Electrical stimulation for epilepsy: experimental approaches.
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ABSTRACT:
SUBMITTER: Rolston JD
PROVIDER: S-EPMC3190668 | biostudies-other | 2011 Oct
REPOSITORIES: biostudies-other
Publications
Electrical stimulation for epilepsy: experimental approaches.
Rolston John D JD Desai Sharanya Arcot SA Laxpati Nealen G NG Gross Robert E RE
Neurosurgery clinics of North America 20111001 4
Direct electrical stimulation of the brain is an increasingly popular means of treating refractory epilepsy. Although there has been moderate success in human trials, the rate of seizure freedom does not yet compare favorably to resective surgery. It therefore remains critical to advance experimental investigations aimed toward understanding brain stimulation and its utility. This article introduces the concepts necessary for understanding these experimental studies, describing recording and sti ...[more]
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Project description:Many neurological and psychiatric diseases are associated with clinically detectable, altered brain dynamics. The aberrant brain activity, in principle, can be restored through electrical stimulation. In epilepsies, abnormal patterns emerge intermittently, and therefore, a closed-loop feedback brain control that leaves other aspects of brain functions unaffected is desirable. Here, we demonstrate that seizure-triggered, feedback transcranial electrical stimulation (TES) can dramatically reduce spike-and-wave episodes in a rodent model of generalized epilepsy. Closed-loop TES can be an effective clinical tool to reduce pathological brain patterns in drug-resistant patients.
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Project description:ObjectiveThe objective of this analysis was to evaluate the effectiveness of deep brain stimulation (DBS) and vagus nerve stimulation (VNS) for the treatment of drug-resistant epilepsy in adults and children.Data sourcesA literature search was performed using MEDLINE, EMBASE, the Cochrane Library, and the Centre for Reviews and Dissemination database, for studies published from January 2007 until December 2012.Review methodsSystematic reviews, meta-analyses, randomized controlled trials (RCTs), and observational studies (in the absence of RCTs) of adults or children were included. DBS studies were included if they specified that the anterior nucleus of thalamus was the area of the brain stimulated. Outcomes of interest were seizure frequency, health resource utilization, and safety. A cost analysis was also performed.ResultsThe search identified 6 studies that assessed changes in seizure frequency after electrical stimulation: 1 RCT on DBS in adults, 4 RCTs on VNS in adults, and 1 RCT on VNS in children. The studies of DBS and VNS in adults found significantly improved rates of seizure frequency, but the study of VNS in children did not find a significant difference in seizure frequency between the high and low stimulation groups. Significant reductions in hospitalizations and emergency department visits were found for adults and children who received VNS. No studies addressed the use of health resources for patients undergoing DBS. Five studies reported on adverse events, which ranged from serious to transient for both procedures in adults and were mostly transient in the 1 study of VNS in children.LimitationsWe found no evidence on DBS in children or on health care use related to DBS. The measurement of seizure frequency is self-reported and is therefore subject to bias and issues of compliance.ConclusionsBased on evidence of low to moderate quality, both DBS and VNS seemed to reduce seizure frequency in adults. In children, VNS did not appear to be as effective at reducing seizure frequency, but children had significantly fewer hospitalizations and ED visits after VNS implantation. Despite the considerable risks associated with these invasive procedures, long-term adverse events appear to be limited.Plain language summaryElectrical stimulation of specific areas of the brain is a procedure used to control epileptic seizures when more conventional treatments are not working. Most adults and children with epilepsy are able to control their seizures with medication, but for some patients, drugs are not effective and surgery to remove the part of the brain where the seizures start is not an appropriate option. This study looked at the research available on the effectiveness, safety, and cost of two types of electrical stimulation devices currently licensed for treatment of epilepsy for adults and children in Canada: vagus nerve stimulation (VNS) and deep brain stimulation (DBS). Both approaches appear to be effective at reducing the frequency of seizures in adults. However, the evidence on DBS is limited to a single study with adults; we found no studies of DBS with children. Studies on VNS showed that both adults and children had fewer hospitalizations and emergency department visits after the procedure. Both procedures carry serious risks, but several longer-term studies have found that adverse events appear to be limited. The cost of VNS, including the process of assessing whether or not patients are good candidates for the procedure, is estimated to be about $40,000 per person (and higher for DBS because the device is more expensive and the operating time is longer). Of the 70,000 people in Ontario with epilepsy, about 1,400 (300 children and 1,110 adults) may be candidates for VNS to reduce their seizures.
