Which tests are used to assess dysdiadochokinesia?

• A. Rapid alternating finger movement
• B. Both A and B
• C. Rapid alternating pronation/supination
• D. None

Answer: (B)

Dysdiadochokinesia is a sign of cerebellar dysfunction, showing up as trouble performing rapid, alternating movements. To assess it, clinicians use tasks that require quick switching of motor plans: rapid alternating finger tapping and rapid alternating pronation/supination of the forearm. In dysdiadochokinesia, these movements become slow, irregular in rhythm, or reduced in amplitude. Since both maneuvers test the same ability to rapidly alternate dynamic hand and forearm movements, both are used to detect the sign. Therefore, the best choice is that both tests are used.