Relationship between reaction time variability and motor skill development in ADHD

Slower and more variable reaction times to computerized tasks have been documented in children diagnosed with attention deficit/hyperactivity disorder (ADHD). Recent research supports a role for attentional lapses in generating abnormally variable and slow responses. However, given the association between ADHD and impairments in motor control, we hypothesized that slower or more variable reaction times might also correlate with motor development. The aim of this case-control study was to explore the relationship between motor function, reaction speed and variability, and ADHD. After comprehensive educational and clinical assessments, motor skill development was evaluated in 35 children ages 9 to 14 (19 with ADHD) using the Physical and Neurological Examination for Subtle Signs (PANESS) test battery. Finger-sequencing speed and variability were quantified with goniometers. Reaction times were measured with 20 trials each of computerized simple and choice (binary) tasks. Compared to healthy controls, children with ADHD had slower and more variable reaction times, and these findings correlated with impaired motor development (PANESS) and slow and variable finger sequencing (goniometers). Further studies of motor development in ADHD may identify factors influencing speed and variability of reaction times.     

Relationship between reaction time variability and motor skill development in ADHD

Slower and more variable reaction times to computerized tasks have been documented in children diagnosed with attention deficit/hyperactivity disorder (ADHD). Recent research supports a role for attentional lapses in generating abnormally variable and slow responses. However, given the association between ADHD and impairments in motor control, we hypothesized that slower or more variable reaction times might also correlate with motor development. The aim of this case-control study was to explore the relationship between motor function, reaction speed and variability, and ADHD. After comprehensive educational and clinical assessments, motor skill development was evaluated in 35 children ages 9 to 14 (19 with ADHD) using the Physical and Neurological Examination for Subtle Signs (PANESS) test battery. Finger-sequencing speed and variability were quantified with goniometers. Reaction times were measured with 20 trials each of computerized simple and choice (binary) tasks. Compared to healthy controls, children with ADHD had slower and more variable reaction times, and these findings correlated with impaired motor development (PANESS) and slow and variable finger sequencing (goniometers). Further studies of motor development in ADHD may identify factors influencing speed and variability of reaction times.     

The test–retest reliability of the latent construct of executive function depends on whether tasks are represented as formative or reflective indicators

This study investigates the test–retest reliability of a battery of executive function (EF) tasks with a specific interest in testing whether the method that is used to create a battery-wide score would result in differences in the apparent test–retest reliability of children’s performance. A total of 188 4-year-olds completed a battery of computerized EF tasks twice across a period of approximately two weeks. Two different approaches were used to create a score that indexed children’s overall performance on the battery—i.e., (1) the mean score of all completed tasks and (2) a factor score estimate which used confirmatory factor analysis (CFA). Pearson and intra-class correlations were used to investigate the test–retest reliability of individual EF tasks, as well as an overall battery score. Consistent with previous studies, the test–retest reliability of individual tasks was modest (rs ≈ .60). The test–retest reliability of the overall battery scores differed depending on the scoring approach (r_mean = .72; r_{factor_score} = .99). It is concluded that the children’s performance on individual EF tasks exhibit modest levels of test–retest reliability. This underscores the importance of administering multiple tasks and aggregating performance across these tasks in order to improve precision of measurement. However, the specific strategy that is used has a large impact on the apparent test–retest reliability of the overall score. These results replicate our earlier findings and provide additional cautionary evidence against the routine use of factor analytic approaches for representing individual performance across a battery of EF tasks.     

Bilingual experience and executive functioning in young children

Advanced inhibitory control skills have been found in bilingual speakers as compared to monolingual controls (Bialystok, 1999). We examined whether this effect is generalized to an unstudied language group (Spanish-English bilingual) and multiple measures of executive function by administering a battery of tasks to 50 kindergarten children drawn from three language groups: native bilinguals, monolinguals (English), and English speakers enrolled in second-language immersion kindergarten. Despite having significantly lower verbal scores and parent education/income level, Spanish-English bilingual children's raw scores did not differ from their peers. After statistically controlling for these factors and age, native bilingual children performed significantly better on the executive function battery than both other groups. Importantly, the relative advantage was significant for tasks that appear to call for managing conflicting attentional demands (Conflict tasks); there was no advantage on impulse-control (Delay tasks). These results advance our understanding of both the generalizability and specificity of the compensatory effects of bilingual experience for children's cognitive development.     

