Dynamic Systems Theory: A Framework for Exploring Readiness to Change in Children with Cerebral Palsy

Keeping Current. © Karen Sauve and Doreen Bartlett, 2010

What is Dynamic Systems Theory?

Dynamic Systems Theory (DST) is a theory of motor development that can be applied to the management of children with Cerebral Palsy (CP; Darrah & Bartlett, 1995). It is especially useful in the understanding of how movement develops and changes (Smith & Thelen, 1993), and can provide insight into a child's readiness to acquire new motor abilities. This theory proposes that movement is produced from the interaction of multiple sub-systems within the person, task and environment (Thelen, 1989). All of the sub-systems spontaneously self-organize, or come together and interact in a specific way, to produce the most efficient movement solution for each specific task (Thelen, 1989). DST also proposes that no sub-system is most important in this process (Thelen, Kelso, & Fogel, 1987). Thus, clinicians need to consider and evaluate all aspects of the task, person, and environment when trying to help a child learn a new motor ability.

According to DST, development is a non-linear process (Thelen, 1989). This suggests that movement is not developed in a continuous manner, at a steady rate. Rather, a small, but critical change in one sub-system can cause the whole system to shift, resulting in a new motor behaviour (Smith & Thelen, 1993). This phase shift, or transition period is critical to DST's application to motor development.

DST can be used as a framework to guide intervention with many children who have motor challenges. In this review, DST will be considered as a framework to guide intervention for children with CP.

Why is DST important for children with CP?

CP is a condition that affects movement and posture, with possible limitations in activity and participation (Rosenbaum, Paneth, Leviton, Goldstein, & Bax, 2007). Children with CP often receive rehabilitation services from the time they are diagnosed, in the first couple years of life, until adulthood. These services for children with CP and their families typically include various forms of intervention, consultation, education, and support. The goals of pediatric rehabilitation are ultimately to promote the child's safe participation in his or her home, school, and community environments, while learning functional activities (Russell, 2005). Physiotherapy intervention commonly focuses on the development and achievement of motor abilities, or the child's "capacity to perform a movement" (Bartlett & Palisano, 2000, p. 599). Functional mobility is thought to be an important outcome of physiotherapy intervention for children with CP (Tieman, Palisano, Gracely, & Rosenbaum, 2007). Physiotherapy services also aim to promote long-term health and prevent further impairments as the child grows and changes (Bartlett & Palisano, 2000).

Reviews of physiotherapy practices reveal that children with CP commonly receive one session of physiotherapy per week for years, regardless of how their motor abilities are changing or their readiness to learn new tasks (Kaminker, Chairello, O'Neil, & Dichter, 2004). Several studies have examined changing this approach to physiotherapy, and instead offering intensive bursts of therapy for a set period of time, followed by a rest period. 

This type of therapy schedule has been found to have a number of benefits, including:

  • Improved motor outcomes during intensive bursts (Bower & McLellan, 1992; Schreiber, 2004; Trahan & Malouin, 2002)
  • Maintenance of motor abilities or even continued improvements in motor outcomes during rest breaks as the child can practice the new abilities in various settings (Bower & McLellan, 1992; Schreiber, 2004; Trahan & Malouin, 2002)
  • Improved communication between therapists and families (Trahan & Malouin, 2002)
  • Promotion of family-centred care (Trahan & Malouin, 2002)
  • Improved cost-effectiveness (Schreiber, 2004; Trahan & Malouin, 2002).

Although this approach has been found to offer many benefits, it remains unclear as to when to provide bursts of intensive therapy. How do clinicians know when a child is most ready to benefit from intensive therapy? If we can determine this readiness to change in children with CP clinically, we can potentially optimize motor outcomes and efficiency of therapy services.

Transition periods can be identified by a time of increased variability (Thelen, 1989), during which new movements are most likely to emerge (Darrah & Bartlett, 1995). This is critical for therapy services. Law and colleagues (1998) related the concept of transition periods to that of developmental readiness for change in motor abilities, suggesting that transition periods can act as an indicator of readiness. DST suggests that intervention will be most beneficial during these transition times, as it is the time when we are most likely to impact change, and new motor abilities develop. In short, DST can be used as an important framework for children with CP as it proposes that there will be increased variability during transition periods (Thelen, 1989), which means that children will be experimenting with movement options, potentially demonstrating variability in their motor performance.

What do we know about variability?

Researchers have suggested that a certain amount of variability is important for a healthy system and allows for change in motor behaviour (Stergiou, Harbourne & Cavanaugh, 2006). These same researchers proposed that there is an "optimal" amount of variability that allows us to be flexible in our movement options and adapt to changes in tasks and environments. We also know that too much variability (instability) and too little variability (rigidity) both result in unhealthy systems that cannot adapt to change (Stergiou et al., 2006).

Evidence also shows us that there is variability in development. Darrah and colleagues (1998) found that typical infants demonstrate variable patterns in motor development as measured by the Alberta Infant Motor Scale. These researchers showed that there are "peaks and valleys" in typical development. This means that there are periods in typical motor development when an infant learns no new abilities, followed by times when they suddenly develop several new motor abilities (Darrah et al., 1998). If children with CP demonstrate these same trends in motor development, then this suggests that therapy should be provided before the child experiences a peak. Therapists can use these "peaks" to help children learn new motor abilities, and then set up opportunities for the child to practice those new abilities during the "valleys" in motor development.

What don't we know?

We do not know how to identify transition states clinically yet. There remain several unanswered questions about this. Are there certain clinical signs we can watch for to know when a child is about to learn new tasks, or ready to develop new abilities? We do not know how to measure variability clinically. What is considered optimal variability? How much variability is needed to change a motor behaviour? We do not fully understand what contributes to a child's readiness to change or what factors might influence it. Are there certain qualities or characteristics in a child that might influence their readiness to learn new motor abilities, such as motivation? Are there factors in a child's environment that can be modified, to make a child more ready to learn new motor tasks?

