Regression-based Norms Research Articles

Test of Everyday Attention for Children (TEA-Ch): Greek Normative Data and Discriminative Validity for Children with Combined Type of Attention Deficit-Hyperactivity Disorder

ABSTRACT We examined the utility of the Test of Everyday Attention for Children (TEA-Ch) for Greek children. Discrete and regression-based norms, controlling for demographic characteristics and intelligence, were derived from the performance of 172 children. We also assessed the ability of the TEA-Ch to differentiate children with ADHD-Combined Type (ADHD-C) from healthy matched peers. Children with ADHD-C displayed dysfunction in multiple attentional domains. Discriminant function analysis indicated that two subtests (Sky Search and Walk, Don’t Walk) correctly classified 84.2% of children with ADHD-C.

Regression-based normative data and equivalent scores for Trail Making Test (TMT): an updated Italian normative study.

The Trail Making Test (TMT) is widely used to assess psychomotor speed and attentional set-shifting. Since the regression-based norms and equivalent scores (ESs) for the TMT Italian version trace back to more than 20years ago, we aimed at providing updated normative data for basic (Part A and Part B) and derived (Score B-A and Score B/A) TMT scores collected in a larger sample with an extended age range. Three hundred fifty-five Italian volunteers stratified for sex (166 men), age decades (age range 20-90years), and educational level (from primary school to university) completed the TMT and the Montreal Cognitive Assessment (MoCA). Multiple linear regression analyses revealed that age and educational level significantly influenced performances on basic and derived TMT scores except for B/A, which was associated only with the educational level. From the derived linear equations, correction grids for basic and derived TMT raw scores were developed. Inferential cutoff scores, estimated using a non-parametric technique, and ES were computed. Basic and derived TMT scores showed a good test-retest reliability (all rs ≥ 0.50); Part B (rs= - 0.48, p < 0.001) and Score B-A (rs= - 0.49, p< 0.001) were moderately associated with MoCA total score. This study confirms the association of basic and derived TMT raw scores with sociodemographic variables and provides updated correction grids and ES for assessing the attentional/executive functions in clinical and research fields.

Development of the Greek version of the Face Name Associative Memory Exam (GR-FNAME12) in cognitively normal elderly individuals

Objective: The Face–Name Associative Memory Examination (FNAME) is a cross-modal associative memory test with a high sensitivity for detecting Alzheimer’s disease-related subtle memory problems at an early preclinical stage. The present study examined the psychometric characteristics of a Greek version of the short form of FNAME (GR-FNAME12) to evaluate the contribution of demographic characteristics, report the range of performance within our sample, and estimate regression-based norms in cognitively normal elderly individuals. Method: In all, 216 cognitively normal elderly individuals were recruited and were administered a version of the short form of the FNAME (GR-FNAME12) that was culture and language specific to Greek-speaking individuals and developed for this study. Results: The construct validity of GR-FNAME12 was determined using principal component analysis thereby revealing two factors: face–name and face–occupation. These match the original version of the test. A significant positive correlation between GR-FNAME12 and two traditional memory measures – the RAVLT and the ROCFT – supported convergent validity. Test–retest reliability was computed for 32 participants. Multiple regression analyses showed that only age and not education or gender significantly predicted performance on the GR-FNAME12. We also estimated regression-based norms for the GR-FNAME12 scales. Conclusion: It was found that the Greek version of the FNAME12 had adequate psychometric properties, and could be administered to Greek-speaking individuals for clinical and research purposes.

Verbal Selective Reminding Test (six-trial administration): Regression-based norms for a portuguese version

ABSTRACTThe Verbal Selective Reminding Test (VSRT) is a widely used measure to evaluate verbal learning and memory associated with different neurological conditions. The goal of this study was to extend the use of the six-version trial of this test to the Portuguese population, through the production of adjusted normative data. The normative sample consists of 309 healthy participants aged between 20 and 70, with an educational level ranging from 4 to 23 years of formal. Gender, education, and age effects were explored. In addition, the reliability of the test was also analyzed and normative data produced. Gender, age, and education were significantly associated with VSRT performance. The test revealed excellent inter-rater reliability and good test–retest reliability. The normative data is presented as a regression-based formula to adjust test scores for gender, education and age. The correspondence between adjusted scores and percentile distribution was calculated. Since a test with appropriate norms is fundamental to an appropriate assessment of memory functioning, the normative data produced in this study improves the applicability of VRST for both clinical and research proposes in the Portuguese population. Further studies might also explore the adequacy of these norms for other Portuguese-speaking countries.

