Development and evaluation of CHIPASAT, an attention test for children: II. Test-retest reliability and practice effect for a normal sample

Executive Functioning in Youth With and Without Chronic Pain: A Comparative Analysis

OBJECTIVES

Preliminary research in youth with chronic pain suggests differences in attention and working memory, which has been similarly demonstrated in adults with chronic pain. There has been little research on other aspects of executive functioning (EF) in this population despite its critical role in problem solving, school functioning, and coping. This study aimed to examine differences in several aspects of EF between youth with chronic pain and a nonchronic pain comparison group using performance-based neuropsychological tests and a behavior rating scale.

MATERIALS AND METHODS

Participants completed ratings of pain; physical, emotional, social, and school functioning; sleep quality; medication; and a general intelligence screener. Standardized neuropsychological tests were used to examine EF with a focus on working memory, divided and alternating attention, inhibition, flexibility, incidental memory, and planning. A parent-report and self-report behavior rating of EF was also administered.

RESULTS

Recruitment from 2 tertiary-care pain clinics resulted in a sample of 26 youth with chronic pain (80.8% girls) and their parents. A comparison group of 30 youth without chronic pain and their parents were recruited from the community. Participants with chronic pain had significantly lower scores on several performance-based tests of working memory/divided attention, inhibition, and flexibility/alternating attention than the comparison group. Statistically significant group differences were also found on behavior ratings of emotion control, shifting, task initiation and completion, working memory, planning and organization, overall emotion and cognitive regulation as well as global EF. Covariate analysis was conducted in all analyses where there were significant group differences and several observed group differences remained.

DISCUSSION

This study is one of few multidimensional examinations of EF in youth with chronic pain, using a comprehensive neuropsychological test battery combined with behavior ratings. Our findings suggest EF differences in youth with chronic pain, across a variety of domains and may suggest risk for specific cognitive processing weaknesses in this population. Medical and educational teams should work toward identification, treatment, and compensatory support for EF within individualized pain management for youth.

Feasibility Randomized Trial for an Intensive Memory-Focused Training Program for School-Aged Children with Acquired Brain Injury

(1) Background: Memory deficits are common sequelae of pediatric Acquired Brain Injury (ABI). Only methods for non-focused cognitive remediation are available to the pediatric field. The aims of this feasibility trial are the description, implementation, and test of an intensive program specific to the training and re-adaptation of memory function in children, called Intensive Memory-Focused Training Program (IM-FTP); (2) Methods: Eleven children and adolescents with ABI (mean age at injury = 12.2 years, brain tumor survivors excluded) were clinically assessed and rehabilitated over 1-month through IM-FTP, including physio-kinesis/occupational, speech, and neuropsychology treatments. Each patient received a psychometric evaluation and a brain functional MRI at enrollment and at discharge. Ten pediatric controls with ABI (mean age at injury = 13.8 years) were clinically assessed, and rehabilitated through a standard program; (3) Results: After treatment, both groups had marked improvement in both immediate and delayed recall. IM-FTP was associated with better learning of semantically related and unrelated words, and larger improvement in immediate recall in prose memory. Imaging showed functional modification in the left frontal inferior cortex; (4) Conclusions: We described an age-independent reproducible multidisciplinary memory-focused rehabilitation protocol, which can be adapted to single patients while preserving inter-subject comparability, and is applicable up to a few months after injury. IM-FTP will now be employed in a powered clinical trial.

The Dyad-Adaptive Paced Auditory Serial Addition Test (DA-PASAT): Normative data and the effects of repeated testing, simulated malingering, and traumatic brain injury

