Eng. Sci. Guest Speaker Abbas Babajani-Feremi, PhD
- March 13, 2015
- 3:00 PM - 4:00 CST
- Cuneo Hall, Room 302
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Engineering Science
Marjorie Reyes, mreyes12@luc.edu - none
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Details
Engineering Science Assistant Professor Candidate:
Abbas Babajani-Feremi, PhD
Friday, March 13, 2015
Cuneo Room 302, 3:00 to 4:00
Research Lecture: Language mapping using four methods: cortical stimulation mapping (CSM), fMRI, TMS, and high gamma electrocorticography (hgECoG)
Bio: Abbas Babajani-Feremi received B.Sc. in Electrical Engineering, M.Sc. and Ph.D. in Biomedical Engineering from University of Tehran, Iran, in 1994, 1997, and 2006, respectively. He worked in the TP Co., Tehran, Iran from 1997 to 2007 and served as the head of the Research & Development (R&D) department of this company. From 2007 to 2011, Dr. Babajani-Feremi worked as an instructor in the Radiology Image Analysis Lab. at the Henry Ford Hospital, Detroit, MI. Then he joined the Department of Anatomy and Neurobiology at the Washington University School of Medicine as a staff scientist in 2011, and worked as part of the Human Connectome Project. Since 2013, he is an Assistant Professor in the Department of Pediatrics at the University of Tennessee Health Science Center. Dr. Babajani-Feremi¿s research interests are signal and image processing, medical imaging, brain connectivity analysis using electroencephalography (EEG), magnetoencephalography (MEG), and functional magnetic resonance imaging (fMRI) as well as language mapping and epilepsy seizure localization.
Abstract: About 1% of people in the United States suffer from epilepsy, and one-fifth of epilepsy is medically intractable. Surgical resection of the seizure focus is an effective treatment for patients with medically intractable epilepsy but it carries the risk of postoperative impairment of essential brain functions, especially language. Presurgical functional mapping is usually performed to minimize this risk. Cortical stimulation mapping (CSM) serves as the clinical ¿gold standard¿ for presurgical language mapping, though it has some limitations. We compared localization of the expressive language cortex using extraoperative CSM with localization based on induced high gamma electrocorticography (hgECoG), functional magnetic resonance imaging (fMRI), and transcranial magnetic stimulation (TMS) in six patients with epilepsy. TMS-induced speech disruption during an object naming task was observed in all patients. The results of fMRI revealed significant activation in language related areas during performance of either an object naming or sentence completion task in 5 out of 6 patients. Electrical stimulation during CSM caused speech arrest in all patients except in one patient. Moreover, electrocorticography recordings obtained during performance of an object naming task revealed significant high gamma activity in all patients. Considering CSM localization results as the gold standard, the average sensitivity/specificity of hgECoG (based on the ¿zero-neighbor¿ approach), fMRI, and TMS across all patients was 70%/79%, 50%/86%, and 80%/80%, respectively. However, when using the ¿next-neighbor¿ approach, the average sensitivity and specificity of hgECoG across all patients were 100% and 86%, respectively. When comparing performance of hgECoG, fMRI, and TMS language mapping using the receiver operating characteristic (ROC) analysis, the average area under the ROC curve (AUC) of hgECoG (next-neighbor/zero-neighbor), fMRI, and TMS across five CSM-positive patients was 1.00/0.86, 0.84, and 0.77, respectively, and thus hgECoG and TMS had the best and worst performance with respect to AUC, respectively. In addition, the optimal values of sensitivity/specificity of hgECoG (based on the next-neighbor approach), hgECoG (based on the zero-neighbor approach), fMRI, and TMS at the cut-off point of the ROC curve were 100%/99%,100%/75%, 87%/89%, and 80%/81%, respectively. Results of the present study suggest that language mapping on the basis of hgECoG, fMRI, and TMS can provide important additional information, therefore, these methods can be used in conjunction with CSM or as an alternative, when the latter is deemed impractical.
