The National Institutes of Health Toolbox-Cognition Battery (NIHTB-CB) is a tablet-based cognitive assessment intended for individuals with neurological diseases of all ages. NIHTB-CB practice effects (PEs), however, need clarification if this measure is used to track longitudinal change. We explored the test–retest PEs on NIHTB-CB performance at 3 months in young healthy adults (n = 22). We examined corrected T-scores normalized for demographic factors and calculated PEs using Cohen’s d. There were significant PEs for all NIHTB-CB composite scores and on 4/7 subtests. This work suggests the need to further assess NIHTB-CB PEs as this may affect the interpretation of study results incorporating this battery.

The aim of this study was to examine whether people differed in change in performance across the first five blocks of an online flanker task and whether those trajectories of change were associated with self-reported aerobic or resistance exercise frequency according to age. A total of 8752 men and women aged 13–89 completed a lifestyle survey and five 45-s games (each game was a block of ~46 trials) of an online flanker task. Accuracy of the congruent and incongruent flanker stimuli was analyzed using latent class and growth curve modeling adjusting for time between blocks, whether the blocks occurred on the same or different days, education, smoking, sleep, caffeinated coffee and tea use, and Lumosity training status (“free play” or part of a “daily brain workout”). Aerobic and resistance exercise were unrelated to first block accuracies. For the more cognitively demanding incongruent flanker stimuli, aerobic activity was positively related to the linear increase in accuracy [B=0.577%, 95% confidence interval (CI), 0.112 to 1.25 per day above the weekly mean of 2.8 days] and inversely related to the quadratic deceleration of accuracy gains (B=−0.619% CI, −1.117 to −0.121 per day). An interaction of aerobic activity with age indicated that active participants younger than age 45 had a larger linear increase and a smaller quadratic deceleration compared to other participants. Age moderates the association between self-reported aerobic, but not self-reported resistance, exercise and changes in cognitive control that occur with practice during incongruent presentations across five blocks of a 45-s online, flanker task. (JINS, 2015, 21, 802–815)

Background: The Consortium to Establish a Registry for Alzheimer's Disease (CERAD) set of tests is frequently used for tracking cognition longitudinally in both clinical and research settings. Repeated cognitive assessments are an important component in measuring such changes; however, practice effects and attrition bias may obscure significant clinical change over time. The current study sought to examine the presence and magnitude of practice effects and the role of attrition bias in a sample of cognitively normal older men enrolled in a prevention trial.

Method: Participants were grouped according to whether they completed five years of follow-up (n = 182) or less (n = 126). Practice effects were examined in these participants as a whole (n = 308) and by group.

Results: Findings indicate that moderate practice effects exist in both groups on the CERAD T-score and that attrition bias likely does not play a contributing role in improved scores over time.

Conclusion: The current study provides additional evidence and support for previous findings that repeated cognitive assessment results in rising test scores in longitudinally collected data and demonstrates that these findings are unlikely to be due to attrition.

Traditional methods for assessing the neurocognitive effects of epilepsy surgery are confounded by practice effects, test-retest reliability issues, and regression to the mean. This study employs 2 methods for assessing individual change that allow direct comparison of changes across both individuals and test measures. Fifty-one medically intractable epilepsy patients completed a comprehensive neuropsychological battery twice, approximately 8 months apart, prior to any invasive monitoring or surgical intervention. First, a Reliable Change (RC) index score was computed for each test score to take into account the reliability of that measure, and a cutoff score was empirically derived to establish the limits of statistically reliable change. These indices were subsequently adjusted for expected practice effects. The second approach used a regression technique to establish “change norms” along a common metric that models both expected practice effects and regression to the mean. The RC index scores provide the clinician with a statistical means of determining whether a patient's retest performance is “significantly” changed from baseline. The regression norms for change allow the clinician to evaluate the magnitude of a given patient's change on 1 or more variables along a common metric that takes into account the reliability and stability of each test measure. Case data illustrate how these methods provide an empirically grounded means for evaluating neurocognitive outcomes following medical interventions such as epilepsy surgery. (JINS, 1996, 2, 556–564.)

