This test is used to evaluate a patient's cerebellar function and position sense.
Performing the Test
Patient stands with both arms extended, palms up and eyes closed
Observe their ability to keep their arms in the same plane
Pronator drift: downward drift of one arm with accompanying pronation and flexion of fingers and elbow; suggests contralateral corticospinal lesion
Loss of position sense: sideward or upward drift
Tap arms down briskly and watch the return to horizontal position
Loss of position sense: unrecognized displacement, poorly corrects when asked
Cerebellar incoordination: arm returns to original position when asked but with overshooting
Bickley, Lynn S. Bates' Guide to Physical Examination and History Taking. 8th ed. Philadelphia, PA: Lippincott Williams & Wilkins: 2003.