The Paced Auditory Serial Addition Test (PASAT) is widely used to evaluate processing speed and executive function in patients with multiple sclerosis, traumatic brain injury, and other neurological disorders. In the PASAT, subjects listen to sequences of digits while continuously reporting the sum of the last two digits presented. Four different stimulus onset asynchronies (SOAs) are usually tested, with difficulty increasing as SOAs are reduced. Ceiling effects are common at long SOAs, while the digit delivery rate often exceeds the subject’s processing capacity at short SOAs, causing some subjects to stop performing altogether. In addition, subjects may adopt an “alternate answer” strategy at short SOAs, which reduces the test’s demands on working-memory and processing speed. Consequently, studies have shown that the number of dyads (consecutive correct answers) is a more sensitive measure of PASAT performance than the overall number of correct sums. Here, we describe a 2.5-minute computerized test, the Dyad-Adaptive PASAT (DA-PASAT), where SOAs are adjusted with a 2:1 staircase, decreasing after each pair of correct responses and increasing after misses. Processing capacity is reflected in the minimum SOA (minSOA) achieved in 54 trials. Experiment 1 gathered normative data in two large populations: 1617 subjects in New Zealand ranging in age from 18 to 65 years, and 214 Californians ranging in age from 18 to 82 years. Minimum SOAs were influenced by age, education, and daily hours of computer-use. Minimum SOA z-scores, calculated after factoring out the influence of these factors, were virtually identical in the two control groups, as were response times (RTs) and dyad ratios (the proportion of hits occurring in dyads). Experiment 2 measured the test-retest reliability of the DA-PASAT in 44 young subjects who underwent three test sessions at weekly intervals. High intraclass correlation coefficients (ICCs) were found for minSOAs (0.87), response times (0.76), and dyad ratios (0.87). Performance improved across test sessions for all measures. Experiment 3 investigated the effects of simulated malingering in 50 subjects: 42% of simulated malingerers produced abnormal (p< 0.05) minSOA z-scores. Simulated malingerers with abnormal scores were distinguished with 87% sensitivity and 69% specificity from control subjects with abnormal scores by excessive differences between training performance and the actual test. Experiment 4 investigated patients with traumatic brain injury (TBI): patients with mild TBI performed within the normal range while patients with severe TBI showed deficits. The DA-PASAT reduces the time and stress of PASAT assessment while gathering sensitive measures of dyad processing that reveal the effects of aging, malingering, and traumatic brain injury on performance.

The effect of badminton training on the ability of same-domain action anticipation for adult novices: Evidence from behavior and ERPs

Many transverse studies have found that athletes can better anticipate the outcome of sequential actions belonging to their domain of motor expertise than non-athletes. However, few studies have causally investigated this issue. Using badminton training as an example, the present study attempted to explore whether sports training affected the same-domain action anticipation ability of adult novices and the related neural mechanisms. To address this issue, participants in the training group attended a 12-week badminton training course (1h/time, 3 times/week). Both the training and control groups were asked to view badminton video clips and predict the landing position of a shuttle before and after 12 weeks. Compared to the control group, the training group showed a decrease in the inverse efficiency score, indicating that badminton training did improve trainees' action anticipation ability. Furthermore, the training group produced larger N2 and P3 components of event-related potential after the training. These findings suggest that sport training may affect inhibitory processes and memory encoding during same-domain action anticipation.

Information-Processing Rates Derived from Chipasat

The Children's Paced Auditory Serial Addition Task (CHIPASAT) was developed to assess auditory verbal attention in children. Using data obtained during our 1991 study of test-retest reliability for a normal sample, we evaluated the mean information-processing rates for the 4 paced trials. Analysis suggests that normal children can maintain a relatively uniform information-processing rate, even when the presentation rate has been doubled.

Practice Effects on Visuomotor and Problem-Solving Tests by Children

Practice effects on a visuomotor test (the Developmental Test of Visuo-Motor Integration), a timed visual discrimination test (the Underlining Test), and two problem-solving tests (the Porteus Mazes Test and the Tower of Hanoi Test) were analyzed. Children of two age groups ( Ms: 7.7 and 11.6 yr.) were chosen to study the effect of age on practice effects. The tests were repeated nine times with test-retest intervals of 2 mo. The Developmental Test of Visuo-Motor Integration showed no practice effects, while the Porteus Mazes Test, the Underlining Test, and the Tower of Hanoi Test showed significant practice effects. Practice effects were larger for the older age group on all the tests, except the Developmental Test of Visuo-Motor Integration. The Developmental Test of Visuo-Motor Integration and the Underlining Test showed good reliability, but those of the problem-solving tasks were less satisfactory. The stability of all the tests, except the Tower of Hanoi Test, was good.

