Why Dense Array EEG?
Adequate Spatial Sampling
For many years, biophysical analyses have shown that information is lost unless an intersensor distance of 1 to 2 centimeters is achieved with EEG sampling (Malmivuo & Plonsey, 1995; Ryynanen et al., 2004; 2006; Srinivasan et al., 1998).
Achieving a 1 to 2 centimeters sampling density would require 500 EEG channels distributed evenly over the surface of the head. With 256-channel sampling, dEEG now approximates adequate spatial sampling. With EGI's medical grade EEG systems, this accuracy is now available to clinicians wherever brain monitoring is required.
Malmivuo, J. & Plonsey, R. (1995). Bioelectromagnetism. New York: Oxford University Press.
Ryynanen, O. R., Hyttinen, J. A., Laarne, P. H., & Malmivuo, J. A. (2004). Effect of electrode density and measurement noise on the spatial resolution of cortical potential distribution. IEEE Trans Biomed Eng, 51(9), 1547-1554.
Ryynanen, O. R., Hyttinen, J. A., & Malmivuo, J. A. (2006). Effect of measurement noise and electrode density on the spatial resolution of cortical potential distribution with different resistivity values for the skull. IEEE Trans Biomed Eng, 53(9), 1851-1858.
Srinivasan, R., Tucker, D. M., & Murias, M. (1998). Estimating the spatial Nyquist of the human EEG. Behavioral Research Methods, Instruments,; Computers, 30, 8-19.
Detecting Clinical Signs
Holmes, M. D. (2008). Dense array EEG: Methodology and new hypothesis on epilepsy syndromes. Epilepsia, 49, 3-14.
Holmes, M. D., Brown, M., & Tucker, D. M. (2004). Are "generalized" seizures truly generalized? Evidence of localized mesial frontal and frontopolar discharges in absence. Epilepsia, 45(12), 1568-1579.
Lantz, G., Grave de Peralta, R., Spinelli, L., Seeck, M., & Michel, C. M. (2003). Epileptic source localization with high density EEG: how many electrodes are needed? Clin Neurophysiol, 114(1), 63-69.
Neurophysiology in the Brain
The result is localization of pathological physiological events with exact registration with the MRI that provides visualization of pathological anatomy (Seeck et al., 2001).
Lantz, G., Spinelli, L., Seeck, M., de Peralta Menendez, R. G., Sottas, C. C., & Michel, C. M. (2003). Propagation of interictal epileptiform activity can lead to erroneous source localizations: a 128-channel EEG mapping study. Journal of Clinical Neurophysiology, 20, 311-319.
Michel, C. M., Grave de Peralta, R., Lantz, G., Gonzalez Andino, S., Spinelli, L., Blanke, O. et al. (1999). Spatiotemporal EEG analysis and distributed source estimation in presurgical epilepsy evaluation. J Clin Neurophysiol, 16(3), 239-66.
Michel, C. M., Murray, M. M., Lantz, G., Gonzalez, S., Spinelli, L., & Grave de Peralta, R. (2004). EEG source imaging. Clin Neurophysiol, 115(10), 2195-2222.
Seeck, M., Michel, C. M., Spinelli, L., & Lazeyras, F. (2001). EEG mapping and functional MRI in presurgical epilepsy evaluation. Rev Neurol (Paris), 157(8-9 Pt 1), 747-51.
Tucker, D. M., Brown, M., Luu, P., & Holmes, M. D. (2007). Discharges in ventromedial frontal cortex during absence spells. Epilepsy and Behavior, 11, 546-557.
Cost Savings in the EEG Laboratory
Saving technician time and increasing patient throughput has caused routine EEG laboratories to see considerable cost savings that quickly overshadow the capital investment in dEEG. EGI's clinical sales representatives can provide representative economic analyses for the capital investment, patient throughput, and cost savings for a full range of EEG laboratories, clinics, and hospitals.
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