Mild head injury and speed of information processing: A prospective study of professional rugby league players

Abstract

The sensitivity of several short tests of speed of information processing to the effects of mild head injury in rugby league football was investigated. The measures used were the Symbol Digit Modalities Test, the Digit Symbol Substitution Test, and the Speed of Comprehension Test. Two studies were conducted, the first to examine the effect of practice, the second to determine sensitivity to cognitive impairment immediately following injury. The first study established alternate form equivalence and demonstrated that performance on the Speed of Comprehension and Digit Symbol Substitution tests improved with practice, whereas the Symbol Digit Modalities test remained stable. A second study of 10 players who subsequently sustained mild head injuries showed that measures of speed of information processing were sensitive to impairment in the postacute phase, whereas an untimed task of word recognition (Spot-the-Word) was not. Speed of Comprehension was more sensitive to postinjury impairment than either the Digit Symbol Substitution or Symbol Digit Modalities tests. A repeated baseline assessment before injury using the higher score to reflect a player's potential, allowed measurement of impaired performance on sensitive tests.     

Brief assessment of cognition in schizophrenia: validation of the Japanese version

This preliminary study was performed to test the reliability and validity of the Brief Assessment of Cognition in Schizophrenia (BACS) as an assessment tool in a Japanese-language version (BACS-J). The subjects for the present study were 30 outpatients with chronic schizophrenia. Each subject gave written informed consent to participate in the research. Cronbach's alpha for the BACS-J was 0.77. The BACS-J composite score was significantly correlated with all primary measures of BACS-J (verbal memory, working memory, motor speed, verbal fluency, attention, and executive function). All BACS-J primary measures and the composite score were significantly correlated between two assessments. The mean score of the Digit Sequencing Task and composite score on the second assessment were significantly larger than those on the first assessment. All BACS-J primary measures except the Symbol Coding Task were significantly correlated with relevant standard neurocognitive tests. Also, the BACS-J composite score was significantly correlated with all standard neurocognitive tests except the Continuous Performance Test. A principal components analysis with varimax rotation resulted in a three-factor solution (executive function and memory; motor speed and general cognitive functions; and working memory). This preliminary study indicates that the BACS-J is a reliable and practical scale to evaluate cognitive function.     

Intensity of recreational physical activity throughout life and later life cognitive functioning in women

Long-term physical activity may affect risk of cognitive impairment but few studies have examined later life cognition in relation to intensity of life-long physical activity. We examined the associations between the intensity of long-term recreational physical activity and neuropsychological functioning in 90 healthy postmenopausal women on tests found to be useful in the early identification of dementia. Information was collected about their participation in strenuous and moderate activities between high school and menopause. Summary measures of long-term strenuous and moderate activity were constructed for each participant. All analyses were adjusted for relevant covariates. The six linear regression analyses showed significant positive associations between moderate activity and Wechsler Adult Intelligence Scale Revised (WAIS-R), Digit Span backward, WAIS-R Digit Symbol, and Trail Making Test Part B. Significant negative relationships were found between strenuous activity and Rey Auditory Verbal Learning Test delayed verbal recall, Complex Figure Test delayed visual memory, WAIS-R Digit Span backward, category fluency, and WAIS-R Digit Symbol. The associations found in the present study suggest that while moderate activity may be protective, long-term strenuous activity before menopause may lower cognitive performance later in life. These results support further investigation of the effects of life-long exercise intensity on cognition in later life.     

Speed and memory in WAIS-R-NI Digit Symbol performance among healthy older adults.

