<prompt> A pole vaulter had a fall during pole vaulting and had paralysis of the arm. Which of the following investigations gives the best recovery prognosis.ElectromyographyMuscle biopsyStrength duration curveCreatine phosphokinase levels  <response>: EMG electromyography is by far the most reliable and effective test to predict about nerve recovery. Diagnostic Tests for Nerve Injuries: EMG: Denervation fibrillation potentials. Appears at 2-3 weeks then spontaneous fibrillation. EMG is the earliest indicator of nerve recovery. Nerve conduction study: reduced in axonotmesis and neurotmesis but cannot differentiate between the 2. Normal nerve conduction velocity on day 10 goes toward neuropraxia. No conduction will indicate neurotmesis. Sweat Test: In autonomous area, presence of sweat rules out complete injury as sweat fibers are most resistant to compression. MRI: Value only in nerve root lesions e.g. Brachial plexus injuries. 