Nicholas C. Barrett

Timing and force control in boys with attention deficit hyperactivity disorder: Subtype differences and the effect of comorbid developmental coordination disorder

This study examined the motor and performance outcomes of boys with subtypes of attention deficit hyperactivity disorder (ADHD) (DSM-IV, [American Psychiatric Association, Diagnostic and statistical manual of mental disorders, 4th ed., Washington, DC, 1994]). It also examined the differences between boys with a single diagnosis of ADHD versus those who have the dual categorisation of ADHD and developmental coordination disorder (DCD). The participants were 157 boys, aged 7.70-12.98 years recruited from a community sample. Parent report was used to classify 143 boys into either a comparison group or one of the three DSM-IV ADHD subtypes. Participants were given a battery of tests that included the Movement Assessment Battery for Children [Movement Assessment Battery for Children, Psychological Corporation/Harcourt Brace-Jovanovich, New York, 1992], the Wechsler Intelligence Scales for Children--Third Edition [Manual for the Wechsler Intelligence Scale for Children, Psychological Corporation, New York, 1992] and a finger tapping task targeting motor processing, preparation, and execution. Boys with subtypes that included inattentive symptomatology had significant difficulties with timing, force output and showed greater variability in motor outcomes. Boys with the comorbid condition (i.e., ADHD and DCD) had particular difficulty with force control. These outcomes identify a need for increased recognition of the clinical and research implications of the relationship between ADHD and motor dysfunction. This potentially impacts on assessment, intervention, theoretical modelling and the general interpretation of cognitive abilities research with children with ADHD.

The Relationship Between Bullying and Self-Worth in Children with Movement Coordination Problems.

BACKGROUND Past research has indicated that there is a negative relationship between victimization and self-worth. Furthermore, children with movement problems such as developmental coordination disorder (DCD) are considered at risk of both victimization and low self-worth. AIMS This study investigated the relationship between peer-victimization and self-worth in a group of children with DCD and control children. SAMPLE Forty-three children aged 7-11 years were identified as at risk of DCD, and were matched on age and gender with 43 control children. METHOD Children were individually assessed using the Multi-dimensional peer victimization scale (MPVS; Mynard & Joseph, 2000) to assess the degree and type of bullying, and the self perception profile for children (SPPC; Harter, 1985) to determine self-worth. RESULTS The two groups did not differ significantly on mean reported self-worth or mean peer-victimization. The relationship between these two measures, however, differed across group and gender. Peer victimization and self-worth were negatively correlated only for the children at risk of DCD. Furthermore, peer victimization accounted for a greater and statistically significant proportion of the variance in the self-worth of girls at risk of DCD compared with boys. This effect of peer-victimization on self-worth in girls with DCD was uniquely attributed to the effects of verbal victimization. CONCLUSIONS Although children with and without motor coordination problems reported equivalent amounts of victimization, there were differences in the impact of that bullying. Specifically, self-worth was negatively affected by bullying for the girls with DCD. Teachers and parents should not only focus on the amount of bullying a child receives, but should also be aware of how bullying impacts differently on self-worth across groups.

Do motor skills in infancy and early childhood predict anxious and depressive symptomatology at school age

Research has identified a relationship between social-emotional problems and motor impairment in both pre-school and school-age children. The aim of the current study was to determine how motor performance in infancy and early childhood is related to levels of anxious and depressive symptomatology at age 6-12 years. Fifty participants were assessed by their parents 11 times between the ages of 4 months and 4 years using the Ages and Stages Questionnaire (ASQ), and once between the age of 6 and 12 years using the Child Behavior Checklist (CBCL). The ASQ scores were used to obtain the stability (variance) of fine and gross motor performance. Once gestational age, sex and age of testing were taken into account, the stability of gross motor scores predicted both the anxiety/depression measure and the anxious score from the CBCL. It appears that how variable a young childs gross motor development is from 4 months to 4 years predicts the level of anxious/depressive symptoms at school age. These findings may assist in the early identification of children at risk of anxiety disorders and depression at school age.

