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 reflects cerebellar difficulty in coordinating rapid, alternating movements. To evaluate it, you have the patient perform quick alternating actions with different parts of the arm. Rapid alternating finger movement tests how fast and regularly the fingers can tap or strike, which gauges distal coordination and timing. Rapid alternating pronation/supination tests how well the forearm can switch between turning the palm up and down, assessing coordination of the forearm and upper limb. Abnormal results typically show irregular rhythm, variable amplitude, or an inability to maintain the rapid pace. Since both tasks probe the same coordination system, both are used to assess dysdiadochokinesia.