Systems science: An answer to dealing with the complexity of cerebral palsy?

Abstract

Cerebral palsy (CP) is characterized by complexity, from epidemiology to pathophysiology to intervention, as many variables ultimately determine an individual's optimal activity and participation. The International Classification of Functioning, Disability and Health (ICF) framework highlights the dynamic interconnectedness of the various domains of functioning: body function/structure, activity, and participation including the important contextual factors, notably the family, using positive language.1 The ICF can potentially be expanded to visualize these dynamic interactions to enable a more holistic exploration of the complexity of CP: systems science provides a way to do this. Systems thinking assists in observing and communicating how various factors are interconnected within a complex system. It is increasingly applied to biomedical research and healthcare2 and has recently been used to model the musculoskeletal system in CP.3 The advantage of systems science is that it facilitates understanding of the interactions of all the factors within the system and between the various systems in both a linear and a non-linear way, and allows exploration and identification of patterns of complexity to arrive at feasible solutions.3 This seems to offer a relevant approach to research and intervention planning in CP. A linear, cause-and-effect approach is offered in many interventions for individuals with CP. For example, to improve walking speed, a period of partial bodyweight support treadmill training may be prescribed, but other factors may require modification to achieve that goal, such as balance in single-leg stance or proprioception. This linear approach contrasts with a non-linear approach which considers the many factors that may impact on a single intervention goal, though in reality both approaches are complementary. Gough and Shortland use causal loop diagrams to describe the interactive pathways leading to musculoskeletal function.3 They use this figure to describe surgical intervention effectiveness in providing lower-limb alignment to improve walking. Diagrams indicate clearly that the intervention may not directly affect the goal of improving walking ability (linear effect). Other factors such as confidence in walking, impaired balance, the physical environment, or altered proprioception and muscle strength that indirectly result from the lower-limb alignment (non-linear factors) may also impact on the goal of improved walking. This view of the musculoskeletal system can be extrapolated to provide a holistic view of the person and family within the context of all ICF domains with a combination of linear and non-linear systems. Causal loops can be constructed to show the links between individual persons and family systems, environmental systems, body function/structure systems, activity and participation systems, financial and service delivery systems, and available intervention systems including those that foster health and well-being. Non-linear thinking also relies on experience, intuition, and knowledge of the various systems and their interconnectedness, and therefore requires expert clinical reasoning skills (problem solving) and communication between all the health professionals involved, with the child and family at the heart of the process.4 Systems science encourages a thinking approach consistent with the conclusion of Wade: ‘The essential feature characterizing rehabilitation is its way of thinking about the patient's problems [challenges] and how to solve them.’5 This can equally apply to habilitation for individuals with CP. If we get the thinking right, then the choice of interventions will be apparent. Development of such holistic models for CP will involve participation of children and their families, multidisciplinary teams of health professionals, data analysts, and other systems thinkers to model the interactions between the many variables. Ultimately, different models will be required based on age and functional levels. Systems science may additionally open a door to quantification of the relationships within and between systems, the overarching goal being to optimize the lived experience of any individual with CP. Not required.