Background: Practice effects have been widely reported in healthy older adults, but these improvements due to repeat exposure to test materials have been more equivocal in individuals with mild cognitive impairment (MCI).

Methods: The current study examined short-term practice effects in MCI by repeating a brief battery of cognitive tests across one week in 59 older adults with amnestic MCI and 62 intact older adults.

Results: Participants with amnestic MCI showed significantly greater improvements on two delayed recall measures (p < 0.01) compared to intact peers. All other practice effects were comparable between these two groups. Practice effects significantly improved scores in the MCI group so that 49% of them were reclassified as “intact” after one week, whereas the other 51% remained “stable” as MCI. Secondary analyses indicated the MCI-Intact group demonstrated larger practice effects on two memory measures than their peers (p < 0.01).

Conclusions: These results continue to inform us about the nature of memory deficits in MCI, and could have implications for the diagnosis and possible treatment of this amnestic condition.

Serial neuropsychological assessment is often conducted to monitor changes in the cognitive abilities of individuals over time. Because practice effects occur and the reliability of test scores is less than perfect, it is difficult to judge whether varying test results should be attributed to chance trends or to real changes in underlying cognitive abilities. In a large sample of adults (age range, 49–81 years), we evaluated the influence of age, gender, and education on test–retest changes in performance after 3 years on Rey's Verbal Learning Test (VLT), the Stroop Color-Word Test (SCWT), and the Letter Digit Substitution Test (LDST). A new statistical method was applied to assess the significance of changes in test performance (i.e., the regression-based change method). The results showed that test–retest changes differed as a function of age for the VLT Total recall 1–3, VLT Total recall 1–5, VLT Delayed recall, and LDST measures. An age × gender interaction was found for the SCWT Interference change score, suggesting that the age-related decline in executive functioning after 3 years was more pronounced for males than for females. A normative change table with appropriate corrections for the relevant independent variables was established. (JINS, 2008, 14, 71–80.)

The current study characterizes cognitive and psychiatric status in hematopoietic stem cell transplantation (HSCT) patients shortly before and after transplant. Thirty adult patients were assessed prospectively 1–2 weeks before transplantation and 100 days posttransplantation on neuropsychological and psychiatric measures. Before transplant, participants showed mild impairments on several neuropsychological measures, with the poorest performances occurring on learning and attention. Psychiatric functioning was significantly elevated compared with normative data. Significant improvements, however, were observed on neuropsychological measures by 100 days after transplant. Depression and anxiety scores also improved. Candidates for HSCT experienced mild diffuse cognitive dysfunction and psychiatric morbidity before the procedure, but these symptoms significantly improved by 3 months following their transplant in this small sample. Education about these possible pretransplant sequelae and the potential for rebound may be helpful to patients and families as they prepare for this treatment and the recovery period (JINS, 2007, 13, 172–177.)

Repeated neuropsychological testing gives rise to practice effects in that patients become familiar with test material as well as test-taking procedures. Using alternate forms prevents the learning of specific test stimuli, potentially mitigating practice effects. However, changing forms could diminish test-retest reliability coefficients. Our objective was to examine test-retest effects in multiple sclerosis (MS) patients randomly assigned to same- (SF) or alternate-form (AF) conditions. Thirty-four MS patients underwent neuropsychological evaluation. The battery included the California Verbal Learning Test II (CVLT-II) and the Brief Visuospatial Memory Test–Revised (BVMT-R), memory tests recommended by a recently convened consensus panel. Patients were randomly assigned to SF or AF groups and then tested at baseline and follow-up examination 1 week later. Analysis of variance tests (ANOVAs) revealed significant group × time interactions, with SF patients showing greater gain than AF patients. SF practice effects were often large, compromising test validity. Reliability coefficients were either equivalent or higher in the AF group, a finding attributed to ceiling effects and reduced variance in the SF group at retest. The generalizability of the findings may be limited to short test-retest intervals and the MS population. Nevertheless, I conclude that the use of CVLT-II and BVMT-R alternate forms likely helps preserve test validity without compromising test-retest reliability. (JINS, 2005, 11, 727–736.)

