Neuropsychological Test Norms for the Assessment of HIV-Associated Neurocognitive Impairment Among South African Adults

Reliable and valid neurocognitive (NC) test batteries that assess multiple domains of cognitive functioning are vital tools in the early detection of HIV-associated NC impairment. The HIV Neurobehavioral Research Center's International Neurobehavioral Battery (HNRC Battery) is one such diagnostic tool and has shown cultural validity in several international neuroHIV studies. However, no published norms are currently available for the full HNRC Battery in South Africa. To accurately interpret NC test results, appropriate reference norms are required. In light of this challenge, data were collected from 500 healthy, HIV-uninfected participants to develop demographically corrected South African norms. When demographically corrected United States of America (U.S.) norms were applied to the performance scores of our neurologically intact, HIV-negative sample, an impairment rate of 62.2% was observed compared to a 15.0% impairment rate when the newly generated South African norms were applied. These results reiterate the findings of other low- and middle-income countries, highlighting the need for localized, country-specific norms when interpreting NC performance.

Does obesity-associated insulin resistance affect brain structure and function of adolescents differentially by sex?

Metabolic abnormalities affect the adolescent brain. For equivalent abnormalities in metabolism young people exhibit deficits in more cognitive domains than adults. We examine sex differences performance for adolescents with obesity/insulin resistance (IR) and evaluated how sex and IR effected frontal lobe structures and executive functioning. 125 adolescents underwent medical, cognitive, and brain-imaging assessments. Participants were categorized as insulin sensitive (IS) (QUICKI ≥ 0.350) or IR (QUICKI < 0.350). Degree of IR may affect brain and cognition differentially by sex. Females had positive associations between QUICKI and anterior cingulate cortex (ACC) volume, medial orbito-frontal cortex (OFC) thickness, and scores on the Stroop and Digit Symbol Substitution (DSST) tests. Females with IR tended to have thinner insular cortices. No such associations were found in males. In female adolescents, IR may negatively affect brain structure and function. No such effects were found for males. Although needing more development, hormonal effects and inflammation are potential contributors.

The executive control correlate of loneliness in healthy older people

Perceived loneliness has implications in both cognitive and affective domains. High loneliness is considered to be a major risk factor for major depressive disorder. Loneliness is also associated with impaired executive control functioning (ECF) including multiple cognitive subdomains, such as working memory, planning, response inhibition, and attention control. However, little knowledge exists as to whether perceived loneliness is associated with impaired functioning of specific ECF components. The relationship between perceived loneliness and the latent dimensions capturing multiple measures across different ECF paradigms has not been established. In this study, we first investigated the latent dimensions of ECF processes across a comprehensive range of paradigms using exploratory factor analysis. We then examined the association of perceived loneliness and the resulted ECF components in older adults while simultaneously controlling for other demographic and affective measures. Four components emerged from the factor analysis: social cognition and processing speed, planning and working memory, selective, divided attention and inhibition control, and sustained attention and motor inhibition. We observed that the second ECF component, planning and working memory, was a significant predictor of perceived loneliness even after controlling for depressive characteristics measured by the Geriatric Depression Scale. Our findings have potential clinical significance in the older population, by showing that planning and working memory functions may predict perceived loneliness, which is also associated with higher risk for major depression. Thus, older individuals who have lower planning and working memory functions may be specifically targeted for possible early prevention of chronic loneliness and depression.

Demographically adjusted normative data for the Halstead category test in a Spanish-speaking adult population: Results from the Neuropsychological Norms for the U.S.-Mexico Border Region in Spanish (NP-NUMBRS)

OBJECTIVE

The present study aimed to develop norms applicable to Spanish-speakers living in the United States (U.S.)- Mexico border region for the Halstead Category Test (HCT), a test of executive function.

