As with E&M and any procedure, a physician can charge an E&M with an EMG if the documentation supports E&M services above and beyond that which is normally a necessary part of the procedure. The CMS NCCI Manual does not address this directly in the context of an EMG procedure, but in the chapter on radiology procedures, you can find the following guideline; in my opinion the concept would apply equally to an E&M performed with an EMG:
"When physician interaction with a patient is necessary to accomplish a radiographic procedure, typically occurring in invasive or interventional radiology, the interaction generally involves limited pertinent historical inquiry about reasons for the examination, the presence of allergies, acquisition of informed consent, discussion of follow-up, and the review of the medical record. In this setting, a separate evaluation and management service is not reported. As a rule, if the medical decision making that evolves from the procurement of the information from the patient is limited to whether or not the procedure should be performed, whether comorbidity may impact the procedure, or involves discussion and education with the patient, an evaluation/management code is not reported separately. If a significant, separately identifiable service is rendered, involving taking a history, performing an exam, and making medical decisions distinct from the procedure, the appropriate evaluation and management service may be reported."