| S-EPMC3817921 | biostudies-literature
Project description:ObjectiveThe objective of this study was to explore the distributed network effects of intracranial electrical stimulation in patients with medically refractory epilepsy using dynamic functional connectivity (dFC) and graph indicators.MethodsThe time-varying connectivity patterns of dFC (state-based metrics) as well as topological properties of static functional connectivity (sFC) and dFC (graph indicators) were assessed before and after the intracranial electrical stimulation. The sliding window method and k-means clustering were used for the analysis of dFC states, which were characterized by connectivity strength, occupancy rate, dwell time, and transition. Graph indicators for sFC and dFC were obtained using group statistical tests.ResultsDFCs were clustered into two connectivity configurations: a strongly connected state (state 1) and a sparsely connected state (state 2). After electrical stimulation, the dwell time and occupancy rate of state 1 decreased, while that of state 2 increased. Connectivity strengths of both state 1 and state 2 decreased. For graph indicators, the clustering coefficient, k-core, global efficiency, and local efficiency of patients showed a significant decrease, but the brain networks of patients exhibited higher modularity after electrical stimulation. Especially, for state 1, there was a significant decrease in functional connectivity strength after stimulation within and between the frontal lobe and temporary lobe, both of which are associated with the seizure onset.ConclusionOur findings demonstrated that intracranial electrical stimulation significantly changed the time-varying connectivity patterns and graph indicators of the brain in patients with medically refractory epilepsy. Specifically, the electrical stimulation decreased functional connectivity strength in both local-level and global-level networks. This might provide a mechanism of understanding for the distributed network effects of intracranial electrical stimulation and extend the knowledge of the pathophysiological network of medically refractory epilepsy.
| S-EPMC10765510 | biostudies-literature
Project description:Electrical neurostimulation is currently used to manage epilepsy, but the most effective approach for minimizing seizure occurrence is uncertain. While functional MRI (fMRI) can reveal which brain areas are affected by stimulation, simultaneous deep brain stimulation (DBS)-fMRI examinations in patients are rare and the possibility to investigate multiple stimulation protocols is limited. In this study, we utilized the intrahippocampal kainate mouse model of mesial temporal lobe epilepsy (mTLE) to systematically examine the brain-wide responses to electrical stimulation using fMRI. We compared fMRI responses of saline-injected controls and epileptic mice during stimulation in the septal hippocampus (HC) at 10 Hz and demonstrated the effects of different stimulation amplitudes (80-230 μA) and frequencies (1-100 Hz) in epileptic mice. Motivated by recent studies exploring 1 Hz stimulation to prevent epileptic seizures, we furthermore investigated the effect of prolonged 1 Hz stimulation with fMRI. Compared to sham controls, epileptic mice showed less propagation to the contralateral HC, but significantly stronger responses in the ipsilateral HC and a wider spread to the entorhinal cortex and septal region. Varying the stimulation amplitude had little effect on the resulting activation patterns, whereas the stimulation frequency represented the key parameter and determined whether the induced activation remained local or spread from the hippocampal formation into cortical areas. Prolonged stimulation of epileptic mice at 1 Hz caused a slight reduction in local excitability. In this way, our study contributes to a better understanding of these stimulation paradigms.
| S-EPMC11349577 | biostudies-literature
Project description:Although electrical neurostimulation has been proposed as an alternative treatment for drug-resistant cases of epilepsy, current procedures such as deep brain stimulation, vagus, and trigeminal nerve stimulation are effective only in a fraction of the patients. Here we demonstrate a closed loop brain-machine interface that delivers electrical stimulation to the dorsal column (DCS) of the spinal cord to suppress epileptic seizures. Rats were implanted with cortical recording microelectrodes and spinal cord stimulating electrodes, and then injected with pentylenetetrazole to induce seizures. Seizures were detected in real time from cortical local field potentials, after which DCS was applied. This method decreased seizure episode frequency by 44% and seizure duration by 38%. We argue that the therapeutic effect of DCS is related to modulation of cortical theta waves, and propose that this closed-loop interface has the potential to become an effective and semi-invasive treatment for refractory epilepsy and other neurological disorders.
