Automatic stepping in the pontomedullary stage of central herniation.

Both spontaneous and reflexive movements may occur during the final stages of herniation and following brain death. We describe spontaneous, rhythmic (0.2 to 0.5 Hz), alternating flexion of the hip, knee, and ankle in two patients during the pontomedullary phase of central herniation following a massive hemispheric infarct. Automatic stepping is likely a spinal automatism generated within the spinal locomotion center and regulated by both ascending and descending brainstem tracts. Clinicians and family members of neurologically devastated patients should be aware that this and other movements can occur during the late stages of central herniation preceding and following brain death.