Bikes used to diagnoses type of Parkinsonism?

Riding bicycles is near and dear to my heart so I was immediately interested in this article about some research being done with Parkinsonian patients who ride bicycle.  The researchers are looking at Parkinsonian patients' without a definitive diagnosis and their ability to ride a bicycle (or not) as a helpful diagnostic factor to determine if patients have iPD or PD+, or other type of PD.

Link:  Bikes to help in diagnosing PD

Jason