Motor imagery and action observation for predictive control in developmental coordination disorder.

Motor planning with and without motor imagery in children with Developmental Coordination Disorder

ABSTRACTThis is the first review to provide both a systematic and meta-analytic approach to characterizing motor planning deficits in children with Developmental Coordination Disorder (DCD). Task complexity appears to be a key factor affecting motor planning in children with DCD. However, the different task-related factors and how they affect motor planning ability has not been examined. By systematically reviewing ten studies examining motor planning in children aged 4- to 14 years with and without DCD using grip selection tasks, task complexity was determined according to grip choices, level of precision, number of action steps and degree of rotation. A meta-analysis (N = 607; DCD = 255) revealed that, overall, those with DCD were 6.8% less likely to plan motor actions comfortably than typically developing children. This ability was moderated by task complexity (I2 = 66.7%), with performance differences ranging from 2.33% for low (g = 0.21) to 13.77% (g = 0.79) for high complexity. The results confirmed that children with DCD are able to plan for comfortable end states for tasks with simple and medium complexity level. When task complexity increased, compared to typically developing children, the motor planning ability of those with DCD was affected to a significantly greater extent. These findings provide important implications for both behavioral and neurological interventions.

Investigating motor planning in children with DCD: Evidence from simple and complex grip-selection tasks

Insights on action observation and imitation abilities in children with Developmental Coordination Disorder and typically developing children

Motor imagery during action observation enhances automatic imitation in children with and without developmental coordination disorder

See related article on page 608 In this issue of the journal, an important new contribution to the literature on Developmental Coordination Disorder (DCD) explores differences in motor imagery ability in three groups – children with attention-deficit–hyperactivity disorder (ADHD), children with DCD, and children with both conditions. This study provides evidence that DCD has a unique neurological basis, calling into question the notion that ADHD and DCD are merely dimensions of a broader syndrome of generalized developmental deficits. The idea that ADHD and DCD share a common cause has its roots in studies demonstrating very high levels of comorbidity between them: in clinical samples of children with one disorder or the other, 30 to 50% typically prove to have both. This has led to approaches like that of Lewis et al., which seek to explore the common ground these conditions share. By failing to take into account comorbidity between these disorders, previous work may have produced erroneous conclusions regarding underlying mechanisms. A case in point is the association between ADHD and abnormal motor overflow or associated movements. It is not clear whether this relationship is due to impaired inhibition related directly to ADHD or to independent coordination problems. Preliminary evidence currently favours the latter.1 The paper by Lewis et al. poses a similar question. As the authors observe, disrupted motor behaviour may arise from a dysfunction in the neurological networks responsible for motor planning and control, as is thought to be the case with DCD, or from deficits in attention and executive functioning associated with ADHD. In other words, the same impaired performance outcome could arise from functional problems in either of two, quite distinct, systems. This understanding would lead then to the conclusion that similarities in certain clinical features of ADHD and DCD are not necessarily indicative of a common neurological dysfunction or etiology. Lewis et al. examined this hypothesis by building on previous work that has established an internal modeling or efference-copy deficit in children with DCD.2 They explored whether deficits in motor imagery, in this case measured using a guided pointing task, were specific to DCD. By comparing performance in groups of children with ADHD alone, DCD alone, and those with comorbid ADHD and DCD, they demonstrated that this particular deficit occurred predominantly in the DCD-only group. The authors concluded that DCD may be associated with disruption to normal function associated with the inferior parietal lobe. While preliminary, these data support the hypothesis of unique neurological bases for DCD and ADHD. Perhaps most importantly, the method used in this study and others (e.g.1) reflects an important paradigm shift in the field. Only by taking into account comorbid ADHD and DCD can we hope to better understand whether these problems share a common etiology. Motor imagery should be of particular interest to researchers and clinicians in DCD because ‘imagined’ movement shares much of the physiological and neurological apparatus of its ‘real’ counterpart. Some have gone so far as to argue that motor imagery is an internal model of actual movement arising in consciousness simply because the actual movement has been inhibited. It is not surprising then, that children with coordination problems exhibit deficits in imagined movements as well as ‘real’ ones. The clinical implications of this work are intriguing. Previous work from members of this same research team has shown that motor imagery training is as effective as more traditional perceptual motor training in facilitating motor skill development in clumsy children. While the authors note the benefits of this approach in relation to ease of application and convenience relative to traditional physical therapy, there may also be psychological benefits. Children with DCD often report low levels of self-efficacy with regard to their physical abilities, and this lack of confidence may be the principal cause of low levels of participation in sports and other physical activities. These negative self-attributions are also likely to have an impact on ‘training’ to improve motor skill development. Children with DCD learn to conceal their problems by avoiding activities that expose their coordination difficulties and this could limit the effectiveness of skill-development-based interventions. Motor imagery, by contrast, is a safe way of developing skills out of public view. In this sense, its benefits may not be limited solely to physical skill development, but may also be conducive to greater psychological and social well-being.