Attentional WM is not necessarily specifically related with fluid intelligence: the case of smart children with ADHD symptoms

Executive functions and, in particular, Attentional (active) Working Memory (WM) have been associated with fluid intelligence. The association contrasts with the hypothesis that children with ADHD exhibit problems with WM tasks requiring controlled attention and may have a good fluid intelligence. This paper examines whether children who are intelligent but present ADHD symptoms fail in attentional WM tasks. The latter result would be problematic for theories assuming the generality of a strict relationship between intelligence and WM. To study these issues, a battery of tests was administered to a group of 58 children who all displayed symptoms of ADHD. All children were between the age of 8 and 11 years, and were described by their teachers as smart. Children were compared to a control group matched for age, schooling, and gender. The battery included a test of fluid intelligence (Raven’s Coloured Matrices), and a series of visuospatial WM tasks. Results showed that children with ADHD were high in intelligence but significantly lower than the controls in WM tasks requiring high attentional control, whereas there was no difference in WM tasks requiring low attentional control. Furthermore, only high attentional control WM tasks were significantly related to Raven’s performance in the control group, whereas all WM tasks were similarly related in the ADHD group. It is concluded that performance in high attentional control WM tasks may be related to fluid intelligence, but also to a specific control component that is independent of intelligence and is poor in children with ADHD.     

The measurement of executive function at age 5: psychometric properties and relationship to academic achievement

This study examined the psychometric properties and criterion validity of a newly developed battery of executive function (EF) tasks for use in early childhood. The battery was included in the Family Life Project (FLP), a prospective longitudinal study of families who were oversampled from low-income and African American families at the birth of a new child (N = 1,292). Ninety-nine percent (N = 1,036) of children who participated in the age 5 home visit completed 1 or more (M = 5.8, Mdn = 6) of the 6 EF tasks. Results indicated that tasks worked equally well for children residing in low-income and not low-income homes, that task scores were most informative about the ability level of children in the low-average range, that performance on EF tasks was best characterized by a single factor, and that individual differences on the EF battery were strongly related to a latent variable measuring overall academic achievement, as well as to individual standardized tests that measured phonological awareness, letter-word identification, and early math skills.     

A novel executive function battery for preschoolers: Sensitivity to age differences

The present study investigated sensitivity to age differences in a novel executive function (EF) battery for children aged 18 months to 5 years, and whether the pattern of associations among the measures was consistent with a hierarchical model of EF development. Participants (n = 261, aged 18–67 months) were administered a battery of novel tasks designed to assess 3 key EF components (working memory, inhibition, and shifting). The results indicate that the EF tasks were sensitive to age differences and provide partial support for the hierarchical model of EF development.     

Prospects for Computerized Memory Training in Normal Elderly: Effects of Practice on Explicit and Implicit Memory Tasks

We gave 12 cognitively normal, elderly adults (mean age = 76.33 years) training and practice on the Colorado Neuropsychology Tests, a computerized battery of explicit and implicit memory tasks. Half the subjects practised on the explicit memory tasks for 1.5 hours a week for 9 weeks with the assistance of a psychologist, while the other half practised on the implicit tasks for the equivalent amount of time. Subjects in both training conditions showed significant improvement within and across training sessions, with those in the implicit memory condition showing the most overall improvement, as indicated by standardized change scores. However, the improved performance on the training tasks did not result in more positive self-assessments of memory capability. In general, subjects displayed favourable attitudes toward the computer technology and were capable of learning to operate the computer software. The results support the practical application of computerized memory training with normal elderly adults.     

