The progression rate of PD is unique to each individual, with some becoming very disabled within a decade, while some only become disabled after two decades. — dpa
Parkinson's disease (PD) is caused by a loss of nerve cells in a part of the brain called the substantia nigra.
This leads to a reduction of dopamine, a chemical that acts as a messenger between the brain and nervous system to control and coordinate body movements, resulting in slow and abnormal movements.