Clinicians routinely monitor electrical signals from the brains of traumatic brain injury (TBI) patients to assess the response to treatments such as anti-seizure drugs. However, determining the specific location of injuries, where abnormal electrical activity is generated, has remained elusive.
Researchers supported by the National Institute of Biomedical Imaging and Bioengineering, combined several imaging technologies to track abnormal electrical signals to the specific injury site. Known as inverse localization, the technique promises to enhance patient-specific monitoring and treatment, optimize surgical effectiveness, and improve clinical outcomes for those suffering from traumatic brain injury.
TBI is a leading cause of death and disability worldwide. It is the leading cause of brain damage in children and young adults and plays a significant role in half of trauma deaths. Each year in the United States, about two million people suffer a TBI, with approximately 10% being moderate to severe injuries. In the US, the mortality rate is estimated to be 21% by 30 days after severe TBI. A study on Iraq War veterans estimated the incidence of TBI among wounded soldiers to be as high as 22%.
Electroencephalography (EEG) plays an important role in monitoring the pathology of acute TBI. EEG records electrical activity along the scalp of the patient and can detect general electrical changes indicative of post-traumatic epileptic (PTE) seizures. PTE seizures after acute TBI occur in 2% to 25% of patients. Because anti-seizure medications are only minimally successful in PTE cases, many patients can benefit from surgery to remove the damaged tissue causing the seizures. Unfortunately, EEG detects electrical activity only on the surface of the scalp, but not deeper in the brain, where the abnormal electrical activity originates.
Neuroscientists funded by the National Institute of Biomedical Imaging and Bioengineering and the National Institute of Neurological Disorders and Stroke, have teamed-up to develop an imaging technique, inverse localization, that pinpoints the specific site of TBI damage in the brain. The work is published in the October 2013 issue of Clinical Neurology and Neurosurgery.
The research team obtained images from three TBI patients using magnetic resonance imaging (MRI) and computed tomography (CT). They combined this information with EEG recordings from each patient and used a computational model to create 3D images of the brain, including cross-sections through the head. This combination of methods revealed the regions with specific TBI damage in each patient. The size of the brain regions identified corresponded to the severity of the patients’ TBI, which ranged from mild to severe.
The researchers believe that the information obtained using the enhanced localization method is a significant step towards improving the success of surgery for post-traumatic epileptic seizures, and for comprehensively helping physicians to better manage and treat TBI.
Senior investigator, John Van Horn, Ph.D., Keck School of Medicine, University of Southern California explains the goals of his research team: “Although our methods successfully identify specific regions of TBI pathology, our real focus is to continue to develop technologies that will better inform clinicians regarding the best management of their patients throughout the entire course of treatment of this debilitating brain injury.”
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- Irimia A, Goh SY, Torgerson CM, Stein NR, Chambers MC, Vespa PM, Van Horn JD. Electoencephalographic inverse localization of brain actitivity in acute traumatic brain injury as a guide to surgery, monitoring and treatment. Clin Neurol Neurosurg. 2013 Oct;115(10):2159-65