Parkinson's disease is a common neurological disorders. Most patients at the age 60 easily suffer from Parkinson's disease. The disease was first described systematically by the British physician Dr. James Parkinson, hence the name. It develops gradually, sometimes starting with a barely noticeable tremor in just one hand. But while a tremor may be the most well-known sign of Parkinson's disease, the disorder also commonly causes stiffness or slowing of movement. In the early stages of Parkinson's disease, your face may show little or no expression or your arms may not swing when you walk. Your speech may become soft or slurred. Parkinson's disease symptoms worsen as your condition progresses over time. Consequences of Parkinson's Disease may include psychological disorder, intelligence going down, infection  , limbs contracture, deformity, ankylosis and injury.