Maturation of Spatial Navigation Strategies: Convergent Findings from Computerized Spatial Environments and Self-Report

Using 2 computerized spatial navigation tasks, we examined the development of cue and place learning in children ages 3 to 10 years, comparing their data to adults. We also examined relations between place learning in computerized and real space. Results showed children use the 2-dimensional space as if it were real space. Results also demonstrated that children ages 3 to 10 years cue learn (locating a visible target) but do not show evidence of mature place learning (locating an invisible target) until around age 10 years. Self-report data indicated an age-related increase in use of relations among distal cues during place learning. Children ages 3 to 4 years did not report using distal cues; most 9- to 10-year-old children reported using multiple distal cues to guide their search during place learning. Results suggest that, as maturation proceeds, children make increasing use of relations among multiple distal cues to guide a search for places in space.     

Repeated assessment of cognition in children and the measurement of performance change.

There is limited understanding of the problems associated with repeated neuropsychological assessment in children, including the statistics used to guide decisions about cognitive change. This study investigated the utility of a computerized assessment battery that was specifically designed for the repeated assessment of cognitive function in children. Eighty-seven participants aged 8 to 12 years completed the battery four times within a 2-hour testing session. The results support the application of this assessment battery for measuring cognitive change in children. A novel method for calculating measurement error is employed, and its use in the detection of cognitive change in individual children is discussed. An estimate of the measurement error within each of the tests is provided, and recommendations are made regarding the application of this assessment battery for measuring cognitive change in children.     

Visuomotor perception in children with attention deficit hyperactivity disorder--combined type.

Children with Attention Deficit Hyperactivity Disorder--Combined Type (ADHD-CT) defined by behavioral characteristics of inattention, impulsivity, and hyperactivity including weaknesses in fine motor coordination and poor motor inhibition frequently exhibit poor handwriting and penmanship. Performance of children on visuomotor tasks is further complicated, as most studies have not excluded children with specific learning disabilities who are known to do poorly on these tests. This study was designed to examine the performance of children diagnosed with this disorder, without learning disabilities on visuomotor tasks. 26 preadolescent patients were administered a battery of tests that included the Bender-Gestalt, Conners' Parent Rating Scale, Continuous Performance Task, and Wide Range Achievement Test-Third Edition Scores on the Bender-Gestalt test averaged significantly lower than Koppitz normative data. This study lends support to the hypothesis that ADHD-CT children without learning disabilities exhibit deficits on tasks requiring visuomotor perception.     

Formula: see text]Executive functions in extremely low birth weight and late-preterm preschoolers: Effects on working memory and response inhibition

Executive function (EF) refers to fundamental capacities that underlie more complex cognition and have ecological relevance across the individual's lifespan. However, emerging executive functions have rarely been studied in young preterm children (age 3) whose critical final stages of fetal development are interrupted by their early birth. We administered four novel touch-screen computerized measures of working memory and inhibition to 369 participants born between 2004 and 2006 (52 Extremely Low Birth Weight [ELBW]; 196 late preterm; 121 term-born). ELBW performed worse than term-born on simple and complex working memory and inhibition tasks and had the highest percentage of incomplete performance on a continuous performance test. The latter finding indicates developmental immaturity and the ELBW group's most at-risk preterm status. Additionally, late-preterm participants performed worse compared with term-born on measures of complex working memory but did not differ from those term-born on response inhibition measures. These results are consistent with a recent literature that identifies often subtle but detectable neurocognitive deficits in late-preterm children. Our results support the development and standardization of computerized touch-screen measures to assess EF subcomponent abilities during the formative preschool period. Such measures may be useful to monitor the developmental trajectory of critical executive function abilities in preterm children, and their use is necessary for timely recognition of deficit and application of appropriate interventional strategies.     