Although roles have been proposed for both graphomotor speed and learning in the execution of Digit Symbol, few data have been available concerning performance across the adult lifespan on the Symbol Copy, paired associates, or free recall measures derived from Digit Symbol and recommended in the WAIS-R-NI. We report findings on 177 healthy older adults (ages 50-90), providing normative data by age group, education level, and gender. As previously reported, Digit Symbol scores decline steeply with age (r = -.64). Symbol Copy speed declines almost as steeply (r = -.58). Incidental learning, however, declines only modestly (r = -.26 on both measures). Symbol Copy is a far stronger correlate of Digit Symbol (r = .72) than are paired associates or free recall (r = .26 and r = .28, respectively). The 2 incidental learning measures do, however, offer valuable supplementary information as part of a comprehensive individual assessment. When low Digit Symbol scores are produced by slowing on Symbol Copy, further evaluation of perceptual and motor speed and dexterity are indicated. When low incidental learning scores are obtained, further evaluation of memory is warranted. Qualitative analysis of errors (e.g., rotations) made on the incidental learning procedures may also be valuable.     

Reliability of a computer-based neurobehavioral assessment test battery for Bangladeshi adolescent children

In developing countries, there is a need for low-cost neurobehavioral (NB) test batteries for vulnerable populations, particularly for children exposed to environmental neurotoxicants. The objective of the current study was to assess the feasibility and test-retest reliability of the Behavioral Assessment and Research System (BARS) in children from a rural community in Bangladesh. Fifty healthy adolescents living in the Health Effects of Arsenic Longitudinal Study (HEALS) area in Araihazar, Bangladesh completed all six tests from the BARS in two test sessions scheduled two weeks apart. The BARS tests evaluated NB functions such as motor coordination, attention, memory, and information processing speed. The reliability assessment, evaluated by test-retest correlations demonstrated moderate to strong correlations (i.e., correlation coefficients ranged from 0.43 to 0.85), which were statistically significant (p < 0.05). Paired t-tests for comparing the test and retest outcomes indicated significant improvement in NB performance, highlighting learning and practice effects. NB performance improved with increasing age in most cases. Adolescent boys performed better than the girls in Finger Tapping, Digit Span, and Simple Reaction Time, whereas the girls performed better in Continuous Performance and Symbol Digit tests. The reliability scores (Pearson’s correlations 0.43−0.85) were consistent with other children studies in different cultural settings. The effects of age and sex on NB tests were also consistent with findings reported in other countries. Overall, the findings of the study support the feasibility of using this computer-based test system to assess vulnerability of brain health due to environmental exposures among rural Bangladeshi children.     

Double cross-validation and improved sensitivity of the rapid screen of mild traumatic brain injury

This study aimed to replicate and cross-validate the Rapid Screen of Concussion (RSC) for diagnosing mild TBI (mTBI). One hundred (81 male, 19 female) cases of mTBI and 35 (23 male and 12 female) cases of orthopaedic injuries were tested within 24 hr of injury. Double cross-validation was used to examine whether total RSC scores obtained in the current sample, generalised to one previously reported. In the new sample, mTBI patients answered fewer orientation questions, recalled fewer words on the learning trial and after a delay, judged fewer sentences in 2 min, and completed fewer symbols in the Digit Symbol Substitution Test than orthopaedic controls. The formulae and cut-offs developed on the original and new samples produced similar sensitivity and overall correct classification rates. Inclusion of the Digit Symbol Substitution Test performance of the new sample improved the sensitivity (80.2%) and specificity (82.6%) in males. It did not improve the correct classification rate in females, which was 89.5% sensitivity and 91.7% specificity before the inclusion of the Digit Symbol Substitution Test. Taken together, these results indicate that a combined score on this 12-min screen yields a measure of level of brain impairment up to 24 hr after mTBI.     

