Brain surgery is a therapeutic option for many patients with intractable seizure disorders and brain tumors. The goals of surgery are twofold – on the one hand the epileptogenic tissue or tumor has to be removed, but on the other hand essential brain regions like primary motor and sensory cortex as well as brain areas supporting language and memory functions have to be spared to avoid neurological deficits caused by the operation. The decision to perform surgery and what brain region to resect is based on several considerations including the clinical examination, history, MRI, noninvasive video-EEG monitoring, neuropsychological testing, metabolic imaging studies (PET, SPECT), functional MRI and Magnetoencephalography. If the above tests are not sufficient for reaching a decision, then an additional diagnostic procedure – invasive monitoring with implanted electrodes – is performed.
cortiQ was developed to identify functional brain regions in real-time with invasive sensors. Using that data, the system constructs and continuously updates a Mental Activity Profile (MAP). This MAP is unique for each patient, reflecting which brain areas are active during specific functions. Medical experts are able to get more relevant information than previously possible, presented in a straightforward fashion with clear and helpful images, with less work than currently required.
As noted, pre-surgical evaluation for epilepsy and other conditions seeks to identify the affected areas (e.g. epileptic foci or tumors), as well as “eloquent” areas. The surgical procedure is then tailored such as to resect the affected areas while simultaneously sparing areas subserving important functions. Currently, the eloquent cortex is identified with electrical cortical stimulation (ECS) within 1.5-7.5 hours and is not completed for the majority of patients - leaving about 12-74% of the covered cortex unexplored. This is so because: (1) the areas had no relevance for the surgical procedure, (2) the stimulation current produced pain or a seizure or (3) time was limited.
cortiQ allows users to position the used electrode grids (selected from the cortiQ grid library) over a schematic brain map. For different tasks performed by the patient (e.g. using the Ritaccio paradigm), high gamma activity is indicated in form of red circles for all electrodes. A big red circle shows that the corresponding electrode is placed over a brain area which is highly active in the performed task.
Electrical cortical stimulation (ECS) is used to verify the correct electrodes incorporated in a specific task or action. Multiple grids and strips are often used to cover large cortical areas (Gerwin Schalk, Wadsworth Center/Albany Med, Albany, USA).
cortiQ provides physicians with real-time results during
pre-surgical evaluation for epilepsy or other conditions.
cortiQ takes advantage of existing ECoG grids (including the Leuthardt grid) and consists of the following components:
cortiQ Flyer: download (pdf, 251 kB)
Christoph Kapeller (2015): Online Control of a Humanoid Robot through Hand Movement Imagination using CSP and ECoG based Features. Presentation.
C. Kapeller, K. Kamada, H. Ogawa, R. Prueckl, N. Kunii, C. Guger (2015): Expressive and receptive language mapping using ECoG and ECS. In proceedings of the DGKN congress, 19. – 21.03.2015, Tübingen, DE. Poster.
Prueckl, R., et al. "Real-Time Software for Functional Mapping of Eloquent Cortex Using Electrocorticography." Biomedical Engineering/Biomedizinische Technik (2013).
Roland, Jarod, et al. "Passive real-time identification of speech and motor cortex during an awake craniotomy." Epilepsy & Behavior 18.1 (2010): 123-128
Brunner, Peter, et al. "A practical procedure for real-time functional mapping of eloquent cortex using electrocorticographic signals in humans." Epilepsy & Behavior 15.3 (2009): 278-286.
Korostenskaja, Milena, et al. "Real-Time Functional Mapping With Electrocorticography in Pediatric Epilepsy Comparison With fMRI and ESM Findings." Clinical EEG and neuroscience 45.3 (2014): 205-211.
Kapeller, Christoph; Kamada, Kyousuke; Ogawa, Hiroshi; Kunii, Naoto; Prueckl, Robert; Kawai, Kensuke; Schalk, Gerwin; Guger, Christoph. Comparison of ECoG and ECS Language Mapping with High-Density Electrodes. 2013 IEEE Neural Engineering Short Papers No. 0521.
Kapeller C, Korostenskaja M, Prueckl R, Chen PC, Lee KH, Westerveld M, Salinas CM, Cook JC, Baumgartner JE, Guger C., CortiQ-based Real-Time Functional Mapping for Epilepsy Surgery. J Clin Neurophysiol. 2015 Jun;32(3):e12-22. doi: 10.1097/WNP.0000000000000131.
G. Schalk, E. C. Leuthardt, P. Brunner, J. G. Ojemann, L. A. Gerhardt, J. R. Wolpaw, Real-time detection of event-related brain activity, Neuroimage 43 (2) (2008) 245–249.
Kamada K, Ogawa H, Kapeller C, Prueckl R, Guger C., Rapid and low-invasive functional brain mapping by realtime visualization of high gamma activity for awake craniotomy. Conf Proc IEEE Eng Med Biol Soc. 2014;2014:6802-5. doi: 10.1109/EMBC.2014.6945190.
Ogawa H, Kamada K, Kapeller C, Hiroshima S, Prueckl R, Guger C., Rapid and minimum invasive functional brain mapping by real-time visualization of high gamma activity during awake craniotomy. World Neurosurg. 2014 Nov;82(5):912.e1-10. doi: 10.1016/j.wneu.2014.08.009. Epub 2014 Aug 7. PMID: 25108295
Yukie Tamura, Hiroshi Ogawa, Christoph Kapeller, Robert Prueckl, Fumiya Takeuchi, Ryogo Anei, Anthony Ritaccio, Christoph Guger, Kyousuke Kamada, Understanding Functional Dynamics of High Gamma Activity on Different Brain Regions during Language Tasks, Journal of Neurosurgery, in press, 2015
Prueckl R, Kapeller C, Potes C, Korostenskaja M, Schalk G, Lee KH, Guger C., CortiQ - clinical software for electrocorticographic real-time functional mapping of the eloquent cortex. Conf Proc IEEE Eng Med Biol Soc. 2013;2013:6365-8. doi: 10.1109/EMBC.2013.6611010.