Developmental Cognitive Neuroscience Perspective on Motor Rehabilitation: The Case for Virtual Reality-Augmented Therapy

IntroductionThe effects of brain dysfunction and injury during childhood have profound developmental consequences for the child and place a significant socio-economic burden on families and the community (1). In the case of cerebral palsy and problems of development like developmental coordination disorder (DCD), the movement difficulties present a huge challenge for therapists (2). The choice of therapy must at once enable therapists to engage the child in the process of treatment, while also maximising the strength of treatment effects in what is often a limited window of time in a clinical setting. The holy grail for therapists is to find a therapeutic modality that will yield quite generalised effects on movement form and functional skill.A principled approach to rehabilitation of manual function has been particularly slow to evolve. Most interventions for children with neurological disorders require intensive practice (e.g., Constraint Induced Movement Therapy-CIMT) and/or have poor patient compliance (3). By comparison, virtual-reality (VR) based treatments afford new options for engaging children, maintaining their level of motivation, and for providing a set of scalable movement tasks that utilise real-time feedback. VR-augmented therapies have been applied successfully in adult movement rehabilitation, however, a systematic approach to rehabilitation in children is yet to evolve (4,5). In this paper, I present a new model for movement rehabilitation of children with motor disorders including cerebral palsy and developmental coordination disorder (DCD), a form of severe movement clumsiness in childhood. From the perspective of developmental cognitive neuroscience, I examine our current understanding of the key concepts of predictive control and multimodal integration. I will show these concepts to be pivotal in re-conceptualising our approach to motor intervention. In doing so, I will highlight principles underlying the use of multimodal, augmented feedback (AF) in therapy, and explain how VR-based systems are the ideal vehicle.Development of motor controlI present a conceptual model for the use of AF in VR-based therapy. A critical task of motor learning and development is the child's ability to extract (implicit) knowledge of the dynamics of their own motor system (6, 7). More precisely, the child must learn the systematic relationship between their own motor output commands and the effects that these commands have on the physical system; this knowledge enables predictive control, an aspect of internal modelling (8). Mature reaching is now thought to be controlled by an integrated system of feedback and feedforward control. This system enables the performer to adjust rapidly in real time to changing environmental constraints, like a moving target, with some movement parameters (like trajectory) changing in as little as 70-80 ms. The ability to implement such changes is only viable to the extent that the nervous system can predict the future location of the moving limb using a forward (internal) model (9). This flexibility is one of the hallmarks of skilled motor behaviour, and develops gradually over childhood (10). That predictive control develops rapidly over childhood has been shown in a range of contexts including force adaptation (11), isometric force control (12), anticipatory postural adjustments (13), and rapid online control of reaching in response to visual perturbation (10). Critically, during middle childhood we see a transition in motor control, with greater reliance on visual feedback, accompanied by longer movement times but not enhanced accuracy (14,15). In later childhood we see a more mature integration of feedback and feedforward control, speeding target-directed responses and improving accuracy.One important feature of the mature motor system is the ability to adapt movement seamlessly and efficiently in real time while maintaining speed and accuracy (16). …