If a routine EEG does not give your doctor all the necessary information, another EEG test with special types electrodes may be recommended. 

  • Sphenoidal (sfee-NOY-dle) electrodes are sometimes used during video-EEG monitoring. They are very thin wires that are placed into your cheek muscle near your jaw. These electrodes can record electrical activity from deep parts of the temporal and frontal lobes.  
    • To place the spenoidal elecctrodes a technologist or doctor will swab your cheek just below your jaw hinge with rubbing alcohol, and may apply an anesthetic (medicine that numbs the area). Then a thin needle, carrying a thin wire, is inserted into the cheek. The needle is removed, and the wire is taped to your skin. You may have a little discomfort that goes away.
    • When the EEG monitoring is done, the thin electrode wire is removed. 
  • Nasopharyngeal (NAY-zo-fa-RIN-je-al) electrodes are sometimes used during EEG tests. They are plastic tubes with a wire inside that ends with a blunt metal tip. Nasopharyngeal electrodes can also record electrical activity deep in the brain. They are now being used less often, because they can be uncomfortable and regular electrodes often can provide the same information.
    • The electrodes are inserted into the nose until the metal tip reaches the upper back part of the nose (the nasopharynx). They are left in place for about 20 or 30 minutes during the EEG test. 
Authored By: 
Steven C. Schachter, MD
Joseph I. Sirven MD
Reviewed By: 
Joseph I. Sirven MD
Patty Obsorne Shafer RN, MN
Thursday, August 22, 2013