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It has been know now for many years that the classical label “cerebral palsy” encompasses a heterogenous group of patients, many of whom have a vascular lesion acquired in the perinatal period as the origin of the neurological deficit. They had a stroke in the perinatal period, frequently involving the territory of the middle cerebral artery. This basic idea was very slow to be established in the field of neonatal neurology, because these lesions are not seen at all in routine ultrasound tests. Also, they are not so obvious in routine CT, the imaging methods available in this environment. High resolution CT is not generally available, and frequently, as well as MRI, warrants sedation. These are factors that may have slowed progress in this topic.
The infantile brain is not only small, but there is no separation between gray and white matter, which makes small lesions more difficult to observe. High resolution CT has only been generally available this century, and rarely in pediatric hospitals. Most physicians are reluctant to order MRIs, because they need sedation with a general anesthetic. Furthermore, MRI really becomes a useful test around 8 years of age, when white and gray matter are separated more fully.
For many parents it was easier to cope with a mysterious origin for their child’s deficit, perhaps because it allowed them to hope for a magic bullet or a miracle of some kind, like stem cell treatments. But it is now clear that MRI and high resolution CT, as well as careful EEG, are abnormal in 90% of the cases.
One group of patients has remained as mysterious as families and health professionals considered all the cerebral palsy group. The MRI is normal in a subset of children with ataxic-hypotonic and dyskinetic cerebral palsy. A study of 991 children from almost all of Canada showed that 103 (10%) had normal MRIs, while the remaining 90% had abnormalities. Those with normal MRIs were those without perinatal adversity and those with spastic diplegic, dyskinetic and ataxic-hypotonic syndromes. The hemiplegic children were those with the higher chance of abnormal MRI, 95%. MRIs were normal in 18% of those with spastic diplegia, 5% of those with spastic triplegia or quasdriplegia, 25% of those with ataxic-hypotonic and 20% of those with dyskinetic syndromes. Even in the ideal setting of the Canadian health system, many children had to be excluded from the study because they did not have a useful MRI.
Arielle Springer et al. Neurology 2019, 93:e88-e96
These facts need to be incorporated into clinical practice, as they modify substantially the outlook for these children’s future. Their mental and neurological prognosis changes in significant fashions. Difrerent theraputic strategies are warranted.
Dr Paulo Bittencourt