Regression-Based Norms for the Symbol Digit Modalities Test in the Dutch Population: Improving Detection of Cognitive Impairment in Multiple Sclerosis

Background/Aims: Appropriate and timely screening instruments that sensitively capture the cognitive functioning of multiple sclerosis (MS) patients are the need of the hour. We evaluated newly derived regression-based norms for the Symbol Digit Modalities Test (SDMT) in a Dutch-speaking sample, as an indicator of the cognitive state of MS patients. Methods: Regression-based norms for the SDMT were created from a healthy control sample (n = 96) and used to convert MS patients' (n = 157) raw scores to demographically adjusted Z-scores, correcting for the effects of age, age², gender, and education. Conventional and regression-based norms were compared on their impairment-classification rates and related to other neuropsychological measures. Results: The regression analyses revealed that age was the only significantly influencing demographic in our healthy sample. Regression-based norms for the SDMT more readily detected impairment in MS patients than conventional normalization methods (32 patients instead of 15). Patients changing from an SDMT-preserved to -impaired status (n = 17) were also impaired on other cognitive domains (p < 0.05), except for visuospatial memory (p = 0.34). Conclusions: Regression-based norms for the SDMT more readily detect abnormal performance in MS patients than conventional norms, identifying those patients at highest risk for cognitive impairment, which was supported by a worse performance on other neuropsychological measures.

Cross-Validation of the Newly-Normed SKT for the Detection of MCI and Dementia

Abstract. New regression-based norms for the SKT Short Cognitive Performance Test were introduced but have not been cross-validated for the detection of mild cognitive impairment (MCI) and dementia. We examined 562 (59.6% female) community-dwelling persons (mean age = 75.8, SD = 5.5) at baseline and followed up with up to three annual visits. Participants were classified as being healthy, with MCI, or with dementia according to the Clinical Dementia Rating (CDR) and the SKT. Overall congruency between the ratings was 57.8%. The correlation between SKT and MMSE scores reached r = –0.67. Sensitivity and specificity for MCI and dementia were 0.89 and 0.60 as well as 0.83 and 0.84, respectively. The SKT detected cognitive decline at early stages but produced increased rates of false positives.

Latent profile analysis of regression-based norms demonstrates relationship of compounding MS symptom burden and negative work events

Objective: We endeavored to clarify how distinct co-occurring symptoms relate to the presence of negative work events in employed multiple sclerosis (MS) patients. Latent profile analysis (LPA) was utilized to elucidate common disability patterns by isolating patient subpopulations. Method: Samples of 272 employed MS patients and 209 healthy controls (HC) were administered neuroperformance tests of ambulation, hand dexterity, processing speed, and memory. Regression-based norms were created from the HC sample. LPA identified latent profiles using the regression-based z-scores. Finally, multinomial logistic regression tested for negative work event differences among the latent profiles. Results: Four profiles were identified via LPA: a common profile (55%) characterized by slightly below average performance in all domains, a broadly low-performing profile (18%), a poor motor abilities profile with average cognition (17%), and a generally high-functioning profile (9%). Multinomial regression analysis revealed that the uniformly low-performing profile demonstrated a higher likelihood of reported negative work events. Conclusions: Employed MS patients with co-occurring motor, memory and processing speed impairments were most likely to report a negative work event, classifying them as uniquely at risk for job loss.

