One of my favorite words is:
dysdiadochokinesia (dis”di-ad”o-ko-ki-ne´zh?)–an inability to perform rapid
alternating movements
It can be a sign of cerebellar dysfunction and is tested by having a person sit and place his palms on his knees, then flip his hands over repeatedly as quickly as possible. A dysdiadochokinetic person will not be able to synchronize this well or will perform it slowly with poor coordination. If you can do this well, you can proudly call yourself diadochokinetic.