Neuropsychological Assessment Of Executive Functions Research Articles

Concurrent Validity of Virtual Reality-Based Assessment of Executive Function: A Systematic Review and Meta-Analysis

This meta-analysis investigated the concurrent validity between virtual reality (VR)-based assessments and traditional neuropsychological assessments of executive function, with a focus on subcomponents such as cognitive flexibility, attention, and inhibition. A total of 1605 articles were identified through searches of PubMed, Web of Science, and ScienceDirect from 2013 to 2023. After removing duplicates, 1313 articles were screened based on their titles and abstracts, with 77 articles selected for full-text eligibility review. Of these, nine articles fully met the inclusion and exclusion criteria for this study. The effect size for overall executive function was assessed, with subcomponents categorized based on the specific assessment tools used in the studies. The effect size for each subcomponent—cognitive flexibility, attention, and inhibition—was then analyzed to provide a more detailed understanding of their relationships with traditional measures. The results revealed statistically significant correlations between VR-based assessments and traditional measures across all subcomponents. Additionally, sensitivity analyses confirmed the robustness of the findings, even when low-quality studies were excluded. These results support the use of VR-based assessments as a valid alternative to traditional methods for evaluating executive function. Moreover, the study highlights the potential of VR-based assessments as a valid alternative to traditional methods, emphasizing the need to address variability in executive function subcomponents and integrate diverse cognitive and motor metrics for greater ecological validity.

Semantic and phonemic verbal fluency tests: Normative data for the Turkish population

Semantic and phonemic verbal fluency tests are widely used neuropsychological assessments of executive functions and language skills and are easy to administer. The aim of this study was to determine the impact of age, education, and gender on semantic and phonemic verbal fluency tests and to establish normative data for Turkish adults aged between 18 and 86 years. The results revealed significant main effects of age and education on all subscores of verbal fluency tests. Furthermore, an interaction effect between age and education was observed on semantic fluency and letter K fluency scores. While no significant differences were found among the 18–29, 30–39, and 40–49 age groups in any of the subscores, performance on the tests decreased with increasing age. Significant differences were observed among all education groups in all subscores. No main or interaction effects of gender were found on any subscore. These normative data could prove useful in clinical and research settings for the assessment of cognitive impairment.

Assessment of Executive Functions in School Considering Motor and Sociodemographic Factors: A Joint Vision for School-Based Occupational Therapists and School Staff

Executive functions (EFs) and motor skills are essential for many school and daily tasks. Many school-based occupational therapists need help addressing EFs. The current study aims to provide new insights into the relationship between executive functions and motor development by considering confounding factors. Ninety-six second-grade children were tested in one state-funded (public) school and another state-subsidised private school. Children were assessed with the Movement Assessment Battery for Children-2 (MABC-2), Neuropsychological Assessment of Executive Functions in Children, and Test of Perception of Differences–R. Families completed a sociodemographic questionnaire, and teachers completed a previous questionnaire and subsequently evaluated the information the occupational therapist provided. Mixed results were obtained regarding the correlation between motor and executive skills. Furthermore, children who received worse scores on the MABC-2 had more difficulties on the EFs tests. The Impulsivity Control Index was not correlated with any motor variable. Our results show that sociodemographic variables (except gender) correlate more with EFs than motor skills. The teachers showed a high degree of agreement with the occupational therapist (4.0 ± 0.8), even in children with good academic performance. They expressed the need for additional training and classroom interventions. A joint vision of motor-executive functioning can facilitate the design of effective interventions, especially in schools with more disadvantaged populations.

Avaliação das funções executivas em adultos pós traumatismo cranioencefálico

Abstract Objective Executive dysfunction after traumatic brain injury may lead to reduced daily functionality due to direct damage to the frontal lobe or to disruption of its connections to other brain regions. This study aimed to compare the performance of adults with and without traumatic brain injury on executive functions tasks. Method The present study had a descriptive transversal design and included 43 participants divided into a clinical group (N = 23, age M = 34.3 [10.86]) and a control group (N = 20, age M = 38.3 [10.7]). The battery consisted of traditional instruments and the Ecological Hotel Task. Results A significant difference was found in the performance of the groups in the planning measures (number of tasks [t = -3.06; p < 0.01] and planning score [t = -3.06; p < 0.01]), highlighting the advantages of using both the traditional performance paradigms and the ecological tasks in neuropsychological assessment of executive functions. Conclusion Results suggested that the ecological task might discriminate better executive dysfunction, emphasizing the importance of using activities that simulate real-life situations of the participants.

