Parkinson's disease is a progressive neurological condition. This means that it causes problems in the brain and gets worse over time. It is caused by a loss of nerve cells in part of the brain called the substantia nigra. This leads to a reduction in a chemical called dopamine in the brain.
There are many potential signs and symptoms of Parkinson’s and each person can experience them differently. The main symptoms of Parkinson's disease are involuntary shaking of particular parts of the body (tremor), slow movement, stiff and inflexible muscles. There are also psychological symptoms that a person may experience (such as depression and/or anxiety), balance problems, loss of sense of smell, sleep problems and memory problems.