Executive functions in extremely low birth weight and late-preterm preschoolers: Effects on working memory and response inhibition

Executive function (EF) refers to fundamental capacities that underlie more complex cognition and have ecological relevance across the individual's lifespan. However, emerging executive functions have rarely been studied in young preterm children (age 3) whose critical final stages of fetal development are interrupted by their early birth. We administered four novel touch-screen computerized measures of working memory and inhibition to 369 participants born between 2004 and 2006 (52 Extremely Low Birth Weight [ELBW]; 196 late preterm; 121 term-born). ELBW performed worse than term-born on simple and complex working memory and inhibition tasks and had the highest percentage of incomplete performance on a continuous performance test. The latter finding indicates developmental immaturity and the ELBW group's most at-risk preterm status. Additionally, late-preterm participants performed worse compared with term-born on measures of complex working memory but did not differ from those term-born on response inhibition measures. These results are consistent with a recent literature that identifies often subtle but detectable neurocognitive deficits in late-preterm children. Our results support the development and standardization of computerized touch-screen measures to assess EF subcomponent abilities during the formative preschool period. Such measures may be useful to monitor the developmental trajectory of critical executive function abilities in preterm children, and their use is necessary for timely recognition of deficit and application of appropriate interventional strategies.     

Executive function in preschool children prenatally exposed to methadone or buprenorphine

Although an increasing number of children are born with prenatal methadone or buprenorphine exposure, little is still known about the potential long-term effects of these opioids. The aim of this study was to investigate executive function (EF) in children of women in opioid maintenance therapy (OMT). A total of 66 children (aged 48–57 months) participated in the study, 35 of which had histories of prenatal methadone or buprenorphine exposure. EF was measured using a battery of neuropsychological tests and the Behavior Rating Inventory of Executive Function—Preschool Version (BRIEF-P). Results showed that children of women in OMT perform lower on tasks of short-term memory and inhibition compared to nonexposed children, which was mainly associated with lower maternal education and employment rate. The OMT group scored significantly lower on all EF tasks compared to the nonexposed group, although scores fell within the average range on all measures. The development of these children should be monitored to assess for the possible problem behaviors and to promote optimal outcomes.     

Executive functions and processing speed in children with mild to borderline intellectual disabilities and externalizing behavior problems

Several studies suggest impaired executive functions (EFs) in children with externalizing behavior problems and average intelligence (e.g., IQ > 85). Even though children with mild to borderline intellectual disabilities (MBID) are at higher risk of developing externalizing behavior problems compared to children with average intelligence, it is not yet clear if impaired EFs are also associated with the occurrence of externalizing behavior problems in children with MBID. In the current study, we therefore assessed three EF components (inhibition, cognitive flexibility, and working memory) as well as processing speed in children with MBID and externalizing behavior problems (n = 71) versus children with MBID with no such problems (n = 70). This was accomplished using a well-established computerized test battery. Even after IQ was controlled for, the children with MBID and externalizing behavior problems showed more impaired working memory performance. Differences for inhibition performance and processing speed were also found but less consistent across the tasks used to measure these aspects of EF. Cognitive flexibility was not more impaired in children with both MBID and externalizing behavior problems relative to children with MBID only. Our findings highlight working memory as a potential target to enhance the treatment of children with MBID and externalizing behavior problems.     

Investigating the links between the subcomponents of executive function and academic achievement: a cross-cultural analysis of Chinese and American preschoolers

Little is known about how components of executive function (EF) jointly and uniquely predict different aspects of academic achievement and how this may vary across cultural contexts. In the current study, 119 Chinese and 139 American preschoolers were tested on a battery of EF tasks (i.e., inhibition, working memory, and attentional control) as well as academic achievement tasks (i.e., reading and mathematics). Results demonstrate that although working memory performance in both cultures was comparable, Chinese children outperformed American children on inhibition and attentional control tasks. In addition, the relation between components of EF and achievement was similar in the two countries. Working memory uniquely predicted academic achievement, with some intriguing patterns in regard to tasks requiring complex processing. Inhibition uniquely predicted counting but did not uniquely predict calculation. Attentional control predicted most aspects of achievement uniformly and was the most robust predictor for reading in both countries. In sum, the data provide insight into both cultural variability and consistency in the development of EF during early childhood.     