To summarize current evidence for early identification and motor-based intervention for children aged 5 years and younger of age with/at risk of developmental coordination disorder (DCD). Using scoping review methodology, we independently screened over 11 000 articles and selected those that met inclusion criteria. Of the 103 included articles, 78 articles were related to early identification and are summarized in a companion article. Twenty-two articles focused on early intervention, with an additional three articles covering both early identification and intervention. Most intervention studies were at a low level of evidence, but provide encouraging evidence that early intervention is beneficial for young children with/at risk of DCD. Direct intervention can be provided to whole classes, small groups, or individuals according to a tiers of service delivery model. Educating and building the capacity of parents and early childhood educators are also key elements of early intervention. Evidence for early intervention for children with/at risk of DCD is emerging with promising results. Further studies are needed to determine best practice for early intervention and whether intervening early can prevent the negative developmental trajectory and secondary psychosocial consequences associated with DCD.

Effects of virtual reality training intervention on predictive motor control of children with DCD – A randomized controlled trial

Mild impairments of motor imagery skills in children with DCD

SummaryRehabilitation, for a large part may be seen as a learning process where old skills have to be re-acquired and new ones have to be learned on the basis of practice. Active exercising creates a flow of sensory (afferent) information. It is known that motor recovery and motor learning have many aspects in common. Both are largely based on response-produced sensory information. In the present article it is asked whether active physical exercise is always necessary for creating this sensory flow. Numerous studies have indicated that motor imagery may result in the same plastic changes in the motor system as actual physical practice. Motor imagery is the mental execution of a movement without any overt movement or without any peripheral (muscle) activation. It has been shown that motor imagery leads to the activation of the same brain areas as actual movement. The present article discusses the role that motor imagery may play in neurological rehabilitation. Furthermore, it will be discussed to what extent the observation of a movement performed by another subject may play a similar role in learning. It is concluded that, although the clinical evidence is still meager, the use of motor imagery in neurological rehabilitation may be defended on theoretical grounds and on the basis of the results of experimental studies with healthy subjects.

Objective: To investigate the efficacy and cortical correlates of action observation and motor imagery in promoting early learning of a complex motor task. Background Consisting evidence indicates that motor imagery (MI) and action observation (AO) are effective cognitive tools for motor learning, but data comparing the corresponding pattern of brain activation are lacking. Design/Methods: Thirty healthy non-athlete right-handed participants (age 22,87 ± sd 3,26 years; M/F 13/17) were randomly assigned into 3 groups: AO (N=9), MI (N=12), Control (N=9). Subjects read a written explanation of the task followed by 7-minute training: AO watched a video of the task, MI imagined it, Control (C) computed mathematics. Then they performed the task (3 min) with kinematics with error-time calculation. Task-related power was calculated with 32-channel EEG during training and execution, within four EEG frequency bands: α1 (10-11 Hz), α2 (12-13 Hz), β1 (16-17 Hz), β2 (22-23 Hz). Results: AO performed significantly better than MI, with significant lower values of ET. During the training period α1 desynchronization was higher for AO group than MI group over the left frontocentral and bilateral parietal areas. During task execution the AO group had a stronger β1 synchronization than MI and C groups over left parietal region. Conclusions: Sensorimotor activation to action observation was related to enhanced motor learning, corresponding to a lower, more efficient cortical activation during subsequent actual performance. The possible efficacy of action observation in promoting learning of a novel complex task may have rehabilitative implications. Disclosure: Dr. Leocani has nothing to disclose. Dr. Natali has nothing to disclose. Dr. Gonzalez Rosa has nothing to disclose. Dr. Velikova has nothing to disclose. Dr. Tettamanti has nothing to disclose. Dr. Comi has received personal compensation for activities with Novartis, Teva Neuroscience, Sanofi-Aventis Pharmaceuticals, Inc., Merck Serono, Bayer Schering, and Biogen Dompe. Dr. Gatti has nothing to disclose.

