It's funny to me that the above study said this:

"For the complex movement test, patients were instructed to perform 10 flexion-extension movements in the elbow joint while simultaneously squeezing a rubber bulb twice during each flexion-extension cycle. "

I tried to show old neuros how I could not extend my arm and bend it towards me, reaching my hand toward my face, while my hand was squeezed in a fist. They didn't care. I get a strange ratcheting effect combined with a strong action tremor.

Anyone else have a problem doing that, or the test in the article?

I also can't trace a picture with my right hand while the left one is merely squeezing something. I slow down the moment my left hand starts to squeeze.