Demographically adjusted norms for Catalan older adults on the Stroop Color and Word Test

A multimodal group-based immersive virtual reality intervention for improving cognition and mental health in patients with post-covid-19 condition. A quasi-experimental design study

Introduction

Adults with Post-COVID-19 Condition (PCC) may show cognitive impairments in attention, processing speed, memory, and executive function. Multimodal programs that combine cognitive training, physical activity and emotional tasks, such as mindfulness-based interventions (MBIs), may offer a suitable alternative for improving PCC treatments. Immersive Virtual Reality (IVR) is a promising technology that can enhance traditional cognitive training, physical activity, and MBIs. The use of IVR technology may increase engagement with these interventions and potentially enhance the individual benefits of cognitive training, exercise and MBIs. The current study evaluated the impact of a multimodal IVR intervention, comparing this with a usual care intervention (control group), in order to assess changes in cognition and mental health in adults with PCC. We also aimed to assess user experience factors such as enjoyment, perceived improvement, and fatigue following each multimodal IVR session within the experimental group.

Method

Thirty-one participants with PCC symptoms were assigned to either the experimental group (IVR, n = 15) or the control group (usual care intervention, n = 16) in a quasi-experimental design study. The multimodal IVR intervention consisted of MBI, cognitive training and physical exercise and was delivered in a 60-min group session with 5 participants, twice a week, for 8 weeks (16 sessions in total). Measures of global cognition, attention, processing speed, verbal episodic memory and subjective memory complaints (primary measures), and depressive and anxiety symptoms and fatigue (secondary measures) were assessed at baseline and also after 8 weeks (post-intervention).

Results

Mixed between-group (group) and within-group (pre-post assessments) ANOVAs revealed significant group*time interactions in global cognition, simple attention, processing speed, memory and depressive symptoms, with large effect sizes (p < 0.05; partial η2 > 0.14). There was also a marginally significant group*time interaction for executive function (p = 0.05). Follow-up analyses comparing pre-and post-intervention outcomes for each group separately showed that the experimental group significantly improved in global cognition, processing speed, memory and depressive symptoms, while the control group showed no significant pre-post changes. Friedman tests showed a significant main effect of time (χ2(2) = 6.609, p = 0.04), with a gradual increase in enjoyment from the first, to the mid, and then to the final session. In addition, perceived improvement scores remained high throughout the intervention, and patient-reported fatigue levels did not fluctuate significantly throughout the intervention.

Conclusion

To our knowledge, no previous research has combined cognitive training, physical exercise and MBI using an IVR paradigm in adults with PCC. Despite their inherent limitations, our findings mark a pioneering step toward improving cognition and mental health outcomes in PCC through the innovative use of new technology and multimodal approaches. This first study should be accompanied by more extensive, randomized clinical trials aimed at further exploring and refining these interventions.

Normative Data Estimation in Neuropsychological Tests: A Systematic Review

OBJECTIVE

To quantify the evolution, impact, and importance of normative data (ND) calculation by identifying trends in the research literature and what approaches need improvement.

METHODS

A PRISMA-guideline systematic review was performed on literature from 2000 to 2022 in PubMed, Pub-Psych, and Web of Science. Inclusion criteria included scientific articles about ND in neuropsychological tests with clear data analysis, published in any country, and written in English or Spanish. Cross-sectional and longitudinal studies were included. Bibliometric analysis was used to examine the growth, productivity, journal dispersion, and impact of the topic. VOSViewer compared keyword co-occurrence networks between 1952-1999 and 2000-2022.

RESULTS

Four hundred twelve articles met inclusion and exclusion criteria. The most studied predictors were age, education, and sex. There were a greater number of studies/projects focusing on adults than children. The Verbal Fluency Test (12.7%) was the most studied test, and the most frequently used variable selection strategy was linear regression (49.5%). Regression-based approaches were widely used, whereas the traditional approach was still used. ND were presented mostly in percentiles (44.2%). Bibliometrics showed exponential growth in publications. Three journals (2.41%) were in the Core Zone. VOSViewer results showed small nodes, long distances, and four ND-related topics from 1952 to 1999, and there were larger nodes with short connections from 2000 to 2022, indicating topic spread.

CONCLUSIONS

Future studies should be conducted on children's ND, and alternative statistical methods should be used over the widely used regression approaches to address limitations and support growth of the field.