Cool executive functions and their association with body mass & fatness and the FTO gene in school-aged children

The FTO gene rs9936909 polymorphism is one of the well-documented single nucleotide polymorphisms in the context of increased risk of obesity, including in children. Few studies have tested the association of the FTO gene with cognitive functions. Deficits of “cool” executive functions (EFs) are considered a potential risk factor for excessive weight. The aims of our study were to investigate whether cool EFs are associated with the Body Mass Index, the Fat Mass Index and the risk of excess body mass and overfatness in neurotypically school-aged children, and whether the FTO gene polymorphism is involved in development of this possible association. The sample consisted of 553 children aged 6–12 years old. A body composition analysis, a neuropsychological assessment of EFs, and FTO polymorphism genotyping were performed in the children studied. The study found a significant association of an interference effect in theStroop Color-Word Interference Task and the risk of excessive body fatness, but not excessive body mass. There were no explicit associations between the FTO genotype and EFs deficits. Environmental factors, and particularly low maternal education, appeared to be the strongest contributors to the increased risk of obesity.

Metabolite changes in prefrontal lobes and the anterior cingulate cortex correlate with processing speed and executive function in Parkinson disease patients.

BackgroundProcessing speed and executive function can be impaired in patients with Parkinson disease (PD). However, the neural factors related to the slowdown in processing speed and dysexecutive function in PD are not completely understood. The objective of this study is to investigate the metabolic changes of the frontal and anterior cingulate cortex (ACC) through the use of 1H magnetic resonance spectroscopy and to explore the association between cognitive function and metabolic ratios.MethodsIn this retrospective case-control study, we conducted neuropsychological assessments of executive function and information processing speed in healthy controls (HCs) and in patients with PD. Chemical information was obtained for the of N-acetyl-aspartate (NAA):creatine (Cr) ratio and the choline-containing compounds (Cho):Cr ratio within the bilateral prefrontal cortex and ACC. Using hierarchical multiple regression analysis, we analyzed the relationship between cognitive function and metabolic ratios in the bilateral prefrontal lobe and ACC in patients with PD.ResultsIn all, 59 patients with PD and 30 HCs were recruited. Patients with PD showed worse performance in executive function and processing speed compared with HCs (P<0.001). In patients with PD, the Cho:Cr ratios in the ACC (Z=2.20, P=0.028) and the right prefrontal cortex (t=2.16, P=0.034) were significantly increased. The hierarchical multiple regressions in patients with PD showed that the NAA:Cr ratio in the ACC correlated with the Stroop A completion times (P<0.05) and that the NAA:Cr ratio of the right prefrontal cortex correlated with the scores of the Wechsler Adult Intelligence Scale (WAIS)-Digit symbol test (P<0.05).ConclusionsInformation processing speed and executive function are impaired in patients with PD. Neuronal integrity and membrane turnover in the ACC and the right prefrontal cortex may be important factors in the slowdown of the information processing speed in patients with PD.

Neuropsychological profile of Turner Syndrome in relation to deficits in academic and psychosocial areas. A case report

Introduction Previous reviews reported an association between Turner Syndrome (TS) and a profile of deficits in some neurocognitive domains (visual-spatial domains, mathematics, and executive functions: cognitive flexibility, working memory, cognitive inhibition, and problem solving), although pointing out individual variability.ObjectivesTo describe the neuropsychological profile of a patient with diagnosis of TS and psychosocial difficulties attended at the Service of Psychiatry, Clinical Psychology and Mental Health at La Paz University Hospital (Madrid).MethodsA descriptive study is conducted on a single case of a 11-year-old woman with diagnosis of TS attended by a clinical psychologist at a child-adolescent Mental health center for social, family and academic difficulties. Neuropsychological assessment was completed in October, 2021. The Wechsler Intelligence Scale for Children-Five Edition (WISC-V) and Neuropsychological Assessment of Executive Functions in Children (ENFEN) batteries were administered.ResultsThe full-scale intelligence quotient was observed in the normal range, with lower scores in non-verbal tasks. Deficits (range from z = -2.00 to -1.75) were observed in tests of working memory, processing speed and complex problem-solving tasks. The results showed great variability in other executive functioning tasks (selective attention tasks: from z = -1.75 to -0.75; and cognitive flexibility tasks: from z = -2.25 to 0.25).ConclusionsThe neurocognitive profile described in the literature was partially consistent with the results obtained in this study. The neuropsychological assessment can support the elucidation of clinical diagnostic and therapeutic factors in TS patients with relevant psychosocial or cognitive difficulties.DisclosureNo significant relationships.

