Book EMG Study (Four Limbs) Appointment Online at the best price in Kolkata/WB from Kolkata Electro Diagnostic Centre. Booking is on 24X7. EMG (Electromyography) All four Limbs is a non-invasive test that measures the electrical activity of muscles in response to a nerve stimulation provided to both legs and arms. This test is used to identify any nerve damage in any of the four limbs.