Metamemory and academic achievement: testing the validity of a group-administered metamemory battery

This study was designed to assess the validity of a recently introduced group-administered battery of metamemory tasks for children and to concurrently assess the relationship between performance on these tasks and academic achievement for second- and fourth-grade normal and learning-disabled (LD) children. Consistent with theoretical predictions and with results from individually administered metamemory tasks, significant age-related performance differences were found for four of the battery's five subtests. However, three of these four performance differences appeared to be due to a floor effect--that is, the second graders performed at chance levels for all but one of the subtests. Nevertheless, modest zero-order correlations between academic achievement measures and scores on metamemory subtests, which did show interpretable age-related performance differences, were found, as were significant group (normal versus LD) differences for fourth graders. In all, these results provided some support for the validity and the utility of the group-administered metamemory battery, although the performance of young children must be interpreted with caution.     

Closing-in behaviour in preschool children

Many pre-school children show closing-in behaviour (CIB) in graphic copying tasks: a tendency to place their copy abnormally close to or even on top of the model. Similar phenomena have been studied in patients with dementia, though it is unclear whether the superficial similarities between CIB in development and dementia reflect common underlying cognitive mechanisms. The aim of the present study was to investigate the cognitive functions involved in CIB in pre-school children. Forty-one children (3–5 years) were assessed for CIB, and completed a neuropsychological battery targeting visuospatial abilities, short term memory (verbal and spatial) and attention (sustained attention, selective attention and attention switching). Binary logistic regression found that performance on the attention subtests was the best unique predictor of CIB. A second analysis, in which the three attention subtests were entered as separate predictors, suggested that attention switching ability was most strongly related to CIB. These results support the view that CIB in children reflects inadequate attentional control. The convergence of these results with similar observations in patients with dementia further suggests that similar cognitive factors underlie CIB in these two populations.     

The effects of bilingualism on toddlers' executive functioning

Bilingual children have been shown to outperform monolingual children on tasks measuring executive functioning skills. This advantage is usually attributed to bilinguals’ extensive practice in exercising selective attention and cognitive flexibility during language use because both languages are active when one of them is being used. We examined whether this advantage is observed in 24-month-olds who have had much less experience in language production. A battery of executive functioning tasks and the cognitive scale of the Bayley test were administered to 63 monolingual and bilingual children. Native bilingual children performed significantly better than monolingual children on the Stroop task, with no difference between groups on the other tasks, confirming the specificity of bilingual effects to conflict tasks reported in older children. These results demonstrate that bilingual advantages in executive control emerge at an age not previously shown.     

Association between fine motor skills and binocular visual function in children with reading difficulties

Performance of fine motor skills (FMS) assessed by a clinical test battery has been associated with reading achievement in school-age children. However, the nature of this association remains to be established. The aim of this study was to assess FMS in children with reading difficulties using two experimental tasks, and to determine if performance is associated with reduced binocular function. We hypothesized that in comparison to an age- and sex-matched control group, children identified with reading difficulties will perform worse only on a motor task that has been shown to rely on binocular input. To test this hypothesis, motor performance was assessed using two tasks: bead-threading and peg-board in 19 children who were reading below expected grade and age-level. Binocular vision assessment included tests for stereoacuity, fusional vergence, amplitude of accommodation, and accommodative facility. In comparison to the control group, children with reading difficulties performed significantly worse on the bead-threading task. In contrast, performance on the peg-board task was similar in both groups. Accommodative facility was the only measure of binocular function significantly associated with motor performance. Findings from our exploratory study suggest that normal binocular vision may provide an important sensory input for the optimal development of FMS and reading. Given the small sample size tested in the current study, further investigation to assess the contribution of binocular vision to the development and performance of FMS and reading is warranted.