Researchers Shine Light On The Brain To Find The Root Of Epileptic Seizures

Main Category: Epilepsy
Also Included In: Neurology / Neuroscience
Article Date: 02 Aug 2006 - 0:00 PDT

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In another clinical research trial in the Department of Neurological Surgery, Dr. Theodore Schwartz, an associate professor and principal investigator, is collaborating with Dr. Minah Suh, an assistant professor, to study if optical imaging - photographing changes in light reflectance off the surface of the brain - is effective at helping doctors identify (and later remove) the source of seizures in patients with focal neocortical epilepsy.

Surgery is the only known cure for epilepsy, but before surgeons can remove the part of the brain where seizures originate, they need to identify it. This is especially difficult with neocortical epilepsy because the neurons that cause a seizure can vary over time and can be located in a part of the brain away from where the seizure actually arises.

Electrophysiological recording, which is currently considered the best technique to map epilepsy, does not work very well because the electrodes placed on the surface of the brain measure too limited an area and often provide an incomplete picture. (This technique does work well with temporal lobe epilepsy, where the seizure source is fixed and near the seizure.)

Optical imaging holds promise. It can sample activity in a much wider section of the brain and is incredibly precise at identifying a seizure source. Surgeons know exactly which part of the brain to remove, and the risk of taking too much and damaging a patient's memory or cognitive ability is greatly minimized. For now, the work is experimental, but Drs. Schwartz and Suh hope that the research they are doing today can help guide surgeons tomorrow.

The procedure involves placing a glass plate on the surface of the brain. This creates a uniform surface that also reduces pulsation artifacts caused by the patient's heartbeat and breathing. In the best-case situation, the patient has a naturally occurring seizure. However, if not, the team can create one with gentle electrical stimulation.

During the seizure activity, natural or created, the team shines light of different wavelengths through the glass plate and onto the brain's surface while a video camera records the activity. What the tape later reveals are hemodynamic changes happening within the brain. Different wavelengths reflect blood volume and oxygen levels as different colors, and when viewing a fast-moving seizure in a "slow-motion replay," Drs. Schwartz and Suh can pinpoint where the seizure is coming from.

The research is conducted during Dr. Schwartz's regularly scheduled resection surgeries, so no additional surgery is done for the sake of the study.

. About the doctors:

Dr. Theodore Schwartz is director of the Center for Epilepsy Surgery, Brain Tumors, Minimally-Invasive Skull Base and Pituitary Surgery, and an associate professor of neurological surgery at Weill Cornell Medcial College. He is also an associate attending neurological surgeon at NewYork-Presbyterian Hospital/Weill Cornell Medical Center.

Dr. Minah Suh is an assistant professor of neuroscience in neurological surgery at Weill Cornell Medical College.

From Weill Cornell Medical College Science Briefs

Joan and Sanford I. Weill Medical College of Cornell University
525 East 68th Street, Box 144
New York, NY 10021
USA
http://www.med.cornell.edu
http://www.nyp.org

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