Dysdiadochokinesia is best assessed with which test?

• A. Finger-to-nose test
• B. Romberg test
• C. Pronator drift test
• D. Rapid alternating movements test

Answer: (D)

Dysdiadochokinesia involves a cerebellar coordination problem where rapid, alternating movements become slow, irregular, or clumsy. The best way to assess this is by the rapid alternating movements test. Have the patient quickly alternate movements such as pronation and supination of the hands, or quick tapping of the thighs. In cerebellar dysfunction, these movements lose smooth rhythm and precision, revealing the deficit.

The finger-to-nose test checks coordination and accuracy (dysmetria) during a single movement toward a target, not the rapid alternation aspect. The Romberg test focuses on proprioception and vestibular function, not cerebellar rapid alternating movements. The pronator drift test screens for upper motor neuron weakness, not diadochokinesia.