Parkinson's disease occurs when certain nerve cells (neurons) in a part of the brain called the substantia nigra die or become impaired. Normally, these cells produce a vital chemical known as dopamine. Dopamine allows smooth, coordinated function of the body's muscles and movement. When approximately 80 percent of the dopamine-producing cells are damaged, the symptoms of Parkinson's disease appear. It usually develops gradually, often starting with a barely noticeable tremor in just one hand.
The key signs of Parkinson’s disease are:
- Tremor (shaking)
- Slowness of movement
- Rigidity (stiffness)
- Difficulty with balance
At present, there is no cure for Parkinson’s disease, but a variety of medications provide dramatic relief from the symptoms. Other treatment options include lifestyle modifications, physical and speech therapy and surgery, such as deep brain stimulation or thalamotomy.