The records of 794 cases of congenital cerebral palsy (CP) seen between 1955 and 1986 in the Cheyne Centre for Children with Cerebral Palsy, Chelsea, London were analyzed. Of 219 cases with dyskinetic or dystonic CP 57 had kernicterus and these were excluded from the analysis. Of the remaining 162 patients birth weight was below the expected mean in two-thirds. The frequency of abnormal births was similar in those born before 37 weeks (32%) and those born at term (30%). Abnormal birth was more common in dyskinetic CP (38%) than in dystonic CP (19%). In kernicterus cases the birth was abnormal in 3.6%. There was a clear positive relationship between abnormal birth and reported asphyxia. A severe outcome was as common in those with an abnormal birth, abnormal neonatal history, or respiratory problems as in those without these complications. The authors concluded that 1) there was no relationship between birth weight or abnormal birth or asphyxia and the ultimate clinical severity of the children and 2) abnormal birth and asphyxia are not direct causes of cerebral damage, but expressions of a preexisting condition resulting in susceptibility to the stress of birth. 
COMMENT. In contrast to the conclusions drawn by Dr. Foley, Hagberg B and Hagberg G in their invited commentary of this paper suggest that in the majority of cases of dyskinetic and dystonic CP negative birth events and birth asphyxia in particular, are the direct cause with several predisposing factors. They allude to the value of MRI studies in the timing of basal ganglia pathology in these cases (see also Ped Neur Briefs Jan 1992; 6:3-4).