Use of the Gross Motor Function Classification System to Optimize Rehabilitation Management of Children with Cerebral Palsy

Keeping Current. ©Doreen Bartlett, 2006

Why is this topic important?

Cerebral palsy (CP) is a condition that results from damage to the brain early in life; however, it is rarely detected at or around the time of birth. Instead, differences with respect to development, in general, and motor development, in particular, become clear to parents through the first year or two of life. A diagnosis of CP can be made by a physician relatively early in the first year, if a child is “severely” involved. Diagnoses are often made between 18 months and two years for children who are “mildly” involved. Parents of children with CP want the best possible care to optimize the developmental outcomes of their children. Deciding what is best for each child is complicated by the fact that children with CP are extremely variable; no two children are alike. As discussed with respect to diagnosis, children with CP can be “mildly” involved such that they are slightly clumsy in their movements. At the other end of the spectrum, those that are “severely” involved typically have very little control over their posture and movement.

Rehabilitation service providers have used a variety of strategies or classification systems to categorize children with CP, in part to assist with making decisions about management. As described above, children can be classified as “mild”, “moderate”, or “severe” in terms of extent of involvement of the movement disorder. Children have been described with respect to the type of movement disorder they have. Some different types include spastic, athetoid, ataxic, hypotonic, and so-called mixed CP. Children can also be described based on the parts of the body that are affected. For example, a child with hemiplegia has involvement of one arm and one leg on the same side of the body. A child with diplegia has greater involvement in the legs than in the arms, and a child with quadriplegia has equal involvement of all four limbs, or greater involvement in the arms than in the legs. As straight-forward as these systems might seem, they are problematic in that they are not reliable (Gorter et al., 2004). Specifically, two people – be they parents, therapists or physicians – rarely agree on the classification of individual children using these strategies. Clearly this is a problem if the purpose of classifying is to help make decisions about care.

So, in brief, this topic is important because the Gross Motor Function Classification System (GMFCS) has been developed as a reliable method of classifying children with CP into categories that many people believe assists with management decisions. Importantly, the GMFCS is structured around a child's ability to function, rather than on severity, type, or distribution of motor involvement. As such, it has inherent meaning for parents, therapists, and physicians.

What is the Gross Motor Function Classification System (GMFCS)?

The GMFCS is a standardized system to classify gross motor function of children with CP aged 12 months to 12 years based on observation of a child's self-initiated movement and need for assistive technology and/or wheeled mobility (Palisano et al., 1997). Classification is made based on a child's usual performance – not best performance – at home, school, and in the community. There are five levels from level I, in which a child is able to walk and run, but has some difficulty with more advanced skills to level V, in which a child has very limited voluntary movement ability. In the original system, there are four age bands: under 2 years, 2 to < 4 years, 4 to < 6 years, and 6 to < 12 years. The system is readily available on the CanChild website.

How was it developed?

The GMFCS was developed in four phases (Palisano et al., 1997).

Phase 1: Drafting the System

• Sources of information included existing classification systems, research on development of children with CP, Gross Motor Function Measure data on 275 children (both total and item scores), and developmental records and videotapes of children with “mild”, “moderate”, and “severe” CP
  
• Through iterative discussion among the study team, a five-level system was proposed
  

The first draft was distributed to therapists in three of the Children's Treatment Centres in Southwestern Ontario.

• 14 physical therapists and 14 occupational therapists provided feedback
  
• Representatives from each centre (13 therapists and 2 developmental paediatricians) attended a ½ day consensus exercise using the Nominal Group Technique
  
• Participants voted on applicability, administration, number of levels, distinctions among levels, ages (agreement of more than 12/15 participants indicated consensus)
  
• System revised using feedback from this stage
  

Phase 3: Validity Testing Using the Delphi Method

• 21 physical therapists, occupational therapists, and developmental pediatricians from North America , Europe, and Australia were invited based on their content expertise; 20 participated
  
• first mailed the revised GMFCS, with an explanation of why the system was being developed, a description of the work to date, and a survey containing 36 statements to which participants responded on a 7-point scale (1 = strongly disagree to 7= strongly agree)
  
• consensus defined as ³ 16/20 rating statement as 5 or higher on the scale
  
• the second Delphi iteration comprised 28 statements addressing the distinction among levels, administration, and ages
  
• final revisions made to the system after the second iteration
  

Phase 4: Reliability Testing

• convenience sample from five Children's Treatment Centres
  
• therapists were asked to generate a list of children with CP under 12 years of age on active caseloads, known to at least two therapists for at least 3 months
  
• 37 children under 2 years old and 40 children older than 2 years
  
• each child's GMFCS level was classified independently by two therapists based on their knowledge of a child's motor abilities
  
• inter-rater reliability: Kappa = 0.55 for children under 2 years, and 0.75 for children 2 to 12 years
  
• stability over time (test-retest reliability): G = 0.79 (Wood & Rosenbaum, 2000)
  

This rigorous development gives confidence to users of the system with children with CP older than 2 years of age.

