If "PD is a small thing" then your PhD is going to win a Nobel Prize!
Following on from BreezyRacers's idea, I find that the side to side tap test (counting the number of times you can type q followed by p in a fixed period using just one finger) gives good results. You can run this test online at:
http://www.parkinsonsmeasurement.org...eToSideTap.htm
John