Central Executive Network and Executive Function in Patients With Alzheimer's Disease and Healthy Individuals: Meta-Analysis of Structural and Functional MRI.

The neural architecture of executive function is of interest given its utility as a transdiagnostic predictor of adaptive functioning. However, a gap exists in the meta-analytic literature assessing this relationship in neuropsychiatric populations, concordance between structural and functional architecture, and the relationship with neuropsychological assessment of executive function. Given the importance of the central executive network (CEN) in Alzheimer's disease, this population may be useful in understanding this relationship in Alzheimer's disease pathology. A meta-analysis of studies (k=21) was conducted to elucidate the relationship between executive function and CEN for structural architecture (k=10; N=1,027) among patients with Alzheimer's disease (k=6; N=250) and healthy control subjects (HCs) (k=4; N=777) and for functional architecture (k=11; N=522) among patients with Alzheimer's disease (k=6; N=306) and HCs (k=5; N=216). Random-effects modeling was used to increase accuracy of conclusions about population means. Analyses revealed a positive brain-behavior relationship (pr=0.032, 95% CI=0.07, 0.54), although there was a lack of statistically significant heterogeneity between functional and structural neuroimaging (Q=9.89, p=0.971, I2=0.00%) and between the Alzheimer's and HC groups in functional (Q=8.18, p=0.612, I2=0.00%) and structural (Q=1.60, p=0.996, I2=0.00%) neuroimaging. Similarly, a lack of statistically significant heterogeneity was revealed between functional and structural neuroimaging among patients with Alzheimer's disease (Q=3.59, p=0.980, I2=0.00%) and HCs (Q=3.67, p=0.885, I2=0.00%). Structural and functional imaging in the CEN are predictive of executive function performance among patients with Alzheimer's disease and HCs. Regardless of how the CEN is affected, behavior is correlated to the degree to which the CEN is affected. Findings are significant in the context of methodological decisions in multimodal neuroimaging research.

Attaining the recesses of the cognitive space.

Existing neuropsychological tests of executive function often manifest a difficulty pinpointing cognitive deficits when these are intermittent and come in the form of omissions. We discuss the hypothesis that two partially interrelated reasons for this failure stem from relative inability of neuropsychological tests to explore the cognitive space and to explicitly take into account strategic and opportunistic resource allocation decisions, and to address the temporal aspects of both behaviour and task-related brain function in data analysis. Criteria for tasks suitable for neuropsychological assessment of executive function, as well as appropriate ways to analyse and interpret observed behavioural data are suggested. It is proposed that experimental tasks should be devised which emphasize typical rather than optimal performance, and that analyses should quantify path-dependent fluctuations in performance levels rather than averaged behaviour. Some implications for experimental neuropsychology are illustrated for the case of planning and problem-solving abilities and with particular reference to cognitive impairment in closed-head injury.

The Wisconsin Card Sorting Test: Split-Half Reliability Estimates for a Self-Administered Computerized Variant

Self-administered computerized assessment has the potential to increase the reach of neuropsychological assessment. The present study reports the first split-half reliability estimates for a self-administered computerized variant of the Wisconsin Card Sorting Test (WCST), which is considered as a gold standard for the neuropsychological assessment of executive functions. We analyzed data from a large sample of young volunteers (N = 375). Split-half reliability estimates for perseveration errors, set-loss errors, and inference errors were all above 0.90. Split-half reliability estimates for response time measures on switch and repeat trials exceeded 0.95. Our results indicated sufficient split-half reliability for a self-administered computerized WCST, paving the way for an advanced digital assessment of executive functions. We discuss potential effects of test formats, administration variants, and sample characteristics on split-half reliability.

