How to report EEG during Non Intracranial and Intracranial Surgery?
During non-intracranial surgery i.e carotid endarterectomy or 
stenting, cardiac surgery, CPT 95955[Electroencephalogram (EEG) during nonintracranial surgery] should be used. This code cannot be billed in conjunction with CPT 95920.
Codes 95812 and 95813 are also used as EEG codes. CPT 95812 [Electroencephalogram (EEG) extended monitoring;41-60 min) and CPT 95813 [greater than 1 hour] can be used for intracranial surgery ( i.e. aneurysm clipping or coiling). These codes should only be billed as one unit regardless of the length of the surgery. Since these codes are not hourly codes, they should not be billed in multiple units like CPT 95920 nor can be billed in conjunction with CPT 95920.