There are many personal victory stories out there. It is better to keep your hopes high than not.
One can not win a battle if he constantly thinks he is going to lose it.
Any article about Parkinson's disease I've read so far makes sure to mention in its introductory paragraph that 'there is no cure for the disease'. Medications only provide symptom relief. Whenever I come across such statements, I mumble 'no shit Sherlock'.
I refuse to accept these statements. My thinking is if my body stopped producing dopamine, I can somehow get it back into regular mode.
One of the books I truly enjoyed recently that justifies this way of thinking is The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science by Norman Doidge, M.D.
It talks about extraordinary triumphant stories. People overcoming such debilitating conditions and living regular lives.