scholarly journals Critical slowing as a biomarker for seizure susceptibility

2019 ◽  
Author(s):  
Matias I. Maturana ◽  
Christian Meisel ◽  
Katrina Dell ◽  
Philippa J. Karoly ◽  
Wendyl D’Souza ◽  
...  

AbstractThe human brain has the capacity to rapidly change state, and in epilepsy these state changes can be catastrophic, resulting in loss of consciousness, injury and even death. Theoretical interpretations considering the brain as a dynamical system would suggest that prior to a seizure recorded brain signals may exhibit critical slowing, a warning signal preceding many critical transitions in dynamical systems. Using long-term intracranial electroencephalography (iEEG) recordings from fourteen patients with focal epilepsy, we found key signatures of critical slowing prior to seizures. Signals related to a critically slowing process fluctuated over temporally long scales (hours to days), longer than would be detectable in standard clinical evaluation settings. Seizure risk was associated with a combination of these signals together with epileptiform discharges. These results provide strong validation of theoretical models and demonstrate that critical slowing is a reliable indicator that could be used in seizure forecasting algorithms.

2021 ◽  
Vol 13 (608) ◽  
pp. eabf6588
Author(s):  
Ankit N. Khambhati ◽  
Alia Shafi ◽  
Vikram R. Rao ◽  
Edward F. Chang

Responsive neurostimulation (RNS) devices, able to detect imminent seizures and to rapidly deliver electrical stimulation to the brain, are effective in reducing seizures in some patients with focal epilepsy. However, therapeutic response to RNS is often slow, is highly variable, and defies prognostication based on clinical factors. A prevailing view holds that RNS efficacy is primarily mediated by acute seizure termination; yet, stimulations greatly outnumber seizures and occur mostly in the interictal state, suggesting chronic modulation of brain networks that generate seizures. Here, using years-long intracranial neural recordings collected during RNS therapy, we found that patients with the greatest therapeutic benefit undergo progressive, frequency-dependent reorganization of interictal functional connectivity. The extent of this reorganization scales directly with seizure reduction and emerges within the first year of RNS treatment, enabling potential early prediction of therapeutic response. Our findings reveal a mechanism for RNS that involves network plasticity and may inform development of next-generation devices for epilepsy.


2006 ◽  
Vol 16 (07) ◽  
pp. 2013-2027 ◽  
Author(s):  
KOSTAS TSAKALIS ◽  
LEON IASEMIDIS

We discuss the key features of theoretical models of networks of coupled chaotic oscillators that produce seizure-like events and bear striking similarities to dynamics of epileptic seizures. Our long-term objective is to understand the basic functional mechanisms that can produce seizures and may ultimately lead to strategies for seizure suppression and control. We show that, from a dynamical systems point of view, a plausible cause of seizures is a pathological feedback in the brain circuitry. This suggests new seizure control approaches, as well as systematic methods to tune existing ones. While the suggested models and control approaches are far from being considered optimal for epileptic seizures, they have interesting physical interpretation and implications for treatments of epilepsy. They also have close ties with a variety of recent practical observations in the human and animal epileptic brain, and with theories from adaptive systems, optimization and chaos.


2019 ◽  
Vol 14 (1) ◽  
pp. 7-13
Author(s):  
N. A. Ermolenko ◽  
I. S. Bakhtin ◽  
I. A. Buchneva

Benign epileptiform discharges of childhood are age-dependent electroencephalogram patterns associated with idiopathic benign focal epilepsy. Multiple studies have demonstrated that focal epileptiform discharges can be registered in patients without any clinical manifestations of epilepsy. Long-term follow-up of clinically healthy children with benign epileptiform discharges of childhood on electroencephalogram demonstrated that 14 % of them developed epileptic seizures with age and 50 % developed various cognitive and behavioral disorders. The question of whether or not to treat such patients (with benign epileptiform discharges of childhood on electroencephalogram but without epileptic seizure) is still being widely discussed. Individual decision making with the consideration of potential risks and benefits for a patient is preferable in this case. Valproic acid is the drug of first choice in these patients.


