inges (brain tumors), spinal cord tumors, tumors of the peripheral nerves (neuroma) * movement disorders such as Parkinson's disease, Huntington's disease, hemiballismus, tic disorder, and Gilles de la Tourette syndrome * demyelinating diseases of the central nervous system, such as multiple sclerosis, and of the peripheral nervous system, such as Guillain-Barr??? syndrome and chronic inflammatory