Binocular low-contrast letter acuity and the symbol digit modalities test improve the ability of the Multiple Sclerosis Functional Composite to predict disease in pediatric multiple sclerosis

BACKGROUND

Outcome measures to capture disability, such as the Multiple Sclerosis Functional Composite (MSFC), were developed to enhance outcome measurements for clinical trials in adults with multiple sclerosis (MS). The MSFC initially included three components: a timed 25-foot walk [T25FW], 9-hole peg test [9HPT], and the Paced Auditory Serial Addition Task [PASAT]. Modifications to the original MSFC, such as adding binocular low-contrast letter acuity (LCLA) or substituting the symbol digit modalities test (SDMT) for the PASAT, improved the capacity to capture neurologic impairment in adults. Similar outcome scales for pediatric MS have not yet been established.

OBJECTIVE

To determine whether the three-component MSFC or a modified MSFC with LCLA and the SDMT better identifies neurological deficits in pediatric MS.

METHODS

We evaluated 5 measures (T25FW, 9HPT, Children's PASAT [ChiPASAT], SDMT, and binocular LCLA [Sloan charts, 1.25% contrast]) in children with MS (disease onset <18 years) and healthy controls. To be able to compare measures whose scores have different scales, Z-scores were also created for each test based on the numbers of standard deviations from a control group mean, and these individual scale scores were combined to create composite scores. Logistic regression models, accounting for age, were used to determine whether the standard 3-component MSFC or modified versions (including 4 or 5 metrics) best distinguished children with MS from controls.

RESULTS

Twenty pediatric-onset MS subjects, aged 6-21 years, and thirteen healthy controls, aged 6-19 years, were enrolled. MS subjects demonstrated worse scores on the 9HPT (p=0.004) and SDMT (p=0.001), but not the 25FTW (adjusted for height, p=0.63) or the ChiPASAT (p=0.10): all comparisons adjusted for age. Decreased (worse) binocular LCLA scores were associated with MS (vs. control status, p=0.03, logistic regression; p=0.08, accounting for age). The MSFC composite score for the traditional 3 components did not differ between the groups (p=0.28). Replacing the ChiPASAT with the SDMT (OR 0.72, p=0.05) better distinguished MS from controls. A modified MSFC-4 with the SDMT replacing the ChiPASAT and including binocular 1.25% LCLA had the greatest capacity to distinguish pediatric MS from controls (OR 0.89, p=0.04, logistic regression). Including all 5 metrics as a composite MSFC-5 did not improve the model (p=0.18).

CONCLUSIONS

A modified MSFC (25FTW, 9HPT, SMDT, and binocular 1.25% LCLA) is more sensitive than the traditional MSFC or its components to capture the subtle impairments that characterize pediatric MS and should be validated in order to be considered for future pediatric MS trials.

Developmental and gender influences on executive function following concussion in youth hockey players

BACKGROUND

Concussion is the most common athletic injury in youth who are simultaneously undergoing rapid developmental changes in the brain, specifically the development of executive functions (EF). The developing brain is more vulnerable to concussive injury with a protracted and different trajectory of recovery than that of adults. Thus, there is a critical need to enhance understanding of how concussion affects EF in youth.

OBJECTIVE

To investigate the effects of age, gender and concussion history (i.e. concussion incidence, recency, severity) on EF in youth hockey players.

METHODS

This 3-year cross-sectional and longitudinal multiple cohort study examined data from 211 hockey players of 8-15 years of age. Mixed-effects modelling was used to examine the influence of age, gender and concussion on EF in youth athletes.

FINDINGS

Baseline analyses revealed significant age and gender effects on measures of EF. Multiple effects of concussion history on measures of cognitive flexibility (F = 2.48, p = 0.03) and psychomotor speed (F = 2.59, p = 0.04) were found.

