Bilateral ballismus in children.

Bilateral ballismus is extremely rare. We found 23 reported cases, and only 2 of these were in children. In older patients the movement disorder is usually due to cerebrovascular disease, but in younger patients a variety of aetiopathological causes may be found. There are few data regarding medical treatment. There have been no previous reports on stereotactic operations. We report on two severely disabled children who underwent stereotactic surgery. A 9-year-old boy suffering from bilateral ballismus after meningoencephalitis was operated on bilaterally (two operations 1 year apart). Another 9-year-old boy, who was suffering from progressive, presumably degenerative, basal ganglia disease, was operated on unilaterally. The nosological and conceptual controversies differentiating bilateral ballismus as a phenomenological entity are reviewed. The therapeutic options, indications, and special problems of stereotactic surgery in these rare cases are discussed.