CBD is one among several different medical conditions with Parkinson-like symptoms and little results with standard antiparkinsonian medication (levodopa).
CBD is characterized by degenerations in the bark of the frontal and parietal lobes, in the basal ganglia, and atrophy of the pyramidal path.
The disease sometimes reveals itself through the strange so-called "Alien hand/arm syndrome" or "Dr. Strangelove syndrome".
Alien hand syndrome is characterized by the patient's hand/arm behaving for shorter or longer periods of time as if it had "life of its own" and cannot be willingly influenced.
The condition is very rare and has been reported, except in CBD, in connection with brain tumor development, after stroke, and after brain surgery. The most common cause of alien hand syndrome is excision of the corpus callosum, a procedure sometimes used in severe epilepsy.