Relaciones de la motivación con la metacognición y el desempeño en el rendimiento cognitivo en estudiantes de educación primaria

Sundry studies have emphasised the importance of motivation in cognitive performance, as well as its link to metacognitive development. The objective here is to explore the motivation variables that influence the performance of cognitive tasks, along with their effect on metacognition. The study sample consists of 354 primary school pupils aged 8-11 at a state school in the Community of Madrid (Spain). The following measuring in-struments have been used for studying the variables: Motivacion para el Aprendizaje y la Ejecucion (MAPE-I) [Motivation for Learning and Execu-tion], a questionnaire on motivation variables; the Junior Metacognitive Awareness Inventory (Jr. MAI), for metacognitive variables, and the bat-tery of tests in the Evaluacion Neuropsicologica de las Funciones Ejecutivas en Ni-nos (ENFEN) [Neuropsychological Assessment of Executive Functions in Children], for assessing cognitive performance. The results reveal a signifi-cant effect between the motivation for focusing on learning and cognitive performance in the tasks that involve inhibition, flexibility, and working memory. We also find a significant effect between increased effort and knowledge regulation. Furthermore, we analyse the relations between the variables by school year to determine the age effect. We evaluate the re-sults’ academic implications.

Assessment of the Effects of Digital Educational Material on Executive Function Performance

The use of digital educational material in classrooms has increased in recent years, now constituting a major market for publishers and companies. The present research addresses a digital material assessment in two different areas. First, the study through an evaluation of internal data collected on the platform shows an analysis of the use and implementation of digital material into the school. Secondly, it exposes an external examination of the effect of using digital material at school on students’ executive functions. The sample consisted of 168 children aged 8–11 from a state school in the Community of Madrid (Spain). The instrument selected for the external assessment of academic progress was the Evaluación Neuropsicológica de las Funciones Ejecutivas en Niños (ENFEN) [Neuropsychological Assessment of Executive Functions in Children]. The Learning Analytics system of the Smile and Learn platform recorded the students’ use during class. According to the usage analysis, the results obtained show preference of using activities from Logic and Spatial worlds. In the external analysis of the effect of the learning material, the results record a significant effect using activities in Logic and Spatial worlds with the Gray Trails task, which involves spatial perception, processing speed, and working memory, among others. A second analysis to contrast the results with a post hoc design approaches relationships among executive functions as involved in tasks like Gray Trails, Interference, and Ring Tasks within the usage of Spatial and Logic activities. The need for further research to improve these materials for enhanced learning and the extrapolation of training from executive functions to other tasks is discussed. Likewise, limitations of the implementation and design of these materials are pointed out.

Desde la perspectiva Neuropsicológica: la lateralidad, fluidez verbal, y conciencia fonológica componentes fundamentales en el desarrollo del proceso lecto escritor

El presente estudio se proyecta en el conocimiento de la importancia de los factores neurológicos: lateralidad, fluidez verbal y conciencia fonológica centrándose en las estructuras cognitivas, la habilidad metalingüística y el aprendizaje de lectoescritura; visión que orienta al desarrollo integral infantil, desde un enfoque constructivista y el conocimiento científico que contribuyen en el aprendizaje y la comprensión, componentes que benefician en el proceso lecto escritor. Por las razones indicadas en la metodología se aplicó el diseño no experimental que relaciona las variables sin un control e intervención directa sobre alguna de ellas; mientras el método descriptivo determinó las causas, efectos y consecuencias que perjudican en el desarrollo del proceso lecto escritor; mediante la investigación correlacional se comprobó la relación entre las variables, mientras el muestreo no probabilístico intencional fue utilizando para diagnosticar las dificultades lateralidad, fluidez verbal y conciencia fonológica, las técnicas e instrumentos aplicados fueron: el Test de lateralidad de la Prueba Neuropsicológica propuesta por (Martín Lobo, 2011), Se utilizó el test (adaptado por Martín Lobo García-Castellón y Vallejo, 2011) del Instituto de Neuropsicología y Educación; que puede aplicarse a partir de los 4 años de edad, compuesto por cuatro pruebas que miden la lateralidad del ojo, oído, pie y mano; subdividiéndose en 10 subpruebas. El Test Evaluación neuropsicológica de las funciones ejecutivas en niños y niñas (Portellano, Martínez, &amp; Zumárraga, 2009), el instrumento Evaluación Neuropsicológica de las Funciones Ejecutivas en Niños (ENFN) se agrupa en cuatro escalas: fluidez (fonológica y semántica); construcción de senderos (flexibilidad cognitiva, capacidad para emplear estrategias, inhibición, memoria de trabajo, atención sostenida y selectiva); anillas (aptitud del niño para descomponer un problema, flexibilidad cognitiva, capacidad de abstracción, memoria de trabajo); interferencia (evaluación de la inhibición); en el estudio se utilizó la prueba de fluidez verbal y conciencia fonológica, los datos numéricos y la información teórica científica contribuyeron en la determinación de conclusiones y resultados.