Attention and processing speed tests: Normative data for Spanish-speaking adults in the United States

BACKGROUND

Hispanics/Latinos are the largest racial/ethnic group among underrepresented populations in the U.S. and multiple sociodemographic, cultural, and linguistic factors have been found to impact their performances on cognitive testing. Despite this, few normative data are available for the heterogeneous Spanish-speaking population in the U.S.

OBJECTIVE

To generate normative data on the Trail-Making Test (TMT), Bells Test, Symbol-Digit Modalities Test (SDMT), and the Brief Test of Attention (BTA) for Spanish speakers residing in the U.S.

METHODS

The sample included 245 Spanish-speaking individuals aged 18- 80 from eight states across the U.S. (California, Connecticut, Florida, Indiana, New Jersey, Oregon, Virginia, and Wisconsin). Participants were administered attention and processing speed measures as part of a comprehensive neuropsychological battery. We used a Bayesian regression approach to estimate normative data, including covariates found to be important for predicting performances on measures of attention and processing speed.

RESULTS

Sociodemographic factors including education, time in the U.S., acculturation, age, and/or sex had differential effects on the TMT-A, TMT-B, SDMT, and the BTA whereas the Bells Test was not influenced by any of these sociodemographic factors.

CONCLUSION

Our findings indicate that while sex, age, and educational attainment are important factors to consider, language and acculturation can also influence attention and processing speed performances among Spanish speakers in the U.S.

UD Interference Test: creation and validation of a new instrument of resistance to interference. Normalisation and standardisation for Spanish population

INTRODUCTION

The UD Interference Test measures processing speed and attention, and is based on the concept of interference of the Stroop Color and Word Test. The main purpose of the study is to provide an alternative version of the Stroop Color and Word Test that overcomes some of the limitations of previous versions in assessing individuals with daltonism or age-related reading difficulties, and to obtain normative and standardised data for the Spanish population.

METHODS

This study is part of the Normacog project. We evaluated 905 individuals (age range, 18-93 years) to analyse the test's reliability and concurrent and construct validity. We evaluated the effect of age, sex, and level of education on UD Interference Test performance and calculated percentiles and age- and education-adjusted scaled scores.

RESULTS

The test has good reliability (α = 0.875) and concurrent (r = 0.443-0.725; P < .001) and construct validity (r = 0.472-0.737; P < .001). We observed age and educational level to have a significant effect on UD Interference Test scores, explaining 12% to 40% of variance. Sex only had a significant effect on the resistance to interference index.

CONCLUSIONS

We present an alternative version of the Stroop Color and Word Test with some advantages over previous versions. We provide standardised and normalised data for the Spanish population to correct the test according to the subject's age and level of education.

UD Interference Test: Creation and validation of a new instrument of resistance to interference. Normalization and standardization for Spanish population

INTRODUCTION

The UD Interference Test measures processing speed and attention, and is based on the concept of interference of the Stroop Test. The main purpose of the study is to provide an alternative version of the Stroop Test that overcomes some of the limitations of previous versions in assessing individuals with daltonism or age-related reading difficulties, and to obtain normative and standardised data for the Spanish population.

METHODS

This study is part of the Normacog project. We evaluated 905 individuals (age range, 18-93 years) to analyse the test's reliability and concurrent and construct validity. We evaluated the effect of age, sex, and level of education on UD Interference Test performance and calculated percentiles and age- and education-adjusted scaled scores.

RESULTS

The test has good reliability (α = 0.875) and concurrent (r = 0.443-0.725; p < .001) and construct validity (r = 0.472-0.737; p < .001). We observed age and educational level to have a significant effect on UD Interference Test scores, explaining 12-40% of variance. Sex only had a significant effect on the resistance to interference index.

CONCLUSIONS

We present an alternative version of the Stroop Color and Word Test with some advantages over previous versions. We provide standardised and normalised data for the Spanish population to correct the test according to the subject's age and level of education.

Multivariate Base Rates of Low Scores on Tests of Executive Functions in a Multi-Country Latin American Sample

The objective of the study was to determine the prevalence of low scores in a diverse Latin American population for two neuropsychological commonly used tests to evaluate executive functions and to compare the number of low scores obtained using normative data from a Spanish-speaking population from Latin America versus an English-speaking population from U.S.A. Healthy adults (N = 5402) were administered the Modified Wisconsin Card Sorting Test and Stroop Color-Word. Low scores on measures of executive functioning are common. Clinicians working with Spanish-speaking adults should take into account the higher probability of low scores on these measures to reduce false-positive diagnoses of cognitive deficits in an individual.