Determinants of Self-Worth in Children with and without Developmental Coordination Disorder

Harter (1987) argues that both competence-importance discrepancy and social support/positive regard constructs predict a childs global self-worth. In the current study, this model was used to ascertain whether both determinants were pertinent to the self-worth of children with Developmental Coordination Disorder (DCD: American Psychiatric Association, 1994) and to control children. A group of 36 children with DCD were compared with a matched group of 36 normally coordinated children. The two groups were matched on variables of age, gender, and verbal IQ. It was found that Harters (1987) model was supported for the group of control children as both the competence-importance discrepancy and the social support/positive regard construct were significant predictors of self-worth. However, for the DCD group, only the competence-importance discrepancy predicted self-worth. The results of this study indicate that future research efforts need to examine an alternative model which incorporates the variables that are relevant to the self-worth of children with DCD.

Limb and gender differences in the development of coordination in early infancy

Young infants produce a variety of spontaneous arm and leg movements in the first few months of life. Coordination of leg joints has been extensively investigated, whereas arm joint coordination has mainly been investigated in the sitting position in the context of early reaching and grasping. The current study investigated arm and leg joint coordination of movements produced in the supine position in 10 fullterm infants aged 6, 12 and 18 weeks. Longitudinal comparisons within limbs (intralimb) as well as between limbs (interlimb, ipsilateral and contralateral) were made as well as an exploration of differences in the development for boys and girls. The relationship between the joint angles was examined by measuring pair-wise cross-correlation functions for the angular displacement curves of the leg (hip, knee and ankle) and arm (shoulder, elbow and wrist) joints of both the right and left side. Both the arms and legs were found to follow a similar pattern of intralimb coordination, although the leg joints were more tightly coupled than the arm joints, particularly the proximal with the middle joint. In support of earlier findings, differences in the development of the right and left side were identified. In addition, gender differences in joint coordination were found for both intralimb and interlimb coordination. This contrasts with the view that gender differences in motor development may be primarily a result of environmental influences.

Comorbid ADHD and DCD: Examining cognitive functions using the WISC-IV

This study explored the cognitive performance of children with Attention Deficit/Hyperactivity Disorder (ADHD) and/or Developmental Coordination Disorder (DCD) using the Wechsler Intelligence Scale for Children-IV. Participants were 62 children with ages between 9 years 8 months and 12 years 7 months. These children were placed into one of the four groups: Comparison (n=26), ADHD (n=14), DCD (n=11), and ADHD+DCD (n=11) groups. The ADHD symptoms were assessed using the Australian Disruptive Behaviours Scale, and motor ability was assessed using the McCarron Assessment of Neuromuscular Development (MAND). Significantly poorer perceptual reasoning ability was seen in DCD and ADHD+DCD groups but not in the ADHD group. The findings provide evidence that a deficit in visuo-spatial ability may underlie DCD but not ADHD. These findings revealed different cognitive profiles for ADHD and/or DCD, thus the current study does not lend support to the common aetiology hypothesis in understanding the basis of ADHD and DCD comorbidity.

The effect of temporal and force changes on the patterning of sequential movements

SummaryThis article examines the programming of relatively long sequences of action with the control of sequential movements being effected through the use of a tapping task involving a sequence of five taps. Subjects were required to tap with their right hand at rates of 150, 200, and 250 ms. There were two conditions, with subjects being required either to increase, in condition 1, or to decrease, in condition 2, the force at one of the five tap positions (all five tap positions were examined), then return to the previous force level. Changes in timing resulting from variations in the force characteristics have previously been discussed in terms of changes in the organizational time required ( Semjen, Garcia-Colera, & Requin, 1984). The current study breaks the intertap interval down into two separate components: the contact interval (finger in contact with the key) and the non-contact interval (interval preceding the tap). Although changes in the non-contact interval could be explained in terms of changes in the organizational time required, changes in the contact interval appeared to be a result of the mechanical changes in force.

