Tremors are a symptom most often associated with Parkinson’s disease, but not everyone with the disease will have them. More importantly, not everyone with tremors has Parkinson's disease. Other symptoms of Parkinson's disease include stiff muscles, slow movement and difficulty with balance or walking. They are caused by a problem with nerve cells in the brain that make a chemical called dopamine. This chemical helps you control and move your muscles smoothly. People usually start to have symptoms between the ages of 50 and 60, but in some people, symptoms start earlier. The Mercy team includes doctors who specialize in neurological or brain-related problems, such as Parkinson's disease and other related symptoms.