By Osman Shabir, M.Sc. Reviewed by Dr. Mary Cooke, Ph.D. Parkinson’s disease is a neurodegenerative disorder clinically characterized by resting tremor, bradykinesia (slow movements), dyskinesia (impairment of movement), dystonia (stiffness of muscles including facial muscles), a stooped posture, sexual and urinary dysfunction, drooling, and in some cases psychiatric symptoms including psychosis, dementia, and depression Pathologically,...