Regression-Based Norms for the Brief Visuospatial Memory Test-Revised in Italian population and application in MS patients

Objective: The Brief Visuospatial Memory Test-Revised (BVMT-R) is one of the most widely used tests for the assessment of learning and memory in the visual/spatial domain. The aim of this study was to use multiple regression to derive normative data for the use of BVMT-R in an Italian population. Method: We employed a regression-based norms procedure to maximally utilize a relatively small sample while controlling for a variety of demographic factors in addition to age. Additionally, we used these norms to compare the performance of Italian healthy controls with patients diagnosed with multiple sclerosis (MS), thereby providing evidence of the method’s validity. Results: A total of 200 healthy volunteers and 70 MS patients participated in this study and completed the BVMT-R according to the published procedures. Regression-based norms were generated for the Italian sample and are presented herein. Conclusions: Using these norms, the performance of the MS patients was found to be significantly worse than that of the controls.

Temporal Stability of the Dutch Version of the Wechsler Memory Scale—Fourth Edition (WMS-IV-NL)

Objective: The Wechsler Memory Scale—Fourth Edition (WMS-IV) is one of the most widely used memory batteries. We examined the test–retest reliability, practice effects, and standardized regression-based (SRB) change norms for the Dutch version of the WMS-IV (WMS-IV-NL) after both short and long retest intervals. Method: The WMS-IV-NL was administered twice after either a short (M = 8.48 weeks, SD = 3.40 weeks, range = 3–16) or a long (M = 17.87 months, SD = 3.48, range = 12–24) retest interval in a sample of 234 healthy participants (M = 59.55 years, range = 16–90; 118 completed the Adult Battery; and 116 completed the Older Adult Battery). Results: The test–retest reliability estimates varied across indexes. They were adequate to good after a short retest interval (ranging from .74 to .86), with the exception of the Visual Working Memory Index (r = .59), yet generally lower after a long retest interval (ranging from .56 to .77). Practice effects were only observed after a short retest interval (overall group mean gains up to 11 points), whereas no significant change in performance was found after a long retest interval. Furthermore, practice effect-adjusted SRB change norms were calculated for all WMS-IV-NL index scores. Conclusions: Overall, this study shows that the test–retest reliability of the WMS-IV-NL varied across indexes. Practice effects were observed after a short retest interval, but no evidence was found for practice effects after a long retest interval from one to two years. Finally, the SRB change norms were provided for the WMS-IV-NL.

Regression-Based Normative Formulae for the Repeatable Battery for the Assessment of Neuropsychological Status for Older Adults.

The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) has become a popular cognitive screening instrument, particularly in elderly patients. Prior studies presented lookup tables for RBANS normative data based on age, gender, education, and race using a group of 718 community-dwelling older adults. However, regression-based normative formulae that simultaneously correct for all demographic variables may be more sensitive for detecting late life cognitive decline. Using data from the prior studies, linear regression was used to generate such formulae in the Indexes and subtests of the RBANS. Results indicated that ∼11% of the variance of Index scores was accounted for by these demographic variables, and 13% of variance in subtest scores. Although some differences were present between the lookup and regression-based norms, it is expected that these current results will present more accurate demographic corrections that allow clinicians and researchers to better interpret individual performances on the RBANS.

Correlates of Incident Cognitive Impairment in the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study

Objective: To identify approximately 500 cases of incident cognitive impairment (ICI) in a large, national sample adapting an existing cognitive test-based case definition and to examine relationships of vascular risk factors with ICI. Method: Participants were from the REGARDS study, a national sample of 30,239 African-American and White Americans. Participants included in this analysis had normal cognitive screening and no history of stroke at baseline, and at least one follow-up cognitive assessment with a three-test battery (TTB). Regression-based norms were applied to TTB scores to identify cases of ICI. Logistic regression was used to model associations with baseline vascular risk factors. Results: We identified 495 participants with ICI of 17,630 eligible participants. In multivariable modeling, income (OR 1.83 CI 1.27,2.62), stroke belt residence (OR 1.45 CI 1.18,1.78), history of transient ischemic attack (OR 1.90 CI 1.29,2.81), coronary artery disease(OR 1.32 CI 1.02,1.70), diabetes (OR 1.48 CI 1.17,1.87), obesity (OR 1.40 CI 1.05,1.86), and incident stroke (OR 2.73 CI 1.52,4.90) were associated with ICI. Conclusions: We adapted a previously validated cognitive test-based case definition to identify cases of ICI. Many previously identified risk factors were associated with ICI, supporting the criterion-related validity of our definition.