2021 ◽  
Vol 11 (2) ◽  
pp. 127-135
Author(s):  
Young Jun Ko ◽  
Il Han Yoo ◽  
Jiwon Lee ◽  
Jeehun Lee ◽  
Mi-Sun Yum ◽  
...  

Background and Purpose: This study was aimed to describe focal epilepsy features of SCN1A mutation-positive Dravet syndrome patients.Methods: A total of 82 SCN1A mutation-positive patients were reviewed retrospectively (39 boys and 43 girls). Seizure type and electroencephalography (EEG) findings were investigated according to the stage, disease onset, and steady state (after age 2 years). Long-term video EEG data were used to classify the seizure type.Results: Focal seizures at onset and the steady state were found in 54.9% (45/82) and 90% (63/70) of patients, respectively. Afebrile focal seizures were an initial seizure in about one fourth of the patients (22/82, 26.8%). Of 48 seizures captured during long-term video EEG monitoring of 30 patients, 19 seizures were classified as focal onset (39.6%). Of the 19 focal seizures, 12 were either focal motor or focal non-motor seizures, and seven were focal onset bilateral tonic-clonic seizure. Focal epileptiform discharges were more frequent than generalized epileptiform discharges at seizure onset and during the clinical course on conventional EEG (3.7% vs. 0%, 52.9% vs. 32.9%, respectively).Conclusions: Our study provides a comprehensive description of focal epilepsy features of SCN1A mutation-positive Dravet syndrome patients. Recognizing these features as defining the clinical spectrum of Dravet syndrome may lead to earlier genetic diagnosis and tailored management.


Author(s):  
A. G. Malov ◽  
M. I. Vshivkov ◽  
M. A. Mamunts

Introduction: Early infantile epileptic encephalopathy (EIEE) is a group of monogenic epilepsies which are caused by mutations in more than 70 genes. Material and methods: The data of a long-term dynamic EEG observation of a girl with EIEE9 (OMIM 300088) caused by a mutation in the PCDH19 gene (OMIM 300460) are presented. Results: Correct etiological diagnosis of the hereditary disease was established only at the age of 14 years. Epilepsy debuted at the age of 8 months as a series of one minute long generalized tonic convulsions with myoclonia in the left arm. After further examination the symptoms were mistakenly regarded as viral encephalitis. Subsequently, clusters of convulsive seizures provoked by febrile states periodically were occurring several times per year irrespective of the type and amount of anticonvulsants taken. Despite the fact, that no significant structural changes in the brain we found during neuroimaging, pharmacoresistant focal epilepsy gradually developed. At the age of 14 years, as part of a pre-surgical examination for two days, the complete abolition of anticonvulsants and the implantation of subdural electrodes were performed. Focal motor seizures with a transition to bilateral tonic-clonic seizures were recorded, during which the primary generation of epileptic activity was localized in the left temporal lobe. А thorough examination with a clarification of the monogenic origin of the disease made it possible to avoid undue surgery on the brain. Discussion: The presented observation is a clear example of why a timely genetic examination is important for establishing correct diagnosis, adequate selection of anticonvulsants and a making a right decision on the possibility of surgical treatment.


2010 ◽  
Vol 24 (4) ◽  
pp. 249-252 ◽  
Author(s):  
Márk Molnár ◽  
Roland Boha ◽  
Balázs Czigler ◽  
Zsófia Anna Gaál

This review surveys relevant and recent data of the pertinent literature regarding the acute effect of alcohol on various kinds of memory processes with special emphasis on working memory. The characteristics of different types of long-term memory (LTM) and short-term memory (STM) processes are summarized with an attempt to relate these to various structures in the brain. LTM is typically impaired by chronic alcohol intake but according to some data a single dose of ethanol may have long lasting effects if administered at a critically important age. The most commonly seen deleterious acute effect of alcohol to STM appears following large doses of ethanol in conditions of “binge drinking” causing the “blackout” phenomenon. However, with the application of various techniques and well-structured behavioral paradigms it is possible to detect, albeit occasionally, subtle changes of cognitive processes even as a result of a low dose of alcohol. These data may be important for the consideration of legal consequences of low-dose ethanol intake in conditions such as driving, etc.


