Stereotypical lower-limb movements of a child with Arnold-Chiari malformation

A one-year-old boy with Arnold-Chiari malformation associated with hydrocephalus and meningocele presented with characteristic stereotypical alternating movements of the lower limbs. The movements were not considered to be epileptic, but to derive from a locomotion pattern-generator in the spinal cord. Persistence of the stereotypical movements implied some deficit of the upper-motor pathways, although the lesion responsible could not be determined.