Normative data for tests of attention and executive functions in a sample of European Portuguese adult population

OBJECTIVE

The main goal of this study was to produce normative data for the Portuguese population on five neuropsychological tests frequently used to assess executive functions and attention: the Modified Wisconsin Card Sorting Test (M-WCST), the Stroop Color and Word Test, the Trail Making Test (TMT), the Brief Test of Attention (BTA), and the Symbol Digit Modalities Test (SDMT).

METHOD

The study included 300 individuals aged between 18 and 93 years, who had educational backgrounds ranging from 3 to 25 years.

RESULTS

The influence of age, education, and sex was explored for each measure, as well as their contribution to explain the performance variance.

CONCLUSIONS

The normative data are presented as regression-based algorithms to adjust direct and derived test scores for sex, age, and education. This study provides a calculator of normative data, derived from the results of the regression models.

Bias-Variance Trade-Off in Continuous Test Norming

In continuous test norming, the test score distribution is estimated as a continuous function of predictor(s). A flexible approach for norm estimation is the use of generalized additive models for location, scale, and shape. It is unknown how sensitive their estimates are to model flexibility and sample size. Generally, a flexible model that fits at the population level has smaller bias than its restricted nonfitting version, yet it has larger sampling variability. We investigated how model flexibility relates to bias, variance, and total variability in estimates of normalized z scores under empirically relevant conditions, involving the skew Student t and normal distributions as population distributions. We considered both transversal and longitudinal assumption violations. We found that models with too strict distributional assumptions yield biased estimates, whereas too flexible models yield increased variance. The skew Student t distribution, unlike the Box–Cox Power Exponential distribution, appeared problematic to estimate for normally distributed data. Recommendations for empirical norming practice are provided.

Cognitive and Motor Norms for Huntington’s Disease

Background

The progression of Huntington’s disease (HD) for gene-expanded carriers is well-studied. Natural aging effects, however, are not often considered in the evaluation of HD progression.

Objective

To examine the effects of natural aging for healthy controls and to develop normative curves by age, sex, and education from the distribution of observed scores for the Symbol Digit Modalities Test, Stroop Word Reading Test, Stroop Color Naming Test, Stroop Interference Test, Total Motor Score, and Total Functional Capacity (TFC) from the Unified Huntington’s Disease Rating Scale (UHDRS) along with a composite score.

Methods

After combining longitudinal REGISTRY and Enroll-HD data, we used quantile regression and natural cubic splines for age to fit models for healthy controls (N = 3,394; N observations = 8,619). Normative curves were estimated for the 0.05, 0.25, 0.50, 0.75, and 0.95 quantiles. Two types of reference curves were considered: unconditional curves were dependent on age alone, whereas conditional curves were dependent on age and other covariates, namely sex and education.

Results

Conditioning on education was necessary for the Symbol Digit, Stroop Word, Stroop Color, Stroop Interference, and composite UHDRS. Unconditional curves were sufficient for the Total Motor Score. TFC was unique in that the curve was constant over age with its intercept at the maximum score (TFC = 13). For all measures, sex effects were minimal, so conditioning on sex was unwarranted.

Conclusions

Extreme quantile estimates for each measure can be considered as boundaries for natural aging and scores falling beyond these thresholds are likely the result of disease progression. Normative curves and tables are developed and can serve as references for clinical characterization in HD.

The Stroop Color and Word Test

The Stroop Color and Word Test (SCWT) is a neuropsychological test extensively used to assess the ability to inhibit cognitive interference that occurs when the processing of a specific stimulus feature impedes the simultaneous processing of a second stimulus attribute, well-known as the Stroop Effect. The aim of the present work is to verify the theoretical adequacy of the various scoring methods used to measure the Stroop effect. We present a systematic review of studies that have provided normative data for the SCWT. We referred to both electronic databases (i.e., PubMed, Scopus, Google Scholar) and citations. Our findings show that while several scoring methods have been reported in literature, none of the reviewed methods enables us to fully assess the Stroop effect. Furthermore, we discuss several normative scoring methods from the Italian panorama as reported in literature. We claim for an alternative scoring method which takes into consideration both speed and accuracy of the response. Finally, we underline the importance of assessing the performance in all Stroop Test conditions (word reading, color naming, named color-word).