  • A few ideas are presented in the literature about the factors that might influence readiness to change:
  • Behavioural factors (Bower, McLellan, Arney, & Campbell, 1996)
  • Personality factors such as motivation (Schreiber, 2004; Smith & Thelen, 1993)
  • Having adequate endurance and tolerance for activity (Schreiber, 2004)
  • Being able to maintain a position longer and with less support (Schreiber, 2004)
  • Starting to initiate weight-shifting independently (Schreiber, 2004)

In addition, a study by Law et al. (1998) suggested that parents were able to identify signs that their child was "ready" to start walking on their own, such as cruising more, or letting go of the parent's hand more often when walking.

How does this apply to clinical practice?

If clinicians, parents, and researchers can determine when a child is about to experience a transition period, then according to DST, they are most ready to acquire new motor tasks. Therapy can then be provided in an intensive burst, promoting new motor abilities when the child is most ready to acquire them. This can then be followed by a rest period, during which the child can be given chances to practice the new motor abilities in a variety of settings. In theory, this would be the optimal therapy schedule to promote best motor outcomes for children with CP.

Where do we go from here?

Further work is needed to understand how to identify a transition period clinically. Therapists need more clinical tools to measure variability, and guidelines around what amount of variability is optimal, and what indicates readiness to change. We also need more research to explore which factors are associated with a child's readiness to change. If we can determine these factors, we can then determine if clinical modifications of any of those factors improves motor outcomes.


Rehabilitation practitioners want to help children with CP participate in life, at home, in school, and in the community. One focus of therapy is the promotion of motor abilities. DST provides a framework to help identify when a child is most ready to learn new motor abilities. DST also suggests that motor development is non-linear, and that there are "peaks and valleys". By determining clinically when a child is most ready for motor change, we can optimize therapy for children with CP. Much is known about the benefits of intensive therapy, followed by rest breaks; however, more questions need to be answered to determine when it is best to offer those bursts of intensive therapy. Through the exploration of factors associated with readiness to change, therapists can gain further knowledge about how to offer the very best to children with CP, to promote safe and full participation.


Funding for Karen Sauve's Masters thesis was provided by Canadian Institutes of Health Research and the University of British Columbia.

Want to know more? Please contact: Karen Sauve at ksauve@cw.bc.ca

  • Click here for list of references

    Bartlett, D., & Palisano, R. J. (2000). A multivariate model of determinants of motor change for children with cerebral palsy. Physical Therapy, 80(6), 598-614.

    Bower, E., & McLellan, D. L. (1992). Effect of increased exposure to physiotherapy on skill acquisition of children with cerebral palsy. Developmental Medicine & Child Neurology, 34, 25-39.

    Bower, E., McLellan, D. L., Arney, J., & Campbell, M. J. (1996). A randomized controlled trial of different intensities of physiotherapy and different goal-setting procedures in 44 children with cerebral palsy. Developmental Medicine & Child Neurology, 38, 226-237.

    Darrah, J., & Bartlett, D. (1995). Dynamic systems theory and management of children with cerebral palsy: Unresolved issues. Infants and Young Children, 8(1), 52-59.

    Darrah, J., Redfern, L., Maguire, T. O., Beualne, A. P., & Watt, J. (1998). Intra-individual stability of rate of gross motor development in full-term infants. Early Human Development, 52, 169-179.

    Kaminker, M. K., Chairello, L. A., O’Neil, M. E., & Dichter, C. G. (2004). Decision making for physical therapy service delivery in schools: A nationwide survey of pediatric physical therapists. Physical Therapy, 84, 919-933.

    Law, M., Darrah, J., Pollock, N., King, G., Rosenbaum, P., Russell, D., Palisano, R., Harris, S., Armstrong, R., & Watt, J. (1998). Family-centred functional therapy for children with cerebral palsy: An emerging practice model. Physical & Occupational Therapy in Pediatrics, 18(1), 83-102.

    Rosenbaum, P. L., Paneth, N., Leviton, A., Goldstein, M., & Bax, M. (2007). A report: The definition and classification of cerebral palsy April 2006. Developmental Medicine & Child Neurology, 49(s109), 8-14.

    Russell, D. J. (2005). The Gross Motor Function Measure: Impact on childhood disability research and clinical decision-making. Enchede, Netherlands: Print Partners Ipskamp.

    Schreiber, J. (2004). Increased intensity of physical therapy for a child with gross motor developmental delay: A case report. Physical & Occupational Therapy in Pediatrics, 24(4), 63-78.

    Smith, L. B., & Thelen, E. (1993). A dynamic systems approach to development: Applications. Cambridge, MA: The MIT Press / Bradford Books.

    Stergiou, N., Harbourne R. T., & Cavanaugh, J. T. (2006). Optimal movement variability: A new theoretical perspective for neurologic physical therapy. Journal of Neurologic Physical Therapy, 30(3), 120-129.

    Thelen, E. (1989). The (re)discovery of motor development: Learning new things from an old field. Developmental Psychology, 25(6), 946-949.

    Thelen, E., Kelso, J. A. S., & Fogel, A. (1987). Self-organizing systems and infant motor development. Developmental Review, 7, 39-65.

    Tieman, B., Palisano, R. J., Gracely, E. J., & Rosenbaum, P. L. (2007). Variability in mobility of children with cerebral palsy. Pediatric Physical Therapy, 19, 180-187.

    Trahan, J., & Malouin, F. (2002). Intermittent intensive physiotherapy in children with cerebral palsy: A pilot study. Developmental Medicine & Child Neurology, 44, 233-239.