dysdiadochokinesia

dysdiadochokinesia /dis′dī·ədō′kōkinē′zhə/ [Gk, dys + diadochos, working in turn, kinesis, movement] , an inability to perform rapidly alternating movements, such as rhythmically tapping the fingers on the knee. The cause is a cerebellar lesion and is related to dysmetria, which also involves inappropriate timing of muscle activity.