Test–retest reliability and practice effects for the ANAM General Neuropsychological Screening battery

Objective: As the use of computer-based neurocognitive assessment is rapidly expanding, the need to systematically study and document key psychometric properties of these measures has become increasingly more salient. To meet this aim, this study examined test–retest reliability and practice effects for the Automated Neuropsychological Assessment Metrics General Neuropsychological Screening battery (ANAM GNS) in a sample of 94 community dwelling adults. Method: ANAM GNS was administered and then repeated (alternate form) after 30 days. Test–retest reliability, practice effects, and the standard error of measurement were calculated. Using these estimates, reliable change indices were calculated to determine degree of performance change needed to exceed chance and measurement error (with 90% confidence interval). Results: The test–retest reliability for the ANAM composite score was .91. Performance significantly improved upon retest, but the effect size was small consistent with minimal practice effects. The threshold indicating change beyond chance or measurement error with 90% certainty was .9 (z-score). Conclusions: Findings suggest that the ANAM GNS has excellent test–retest reliability upon retest at 30 days. Small practice effects can be expected. Change greater than .9 standard deviations in the ANAM composite score is likely to represent meaningful clinical change. This paper presents initial psychometric data from the ANAM GNS and supports its use as a reliable measure of cognition.     

Reliability Concerns in the Repeated Computerized Assessment of Attention in Children

Assessment of attentional processes via computerized assessment is frequently used to quantify intra-individual cognitive improvement or decline in response to treatment. However, assessment of intra-individual change is highly dependent on sufficient test reliability. We examined the test–retest reliability of selected variables from one popular computerized continuous performance test (CPT)—i.e., the Conners’ CPT – Second Edition (CPT-II). Participants were 39 healthy children (20 girls) ages 6–18 without intellectual impairment (mean PPVT-III SS = 102.6), LD, or psychiatric disorders (DICA-IV). Test–retest reliability over the 3–8 month interval (mean = 6 months) was acceptable (Intraclass Correlations [ICC] =.82 to.92) on comparison measures (Beery Test of Visual Perception, WISC-IV Block Design, PPVT-III). In contrast, test–retest reliability was only modest for CPT-II raw scores (ICCs ranging from.62 to.82) and T-scores (ICCs ranging from.33 to.65) for variables of interest (Omissions, Commissions, Variability, Hit Reaction Time, and Attentiveness). Using test–retest reliability information published in the CPT-II manual, 90% confidence intervals based on reliable change index (RCI) methodology were constructed to examine the significance of test–retest difference/change scores. Of the participants in this sample of typically developing youth, 30% generated intra-individual changes in T-scores on the Omissions and Attentiveness variables that exceeded the 90% confidence intervals and qualified as “statistically rare” changes in score. These results suggest a considerable degree of normal variability in CPT-II test scores over extended test–retest intervals, and suggest a need for caution when interpreting test score changes in neurologically unstable clinical populations.     

Magnetic resonance imaging predictors of cognition in mild cognitive impairment

OBJECTIVES: To describe magnetic resonance imaging characteristics in a large sample of subjects with mild cognitive impairment (MCI) and to investigate associations between these characteristics and cognition. DESIGN: Cohort study. SETTING: Baseline data of a randomized, double-blind, placebo-controlled clinical trial of galantamine in MCI. PATIENTS: Included in the study were 896 subjects with MCI (age [mean +/- SD], 70 +/- 9 years; 54% women) with available clinical and magnetic resonance imaging data. MAIN OUTCOME MEASURES: Neuropsychology: Alzheimer Disease Assessment Scale, cognitive subscale, MCI version, assessing global cognition; delayed recall on the New York University Paragraph Recall Test, assessing episodic memory; and Digit Symbol Substitution Test, assessing executive function. Neuroimaging: Medial Temporal Lobe Atrophy (MTA) Rating Scale (0-4) and Age-Related White Matter Changes Scale (0-30), assessing white matter hyperintensities (WMHs); and lacune counts. RESULTS: Median MTA score was 2 (range, 0-4), and mean (+/- SD) Age-Related White Matter Changes Scale score 6.0 (+/- 4.7). Lacunes were present in 33% of subjects. In unadjusted models, increasing MTA and WMHs were associated with poorer performance on all cognitive tests, and lacunes with poorer performance on the Alzheimer Disease Assessment Scale, cognitive subscale, MCI version, and the Digit Symbol Substitution Test. In multivariable models, including magnetic resonance imaging measures simultaneously, MTA remained a predictor of cognition, whereas WMH had no independent predictive value. There was an interaction between MTA and lacunes: the strength of the association with the Digit Symbol Substitution Test increased with decreasing MTA. CONCLUSIONS: Medial temporal lobe atrophy seems to be a more important predictor of cognition than small-vessel disease in MCI. Lacunes were associated with performance on the Digit Symbol Substitution Test, especially in subjects with milder MTA. Although WMHs were prevalent and associated with cognition in unadjusted analyses, there was no discernible association between WMHs and the cognitive measures in this study after adjustment for age.     

