Parkinson’s disease is a condition that is created when nerve cells in the brain are damaged. These nerve cells control motor functions - IE someone’s movement. It’s a common condition in the United States, but it often requires that a formal medical diagnosis is given before treatment can begin. There’s no cure for this condition, but treatment is able to help those affected live a more normal life than if they didn’t have that treatment.
Parkinson’s often means that the person affected will have tremors and stiff muscles. The tremors and stiff muscles come from the fact that the nerves can’t function right, so the body doesn’t know what to do with itself. Medications can help the nerves work with what they’ve got.