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Project description:BackgroundThe diagnosis of idiopathic epilepsy (IE) in dogs is based on exclusion of other potential causes of seizures. Recently, a novel magnetic resonance imaging (MRI) sequence that utilizes a variant of the rotary saturation approach has been suggested to detect weak transient magnetic field oscillations generated by neuronal currents in humans with epilepsy.Hypothesis/objectivesEffects on the magnetic field evoked by intrinsic epileptic activity can be detected by MRI in the canine brain. As proof-of-concept, the novel MRI sequence to detect neuronal currents was applied in dogs.AnimalsTwelve dogs with IE and 5 control dogs without a history of epileptic seizures were examined.MethodsProspective case-control study as proof-of-concept. All dogs underwent a clinical neurological examination, scalp electroencephalography, cerebrospinal fluid analysis, and MRI. The MRI examination included a spin-locking (SL) experiment applying a low-power on-resonance radiofrequency pulse in a predefined frequency domain in the range of oscillations generated by the epileptogenic tissue.ResultsIn 11 of 12 dogs with IE, rotary saturation effects were detected by the MRI sequence. Four of 5 control dogs did not show rotary saturation effects. One control dog with a diagnosis of neuronal ceroid lipofuscinosis had SL-related effects, but did not have epileptic seizures clinically.Conclusions and clinical importanceThe proposed MRI method detected neuronal currents in dogs with epileptic seizures and represents a potential new line of research to investigate neuronal currents possibly related to IE in dogs.
| S-EPMC8692176 | biostudies-literature
Project description:Closed-loop brain stimulation is a promising alternative to treat drug-resistant epilepsies. In contrast to optogenetic interventions, transcranial electrical stimulation (TES) does not require cellular modification of neurons to be effective, and it is less invasive compared to deep brain stimulation. Furthermore, on-demand TES of targeted brain regions allows the potential for normal function of these networks during interictal periods, a possibility that is eliminated by resective surgical treatment approaches. To further explore the translation of closed-loop TES for treatment of epilepsy, we show here for the first time that unsupervised closed-loop TES in rats can consistently interrupt seizures for 6 weeks and has the potential to control seizure activity up to 4 months (longest periods examined). On-demand TES significantly reduced the time spent in seizure and the individual seizure duration, although significantly higher seizure rate was observed during the treatment. The 6 week long stimulation had no residual adverse effects on the electrophysiologic characteristics of the brain after the termination of the treatment and did not induce glial remodelling in the brain. Our findings demonstrate the safety and effectiveness of minimally invasive, potentially lifelong TES treatment of epilepsy either alone or as a complement to drug treatments.
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Project description:Human myogenic progenitor cells (MPCs) were isolated from the gracilis of two patients (1 female and 1 male) undergoing anterior cruciate ligament reconstruction (age 30-34 years) using a human anti-CD56 (1:20, Cat# 355503, Biolegend) antibody for FACS. Cells were passaged 2-3 times in growth media consisting of Ham’s F-10 (Thermofisher), 20% fetal bovine serum (FBS, Atlanta Biological, Minneapolis, MN, USA), 1% penicillin/streptomycin and 10ng/ml basic fibroblast growth-factor (bFGF, Peprotech, Rocky Hill, NJ, USA). Cells were differentiated into myotubes for 5 days using MyoCult differentiation media (Stemcell Technologies, Vancouver, Canada). On the fifth day, fresh media was added just prior to electrical pulse stimulation (E). Cells were then either stimulated at 12 V, 1 Hz, 2 ms for 24 hr (IonOptix C‐Pace EP, Westwood, MA, USA) or had electrodes placed in wells with no stimulation (E(+) or E(-)), followed by immediate RNA extraction using Qiazol (Qiagen, Hilden, Germany).
2021-08-20 | E-MTAB-10833 | biostudies-arrayexpress
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2010-06-01 | E-GEOD-14391 | biostudies-arrayexpress
Project description:BACKGROUND: Abdominal pain is often variable in intensity and difficult to characterise due to its referred pain pattern. Clinical pain is furthermore confounded by various emotional and cognitive factors. AIMS: To develop and apply an experimental model to induce localised gastric pain. SUBJECTS: Twelve healthy male volunteers. METHODS: Stimulating electrodes were mounted on a biopsy forceps and electric stimuli were delivered during gastroscopy. Single, five repeated, and continuous stimuli were given at four locations in the stomach. Pain detection thresholds and pain intensities were assessed together with localisation of the referred pain area. RESULTS: Pain detection thresholds were higher in the prepyloric region compared with those obtained at the lesser and greater curvature. Increasing stimulus intensity resulted in augmented pain perception and repeated stimuli elicited pain at a lower stimulus intensity than single stimuli. Continuous stimuli evoked constant (33%), increasing (33%), or decreasing (33%) pain. The localisation of referred pain varied considerably in the subjects. CONCLUSIONS: The model seems relevant to study basic pain mechanisms elicited by localised stimuli in the stomach. The experimental data support the premise that a gastric focus should always be suspected in patients referred with different kinds of abdominal pain.
| S-EPMC1891591 | biostudies-other