IMPLICATIONS

This study highlights the impact of age, gender and concussion on EF in youth. These findings provide foundational knowledge to better manage cognitive sequelae following sports-related concussion.

Working memory impairment and its associated sleep-related respiratory parameters in children with obstructive sleep apnea

STUDY OBJECTIVE

Working memory deficits in children with obstructive sleep apnea (OSA) have been reported in previous studies, but the results were inconclusive. This study tried to address this issue by delineating working memory functions into executive processes and storage/maintenance components based on Baddeley's working memory model.

METHODS

Working memory and basic attention tasks were administered on 23 OSA children aged 8-12 years and 22 age-, education-, and general cognitive functioning-matched controls. Data on overnight polysomnographic sleep study and working memory functions were compared between the two groups. Associations between respiratory-related parameters and cognitive performance were explored in the OSA group.

RESULTS

Compared with controls, children with OSA had poorer performance on both tasks of basic storage and central executive components in the verbal domain of working memory, above and beyond basic attention and processing speed impairments; such differences were not significant in the visuo-spatial domain. Moreover, correlational analyses and hierarchical regression analyses further suggested that obstructive apnea-hypopnea index (OAHI) and oxygen saturation (SpO2) nadir were associated with verbal working memory performance, highlighting the potential pathophysiological mechanisms of OSA-induced cognitive deficits.

CONCLUSIONS

Verbal working memory impairments associated with OSA may compromise children's learning potentials and neurocognitive development. Early identification of OSA and assessment of the associated neurocognitive deficits are of paramount importance. Reversibility of cognitive deficits after treatment would be a critical outcome indicator.

Increased serotonin transporter gene (SERT) DNA methylation is associated with bullying victimization and blunted cortisol response to stress in childhood: a longitudinal study of discordant monozygotic twins

BACKGROUND

Childhood adverse experiences are known to induce persistent changes in the hypothalamic-pituitary-adrenal (HPA) axis reactivity to stress. However, the mechanisms by which these experiences shape the neuroendocrine response to stress remain unclear. Method We tested whether bullying victimization influenced serotonin transporter gene (SERT) DNA methylation using a discordant monozygotic (MZ) twin design. A subsample of 28 MZ twin pairs discordant for bullying victimization, with data on cortisol and DNA methylation, were identified in the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative 1994-1995 cohort of families with twins.

RESULTS

Bullied twins had higher SERT DNA methylation at the age of 10 years compared with their non-bullied MZ co-twins. This group difference cannot be attributed to the children's genetic makeup or their shared familial environments because of the study design. Bullied twins also showed increasing methylation levels between the age of 5 years, prior to bullying victimization, and the age of 10 years whereas no such increase was detected in non-bullied twins across time. Moreover, children with higher SERT methylation levels had blunted cortisol responses to stress.

CONCLUSIONS

Our study extends findings drawn from animal models, supports the hypothesis that early-life stress modifies DNA methylation at a specific cytosine-phosphate-guanine (CpG) site in the SERT promoter and HPA functioning and suggests that these two systems may be functionally associated.

Intra-individual variability among children with ADHD on a working memory task: an ex-Gaussian approach

Intra-individual variability on a computer-based working memory task was examined among 25 children/adolescents with ADHD and 24 typically developing peers. Participants completed the Visual Serial Addition Task (VSAT) and reaction time data were fit to an ex-Gaussian distribution. ADHD participants demonstrated significantly more variable performance than controls, and effects of working memory load were observed. Event rate, however, had no influence on group differences in performance. Follow-up correlations revealed associations between VSAT performance and ADHD symptomatology. This study supports intra-individual variability as a hallmark feature of ADHD beyond the domain of response inhibition and reinforces the need to consider variability in ADHD more broadly.