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.

Regression-Based Norms for a Bi-factor Model for Scoring the Brief Test of Adult Cognition by Telephone (BTACT).

The current study developed regression-based normative adjustments for a bi-factor model of the The Brief Test of Adult Cognition by Telephone (BTACT). Archival data from the Midlife Development in the United States-II Cognitive Project were used to develop eight separate linear regression models that predicted bi-factor BTACT scores, accounting for age, education, gender, and occupation-alone and in various combinations. All regression models provided statistically significant fit to the data. A three-predictor regression model fit best and accounted for 32.8% of the variance in the global bi-factor BTACT score. The fit of the regression models was not improved by gender. Eight different regression models are presented to allow the user flexibility in applying demographic corrections to the bi-factor BTACT scores. Occupation corrections, while not widely used, may provide useful demographic adjustments for adult populations or for those individuals who have attained an occupational status not commensurate with expected educational attainment.

Neurocognitive change in the era of HIV combination antiretroviral therapy: the longitudinal CHARTER study.

Human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) can show variable clinical trajectories. Previous longitudinal studies of HAND typically have been brief, did not use adequate normative standards, or were conducted in the context of a clinical trial, thereby limiting our understanding of incident neurocognitive (NC) decline and recovery. We investigated the incidence and predictors of NC change over 16-72 (mean, 35) months in 436 HIV-infected participants in the CNS HIV Anti-Retroviral Therapy Effects Research cohort. Comprehensive laboratory, neuromedical, and NC assessments were obtained every 6 months. Published, regression-based norms for NC change were used to generate overall change status (decline vs stable vs improved) at each study visit. Survival analysis was used to examine the predictors of time to NC change. Ninety-nine participants (22.7%) declined, 265 (60.8%) remained stable, and 72 (16.5%) improved. In multivariable analyses, predictors of NC improvements or declines included time-dependent treatment status and indicators of disease severity (current hematocrit, albumin, total protein, aspartate aminotransferase), and baseline demographics and estimated premorbid intelligence quotient, non-HIV-related comorbidities, current depressive symptoms, and lifetime psychiatric diagnoses (overall model P < .0001). NC change is common in HIV infection and appears to be driven by a complex set of risk factors involving HIV disease, its treatment, and comorbid conditions.

Reliability of Regression-Based Normative Data for the Oral Symbol Digit Modalities Test: An Evaluation of Demographic Influences, Construct Validity, and Impairment Classification Rates in Multiple Sclerosis Samples

The oral Symbol Digit Modalities Test (SDMT) has been recommended to assess cognition for multiple sclerosis (MS) patients. However, the lack of adequate normative data has limited its clinical utility. Recently published regression-based norms may resolve this limitation but, because these norms were derived from a relatively small sample, their stability is unclear. We aimed to evaluate the stability of regression-based SDMT norms by comparing existing norms to a cross-validation dataset. First, regression-based normative data were created from a similarly-sized, independent, control sample (n = 94). Next the original and cross-validation norms were compared for equivalency, management of demographic influences, construct validity, and impairment classification rates in a mildly affected MS sample (n = 70). Lastly, similar comparisons were made for a large, representative MS clinic sample (n = 354). We found construct validity and management of demographic influences were equivalent for the two sets of regression-based norms but lower T-scores were obtained using the original dataset, resulting in discrepancies in impairment classification. In conclusion, regression-based norms for the oral SDMT attenuate demographic influences and possess adequate construct validity. However, norms generated using small samples may yield unreliable classification of cognitive impairment. Larger, representative databases will be necessary to improve the clinical utility of regression-based norms.