METHODS

Healthy native Spanish-speakers (N = 252; Age: range 19-60 years, M = 37.28, SD = 10.24; Education: range 0-20 years; M = 10.65, SD = 4.33; 58.33% women) living in the U.S.-Mexico border region of California and Arizona completed the HCT as part of a comprehensive neuropsychological test battery. The univariable and interactive effects of demographic variables on HCT raw scores were examined. Total scores were normed using fractional polynomial equations, controlling for age, education, and gender. T-scores were also computed for HCT scores of the current Spanish-speaking normative sample using published, demographically-adjusted norms for English-speaking non-Hispanic Whites and Blacks. Impairment rates (T-Scores < 40) were calculated using published and current norms.

RESULTS

Age was significantly associated with increased number of errors, and education and male gender were associated with decreased number of HCT errors (total raw scores). Applying norms developed for English-speaking non-Hispanic Whites and Blacks resulted in overestimation of impairment rates in the current sample (impairment: 48% with White norms and 27% with Black norms). This pattern was evident across levels of education except in participants with 13+ years of education, where rates of impairment using non-Hispanic Black norms were comparable to those based on newly developed norms.

CONCLUSION

The present study presents norms for the HCT in a sample of U.S. Spanish-speakers, providing an important tool for identifying executive dysfunction in this population.

Psychometric Equivalence of the Computerized and Original Halstead Category Test Using a Matched Archival Sample

Objective: Investigate the equivalence of several psychometric measures between the traditional Halstead Category Test (HCT-Original Version [OV]) and the computer-based Halstead Category Test (HCT-Computerized Version [CV]). Method: Data were from a diagnostically heterogeneous, archival sample of 211 adults administered either the HCT by computer (n = 105) or cabinet (n = 106) as part of a neuropsychological evaluation. Groups were matched on gender, race, education, Full Scale Intelligence Quotient, and Global Neuropsychological Deficit Score. Confirmatory factor analysis was used to examine structural equivalence. Score, variability, and reliability equivalency were also examined. Differential item and test functioning under a Rasch model were examined. Results: An identified factor structure from research of the HCT-OV fit the HCT-CV scores adequately: χ²(4) = 8.83, p = .07; root mean square error of approximation = 0.10 [0.00, 0.20]; standardized root mean residual = 0.03; comparative fit index = 0.99. Total scores and variability of subtest scores were not consistently equivalent between the two administration groups. Reliability estimates were, however, similar and adequate for clinical practice: 0.96 for HCT-OV and 0.97 for HCT-CV. About 17% of items showed possible differential item functioning, though just three of these items were statistically significant. Differential test functioning revealed expected total score differences of <1% between versions. Conclusion: The results of this study suggest that the HCT-CV functions similar to the HCT-OV with there being negligible differences in expected total scores between these versions. The HCT-CV demonstrated good psychometric properties, particularly reliability and construct validity consistent with previous literature. Further study is needed to generalize these findings and to further examine the equivalency of validity evidence between versions.

Computerized and on-line neuropsychological testing for late-life cognition and neurocognitive disorders: are we there yet?

PURPOSE OF REVIEW

Cost-effective, valid, efficient and accessible tests for the detection of late-life neurocognitive disorders are crucial, as early identification facilitates appropriate early intervention. Proponents of computerized neuropsychological assessment devices (CNADs) assert that technology-based assessments improve upon traditional neuropsychological tests. However, there remain fundamental questions of validity, reliability, normative data and administration, raising the question of whether CNADs are appropriate alternatives.

RECENT FINDINGS

Since publication of the 2012 American Academy of Clinical Neuropsychology and National Academy of Neuropsychology joint position paper outlining appropriate standards for CNAD development, the field has not significantly advanced, with the majority of recommendations inadequately addressed.

SUMMARY

Whilst there is a pressing need for innovative and readily applicable cognitive tests, these requirements do not outweigh the necessity for valid measures. Overall, the psychometric quality, standardization, normative data and administration advice of CNADs for neurocognitive disorders are lacking. Therefore, the risk of diagnostic errors is potentially high and poor clinical decisions could potentially arise, having significant impact upon individuals in terms of their well being and access to treatment. We recommend clinicians and researchers make informed decisions about CNAD suitability for their clients and their individual requirements based upon published psychometric and other test information.