Definition and classification of GP: medical-legal and service implications

Abstract

The implications of a revised definition and classification system for cerebral palsy (CP) obviously extend well beyond clinical care and research. My commentary will focus on two disparate areas of concern: specific topics related to medicallegal issues and brief comments concerning potential effects on service provision. Important issues from the medical-legal perspective include the definition itself and issues relevant to causation in the classification section, specifically neuroimaging and etiological understanding. For nearly 150 years, causation theories for CP have been linked to intraparturn events. Despite decades of epidemiological research to the contrary, the causal connection in the public mind between CP: ‘brain damage’, and obstetrical misadventure continues to encourage litigation with highly significant professional and economic implications for health care and society.24 Consensus publications identify spastic quadriplegic and/or dyskinetic CP as an essential criterion for consideration of intraparturn hypoxic-ischemic injury as the cause of later disab i l i t~ .~ .~ The revised definition does not affect this perspective. Despite initial concerns that the new term ‘disturbances’ might broaden the concept of CP to include children with developmental coordination or dyspraxic conditions, the full document clearly specifies patterns of motor disability as spastic, dyskinetic, or ataxic and thereby preserves the traditional designations and relationship between CP pattern and potential etiologies. In the Classification section, the brief comments on neuroimaging are noteworthy. The committee correctly notes that the classification of CP by imaging criteria is still in development but forcefully endorses the previous recommendation of the American Academy of Neurology on the importance of such testing whenever feasible.’ This statement cannot be over-emphasized in the medical-legal context. Currently, allegations of ‘brain injury’ do not require the demonstration of such injury or in fact, any anatomic abnormality. This unfortunately permits CP and other impairments to be presented as evidence of ‘brain injury’ a seriously uninformed perspective. Such a view fails to acknowledge the value of MRI in identifying injury patterns, and even more importantly, overlooks the significance of brain malformations and genetic/ metabolic disorders in producing the CP phenotype. The critical issues of causation and timing are also addressed directly in the revision document. The annotation on the definition states that ‘a full understanding of causal pathways and mechanisms leading to CP remains elusive’ and then amplifies this perspective in the section on Cause and Timing. In discussing causation, the current understanding of the importance of multiple interacting risk factors, the lack of a specific etiological relationship between adverse circumstances and CE and the absence of a known cause in many cases are stated explicitly. This section concludes with the important caveat that, ‘clinicians should avoid making the assumption that adverse events in the prenatal, perinatal, and postnatal life of a child with CP [are] sufficient to permit an etiological classification that implies a causal role for these events in the genesis of CP’. In summary, the committee’s statements provide an authoritative reminder about what is actually known and not known about causation and will be useful to those who are asked to render legal opinions in cases involving CP. With respect to service provision, the diagnosis of CP is generally understood to indicate the presence of significant motor impairments which require educational and community-based services. The new definition maintains the central position of motor impairment but expands the focus considerably by emphasizing the importance of associated neurodevelopmental and musculoskeletal complications. The revision also places these impairments in a functional context by adopting the World Health Organization concept of ‘activity limitation’ as a defining criterion.8 These are significant modifications of the traditional focus on motor impairments alone and should have a major impact on services for those with CI! Care providers, educational institutions, advocacy groups, policy makers and others will need to adapt current approaches by placing increased emphasis on associated impairments as they consider the multiplicity of challenges facing individuals with CP. Such an expansion of the core concept of CP is likely to challenge current systems of care. Carried to their logical extent these changes in definition present rather daunting challenges and are likely to require significant modifications in the application of economic and manpower resources. Despite these practical difficulties, the revised definition presents a welcome opportunity to broaden the focus on CP. I believe that the net effect will be to stimulate progress on multiple fronts including neurobiological understanding, management approaches, and societal participation.