EMG studies test the nerve supply to a muscle or group of muscles. Fine needles are inserted into the muscle being tested and the patient is asked to contract and relax that muscle. This type of testing is used in the diagnosis of nerve root compressions, plexopathies, myopathies and acute and chronic denervation following injury or disease. Typical symptoms requiring EMG studies are muscle-weakness and wasting, abnormal muscle twitches and abnormal movements. The American Association of Electrodiagnostic and Neuromuscular Medicine (AANEM) recommends that EMGs should be provided almost as a routine in conjunction with NCS. The AANEM is the preeminent professional body of Neurologists who sub-specialise in neurophysiology, and this is therefore the practice followed by CNS.