It occurs when cells are destroyed in certain parts of the brain stem. These cells should release dopamine, a chemical messenger in the brain. Loss of dopamine is the primary cause of Parkinson s Disease. It results in the damaging of muscles and nerves controlling movement and coordination. In turn, this results in the familiar hand tremor.
Tremors can also occur in the head, lips, tongue and feet.
Some people even experience internal tremors. Another symptom is known as Bradykinesia slowness of movement, decrease in automatic movement and difficulty of initiating movement. As of yet, there is no known cause of Parkinson s Disease. Researchers are currently trying to understand why there is a drop in dopamine in affected people. Current indications are that the causes are both genetic and environmental.