This test is used to evaluate a patient's cerebellar function and position sense.

Performing the Test

  1. Patient stands with both arms extended, palms up and eyes closed
  2. 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
  3. 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


  1. Bickley, Lynn S. Bates' Guide to Physical Examination and History Taking. 8th ed. Philadelphia, PA: Lippincott Williams & Wilkins: 2003.