Blunted cortisol responses to stress signal social and behavioral problems among maltreated/bullied 12-year-old children

BACKGROUND

Evidence from animal and human studies suggests that early-life stress such as physical maltreatment has long-lasting effects on the hypothalamic-pituitary-adrenal (HPA) axis and is associated with blunted HPA axis reactivity in adulthood. Few studies have investigated whether blunted HPA axis reactivity observed in children exposed to early-life stress signals social, emotional, and behavioral problems.

METHODS

Participants were 190 12-year-old children (50.5% males) recruited from the Environmental Risk Longitudinal Twin Study, a nationally representative 1994 to 1995 cohort of families with twins. Cortisol responses to psychosocial stress were measured in maltreated/bullied (n = 64) and comparison children (n = 126). We ascertained maltreatment and bullying victimization using mothers' reports and assessed children's social, emotional, and behavioral problems at ages 5 and 12 using mothers' and teachers' reports.

RESULTS

Piecewise multilevel growth curve analyses indicated that maltreated/bullied and comparison children showed distinct cortisol responses to stress. Specifically, maltreated/bullied children had lower cortisol responses than comparison children who exhibited a significant increase. Lower cortisol responses were, in turn, associated with more social and behavioral problems among maltreated/bullied children.

CONCLUSIONS

These findings provide support for the influence of childhood harm on blunted HPA axis reactivity and its potential impact on children's functioning. Our findings emphasize the need to integrate stress biomarkers in guiding prevention efforts for young victims.

A discordant monozygotic twin design shows blunted cortisol reactivity among bullied children

OBJECTIVE

Childhood adverse experiences are known to engender persistent changes in stress-related systems and brain structures involved in mood, cognition, and behavior in animal models. Uncertainty remains about the causal effect of early stressful experiences on physiological response to stress in human beings, as the impact of these experiences has rarely been investigated while controlling for both genetic and shared environmental influences.

METHOD

We tested whether bullying victimization, a repeated adverse experience in childhood, influences cortisol responses to a psychosocial stress test (PST) using a discordant monozygotic (MZ) twin design. Thirty pairs (43.3% males) of 12-year-old MZ twins discordant for bullying victimization were identified in the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative 1994-1995 cohort of families with twins.

RESULTS

Bullied and nonbullied MZ twins showed distinct patterns of cortisol secretion after the PST. Specifically, bullied twins exhibited a blunted cortisol response compared with their nonbullied MZ co-twins, who showed the expected increase. This difference in cortisol response to stress could not be attributed to children's genetic makeup, their familial environments, pre-existing and concomitant individual factors, or the perception of stress and emotional response to the PST.

CONCLUSION

Results from this natural experiment provide support for a causal effect of adverse childhood experiences on the neuroendocrine response to stress.

The reliability of the MSFC and its components

BACKGROUND

The Multiple Sclerosis Functional Composite (MSFC) is a multidimensional measurement tool for multiple sclerosis (MS) including a measure of ambulation (Timed 25-foot Walk [TWT]), arm function (Nine-Hole Peg Test [9HPT]) and cognition (Paced Auditory Serial Addition Test [PASAT]).

OBJECTIVES

To assess the reliability and practice effects in the Finnish version of the MSFC and its components.

MATERIALS AND METHODS

Ten relapsing-remitting MS patients and 10 healthy controls underwent five testing sessions with the MSFC over a 4-week period.

RESULTS

The MSFC showed excellent intra- (0.99) and inter-rater (1.0) reliability. The MSFC, especially the 9HPT and the PASAT showed significant practice effects. On the 9HPT the controls remained stable whereas the patients improved their performance; on the PASAT both groups improved.

CONCLUSIONS

The MSFC showed excellent intra- and inter-rater reliability although the 9HPT and the PASAT were prone to considerable practice effects.

