MUSCLE PATHOLOGY AND CLINICAL MEASURES OF DISABILITY IN CHILDREN WITHCEREBRAL-PALSY

We performed a histologic and morphometric study of spastic muscle fro m 10 children with diplegic cerebral palsy, comparing muscle structure with the gait parameters of energy expenditure index and dynamic elec tromyography. Variations in fiber area within and between fiber types were increased significantly in children with cerebral palsy. In each of the control subjects, the combined coefficient of variation for typ e-1 and type-2 fiber area was less than 25% and the average was 17%; i n the subjects with cerebral palsy, the combined coefficient of variat ion was more than 25% and the average was 36% (p less than or equal to 0.004). The average difference between the mean area of type-1 and ty pe-2 fibers was 26.7 +/- 18.9% for subjects with cerebral palsy and 4. 2 +/- 2.4% for control subjects (p less than or equal to 0.004). There was a 67% predominance of one fiber type in the subjects with cerebra l palsy compared with a 55% predominance in the control subjects (p le ss than or equal to 0.03). The difference between the total area of ty pe-1 and type-2 fibers was 57% in the subjects with cerebral palsy and 17% in the control subjects (p less than or equal to 0.002). There wa s a significant correlation between the combined coefficient of variat ion of fiber area and the energy expenditure index (r = 0.77, p less t han or equal to 0.03). The difference between the mean area of type-1 and type-2 fibers correlated with prolongation of electromyographic ac tivity (r = 0.69, p less than or equal to 0.05). No abnormalities in f iber ultrastructure were found in the subjects with cerebral palsy. Ch ildren with cerebral palsy had abnormal variation in the size of muscl e fibers and altered distribution of fiber types. The values for varia tion in fiber area correlated with the energy expenditure index and wi th prolongation of electromyographic activity during walking.