Qualifying and quantifying minimal hepatic encephalopathy

Minimal hepatic encephalopathy is the term applied to the neuropsychiatric status of patients with cirrhosis who are unimpaired on clinical examination but show alterations in neuropsychological tests exploring psychomotor speed/executive function and/or in neurophysiological variables. There is no gold standard for the diagnosis of this syndrome. As these patients have, by definition, no recognizable clinical features of brain dysfunction, the primary prerequisite for the diagnosis is careful exclusion of clinical symptoms and signs. A large number of psychometric tests/test systems have been evaluated in this patient group. Of these the best known and validated is the Portal Systemic Hepatic Encephalopathy Score (PHES) derived from a test battery of five paper and pencil tests; normative reference data are available in several countries. The electroencephalogram (EEG) has been used to diagnose hepatic encephalopathy since the 1950s but, once popular, the technology is not as accessible now as it once was. The performance characteristics of the EEG are critically dependent on the type of analysis undertaken; spectral analysis has better performance characteristics than visual analysis; evolving analytical techniques may provide better diagnostic information while the advent of portable wireless headsets may facilitate more widespread use. A large number of other diagnostic tools have been validated for the diagnosis of minimal hepatic encephalopathy including Critical Flicker Frequency, the Inhibitory Control Test, the Stroop test, the Scan package and the Continuous Reaction Time; each has its pros and cons; strengths and weaknesses; protagonists and detractors. Recent AASLD/EASL Practice Guidelines suggest that the diagnosis of minimal hepatic encephalopathy should be based on the PHES test together with one of the validated alternative techniques or the EEG. Minimal hepatic encephalopathy has a detrimental effect on the well-being of patients and their care-givers. It responds well to treatment with resolution of test abnormalities and the associated detrimental effects on quality of life, liver-related mortality and morbidity. Patients will only benefit in this way if they can be effectively diagnosed. Corporate efforts and consensus agreements are needed to develop effective diagnostic algorithms.

Stroop Color-Word Interference Test: Normative data for the Latin American Spanish speaking adult population

OBJECTIVE

To generate normative data on the Stroop Test across 11 countries in Latin America, with country-specific adjustments for gender, age, and education, where appropriate.

METHOD

The sample consisted of 3,977 healthy adults who were recruited from Argentina, Bolivia, Chile, Cuba, El Salvador, Guatemala, Honduras, Mexico, Paraguay, Peru, and, Puerto Rico. Each subject was administered the Stroop Test, as part of a larger neuropsychological battery. A standardized five-step statistical procedure was used to generate the norms.

RESULTS

The final multiple linear regression models explained 14-36% of the variance in Stroop Word scores, 12-41% of the variance in the Stoop Color, 14-36% of the variance in the Stroop Word-Color scores, and 4-15% of variance in Stroop Interference scores. Although t-tests showed significant differences between men and women on the Stroop test, none of the countries had an effect size larger than 0.3. As a result, gender-adjusted norms were not generated.

CONCLUSIONS

This is the first normative multicenter study conducted in Latin America to create norms for the Stoop Test in a Spanish-Speaking sample. This study will therefore have important implications for the future of neuropsychology research and practice throughout the region.

Sample Size Requirements for Traditional and Regression-Based Norms

Test norms enable determining the position of an individual test taker in the group. The most frequently used approach to obtain test norms is traditional norming. Regression-based norming may be more efficient than traditional norming and is rapidly growing in popularity, but little is known about its technical properties. A simulation study was conducted to compare the sample size requirements for traditional and regression-based norming by examining the 95% interpercentile ranges for percentile estimates as a function of sample size, norming method, size of covariate effects on the test score, test length, and number of answer categories in an item. Provided the assumptions of the linear regression model hold in the data, for a subdivision of the total group into eight equal-size subgroups, we found that regression-based norming requires samples 2.5 to 5.5 times smaller than traditional norming. Sample size requirements are presented for each norming method, test length, and number of answer categories. We emphasize that additional research is needed to establish sample size requirements when the assumptions of the linear regression model are violated.