Fine Tuning of the Digit Symbol Paired Associate Recall Test for Practitioner Purposes in Clinical and Research Settings

Guidelines are presented to facilitate the use of the WAIS Digit Symbol measure of paired associate recall as a neuropsychological instrument. Currently three formal variants of the test exist with accompanying normative data (the original WAIS–R-NI form; a WAIS–R Short Form; a longer WAIS-III form), providing a potential source of confusion which may limit its application. To circumvent this, the present article critically evaluates: (i) variations in test forms and their advantages; (ii) available norms in terms of age and education, with pointers for more differentiated guidelines in this regard; and (iii) the desirability of incorporating a delayed recall variant of the test. Finally, a synopsis of data is presented that supports the screening potential of Digit Symbol paired associate recall in cases of mild neurocognitive dysfunction.     

Stability of Executive Functioning Measures in 8–17-Year-Old Children With Unilateral Cerebral Palsy

The study investigated the stability of executive functioning (EF) measures in children and adolescents aged 8–17 years with unilateral cerebral palsy (CP). Here 44 participants with unilateral CP (mean age = 11 years, 11 months; Manual Abilities Classification Scale Level I = 6 and Level II = 37; Gross Motor Function Classification Scale Level I = 22 and Level II = 22) were randomized into the wait-list control group of a large randomized controlled trial. Participants had baseline testing with Wechsler Intelligence Scale for Children – Fourth Edition Short Form (WISC-IV-SF) and Delis-Kaplan Executive Function System (D-KEFS) subtests. Parents completed the Behavior Rating Inventory of Executive Functioning (BRIEF). Participants were re-assessed 20 ±2 weeks later with a shortened test battery including the D-KEFS subtests; Digit Span, Coding and Symbol Search (WISC-IV); and BRIEF. Pearson’s test–retest reliabilities and Reliable change scores were calculated. Results indicated excellent to fair test–retest reliabilities (r = 0.91–0.74) for all measures except Digit Span Backwards (r = 0.62), Inhibition (r = 0.69), and Initiate (r = 0.68). Reliable change scores applying 90% confidence intervals for estimating reliable change while accounting for practice effects were provided for all measures. The data support the stability of EF measures in this population.     

The Misplaced Objects Test: a measure of everyday visual memory

The Misplaced Objects Test is a computerized test of object location recall. The test is structurally similar to tasks used in the evaluation of age and drug effects in preclinical animal research. Delayed recall of 20 common objects which the subject has placed using a touch sensitive screen in a computer-simulated 12-room house is evaluated with three measures. Scores include the number of objects found on the first attempt (Found 1), the number of objects found on the second attempt (Found 2), and the total number of objects found on both attempts (Found T). Performance was evaluated in relation to age, gender, education, and affective status, as well as in relation to several traditional neuropsychological measures. Misplaced Objects Test performance was most strongly associated with age and Wechsler Memory Scale Paired Associate Learning. Additional significant relationships were found with gender, education, and the WAIS Digit Symbol subtest. Potential future applications of the test were discussed.     

Normative Data for a Working Memory Test: the Four Word Short-Term Memory Test

Clinicians and researchers who use neuropsychological tests to track functioning over time are in need of a method to correct for the effects of practice. Drawing from a large database of healthy, male subjects, we present data that can be used to calculate predicted retest scores for eight widely used neuropsychological instruments either via simple regression or reliable change index (RCI) methods. These methods are useful for individuals assessed across a wide time interval, 4–24 months. Limitations are discussed regarding the applicability of the data. Those with a need to factor out the effects of practice, test–retest reliability and other statistical confounds will find the information within this article useful.     

