Science subjournal: even well controlled epilepsy can interfere with human thinking and memory

October 22, 2019 / Biovalley BIOON / - -- in a new study, researchers from Stanford University School of medicine may help explain why even those who benefit from drugs for epilepsy often continue to experience difficulties in thinking, perception and clear memory The reason is that the pathological buzz of EEG activity interferes with the normal activity of brain Some drugs or implants could be improved to reduce these cognitive deficits, the researchers said The relevant research results were published in the Journal of Science Translational Medicine on October 16, 2019 The title of the paper is "cognitive rehabilitation state caused by intermittent epileptic high-frequency complications in the human brain" The picture is from cc0 public domain This kind of electrical interference has important consequences To study this, the researchers tested the ability of six patients with sensors implanted in the brain to solve certain types of problems during periods when this pathological electrical activity conflicts with the normal response of the patient's brain This pathological electrical activity, called high frequency oscillation (HFO), is related to seizures Josef parvizi, Ph.D., a professor of Neurology and neuroscience and co-author of the paper and director of the Stanford University's intractable epilepsy program, said HFO could not be detected by the naked eye, even by the eyes of trained neuroscientists A brief interruption of brain function parvizi said HFO occurs multiple times in a minute in epilepsy prone tissues, even in the brains of people whose seizures have been well controlled by drugs The new study shows that even in patients who are successfully treated, brain circuits that are prone to abnormal electrical activity fail to function most of the time In the new study, HFO reduced participants' ability to perform simple cognitive tasks accurately if it occurred within a few hundred milliseconds before the epileptic brain region began processing information It also slowed their response time, and they reported a drop in their confidence in the accuracy of the response The researchers found that this happened because HFO interfered with healthy high-frequency broadband (HFB) events during this period HFB is related to the brain circuitry that starts to do something it should do, such as processing visual information or recalling previous experiences The researchers found that HFO can disrupt healthy brain activity for about a second "The cognitive need for brain circuits that have just experienced HFO is like a doorbell that rings when you've just had a punch in the nose and two eyes and still have Venus," parvizi said You may not even hear the doorbell You will not open the door " Epilepsy is often compared to an electrical storm in the brain, which affects about 1% of the population The drug benefits about two-thirds of people diagnosed with the disease Implantable devices that deliver electrical impulses to the brain can sometimes succeed in the event of drug failure For patients with intractable epilepsy, surgical removal of the affected tissue can be selected In the new study, parvizi and the first author of the paper, Dr Su Liu, a postdoctoral researcher at Stanford University, studied six adult patients with refractory epilepsy who were being evaluated at the Stanford University Health Care Center for surgery To help clarify the origin of their seizures, parvizi and Liu implanted electrodes into their brains The study found that although the six patients who agreed to the study were at rest, they experienced HFO several times a minute, and curiously, they did not have a significant seizure To induce healthy HFB in epilepsy prone tissues of these participants, the two researchers assigned them visual or memory tasks With the data recorded by these electrodes, parvizi and Liu use machine learning technology to train computers so as to distinguish HFO and HFB accurately and reliably In all six patients, if spontaneous HFO occurs about a second before the task triggered HFB, it will destroy, delay, reduce and often completely eliminate HFB Behavioral tests in some patients whose memory is affected show that when this happens, their memory is poor, their reaction time is longer, and their confidence in answering questions caused by memory is reduced Hope for epileptics another important conclusion of this new study is that epileptic tissues behave normally outside the HFO window "This should change our view of epilepsy," parvizi said For a long time, people's general impression is that epileptics have 'sick brain' The best treatment for their 'sick tissue' is to take it out But this new study tells us that in most cases, when the epilepsy prone brain tissue does not experience HFO, its function is as good as the surrounding electrical stable brain tissue, at least in the patients we studied, they have no obvious brain structure abnormality " Although neurosurgeons can help patients decide whether to surgically remove epileptic brain tissue to eliminate or reduce the frequency of seizures, he said, they may also need to consider how long the tissue will function normally If the frequency of spontaneous HFO in the epileptic brain is relatively low, it still retains many cognitive processing abilities "Maybe you don't want to dump the baby with the bath water," parvizi said In principle, implantable devices placed in a patient's brain can distinguish between these two types of electrical activity, destroying HFO with a burst of electrical pulse while retaining HFB, parvizi said Stanford University's office of technology licensing applied for temporary patents in the United States for intellectual property rights related to these research results (bio Com) reference: 1.su Liu et al Cognitive rehabilitation state caused by intermittent epileptic high-frequency organisms in the human brain Science Translational Medicine, 2016, doi:10.1126/scitranslmed.aax7830 2.Study shows why even well-controlled epilepsy can disrupt thinking https://medicalxpress.com/news/2019-10-well-controlled-epilepsy-disrupt.html