A peer-reviewed, evidence-based journal for clinicians in the field of neuroscience
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Current Trends in Epilepsy Management [December 2015] 7 NOVEL DEVICES AND TECHNOLOGIES PROVIDE INSIGHTS INTO SEIZURE CONTROL, SURGICAL TARGETS, FOR PEOPLE WITH EPILEPSY Three studies presented at the American Epilepsy Society's (AES) 69th Annual Meeting describe novel devices and technologies that could reshape current understanding of the complex mechanisms underpinning seizure development in the brain. Two of the three studies unveil information about the neural networks that produce and propagate seizure activity, providing information that could help refine and target surgical interventions. In the first study, (abstract 2.076|A.05) researchers from the University of Pennsylvania describe an array of transparent electrodes that can capture high-resolution images of neuronal activity in a live animal brain while simultaneously gathering electrophysiological information about neuron function. The team previously demonstrated the technology in a single graphene electrode affixed to laboratory samples of brain tissue. According to the authors, graphene is an ideal material because of its flexibility, high electrical conductivity and opportunity to customize features on its surface. Now, the researchers describe their use of novel nanofabrication techniques to construct graphene-based neural arrays for recording and stimulation. Experiments in live, anesthetized rats revealed that the electrodes are capable of recording epileptiform activity with a high signal-to- noise ratio, high spatial and temporal resolution, and without light-induced artifacts. A second study (abstract 2.081|A.06) explores new techniques for mapping the neural networks that give rise to and exacerbate seizure activity, providing information that could potentially help boost the success of epilepsy surgery. Researchers from the Cleveland Clinic studied 15 patients with drug-resistant epilepsy who underwent a procedure called stereoelectroencephalography (SEEG), in which electrodes are surgically implanted into the brain to record electrical activity and map out putative epileptic networks. Researchers then used fMRI to record the patients' brain activity during direct electrical stimulation of the networks. Central branch points, or nodes, in the network were removed by surgery or laser ablation. According to the authors, the method produced robust maps of epileptic networks and facilitated successful surgical outcomes in 14 of the 15 patients. In a third study, (abstract 2.083) researchers from the University of Toronto describe a device capable of detecting and diminishing seizure activity. The closed- loop device aims to treat epilepsy by delivering a brief electrical stimulation at early or late stages of seizure formation, similar to how a pacemaker might stop abnormal heart rhythms. Researchers developed seizure-detection algorithms for the device in two rat models of epilepsy and programmed two iterations of the device – known as CLS-V1 and CLS-V2 – to deliver the brief electrical stimulation before, or within seconds of, seizure onset. They tested the devices on rats with seizures described as either acute (repeated seizures over a 2-hour period) or chronic (an average of five seizures per day for multiple days). Their findings reveal that the CLS-V1 device, which detected seizures about 21 to 53 seconds before onset in the acute and chronic groups, respectively, was slightly less accurate than the CLS-V2 device, which detected seizures two to four seconds after onset in the acute and chronic groups. However, the CLS-V1 was much more effective, reducing seizure frequency by 81 percent in rats with acute epilepsy and 90 percent in rats with chronic epilepsy. By contrast, the CLS-V2 reduced seizure frequency by 58 percent and 76 percent in the acute versus chronic groups. FOUR STUDIES EXPLORE MEMORY DECLINE IN PEOPLE WITH EPILEPSY Four studies presented at the AES uncover the biological factors that mediate memory decline in people with epilepsy, particularly those with seizures that affect the temporal lobe. In the first study, (abstract 2.326) researchers from the University of São Paulo report that patients with hippocampal sclerosis (TLE-HS) have everyday dramatic memory deficits that may not be detected via traditional neuropsychological tests. Noting the inconsistency between neuropsychological test results, and patient complaints of memory loss in everyday life, the researchers set out to generate a more realistic picture of memory performance in these patients. Comparisons of cognitive performance in 30 people with TLE-HS and 27 age- and gender-matched healthy participants revealed that patients with TLE-HS were less likely to recall the names of unfamiliar people, places where personal items were stored or detailed stories. Patients with TLE-HS also had difficulty orienting themselves in time and space. The authors further report that cognitive performance was significantly lower in patients with poor seizure control and those taking multiple antiepileptic drugs. In a second study, (abstract 3.312) American Epilepsy Society Highlights of Noteworthy Studies Presented During This Year's Meeting 69 TH ANNUAL MEETING—DECEMBER 4–9, 2015 The American Epilepsy Society is a medical and scientific society whose members are engaged in research and clinical care for people with epilepsy. For more than 75 years, AES has provided a dynamic global forum where professionals from academia, private practice, not-for-profit, government and industry can learn, share and grow. Find out more at aesnet.org.