Research Using dEEG in Presurgical Planning

Comparing dense array scalp EEG to simultaneous intracranial EEG

Yamazaki, M., Tucker, D.M., Fujimoto, A., Yamazoe, T., Okanishi, T., Yokota, T., Enoki, H., & Yamamoto, T. (2012). Comparison of dense array EEG with simultaneous intracranial EEG for interictal spike detection and localization. Link to original paper.

  • The first study to compare dense array EEG (dEEG) directly with simultaneous intracranial EEG (icEEG).
  • icEEG and 256-channel scalp dEEG were recorded simultaneously in seven patients with mesial temporal lobe epilepsy. The scalp dEEG analysis detected 45% of the spikes that were ­detected using icEEG. Analyzing the same data using a 10-20 montage to simulate conventional EEG, only 22% of the icEEG spikes were detected.
  • By applying source estimation algorithms to the dEEG data, the researchers determined that all spikes detected with scalp dEEG were localized to the mesial temporal lobe and close to the position confirmed by icEEG.
  • The authors conclude that 256-channel dEEG represents a significant improvement over conventional EEG in guiding placement of icEEG electrodes. Thus, use of high-channel scalp dEEG may be clinically useful for presurgical planning.

Comparing dense array EEG to conventional EEG, MRI, PET, and SPECT

Brodbeck, V., Spinelli, L., Lascano, A.M., Wissmeier, M., Vargas, M., Vulliemoz, S., Pollo, C., Schaller, K., Michel, C.M., & Seeck, M. (2011). Electroencephalographic source imaging: a prospective study of 152 operated epileptic patients. Brain 134(10), 2887–2897. doi:10.1093/brain/awr243. Link to original paper.

  • The first large-scale study (152 patients) of the relative contribution of 128- and 256-channel dense array EEG (dEEG) to the presurgical planning process.
  • Presurgical tests included MRI, PET, SPECT, and interictal electrical source imaging (ESI) with either conventional EEG (19-29 electrodes) or dEEG (EGI's 128-or 256-electrode Geodesic EEG System).
  • Electrical source imaging (ESI) using dEEG recording of interictal epileptogenic discharges combined with individual MRI head models had the highest sensitivity and specificity for identifying the correct part of the brain to remove during surgery.
  • The authors noted that, compared to other methods, ESI with dEEG is relatively inexpensive. It also reduces workload because it does not require sedation.

Comparing long term dense array scalp EEG intracranial EEG

Holmes, M., Tucker, D., Quiring, J., Hakimian, S., Miller, J. & Ojemann, J. (2010). Comparing noninvasive dense array and intracranial electroencephalography for localization of seizures. Neurosurgery 66, 354–362. Link to original paper.

  • Long term monitoring (LTM) with dEEG was compared with intracranial (icEEG) recordings for localizing ictal onsets.
  • dEEG localized ictal onsets to the same regions as icEEG monitoring in 8 of 10 cases and icEEG disclosed an additional ictal focus in 2 of these patients.
  • “Dense array electroencephalography has the potential to assist in the noninvasive localization of epileptic seizures and to guide the placement of invasive electrodes for localizing seizure onset.”

 

More research papers on this subject

Malpass, K. (2011). Epilepsy: Electric source imaging — an inexpensive and reliable method to estimate the epileptic focus. Nature Reviews Neurology 7, 658. doi:10.1038/nrneurol.2011.186

Brodbeck, V., Spinelli, L., Lascano, A., Pollo, C., Schaller, K., Vargas, M., Wissmeyer, M., Michel, C. & Seeck, M. (2010). Electrical source imaging for presurgical focus localization in epilepsy patients with normal MRI. Epilepsia, 51(4), 583–591.

Grouiller, F., Thornton, R., Groening, K., Spinelli, L., Duncan, J., Schaller, K., Siniatchkin, M., Lemieux, L., Seeck, M., Michel, C. & Vulliemoz, S. (2011). With or without spikes: localization of focal epileptic activity by simultaneous electroencephalography and functional magnetic resonance imaging. Brain 134(Pt 10), 2867-2886.

Holmes M. (2008) Dense array EEG: Methodology and new hypothesis on epilepsy syndromes. Epilepsia, 49(Suppl. 3), 3-14.

Holmes, M., Brown, M., Tucker, D., Saneto, R., Miller, K., Wig, G. & Ojemann, J. (2008). Source analysis of extratemporal seizure using dense array EEG: comparison with intracranial recordings. Journal of Pediatric Neurosurgery 44(6), 474-479.

Michel, C., Lantz, G., Spinelli, L., Grave de Peralta, R. Landis, T. & Seeck, M. (2004). 128-channel EEG source imaging in epilepsy: clinical yield and localization precision. Journal of Clinical Neurophysiology, 21, 71-83.

Ramon, C., Holmes, M., Freeman, W., McElroy, R. & Rezvanian, E. (2008). Comparative analysis of temporal dynamics of EEG and phase synchronization of EEG to localize epileptic sites from high density scalp EEG interictal recordings. Conference Proceedings IEEE Engineering in Medicine & Biology Society, 2008, 4548-4550.

Sperli, F., Spinelli, L., Seeck, M., Kurian, M., Michel, C. & Lantz, G. (2006). EEG source imaging in pediatric epilepsy surgery: a new perspective in presurgical workup. Epilepsia, 47(6), 981–990.

Yamazaki, M., Terrill, M., Fujimoto, A., Yamamoto, T., Tucker, D. (2012). Integrating dense array EEG in the presurgical evaluation of temporal lobe epilepsy. ISRN Neurology, 2012, 924081. doi:10.5402/2012/924081.