Seizure-related automatic locomotion triggered by intracerebral electrical stimulation.

We describe the case of an eight-year-old boy, who underwent a video-stereo EEG (SEEG) investigation for the presurgical assessment of drug-resistant epilepsy, related to a right fronto-lateral cortical dysplasia and who became seizure-free after epilepsy surgery. The unexpected finding of the investigations was that intracerebral, high frequency (50 Hz) electrical stimulation (HFS) triggered the emergence of automatic and involuntary forward-backward locomotion during a focal seizure while the boy was standing. This clinical manifestation was different from the chaotic motor activity described during epileptic wanderings. The stimulation of the same fronto-lateral region, while the patient was lying, produced only the subjective sensation that the legs were moving, although there was no physical manifestation of this. Human locomotion is an innate motor behavior that is normally due to the activation of the spinal network for locomotion (central pattern generator). The emergence of different stereotyped motor behaviors during focal epileptic seizures or sleep disorders has recently been interpreted as a release of subcortical central pattern generators (Tassinari et al. 2005). In view of this, we hypothesize that the involuntary and robot-like locomotion of our patient could be the ictal expression of the release of subcortical locomotor CPGs.