Different authors have used different estimates of variability in the denominator of the Reliable Change Index (RCI). Maassen attempts to clarify some of the differences and the assumptions underlying them. In particular he compares the ‘classical’ approach using an estimate SEd supposedly based on measurement error alone with an estimate SDiff based on the variability of observed differences in a population that should have no true change. Maassen concludes that not only is SEd based on classical theory, but it properly estimates variability due to measurement error and practice effect while SDiff overestimates variability by accounting twice for the variability due to practice. Simulations show Maassen to be wrong on both accounts. With an error rate nominally set to 10%, RCI estimates using SDiff wrongly declare change in 10.4% and 9.4% of simulated cases without true change while estimates using SEd wrongly declare change in 17.5% and 12.3% of the simulated cases (p < .000000001 and p < .008, respectively). In the simulation that separates measurement error and practice effects, SEd estimates the variability of change due to measurement error to be .34, when the true variability due to measurement error was .014. Neuropsychologists should not use SEd in the denominator of the RCI. (JINS, 2004, 10, 899–901.)

Researchers and clinicians using Jacobson and Truax's index to assess the reliability of change in patients, or its counterpart by Chelune et al., which takes practice effects into account, are confused by the different ways of calculating the standard error encountered in the literature (see the discussion started in this journal by Hinton-Bayre). This article compares the characteristics of (1) the standard error used by Jacobson and Truax, (2) the standard error of difference scores used by Temkin et al. and (3) an adaptation of Jacobson and Truax's approach that accounts for difference between initial and final variance. It is theoretically demonstrated that the last variant is preferable, which is corroborated by real data. (JINS, 2004, 10, 888–893.)

Performance on many cognitive and neuropsychological tests may be improved by prior exposure to testing stimuli and procedures. These beneficial practice effects can have a significant impact on test performance when conventional neuropsychological tests are administered at test–retest intervals of weeks, months or years. Many recent investigations have sought to determine changes in cognitive function over periods of minutes or hours (e.g., before and after anesthesia) using computerized tests. However, the effects of practice at such brief test–retest intervals has not been reported. The current study sought to determine the magnitude of practice effects in a group of 113 individuals assessed with an automated cognitive test battery on 4 occasions in 1 day. Practice effects were evident both between and within assessments, and also within individual tests. However, these effects occurred mostly between the 1st and 2nd administration of the test battery, with smaller, nonsignificant improvements observed between the 2nd, 3rd, and 4th administrations. On the basis of these results, methodological and statistical strategies that may aid in the differentiation of practice effects from drug-induced cognitive changes are proposed. (JINS, 2003, 9, 419–428.)

Measuring recovery of function may mean testing the same individual many times, a procedure that is inevitably open to improvement due to learning on the specific tests rather than recovery per se. This is particularly likely to be an issue with measures of memory performance. We therefore studied the performance of normal and brain-injured people across 20 successive test sessions on measures of orientation, simple reaction time, forward and backward digit span, visual and verbal recognition, word list learning and forgetting, and on three semantic memory measures, namely, letter and category fluency and speed of semantic processing. Differences in overall performances between the two groups occurred for all tests other than orientation, digit span forward, and simple reaction time, although the tests differed in their degree of sensitivity. The tests varied in the presence or absence of practice effects and in the extent to which these differed between the two groups. Data are presented that should allow investigators to select measures that are likely to optimize sensitivity while minimizing possible confounding due to practice effects. (JINS, 2000, 6, 469–479.)

Test–retest reliabilities and practice effects of a broad range of neuropsychological measures were examined in 384 normal or neurologically stable adults. Median test–retest interval was 11 months (range 3–16 months). The reliability estimates for most of the measures are reasonably good, ranging from .70 to low .90s. An exception is the relatively poor reliabilities of most memory measures. For all test measures, the value on initial testing is a strong determinant of the value on the second examination. Practice effects are seen on most measures. The magnitude of the practice effects, however, varies as a function of type of measure, test–retest interval, age, and overall competency level of the participant. This study provides several types of retest information that may be useful for future research and clinical work: comparative reliabilities of the various measures, estimate of error variability associated with each administration, standard deviation of the change, and comparative magnitude of practice effects on various tests. (JINS, 1999, 5, 346–356.)