Test-retest norms and reliable change indices for the MicroCog Battery in a healthy community population over 50 years of age

The increasing availability of computerized test batteries used to assess neuropsychological changes requires the availability of suitable test-retest normative data. Reliable change indices can then be used to evaluate significance of change in an individual's performance on retesting. We tested (N = 40) neurologically normal adults on three occasions (initially, two weeks, and three months) on the MicroCog: Assessment of Cognitive Functioning computerized testing instrument. Normative retest data are presented for two analytic techniques: the Reliable Change Index adjusted for practice and the Standardized Regression-Based technique. At two weeks, the correlation coefficients ranged from .49 to .84, with all scores demonstrating significant practice effects. At 3 months, coefficients ranged from .50 to .83, with all scores except Attention / Mental Control demonstrating significant practice compared to baseline. Regression equations were generated for all scores using age, sex, education level, and score at Time 1 as predictors. For all measures the only significant predictor was the Time 1 score. The reliable change indices and regression equations presented here can be used to determine the significance of change from predicted retest scores in a matched interventional cohort.     

The misplaced objects test: A measure of everyday visual memory

Abstract

The Misplaced Objects Test is a computerized test of object location recall. The test is structurally similar to tasks used in the evaluation of age and drug effects in preclinical animal research. Delayed recall of 20 common objects which the subject has placed using a touch sensitive screen in a computer-simulated 12-room house is evaluated with three measures. Scores include the number of objects found on the first attempt (Found 1), the number of objects found on the second attempt (Found 2), and the total number of objects found on both attempts (Found T). Performance was evaluated in relation to age, gender, education, and affective status, as well as in relation to several traditional neuropsychological measures. Misplaced Objects Test performance was most strongly associated with age and Wechsler Memory Scale Paired Associate Learning. Additional significant relationships were found with gender, education, and the WAIS Digit Symbol subtest. Potential future applications of the test were discussed.     

Neuropsychological functioning in depressed versus nondepressed participants with Alzheimer's disease

Differences in cognitive functioning between participants with Alzheimer's Disease (AD) reporting depressive symptomatology (AD-Dep; n = 37) and a control group of nondepressed participants with AD (AD-Con; n = 98) were investigated based on hypothesized impairments of attention/concentration, psychomotor speed, and simple motor speed. Groups did not differ in age, education, overall severity of dementia, auditory comprehension, or use of psychotropic medications. AD-Dep participants performed significantly more poorly than AD-Con participants on 3 of the 13 measures on which they were hypothesized to exhibit greater impairment (WAIS-R Block Design, WAIS-R Digit Symbol, and speeded motor programming); and there were trends toward poorer performance on four additional measures (WAIS-R Object Assembly, WAIS-R Picture Arrangement, WAIS-R Digit Span-backward, and letter fluency). There was only one significant effect for the 13 measures on which no group differences were hypothesized; the AD-Dep participants unexpectedly obtained better WMS-R Logical Memory delayed recall scores than the AD-Con participants. Finally, AD-Dep participants exhibited an unexpected pattern of greater right hand advantage on the Finger Tapping Test.     

Test–Retest Norms and Reliable Change Indices for the MicroCog Battery in a Healthy Community Population Over 50 Years of Age

The increasing availability of computerized test batteries used to assess neuropsychological changes requires the availability of suitable test–retest normative data. Reliable change indices can then be used to evaluate significance of change in an individual's performance on retesting. We tested (N = 40) neurologically normal adults on three occasions (initially, two weeks, and three months) on the MicroCog: Assessment of Cognitive Functioning computerized testing instrument. Normative retest data are presented for two analytic techniques: the Reliable Change Index adjusted for practice and the Standardized Regression-Based technique. At two weeks, the correlation coefficients ranged from .49 to .84, with all scores demonstrating significant practice effects. At 3 months, coefficients ranged from .50 to .83, with all scores except Attention / Mental Control demonstrating significant practice compared to baseline. Regression equations were generated for all scores using age, sex, education level, and score at Time 1 as predictors. For all measures the only significant predictor was the Time 1 score. The reliable change indices and regression equations presented here can be used to determine the significance of change from predicted retest scores in a matched interventional cohort.     

