Pronator drift test is done for lesion of

When the patient extends both arms upright in the supinated position and holds them at shoulder height for at least 10 seconds (Patients should be asked to keep eyes open initially and later test again with eyes closed):Normal response:Palm will remain flat, elbows straight and the limbs horizontal ORSymmetrical detion from this position (i.e. on both the sides - dominant hand may pronate slightly more than the non-dominant hand)Positive pronator drift: Components of pronator drift as mentioned above is seen in the weaker side (asymmetric response) which indicates a lesion in contralateralPseduodrift:Slight pronation, without downward drift of the dominant armNot necessarily abnormal - must be interpreted in clinical context InterpretationPositive with eyes open: Motor deficitPositive with eyes closed: Sensory deficit (Posterior column)Outward and upward drift: Cerebellar drift"Updrift" (involved arm rising overhead without patient awareness): Parietal lobe lesions (loss of position sense)Drift without pronation: Functional upper limb paresis (Conversion disorder)Ref: Ganong&;s review of medical physiology, 23rd edition, Page no:242