Steven J. Korzeniewski
For the past thirty years, it has been possible to take a picture of the brain. Brain images can be made without putting any kind of camera into the body! The first machine to make these images used x-rays, and is called computed tomography (CT). Soon there was a second machine that used magnets and radio waves, called magnetic resonance imaging (MRI). These new technologies opened up a whole new world of understanding of the brain.
Cerebral palsy (CP) involves injury in the brain while it’s developing. Brain imaging can show us some of these injuries. Until recently, only a few children with cerebral palsy ever got their brain imaged. For example, premature babies at high risk for brain injuries were studied with CT or MRI scans.
Now for the first time, recent guidelines for diagnosing CP encourage neuro-imaging (brain scans) of all children with cerebral palsy of unknown cause (1). The guidelines were published in the journal Neurology and developed by an expert committee assembled by the American Academy of Neurology. The committee preferred using MRI instead of CT for images. Interestingly enough, not every neurologist agrees with these guidelines, as indicated by their letters to the journal after the guidelines were published. (2-3).
The main question for parents of a child with CP and adults with CP is: What is the benefit of an MRI? It is very unlikely that imaging information will change the medical management of person with CP. But brain images are starting to teach us about the causes and timing of CP.
So far, scientists are finding some interesting clues in brain image studies of CP in children. Usually we think of CP as an injury to the developing brain. But brain imaging studies show about 10%-15% of CP is caused early on by brain malformations. Malformations are a kind of faulty construction, and are thought to happen in the first half of pregnancy. We have learned that a particular form of brain damage (called periventricular leukomalacia or PVL), is not only found in premature infants but also in full term infants. We have also learned that some children with CP have damage to the basal ganglia, the same part of the brain that is injured in Parkinson's disease. And in about 10% of children, we don't see anything at all that looks abnormal in the images of their brain. Every so often, the images show that a child who has been diagnosed with CP actually has a different disorder.
Imaging the brain does not usually change the prognosis (our expectations) or outcome in CP. But the images can provide information about what might have happened to cause the CP. In children whose CP is due to a brain malformation, it may be important to talk to genetic counselors if the family is considering having more children. Hopefully, as we learn more about imaging we will better understand the causes of CP and how we might prevent and treat brain injury.
References
1. Ashwal S, Russman BS, Blasco PA, Miller G, Sandler A, Shevell M, et al. Practice Parameter: Diagnostic assessment of the child with cerebral palsy: Report of the Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society. Neurology 2004;62(6):851-863.
2. Mink JW, Jenkins ME. Practice Parameter: Diagnostic assessment of the child with cerebral palsy-correspondence. Neurology 2004.
3. Whelan MA. Practice Parameter: Diagnostic assessment of the child with cerebral palsy- correspondence. Neurology 2004;62.