Neuropsychological Functioning in Depressed Versus Nondepressed Participants with Alzheimer's Disease

Differences in cognitive functioning between participants with Alzheimer's Disease (AD) reporting depressive symptomatology (AD-Dep; n = 37) and a control group of nondepressed participants with AD (AD-Con; n = 98) were investigated based on hypothesized impairments of attention/concentration, psychomotor speed, and simple motor speed. Groups did not differ in age, education, overall severity of dementia, auditory comprehension, or use of psychotropic medications. AD-Dep participants performed significantly more poorly than AD-Con participants on 3 of the 13 measures on which they were hypothesized to exhibit greater impairment (WAIS-R Block Design, WAIS-R Digit Symbol, and speeded motor programming); and there were trends toward poorer performance on four additional measures (WAIS-R Object Assembly, WAIS-R Picture Arrangement, WAIS-R Digit Span-backward, and letter fluency). There was only one significant effect for the 13 measures on which no group differences were hypothesized; the AD-Dep participants unexpectedly obtained better WMS-R Logical Memory delayed recall scores than the AD-Con participants. Finally, AD-Dep participants exhibited an unexpected pattern of greater right hand advantage on the Finger Tapping Test.     

Fine tuning of the digit symbol paired associate recall test for practitioner purposes in clinical and research settings

Guidelines are presented to facilitate the use of the WAIS Digit Symbol measure of paired associate recall as a neuropsychological instrument. Currently three formal variants of the test exist with accompanying normative data (the original WAIS-R-NI form; a WAIS-R Short Form; a longer WAIS-III form), providing a potential source of confusion which may limit its application. To circumvent this, the present article critically evaluates: (i) variations in test forms and their advantages; (ii) available norms in terms of age and education, with pointers for more differentiated guidelines in this regard; and (iii) the desirability of incorporating a delayed recall variant of the test. Finally, a synopsis of data is presented that supports the screening potential of Digit Symbol paired associate recall in cases of mild neurocognitive dysfunction. For the purposes of this paper, the term WAIS is used with broad reference to all variations of the original Wechsler Adult Intelligence Scale (1955) upon which they were based, including the WAIS-R (1981) and WAIS-III (1997) updated editions, and the South African WAIS (1969). The terms South African WAIS (South African Wechsler Adult Intelligence Scale), WAIS-R (Wechsler Adult Intelligence Scale - Revised), and WAIS-III (Wechsler Adult Intelligence Scale-III), refer to these specific versions of the test.     

Heritability of cognitive performance in aging twins. The National Heart, Lung, and Blood Institute Twin Study

The genetic contribution to performance on scales designed to measure mild to moderate decrements in cognitive functioning in a population at risk is unknown. In the present analysis, 134 monozygotic and 133 dizygotic male twin pairs (mean age, 63 years) were given three cognitive tests: the Mini-Mental State examination, the Iowa Screening Battery for Mental Decline, and, for comparison, the Digit Symbol Substitution Test from the Wechsler Adult Intelligence Scale. The primary objective of the analysis was to test for a significant heritable component to performance on these measures. A secondary objective was to determine the extent to which shared variance with significant confounders such as education, age, and depression affects the outcome of the heritability analysis. Results indicate that performance on tests intended to measure cognitive decline in the elderly does have a significant genetic component and that these estimates tend to increase after adjustment for covariates. Heritability estimates adjusted for covariates were 30% for the Iowa Screening score, 60% for the Mini-Mental State score, and 67% for the Digit Symbol Substitution score.