancer survivors may experience neurocognitive problems, a finding that has led the Children's Oncology Group to recommend regular evaluation. However, for a variety of reasons, including costs, time restraints, health insurance, and access to professional resources, these guidelines are often difficult to implement. We report reliability and validity data on a brief neurocognitive screening method that could be used to routinely screen patients in need of comprehensive follow-up.

Patients and Methods

Two hundred forty consecutive patients were screened during their annual visits to a long-term survivor clinic using standard neurocognitive measures and brief parent rating. From this total, 48 patients had a second screening, and 52 patients had a comprehensive follow-up evaluation. Test-retest reliability and predictive and discriminative validity were examined.

Results

Good test-retest reliability was demonstrated, with an overall r = 0.72 and all individual subtest correlations greater than r = 0.40. Although means tended to improve from first to second testing, no significant changes were detected (all P > .10). The screen accurately predicted global intellect (F6,45 = 11.81, P < .0001), reading skills (F6,45 = 4.74, P < .001), and mathematics (F6,45 = 3.35, P < .008). Parent rating was a marginal indicator of global intellect only.

Conclusion

The brief neurocognitive screening was a better predictor of child functioning than specific parent rating. This brief measure, which can be completed in 30 minutes, is a practical and reliable method to identify cancer survivors in need of further neurocognitive follow-up.