Response amendments during manual aiming movements to double-step targets

The present paper reports a double-step analysis of a discrete aiming movement. A second target step was presented during the trajectory of the response to an initial step and represented an artificially induced movement error signal. Two stimulus patterns involving steps in the same direction (an undershoot error signal) and opposite direction (an overshoot error signal) to the initial step were examined. Moreover, in a random error condition the subject had no advance information regarding the direction of the error. In a deliberate error condition the subject knew in advance whether any subsequent error would be an undershoot or overshoot. Response parameters were considered as a function of the interstep interval which was randomly varied across trials. In terms of movement time, the standard deviations and a constant amendments score of double-step trials, subjects could respond more appropriately and effectively to a deliberate rather than a random error, and an undershoot error rather than an overshoot error. These results are discussed in terms of a mixed-mode of visuo-spatial error updating and related to the generalized motor program hypothesis.

Rationale, design and methods for a randomised and controlled trial to evaluate "Animal Fun" - a program designed to enhance physical and mental health in young children

BackgroundChildren with poor motor ability have been found to engage less in physical activities than other children, and a lack of physical activity has been linked to problems such as obesity, lowered bone mineral density and cardiovascular risk factors. Furthermore, if children are confident with their fine and gross motor skills, they are more likely to engage in physical activities such as sports, crafts, dancing and other physical activity programs outside of the school curriculum which are important activities for psychosocial development. The primary objective of this project is to comprehensively evaluate a whole of class physical activity program called Animal Fun designed for Pre-Primary children. This program was designed to improve the childs movement skills, both fine and gross, and their perceptions of their movement ability, promote appropriate social skills and improve social-emotional development.MethodsThe proposed randomized and controlled trial uses a multivariate nested cohort design to examine the physical (motor coordination) and psychosocial (self perceptions, anxiety, social competence) outcomes of the program. The Animal Fun program is a teacher delivered universal program incorporating animal actions to facilitate motor skill and social skill acquisition and practice. Pre-intervention scores on motor and psychosocial variables for six control schools and six intervention schools will be compared with post-intervention scores (end of Pre-Primary year) and scores taken 12 months later after the childrens transition to primary school Year 1. 520 children aged 4.5 to 6 years will be recruited and it is anticipated that 360 children will be retained to the 1 year follow-up. There will be equal numbers of boys and girls.DiscussionIf this program is found to improve the childs motor and psychosocial skills, this will assist in the childs transition into the first year of school. As a result of these changes, it is anticipated that children will have greater enjoyment participating in physical activities which will further promote long term physical and mental health.Trial registrationThis trial is registered in the Australian and New Zealand Clinical trials Registry (ACTRN12609000869279).

Effect of postural instability on drawing errors in children: A synchronized kinematic analysis of hand drawing and body motion

To investigate the role that postural stability plays in fine motor control, we assessed kinematics of the head, shoulder, elbow, and the pen during an accuracy drawing task in 24 children. Twelve children were classified into an accurate drawing (AD) group and 12 children into an inaccurate drawing (ID) group based on a manual dexterity task from the movement assessment battery for children [Henderson, S. E., & Sugden, D. A. (1992). Movement assessment battery for children. London: Psychological Corporation.]. Their parents completed a questionnaire to assess childrens inattention, hyperactivity, and impulsivity. An electromagnetic tracking system was used to monitor 3-D kinematic data of the body parts, while 2-D kinematic data of pen movement was simultaneously collected from a computer digitizer tablet. If a sudden body motion (1cm/s) occurred within a time window from one second prior to the onset of the drawing error to the end of the error, we considered that the error coincided with the extraneous body movement. For each drawing trial, the coincidence rate was computed as (number of coincidences)/(number of errors). The ID group had a significantly higher coincidence rate of head and shoulder movements compared with elbow movements, whereas coincidence rates did not differ between the three body parts in the AD group. Parental ratings of childrens behavioral ratings of inattention, hyperactivity, and impulsivity were not correlated with the coincidence rates. The results indicated that inaccurate drawing was a result of postural instability rather than fidgeting caused by inattention or hyperactivity/impulsivity.