The Reliability of the Wisconsin Card Sorting Test in Clinical Practice.

The Wisconsin Card Sorting Test (WCST) represents the gold standard for the neuropsychological assessment of executive function. However, very little is known about its reliability. In the current study, 146 neurological inpatients received the Modified WCST (M-WCST). Four basic measures (number of correct sorts, categories, perseverative errors, set-loss errors) and their composites were evaluated for split-half reliability. The reliability estimates of the number of correct sorts, categories, and perseverative errors fell into the desirable range (rel ≥ .90). The study therefore disclosed sufficiently reliable M-WCST measures, fostering the application of this eminent psychological test to neuropsychological assessment. Our data also revealed that the M-WCST possesses substantially better psychometric properties than would be expected from previous studies of WCST test-retest reliabilities obtained from non-patient samples. Our study of split-half reliabilities from discretionary construed and from randomly built M-WCST splits exemplifies a novel approach to the psychometric foundation of neuropsychology.

The effect of prenatal smoke exposure on child neuropsychological function: a prospective mother–child cohort study

ABSTRACTObjective: To study prospectively the effect of prenatal smoke exposure (PSE) on child neuropsychological function and intelligence quotient (IQ).Background: PSE has been associated with adverse effects on child neurodevelopment. However, some studies reported that these associations disappear after adjustment for potential confounders.Methods: A cohortof 248 mothers-child dyad was followed from the first trimester of pregnancy until children were 7.5 years old. PSE was recorded during pregnancy by questionnaire and plasma cotinine. The Wechsler Intelligence Scale for Children, the Neuropsychological Assessment of Executive Functions for Children (ENFEN) and the School Neuropsychological Maturity Questionnaire were administered at 7.5 years of age. The effect of PSE on child IQ and neuropsychological function was assessed with ANCOVA, adjusting for obstetric, neonatal and sociodemographic factors.Results: Children whose mothers smoked throughout pregnancy scored lower in interference (ENFEN) compared to unexposed children (F = 4.1; p = .008). The results showed no differences in other executive functions, verbal and visual memory and IQ between the PSE groups.Conclusion: PSE had little effect on child neuropsychological outcome and was limited to mental flexibility. Nevertheless, these findings support further efforts aimed at encouraging mothers to quit smoking in pregnancy.

The dual-process model in young adults with a consistent binge drinking trajectory into adulthood

BackgroundBinge Drinking (BD) generally declines once students have left university. However, many individuals continue to partake in BD into adulthood, constituting a scarcely investigated high-risk group towards whom interventions should be prioritized. Following the dual-process model, we examined the relationship between BD and both the reflective system (executive functions) and the affective system (alcohol bias) in young adults with a consistent BD trajectory. We considered impulsivity as a moderator in the relationship between BD and alcohol bias. MethodsA cohort of 63 (31♀) young adults were followed for eleven years (18–29 years old). In the last assessment, participants, with high and low drinking trajectories underwent neuropsychological assessment of executive functions (working memory [SOPT], cognitive flexibility [TMT −Verbal Fluency], inhibition [Stroop]) and alcohol bias (Addiction Stroop). The Barratt Impulsivity Scale measured impulsivity. Generalized linear mixed models and regression-based moderation models were applied. ResultsBD was associated with weak inhibitory control, poor working memory and greater alcohol bias moderated by non-planning impulsivity. At moderate levels of non-planning impulsivity, BD was associated with greater alcohol bias. This association was not found at high levels of impulsivity. These deficits were related to loss of control over drinking and severity of alcohol use. ConclusionsThe imbalance between poor cognitive control and greater alcohol bias may contribute to the persistence of BD into adulthood. The findings highlight the complexities of the dual-process model, with intervention implications.

