Seminar 3 –
Characteristics and Comorbidity
Mark Mon-Williams:
University of Aberdeen
Why robot systems could help children with Developmental Coordination Disorder
Mark Mon-Williams, Alastair Cozens, Richard Carson, Martin Levesley, Rob Richardson, Peter Culmer and Bipinchandra Bhakta
Our knowledge of the underlying mechanisms in DCD is sparse. It appears that a large number of children with DCD do not differ from their peers in their ability to plan a complex movement sequence (Smyth & Mason, 1997). Thus, the problems experienced by many children with DCD appear to be related to deficits in programming relatively fundamental actions, such as reach-to-grasp movements (prehension).
Although our understanding of the motor deficits in DCD is increasing there is a relative lack of effective interventions. Pless et al (2000) undertook a systematic review which indicated that motor skill intervention is most effective when applied with (a) children with DCD over five years of age, (b) the ‘specific skill’ theoretical approach, (c) intervention conducted in a group setting or as a home program, and (d) intervention frequency of at least three to five times per week. Sugden and Chambers (2003) investigated the role of parents and teachers in developing a child’s skills using a combination of techniques, some of which included task specific reach-to-grasp activities.
Current methods of undertaking upper limb exercise are principally limited by the intensity of appropriate exercise which can be delivered. Exercises assisted by a therapist are inevitably labour-intensive and therefore resource-limited. From the child’s perspective, formal exercises are often unexciting; it is therefore difficult to maintain enthusiasm in the absence of the therapist. For these reasons, the use of assistive technologies offers the possibility of providing programs of simpler exercises for children to pursue independently, releasing physical and occupational therapy time to focus on other complex treatments. The use of technology to engage children with other types of neurological conditions has been investigated (e.g. cerebral palsy). Various devices already enable children to engage in perceptual-motor exercises despite upper limb impairment, such as tasks involving a ‘furry toy’ operated by the voice or body movement, a robotic arm operated by push buttons/laser pointers/head switches, and a musical instrument operated through a unique control panel. The use of computer games for children with Cerebral Palsy (CP) has been extended to use computer game technology requiring movement in 3D. Akhutina et al (2003) tested three different representations of a specific test with children who had CP. Their results showed that the use of a ‘virtual’ environment has a positive effect on the child’s spatial awareness; coupled with more traditional table-top games these systems offer improvements in overall functioning. The technological approaches cited above have demonstrated the willingness and enthusiasm of children with disability to engage with technology. Nonetheless, none of these approaches used technology to assist the child in undertaking appropriate movements.
Partial information that specifies only one dimension of the movement goal (i.e. the position of the object relative to the body midline) is used by adults and children as young as 4-6 years but is apparently not utilised by children with DCD when preparing a complex prehension movement (Mon-Williams 2005).
A similar finding has been reported for adolescents with Down syndrome (Mon-Williams et al., 2001). The lack of advantage provided by the partial information does not appear to be related to a general depression of cognitive ability but rather is associated with deficits of movement control per se.
Such findings can be interpreted as showing that people with movement problems are not willing to adopt a strategy that requires complex on-line control. From a theoretical basis this might lead one to suppose that motor learning is problematic within these children.
It is reasonable to consider DCD a problem of motor learning. Thus, an understanding of this disorder requires a consideration of how humans learn motor skills. Figure 1 provides a schematic illustrating notions central to motor skill learning. The fundamental idea is that motor learning consists of a process of building up internal models (controllers) that represent specific movement skills. It is our contention that these normal processes of motor learning are disrupted in DCD by the presence of noise. It can be seen that the presence of noise within the learning system will hinder the acquisition of skilled movement. The consequences of such deficits include an increased time in movement preparation (indexed by reaction time), an increase in online feedback corrections to unfolding movements (indexed by movement duration) and difficulties in using feedback to correct movements. The data we have collected over a series of experiments are consistent with such a picture.
Figure 1. Schematic of motor learning adapted from Wolpert, Ghahramani and Flanagan (2001).
The question facing therapists is how the consequences of noise within the system can be minimized in order to allow stability of motor learning. One sensible strategy is to guide the child’s hands along appropriate movement trajectories. Occupational therapy and physiotherapy encourages children to use their arm in an appropriate manner but access to therapy is limited and children can get frustrated with uninteresting repetitive practice.
Low cost computer joystick/video games robotic systems allow young children with DCD (5 – 12 years) to practice useful upper limb movements in an enjoyable game setting where the resulting exercise has potential therapeutic benefit. The equipment is particularly useful for helping children in tasks such as the acquisition of handwriting skills. We have acquired systems that we have adapted for therapeutic purposes. We anticipate that this equipment could be used within the NHS, school and home settings. This development of such equipment has potential to: benefit most children with DCD over age 5 years; become widely available because of low cost; be adjustable to the child’s arm movement difficulties; be part of the treatment program for movement problems experienced by these children.
References
1. Akhutina T et al (2003) Improving spatial functioning in children with cerebral palsy using computerized and traditional game tasks. Disabil Rehabil. 25: 1361-1371.
2. Smyth, M.M., & Mason, U.C. (1997) Planning and execution of action in children with and without DCD. Journal of Child Psychology and Psychiatry, 38, 1023-1037.
3. Mon-Williams, M et al (2001). The preparation of reach to grasp movements in adults with Down Syndrome. Human Movement Science, 20, 587-602.
4. Mon-Williams, M et al (2005) The preparation of reach-to-grasp movements in adults, children and children with developmental coordination disorder. The Quarterly Journal of Experimental Psychology (A) 58, 1249-1263
5. Pless M, Carlsson M. (2000) Effects of motor skill intervention on DCD: A meta-analysis. Adapted Physical Activity Quarterly 17: 381-401
6. Sugden DA, Chambers ME. (2003) Intervention in children with DCD: The role of parents and teachers. British Journal of Educational Psychology 73: 545-561
7. Wolpert DM et al (2001) Perspectives and problems in motor learning Trends in Cognitive Science 5, 487-494.