Reliabilität von Aufmerksamkeits- und verbalen Gedächtnistests bei gesunden Kindern und Jugendlichen - Implikationen für die klinische Praxis

Zusammenfassung: Fragestellung: Die neuropsychologische Diagnostik eignet sich zur differenzierten Beschreibung von kognitiven Leistungen bei Patienten mit kinder- und jugendpsychiatrischen Erkrankungen. In dieser Arbeit werden zunächst ein kurzer theoretischer Hintergrund für die neuropsychologischen Funktionen Aufmerksamkeit und verbales Gedächtnis gegeben und ausgewählte klinische Befunde dargestellt. Des Weiteren wird ein Beispiel einer neuropsychologischen Testbatterie vorgestellt, die im Kinder- und Jugendbereich eingesetzt werden kann. Methodik: Die Retest-Reliabilität dieser Testbatterie wurde in einem Wiederholungszeitraum von 6 Wochen bei 33 gesunden Kindern untersucht. Ergebnisse: Generell konnte eine gute Reliabilität nachgewiesen werden, obwohl es zwischen einigen abhängigen Variablen Unterschiede gab. Lerneffekte aufgrund der Wiederholung wurden vornehmlich bei den jüngeren Kindern nachgewiesen. Schlussfolgerung: Die ausgewählten neuropsychologischen Tests scheinen für die klinische Anwendung geeignet zu sein, wie z. B. die Untersuchung von kognitiven Defiziten und die Evaluierung von psychopharmakologischen Behandlungen. Es ist jedoch zu beachten, dass in Abhängigkeit vom Alter die Retest-Reliabilität unterschiedlich ist.

Methylphenidate Does Not Improve Cognitive Function in Healthy Sleep-Deprived Young Adults

Background

Abuse of methylphenidate, a treatment of attention-deficit/hyperactivity disorder, is reported to be increasing among students for the purpose of improving cognition.

Methods

A single capsule, containing methylphenidate (20 mg) or placebo, was administered to healthy young adults orally following 24 hours of sleep deprivation. Measurements included percent change in score from sleep-deprived baseline on four standardized tests of cognitive function: Hopkins Verbal Learning, Digit Span, Modified Stroop, and Trail Making tests. Measurements also included percent changes in blood pressure and heart rate from sleep-deprived baseline and plasma methylphenidate concentration.

Results

Differences in cognitive test performance were not observed between intervention groups. In subjects receiving methylphenidate, mean percent changes from baseline for systolic blood pressure and heart rate were increased relative to placebo between 90 and 210 minutes following capsule administration (maximum increases of 9.45% and 11.03%, respectively). The timing of peak differences in physiologic measures did not correlate with peak serum methylphenidate concentrations. Exit questionnaire ratings of “capsule effect” and perceived performance on the postcapsule administration of the most challenging cognitive test were both higher ( p = .044 and p = .009, respectively) for the methylphenidate group than for the placebo group. Conclusions: Cognitive improvement among sleep-deprived young adults was not observed following methylphenidate administration. Benefits perceived by abusers may relate to increased confidence and sense of well-being, as well as to sympathetic nervous system stimulation. Moreover, methylphenidate administration results in physiologic effects that could be harmful to certain individuals.

The Brief Repeatable Battery of Neuropsychological Tests for Multiple Sclerosis: a preliminary serial study

The Brief Repeatable Battery of Neuropsychological Tests (BRB-N) for MS consisting of the selective reminding, 10/36 spatial recall, symbol digit modalities, paced auditory serial addition (PASAT) and word list generation tests is a sensitive measure of early cognitive impairment in MS patients. We administered it to 19 chronic stable MS patients every 60 days for 120 days to examine variability. The mean coefficient of variation for the tests ranged from 18% to 22%. A significant practice effect was seen in the PASAT results (P < 0.05) using the Wilcoxon signed rank test. These results suggest that cognitive fluctuations analogous to motor fluctuations may occur in MS patients and that the BRB-N may be useful in clinical trials of agents expected to alter cognitive function in MS patients if test-retest variability and practice effects are taken into account. Further study is warranted.

Issues associated with repeated neuropsychological assessments

Distinguishing practice effects from other factors in repeated neuropsychological assessments are discussed in the context of research studies and clinical/forensic assessments. Potential methodological procedures for reducing the impact of practice effects in research settings are outlined. In contrast, the potential clinical utility and interpretation of practice effects in clinical assessments and forensic evaluations are highlighted.