Author(s):  
Peter R. Breggin

BACKGROUND: The vaccine/autism controversy has caused vast scientific and public confusion, and it has set back research and education into genuine vaccine-induced neurological disorders. The great strawman of autism has been so emphasized by the vaccine industry that it, and it alone, often appears in authoritative discussions of adverse effects of the MMR and other vaccines. By dismissing the chimerical vaccine/autism controversy, vaccine defenders often dismiss all genuinely neurological aftereffects of the MMR (measles, mumps, and rubella) and other vaccines, including well-documented events, such as relatively rare cases of encephalopathy and encephalitis. OBJECTIVE: This report explains that autism is not a physical or neurological disorder. It is not caused by injury or disease of the brain. It is a developmental disorder that has no physical origins and no physical symptoms. It is extremely unlikely that vaccines are causing autism; but it is extremely likely that they are causing more neurological damage than currently appreciated, some of it resulting in psychosocial disabilities that can be confused with autism and other psychosocial disorders. This confusion between a developmental, psychosocial disorder and a physical neurological disease has played into the hands of interest groups who want to deny that vaccines have any neurological and associated neuropsychiatric effects. METHODS: A review of the scientific literature, textbooks, and related media commentary is integrated with basic clinical knowledge. RESULTS: This report shows how scientific sources have used the vaccine/autism controversy to avoid dealing with genuine neurological risks associated with vaccines and summarizes evidence that vaccines, including the MMR, can cause serious neurological disorders. Manufacturers have been allowed by the US Food and Drug Administration (FDA) to gain vaccine approval without placebo-controlled clinical trials. CONCLUSIONS: The misleading vaccine autism controversy must be set aside in favor of examining actual neurological harms associated with vaccines, including building on existing research that has been ignored. Manufacturers of vaccines must be required to conduct placebo-controlled clinical studies for existing vaccines and for government approval of new vaccines. Many probable or confirmed neurological adverse events occur within a few days or weeks after immunization and could be detected if the trials were sufficiently large. Contrary to current opinion, large, long-term placebo-controlled trials of existing and new vaccines would be relatively easy and safe to conduct.


Author(s):  
Selma Büyükgöze

Brain Computer Interface consists of hardware and software that convert brain signals into action. It changes the nerves, muscles, and movements they produce with electro-physiological signs. The BCI cannot read the brain and decipher the thought in general. The BCI can only identify and classify specific patterns of activity in ongoing brain signals associated with specific tasks or events. EEG is the most commonly used non-invasive BCI method as it can be obtained easily compared to other methods. In this study; It will be given how EEG signals are obtained from the scalp, with which waves these frequencies are named and in which brain states these waves occur. 10-20 electrode placement plan for EEG to be placed on the scalp will be shown.


2004 ◽  
pp. 406-412
Author(s):  
Paul Okunieff ◽  
Michael C. Schell ◽  
Russell Ruo ◽  
E. Ronald Hale ◽  
Walter G. O'Dell ◽  
...  

✓ The role of radiosurgery in the treatment of patients with advanced-stage metastatic disease is currently under debate. Previous randomized studies have not consistently supported the use of radiosurgery to treat patients with numbers of brain metastases. In negative-results studies, however, intracranial tumor control was high but extracranial disease progressed; thus, patient survival was not greatly affected, although neurocognitive function was generally maintained until death. Because the future promises improved systemic (extracranial) therapy, the successful control of brain disease is that much more crucial. Thus, for selected patients with multiple metastases to the brain who remain in good neurological condition, aggressive lesion-targeting radiosurgery should be very useful. Although a major limitation to success of this therapy is the lack of control of extracranial disease in most patients, it is clear that well-designed, aggressive treatment substantially decreases the progression of brain metastases and also improves neurocognitive survival. The authors present the management and a methodology for rational treatment of a patient with breast cancer who has harbored 24 brain metastases during a 3-year period.


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