Reliability of the Diagnosis of Cerebral Palsy, 10/200

The diagnosis of cerebral palsy is a clinical diagnosis based upon family history, maternal obstetrical history and examination of the child. Depending on the above, the diagnosis of CP can sometimes be made shortly after birth, but is often postponed until the child is 18-24 months of age in order to provide an opportunity to evaluate the functional status of the child and the progression (and regression) of its symptoms.

In a recent study, Dr. Nigel Paneth and his collaborators studied the reliability of the classification of cerebral palsy in low-birth weight children in four countries.¹ They point out that not only is it important to have reliable criteria for the diagnosis of the individual child, but also to be able to compare data from one study with those from another. Are the studies discussing similar disorders?

The authors used data from studies in four countries: USA, Holland, Canada and Germany. Their review demonstrated that experienced pediatricians from different countries, when examining the childrens records:

• Usually achieve good to excellent agreement on distinguishing low-birth weight children with "disabling CP" from children who are not functionally limited but have physiological deficits (impairments) characteristic of CP,

• Distinguishing "non-disability CP" from normal function was less reliable.

All children with C.P. have physiological impairments such as muscle spasticity, poor muscle tone, poor muscle coordination, increased reflexes, and /or abnormal movements. These impairments may or may not restrict function such as walking, jumping, fine motor control, speech or self feeding; these functional restrictions are usually referred to as disabilities. Disabilities become handicaps depending upon the needs of the person (the same disability could be a handicap to a carpenter but not to a computer operator). All CP children have impairments; however, not all CP children have disabilities or handicaps.

The authors propose that in making the diagnosis of cerebral palsy it is important to consider and include information about both functional loss (disability) as well as the presence of impairments. This is particularly important in differentiating the child with non-disabling CP from the "clumsy" child, who for a variety of reasons has a delay in developing motor skills.

Comment:
In 1964, a prestigious pediatrician, Dr. Martin Bax, defined cerebral palsy as "a disorder of movement and posture due to a deficit or lesion of the immune brain."² Over time, the adjective "non-progressive" was added to characterize the deficit or lesion. This definition has served well as a basis for the diagnosis of cerebral palsy. However, the criteria for making the diagnosis: the signs, symptoms and consequences of the non-progressive deficit or lesions of the immature brain are less standardized. This is particularly important since we now recognize that there are several "types" of cerebral palsy due to different brain lesions. The present lack of standardization of criteria often makes it difficult to generalize findings from a specific study to the general population or to compare the results of several studies.

The UCP Research and Educational Foundation has established an international committee of experts to review Dr. Baxs 1964 definition of cerebral palsy in light of 2003 information and to explore the specific impairment and disability elements that need to be used in the diagnosis of CP. Dr. Bax is a member of that Committee and his expertise will add much to its deliberations.

¹ Paneth, N. et. al (2003) Reliability of classification of cerebral palsy in low-birth weight children four countries, Dev Med Child Neurology, 45:628-633
² Bax, M. (1964) Terminology and Classification of Cerebral Palsy. Dev Med Child Neurology, 6:295-297