Authors :
Presenting Author: Dan Dimitriu, MD – Atrium Health
Lauren Feldman, DO – Atrium Health
Yuan Fan, MD, PhD – Atrium Health
Rani Singh, MD – Atrium Health
Katherine Van Poppel, MD – Atrium Health
Beverly Williams, REEGT – Atrium Health
Dmytro Bielushchenko, REEGT – Atrium Health
Ashley Hastings, REEGT – Atrium Health
John Ebersole, MD – Atrium Health
Rajdeep Singh, MD – Atrium Health
Rationale:
Functional localization by scalp EEG of the epileptogenic focus is a key element of the presurgical evaluation. However, most epilepsy centers in the U.S. rely on visual inspection of EEG traces, usually displayed in a 10-20 longitudinal bipolar montage that was filtered to a 1-70hz bandpass, to provide this information at presurgical conferences for stereo-EEG (SEEG) planning or surgery. Additional benefits of digital recording and analysis, including EEG voltage topography and source modeling (ESM), are seldom used routinely.
Methods:
Long-term scalp EEG monitoring was performed on 25 consecutive surgical candidates using either 23 or 25 electrodes, including sub-temporal. We compared the spike and seizure localization recorded in their LTM reports to subsequent reports of EEG dipole source modeling of the same data using Curry 9 software. The goal was to demonstrate the degree of improved localization provided by ESM.
Results:
Descriptions of localization in standard LTM reports were often vague. Terms were often regional, such as “fronto-temporal,” for 50% of spikes and 56% of seizures. Localization by the names of phase reversing channels was found for 12% of spikes and 7% of seizures. At best localization was specifically lobar for 27% of spikes and 26% of seizures. To the contrary, ESM reporting was uniformly sublobar in specifying a particular portion of a lobe for localizing spikes and seizure onsets, such as “infero-lateral temporal tip.” Sublobar localization was also obtained in seizures previously reported as unlocalized or generalized (11%)
Conclusions:
Unfortunately for many epilepsy centers, localization of epileptic foci by scalp EEG has not changed much in 50 years despite the digital revolution. Legacies of the pen-writing EEG age persist. Digital analysis of properly filtered scalp EEG by voltage topography and source modeling adds considerably to the spike and seizure localization necessary for optimal SEEG planning and surgical considerations.
Funding: none