What training is required to use the GMFCS?

• Therapists and physicians can reliably use the GMFCS with no training, simply by reading the brochure (available on the CanChild website) (Palisano et al., 1997)
  
• Parents can reliably classify their children aged 6 to 12 years (Morris, Galuppi, & Rosenbaum, 2004) and 2 to 4 years (Dietrich, Abercombie, Fanning, & Bartlett , 2005) using modified forms
  
• Anecdotal experience with physical therapy students at The University of Western Ontario indicates that they can accurately classify videotaped children following a review of the brochure
  

How can the GMFCS be used to optimize management?

This reliable and valid classification system has the potential to optimize management of children with CP older than 2 years of age in many ways. The following points are just a few of them. Using the GMFCS:

Enhances Communication

• The system provides a simple and clear description of current motor ability for communication among all team members, including families.
  
• The system provides a basis from which students in the rehabilitation disciplines can better understand the range of variation in manifestation of children with CP.
  

Sharpens Focus on Function

• More useful than severity, type, and distribution of involvement in clinical management
  
• Aligned with the current focus on function in rehabilitation
  
• Consistent with the shift in focus from impairment-level variables to consideration of activity and participation (World Health Organization, 2001)
  

Assists with Realistic Goal Setting (combined with motor growth curves, Rosenbaum et al., 2002)

• Children in level I can expect to have the physical ability of a 5-year-old child, with difficulty with higher-level skills
  
• Children in level II can expect to have some limitations in walking outdoors as they mature
  
• Children in level III can expect to have the ability to walk indoors on a level surface with a mobility device, and to use a wheelchair for community mobility
  
• Children in level IV can expect reliance on wheeled mobility in home, school, and community settings, although they might be able to walk with a walker indoors
  
• Children in level V can expect limited self-mobility, even with assistive technology
  

Assists with Intervention Planning (see Morris, 2002; Morris & Bartlett, 2004)

This aspect is open for much exploration and refinement. Examples include:

• Achievement of gross motor function for children in levels I, II, and III
  
• Consideration of gait aides for children in level III
  
• Prescription of wheelchairs for children in levels III, IV, and V
  
• Variations in spasticity management for children in levels I, II, and III vs IV and V
  
• Variations in orthopedic surgeries by GMFCS level
  
• Variations in orthotic management by GMFCS level
  
• Identifying variations in secondary impairments such as muscle hypoextensibility, contractures, muscle weakness and poor endurance and instituting prevention strategies
  

Facilitates Evidence-Based Practice

• Sample characteristics can be clearly communicated using GMFCS levels and readers can quickly see to whom the research results are applicable
  
• “Severity of involvement” can be explored using the GMFCS (e.g. effect modification, subgroup analysis, effect of comorbidities) (see Kennes et al., 2002)
  

Assists with Caseload Distribution

• Should therapists “specialize” in GMFCS level?
  
• Should therapists be generalists, with skills to work with children at all GMFCS levels?
  

Facilitates Resource Allocation

• GMFCS can be used to determine resources needed to serve children at different levels
  
• Can assist with need for volunteer support in recreation programs
  
• Can assist with need for educational assistance in schools
  

Contributes to Continuing Competency

• Therapists can demonstrate their continuing competency by contributing to knowledge about variation in intervention protocols for children at different GMFCS levels.
  

Where do we go from here?

This has been a brief introduction of the clinical utility of the GMFCS. Future work includes: refinement of descriptions under 2 years of age in an effort to enhance reliability, preparation of an adolescent age band, and obtaining consensus on appropriate rehabilitation interventions for children at different GMFCS levels.

Summary

The GMFCS is reliable, valid and easy to use in a clinical or community setting. Use of the GMFCS enhances communication, sharpens a focus on function, and assists with realistic goal setting and intervention planning. It also facilitates evidence-based practice and assists with caseload distribution, resource allocation, and continuing competency. Optimization of rehabilitation management of children with cerebral palsy will be realized by continuing to integrate the GMFCS into all aspects of practice.

Update written by:

Doreen Bartlett, PhD, PT, Associate Member, CanChild , Associate Professor, School of Physical Therapy , Faculty of Health Science, The University of Western Ontario , London , ON .

Want to know more?

Contact: Doreen Bartlett, PhD, PT, djbartle@uwo.ca