Seminar 4 –
Intervention
Mike Wade:
University of Minneapolis, USA
Theoretical perspectives about DCD: Do we keep rounding up the “usual suspects?”
This paper presented a review of the three dominant paradigms for investigating the motor performance of children at risk for DCD. These are information processing (IP), what I refer to as the Brain Science Model (BSM), and Dynamical Systems Model (DSM). We compare and contrast the central assumption of each model, review data generated by each model and the style of analysis. Finally we discuss some specific studies and comment on the influence that these different theoretical approaches may have on practice.
The talk reflects essentially the chapter we contributed to the Sugden and Chambers book, Children with Developmental Coordination Disorders, published by Whurr, London, (2005). The underpinnings of the IP perspective assumes an internal mechanism to make sense of information from the environment. We illustrate this with some of the typical terminology that is used with this theoretical approach. This approach spawned the idea of a motor program and discusses one or two of the key papers that argue for this theoretical account of DCD from a motor skills perspective. The one featured in the presentation is the timing model Wing and Kristofferson (1973).
An extension of the IP model is currently utilized in neuroscience to look more closely at some of the empirical efforts that distinguish the influence of the cerebellum and basal ganglia, which may differentiate differences between coordination and control (kinematics versus kinetics). We discuss briefly Edelman’s Neurogroup Selection Theory, (Sporns & Edelman, 1993) which proposes that development is guided both by behavior and by experience. Edelman’s Neurogroup Selection Theory (ENST) proposes two phases: a primary phase, where motor activity is variable, and not influenced by the environment and lacks adaptation to specific content; and a secondary phase that is function-specific and signals a transition from primary to the secondary phase. The suggestion here is that minor neurological disorder (MND) may be a microscopic account of the neurology of an individual diagnosed as DCD. MND is linked to clumsiness and as children with DCD are often considered “clumsy” this model can account for the perceptual motor behavior of children diagnosed with DCD. In a similar vein, the Hadders-Algra (2003) also connect the diagnosis of MND with DCD, given that there are approximately 15% of nine-year-old children who fall under the category of MND, (i.e.: normal, but non-optimal brain dysfunction) and this mirrors many children who are also diagnosed as DCD.
The ENST provides a roadmap and may offer a rapprochement between a strict IP perspective and a more dynamical, self-organizing approach to the neurology of individuals diagnosed with DCD. The drawback is that currently, the empirical evidence to support this is view lacking.
Finally we review the Dynamic Systems Theory (DST) and present background
of the two individuals who have influenced this view: the Russian physiologist
Nicolai Bernstein and the American psychologist James J. Gibson. It is Gibson’s
views on perception and Bernstein’s questioning of how the musculo-skeletal
system constrains the many degrees of freedom that are required for skilled
activity to occur, that has raised a serious questioning of standard IP accounts
of motor skills.
Bernstein’s “degrees of freedom problem” make “internal
representation” as a means to control skill difficult to explain. Gibson’s
ecological view of psychology and his idea of an affordance lead to a more
serious focus on the role and the nature of tasks and how the task engages
the performer in the ongoing interactions between task, performer, and environment.
Skilled activity requires taking into account the “holy trinity” of task, environment, and performer. We have spent it seems more time studying the performer and the environment, with considerably less attention paid to the nature of the task. Here we make the case that what is needed in order to better understand perceptual motor behavior and the a-typical performance of individuals, such as those with DCD, in an effort to better organize tasks within some kind of taxonomy with a view to developing a theory of tasks.
While this is easier said than done, we do need to better understand the relationship between cognitive tasks that also permit us to write the equivalent equations of motion. Tasks that combine cognition and action as opposed to only cognition are, we suggest, a research direction worth exploring.
We conclude our presentation by presenting data from our laboratory, which investigates haptic and perceptual judgments of children (both DCD and TDC) performing motor tasks.
References
1. Hadders-Algra, M. (2003). Developmental Coordination Disorder: is clumsy
motor behavior caused by a lesion in the brain at an early age? Neural
Plasticity 10: 39-50.
2. Sporns, O., Edelman, G.M. (1993). Solving Berstein’s problem: a proposal for the development of coordinated movement by selection. Child Development 64: 960-981
3. Wade, M.G., Johnson, D. & Mally, R. (2005) A dynamical systems perspective of Developmental Coordination Disorder in Children with Developmental Coordination Disorder. Edited by Sugden, D.A. & Chambers, M. Published by Whurr, London, UK. pp 72-92
4. Wing, A.M., Kristofferson, A.B. (1973). The timing of interresponse intervals. Perception and Psychophysics 13, 455-460.