Parkinson's Disease: Understanding and Managing the DiseaseAbout This Hardback A progressive nervous system disorder that affects movement is referred to as Parkinson's disease. A few of its symptoms are tremors, slowed movement, rigid muscles, impaired posture and balance, loss of automatic movements, speech and writing changes. Factors such as genes, environment, and presence of Lewy bodies containing alpha synuclein can play a role in its development. There is no specific test to diagnose Parkinson's