Semantic Fluency and Phonemic Fluency: Regression-based Norms for the Portuguese Population

The main goal of this study was to produce adjusted normative data for the Portuguese population on two verbal fluency measures: the semantic fluency test (animals category) and the phonemic fluency test (letters M, R, and P). The study included 950 community-dwelling individuals (624 womenand 326 men) aged between 18 and 98 (mean = 57.8, SD = 19.0), who had educational backgrounds ranging from 0 to 20 years (mean = 8.8, SD = 5.2). The results showed that age and education were significantly associated with semantic fluency and phonemic fluency performance. These demographic characteristics accounted for 42% of the semantic fluency and between 23% and 31% of the phonemic fluency performance variance. No significant sex effects were found. The normative data are presented as regression-based algorithms to adjust test scores for age and education, with subsequent correspondence between adjusted scores and percentile distribution.

Trail Making Test: Regression-based Norms for the Portuguese Population

The main goal of this study was to produce normative data for the Portuguese population on the Trail Making Test (TMT). The study included 1,038 community-dwelling individuals aged between 18 and 93 years, who had educational backgrounds ranging from 3 to 22 years. The results showed that sex, age, and education were significantly associated with TMT performance. These demographic characteristics accounted for 57% of the performance variance at part A and 50% at part B. The normative data are presented as regression-based algorithms to adjust direct and derived test scores for sex, age, and education. The adjusted scores' percentile distributions and their correspondence with scaled scores are also provided.

Development of the Greek Verbal Learning Test: Reliability, Construct Validity, and Normative Standards

We developed a multiple-form list learning test appropriate for use with the Greek population and generated norms for clinical and research use. This task, the Greek Verbal Learning Test (GVLT), was based on the California Verbal Learning Test. We administered the standard version (Form A) to a sample of 354 healthy individuals, as well as two alternative forms (B and C) to a subgroup of the initial sample. Performance on the three forms was equivalent, and each test presented excellent internal consistency. We found good sensitivity and specificity in the testãs (Form A) utility in differentiating individuals with schizophrenia (n = 50) and individuals with traumatic brain injury (n = 53) from healthy adults. A multiple regression analysis indicated that age, education and sex predicted performance. Regression-based norms are also provided. Taken together, these data provide preliminary support for the reliability and construct validity of the GVLT.

Regression-Based Norms Improve the Sensitivity of the National MS Society Consensus Neuropsychological Battery for Pediatric Multiple Sclerosis (NBPMS)

The National Multiple Sclerosis Society Consensus Neuropsychological Battery for Pediatric Multiple Sclerosis (NBPMS) was designed to detect cognitive impairment in children and adolescents with multiple sclerosis. One weakness of the battery is the reliance on published manual-based normative samples varying in size and quality. These primary sources base interpretation on discrete age bands, a practice which may be particularly problematic during periods of rapid development in childhood and adolescence. A further impediment to valid NBPMS interpretation is the lack of control for demographic factors other than age. We endeavored to develop regression-based norms for the NBPMS by gathering a demographically balanced sample of 102 healthy control children and using their performance to derive normalization, controlling for multiple demographic variables (i.e., age, age2, gender, parent education). The regression-based normative equations were applied to the performance of 51 children with MS. For many of the major test scores, the regression-based norms more readily detected impairment. As in the case of adult MS, these results indicate that regression-based norms offer interpretive benefits over their manual-based counterparts.

Normative Data for Neuropsychological Tests in a Rural Elderly Chinese Cohort

Normative information is important for appropriate interpretation of cognitive test scores as a critical component of dementia diagnosis in the elderly population. A cross-sectional evaluation of 1826 participants aged 65 years and older from four rural counties in China was conducted using six cognitive instruments including tests of global cognitive function (the Community Screening Instrument for Dementia), memory (Word List Learning and Recall tasks from the Consortium to Establish a Registry for Alzheimer's Disease, IU Story), language (Animal Fluency Test), and executive function (IU Token). Multiple regression models adjusting for demographic variables were used to provide standardized residuals z-scores and corresponding percentile ranking for each cognitive test. In all cognitive tests older age was associated with worse test performance while exposure to education was related to better cognitive test performance. We also detected a significant gender difference with men scoring better than women and a significant gender by education interaction on two tests. The interaction indicates that gender difference in test scores was much smaller in participants with more education than those who had less or no education. These demographically adjusted, regression-based norms can be a useful tool to clinicians involved with differential diagnosis of cognitive and memory disorders in older adults in rural China.