Innovations In Clinical Neuroscience

Current Trends in Epilepsy 2015

A peer-reviewed, evidence-based journal for clinicians in the field of neuroscience

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Current Trends in Epilepsy Management [December 2015] 8 researchers from the Federal University of São Paulo show that reduced cell density in certain parts of the hippocampus may be linked to deficits in short- and long-term memory in certain patients with TLE-HS. The researchers evaluated memory and language in 72 patients with TLE-HS who were undergoing pre-operative evaluation, then examined samples of brain tissue that were removed from the hippocampus during epilepsy surgery. They report that performance on all elements of the neuropsychological tests was worse in patients with degeneration on the right side of the hippocampus compared with the left side. A third study (abstract 3.244) finds that large brain function networks are affected by focal forms of epilepsy. Researchers from the National Autonomous University of Mexico, the General Hospital of Mexico and Centro Estatal de Salud Mental (CESAM), Queretaro studied patients with temporal lobe epilepsy and healthy participants, using fMRI to monitor brain activity in the cerebral cortex while the groups completed the Sternberg's task. The brain activity was then analyzed along with participants' performance on a neuropsychological evaluation. The groups exhibited similar brain activity despite the observation that patients with epilepsy required significantly longer times to complete the task, and in epilepsy patients (but not in controls) there were specific brain regions that showed a direct relation between their level of activity and the patient's cognitive performance metrics. A fourth study finds that a generalized seizure leads to diminished short and long- term memory by interfering with key signaling pathways in the brain. It is well known that seizures produce learning, memory and behavioral deficits, and that they trigger abnormally high activity of two signaling pathways in the brain: the phosphoinositide 3-kinase (PI3K) and mechanistic target of rapamycin (mTOR) cascades. But whether abnormal signaling is to blame for these deficits remains unclear. Researchers from the Baylor College of Medicine and the Gordon and Mary Cain Foundation Laboratories explored the effects of seizure activity on short- and long-term memory in a rat model of epilepsy. The researchers also tested whether learning and memory deficits could be corrected using drugs that calm the overactive signaling cascades. They report that signaling activity remained high three hours after a seizure, but returned to normal levels within 24 hours. Seizures induced significant deficits in short as well as long-term memory. The memory deficits that could be partially corrected using the drug wortmannin, which inhibits PI3K and mTOR. STUDIES REVEAL THE SURPRISING COMPLEXITY OF COGNITIVE ISSUES IN CHILDREN WITH EPILEPSY Children with epilepsy face a number of challenges compared with their healthy peers, including an increased risk of cognitive impairment. Three studies presented the AES parse the complex underpinnings of cognitive development in these children, revealing a need for smarter assessments and targeted interventions. Traditional neuropsychological assessments have an inherently limited ability to describe how children with epilepsy progress toward developmental milestones, and how relationships between cognitive skills evolve over time. To explore how cognitive milestones develop in children with epilepsy compared with their healthy peers, researchers from the University of Wisconsin-Madison and the University of California-Irvine (abstract 2.338) turned to techniques from a branch of mathematics known as graph theory. The authors administered a comprehensive battery of neuropsychological tests to 178 children ranging in age from 8 to 18 years, including 104 children with new or recent- onset epilepsy and 74 of their normally developing cousins. Tests were administered at baseline and after two years to reveal changes in intelligence, academic achievement, language, memory, executive function, and cognitive/psychomotor speed over time. Results were analyzed via graph theory and traditional analytic approaches. According to traditional analyses, healthy children outscored children with epilepsy at baseline and, because the groups continued to develop in a parallel fashion, these differences remained two years later. Graph analyses, however, revealed a deeper level of complexity, suggesting that cognitive development in both groups is organized around two hubs: verbal intelligence and category switching, or the ability to switch between multiple trains of thought, which is an executive function. The graph analysis further suggested that the neural networks linking various cognitive skills are not well integrated in children with epilepsy compared with their healthy peers. A second study (abstract 1.143) reveals changes in white matter that may help explain the cognitive impairment experienced by children with early-onset epilepsy. Noting that the overall risk of cognitive impairment is not consistent with clinical factors such as seizure frequency, researchers from the University of Edinburgh and Scotland's National Health Service explored the idea that pre-existing abnormalities in white matter integrity are present in children with cognitive impairment and early-onset epilepsy, but not in children with normal cognition. A third study (abstract 1.293) demonstrates how a brief computerized screening strategy can be used to detect cognitive changes in children with epilepsy. Though cognitive screening is routinely performed in children with epilepsy, few studies have explored the reliability of these protocols. Researchers from the University of Pittsburgh School of Medicine examined how accurately the CNS Vital Signs computerized cognitive battery, combined with parent screening tools, could identify children with cognitive and behavioral challenges. The authors studied 33 children, ranging from 8 to 17 years old, who were diagnosed with recent-onset epilepsy who had not yet started taking medication for the condition. The screening tests were repeated at 5.5 months and, in some cases, at 14.5 months. Their findings revealed clinically significant changes in one or more cognitive domains – most often composite memory, cognitive Highlights from the American Epilepsy Society 2015 69th Annual Meeting

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