If you are a neurologist or physiatrist with EMG training in residency, you can perform and bill for EMG.
Re: certification, the AANEM has an exam open to neurologists/physiatrists with 6 months of EMG training in residency and 1 year of independent experience.
The American Board of Psychiatry and Neurology has a clinical neurophysiology board exam open only to Neurologists who have completed a 1 year clinical neurophysiology fellowship.