Children with developmental coordination disorder (DCD) have difficulties with the predictive control of movements. This was shown in studies that target motor imagery and motor planning, and appears to become particularly evident with increases in task complexity. In this study, we used a complex mental chronometry paradigm to examine the development of motor imagery ability in children with DCD, using a longitudinal design. Thirty children were included in the DCD group (aged 6-11years) and age- and gender-matched to 30 controls. The DCD group had a Movement Assessment Battery for Children-2 score ≤16th percentile and the control group ≥25th percentile. Results of this study showed that children with DCD indeed had a significantly lower correlation between executed and imagined movements. Importantly, the increase in the correlation and linear fit during subsequent measurements was comparable for the DCD and control group. Together, these findings suggest a delayed developmental onset of motor imagery ability in DCD, but a similar rate of development over time compared to the control group. Based on these results, it seems likely that explicit motor imagery instructions can be used to improve predictive control in children with DCD.

This study aimed to test the internal modelling deficit (IMD) hypothesis using the mental rotation paradigm. According to the IMD hypothesis, children with Developmental Coordination Disorder (DCD) have an impaired ability to internally represent action. Thirty-six children (18 DCD) completed four tasks: two versions of a single-hand rotation task (with and without explicit imagery instructions), a whole-body imagery task and an alphanumeric rotation task. There was partial support for the hypothesis that children with DCD would display an atypical pattern of performance on the hand rotation task, requiring implicit use of motor imagery. Overall, there were no significant differences between the DCD and control groups when the hand task was completed without explicit instructions, on either response time or accuracy. However, when imagery instructions were introduced, the controls were significantly more accurate than the DCD group, indicating that children with DCD were unable to benefit from explicit cuing. As predicted, the controls were also significantly more accurate than the DCD group on the whole-body task, with the accuracy of the DCD group barely rising above chance. Finally, and as expected, there was no difference between the groups on the alphanumeric task, a measure of visual (or object-related) imagery. The inability of the DCD group to utilize specific motor imagery instructions and to perform egocentric transformations lends some support to the IMD hypothesis. Future work needs to address the question of whether the IMD itself is subgroup-specific.

This cross-sectional and exploratory study aimed to compare motor performance and electroencephalographic (EEG) attention levels in children with developmental coordination disorder (DCD) and those with typical development, and determine the relationship between motor performance and the real-time EEG attention level in children with DCD.Eighty-six children with DCD [DCD: n = 57; DCD and attention deficit hyperactivity disorder (ADHD): n = 29] and 99 children with typical development were recruited. Their motor performance was assessed with the Movement Assessment Battery for Children (MABC) and attention during the tasks of the MABC was evaluated by EEG.All children with DCD had higher MABC impairment scores and lower EEG attention scores than their peers (P < 0.05). After accounting for age, sex, body mass index, and physical activity level, the attention index remained significantly associated with the MABC total impairment score and explained 14.1% of the variance in children who had DCD but not ADHD (P = 0.009) and 17.5% of the variance in children with both DCD and ADHD (P = 0.007). Children with DCD had poorer motor performance and were less attentive to movements than their peers. Their poor motor performance may be explained by inattention.

Neural Correlates of Internal-Model Loading