Propiedades psicométricas y baremación de la prueba ENFEN en zonas rurales y urbanas de Tunja (Colombia)

This research aimed to evaluate the psychometric properties and standardization of the Neuropsychological Assessment of Executive Functions in Children Test (ENFEN in Spanish). This was a non-experimental quantitative and psychometric study with a convenience sample of 367 participants (171 children and 196 girls, 46,6 % and 53,4 %) of both rural and urban areas, aged 6 to 12 years (M = 8,99, SD = 1,88). The method of exploratory factor analysis by principal components was used to establish criterion and content validity against the executive function subscale of the ENI. Exploratory factor analysis yielded a single factor explaining 58,86 % of the total variance, like the original test results. Statistically significant correlations between all subscales and the ENI was found (p &lt;0,05). Results show that the ENFEN is a valid tool for assessing executive functions in children of urban and rural areas which can be used in clinical and research field test.

Avaliação breve do défice executivo em pessoas idosas com Acidente Vascular Cerebral: Validação da Bateria de Avaliação Frontal

Objetivos: O Acidente Vascular Cerebral (AVC) potencia o desenvolvimento de disfunção executiva, conduzindo a défice no desempenho das tarefas do quotidiano. A avaliação neuropsicológica das funções executivas é importante para desenvolver estratégias de reabilitação adequadas. Assim, são objetivos descrever os dados normativos, precisão de diagnóstico, propriedades psicométricas e análise fatorial da Bateria de Avaliação Frontal (FAB), instrumento breve e de rápida administração, numa amostra de idosos com AVC.Métodos: Inserida no projeto Trajetórias do Envelhecimento de Idosos em Resposta Social, esta investigação conta com uma amostra de 112 pessoas idosas com diagnóstico médico de AVC e 157 pessoas idosas de um subgrupo de controlo sem AVC. Os sujeitos apresentam idades compreendidas entre os 60 e os 100 anos (M = 78,20; DP = 7,57) sendo maioritariamente do sexo feminino (n = 194). A avaliação inclui entrevistas e testes neuropsicológicos agrupados em medidas de funcionamento executivo, medidas cognitivas de referência e medidas clínicas de controlo.Resultados: As variáveis idade e escolaridade interferiram nas pontuações obtidas na amostra clínica, não sendo verificado impacto da variável sexo. Para um ponto de corte de 7, a FAB teve uma sensibilidade de 83,4% e especificidade de 66,1 % (AUC = 0,64); revelou um alfa de Cronbach de 0,79 e correlações fortes com os testes executivos (teste de Stroop, Figura Complexa de Rey, fator Atencional-Executivo do Montreal Cognitive Assessment e Alternância nos testes de Fluência verbal). A análise fatorial confirmatória apontou uma estrutura com um fator.Conclusões: A FAB apresenta boa consistência interna, validade convergente e validade de constructo, aparentando ser uma escala útil para avaliar o défice executivo em pessoas idosas com AVC. Dadas algumas limitações do estudo, que poderão explicar a fraca precisão diagnóstica da FAB, são incentivadas investigações futuras pois a FAB revelou-se um instrumento com propriedades psicométricas promissoras.

Neuropsychological assessment of executive functions following pediatric traumatic brain injury

ABSTRACTAssessment of executive functions in the adult is best captured at the stage where full maturation of brain development occurs. Assessment of executive functions of children, however, is considerably more complicated. First, assessment of executive functioning in children represents a snapshot of these developing functions at a particular time linked stage, which may have implications for further development. Second, neuropsychological measures available to assess executive functions in children are limited in number and scope and may not be sensitive to the gradual developmental changes. The present article provides an overview of the salient neurodevelopmental stages of executive functioning and discusses the utilization of recently developed neuropsychological measures to assess these stages. Comments on clinical implications of these findings regarding Traumatic Brain Injury will be provided.

Normative data for Lezak’s Tinkertoy test in healthy Italian adults

The Tinkertoy test is a tool for the neuropsychological assessment of executive functions and a predictor of employability. Originally a children’s toy comprising pieces to assemble freely, the TinkerToy Test examines organizational abilities, planning, and response flexibility. It allows subjects to use their own initiative and does not force them to choose from a series of predetermined alternatives. Tinkertoy test normative values were collected from 256 neurologically healthy Italian subjects. Multivariable analysis showed sex and education to have significant confounding effects. Adjusted and inferential cut-off points were determined and converted into equivalent scores, applying a distribution-free technique.