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Salama H, Salama A, Oscher L, Jallo GI, Shimony N. The role of neuromodulation in the management of drug-resistant epilepsy. Neurol Sci 2024; 45:4243-4268. [PMID: 38642321 DOI: 10.1007/s10072-024-07513-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 04/02/2024] [Indexed: 04/22/2024]
Abstract
Drug-resistant epilepsy (DRE) poses significant challenges in terms of effective management and seizure control. Neuromodulation techniques have emerged as promising solutions for individuals who are unresponsive to pharmacological treatments, especially for those who are not good surgical candidates for surgical resection or laser interstitial therapy (LiTT). Currently, there are three neuromodulation techniques that are FDA-approved for the management of DRE. These include vagus nerve stimulation (VNS), deep brain stimulation (DBS), and responsive neurostimulation (RNS). Device selection, optimal time, and DBS and RNS target selection can also be challenging. In general, the number and localizability of the epileptic foci, alongside the comorbidities manifested by the patients, substantially influence the selection process. In the past, the general axiom was that DBS and VNS can be used for generalized and localized focal seizures, while RNS is typically reserved for patients with one or two highly localized epileptic foci, especially if they are in eloquent areas of the brain. Nowadays, with the advance in our understanding of thalamic involvement in DRE, RNS is also very effective for general non-focal epilepsy. In this review, we will discuss the underlying mechanisms of action, patient selection criteria, and the evidence supporting the use of each technique. Additionally, we explore emerging technologies and novel approaches in neuromodulation, such as closed-loop systems. Moreover, we examine the challenges and limitations associated with neuromodulation therapies, including adverse effects, complications, and the need for further long-term studies. This comprehensive review aims to provide valuable insights on present and future use of neuromodulation.
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Affiliation(s)
- HusamEddin Salama
- Al-Quds University-School of Medicine, Abu Dis, Jerusalem, Palestine
| | - Ahmed Salama
- Al-Quds University-School of Medicine, Abu Dis, Jerusalem, Palestine
| | - Logan Oscher
- Department of Neurosurgery, Institute for Brain Protection Sciences, Johns Hopkins All Children's Hospital, 600 5th Street South, St. Petersburg, FL, 33701, USA
| | - George I Jallo
- Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, USA.
- Department of Neurosurgery, Institute for Brain Protection Sciences, Johns Hopkins All Children's Hospital, 600 5th Street South, St. Petersburg, FL, 33701, USA.
| | - Nir Shimony
- Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, USA
- Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN, USA
- Le Bonheur Neuroscience Institute, Le Bonheur Children's Hospital, Memphis, TN, USA
- Department of Neurosurgery, University of Tennessee Health Science Center, Memphis, TN, USA
- Semmes-Murphey Clinic, Memphis, TN, USA
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Li Q, Shan Y, Wei P, Zhao G. The comparison of DBS and RNS for adult drug-resistant epilepsy: a systematic review and meta-analysis. Front Hum Neurosci 2024; 18:1429223. [PMID: 38962148 PMCID: PMC11220164 DOI: 10.3389/fnhum.2024.1429223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 06/11/2024] [Indexed: 07/05/2024] Open
Abstract
Objective Neuromodulation has been proven to be a promising alternative treatment for adult patients with drug-resistant epilepsy (DRE). Deep brain stimulation (DBS) and responsive neurostimulation (RNS) were approved by many countries for the treatment of DRE. However, there is a lack of systematic studies illustrating the differences between them. This meta-analysis is performed to assess the efficacy and clinical characteristics of DBS and RNS in adult patients with DRE. Methods PubMed, Web of Science, and Embase were retrieved to obtain related studies including adult DRE patients who accepted DBS or RNS. The clinical characteristics of these patients were compiled for the following statistical analysis. Results A total of 55 studies (32 of DBS and 23 of RNS) involving 1,568 adult patients with DRE were included in this meta-analysis. There was no significant difference in seizure reduction and responder rate between DBS and RNS for DRE. The seizure reduction of DBS and RNS were 56% (95% CI 50-62%, p > 0.05) and 61% (95% CI 54-68%, p > 0.05). The responder rate of DBS and RNS were 67% (95% CI 58-76%, p > 0.05) and 71% (95% CI 64-78%, p > 0.05). Different targets of DBS did not show significant effect on seizure reduction (p > 0.05). Patients with DRE who accepted DBS were younger than those of RNS (32.9 years old vs. 37.8 years old, p < 0.01). The mean follow-up time was 47.3 months for DBS and 39.5 months for RNS (p > 0.05). Conclusion Both DBS and RNS are beneficial and alternative therapies for adult DRE patients who are not eligible to accept resection surgery. Further and larger studies are needed to clarify the characteristics of different targets and provide tailored treatment for patients with DRE.
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Affiliation(s)
- Qinghua Li
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yongzhi Shan
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Penghu Wei
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Guoguang Zhao
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- Clinical Research Center for Epilepsy Capital Medical University, Beijing, China
- Beijing Municipal Geriatric Medical Research Center, Beijing, China
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Castellano JF, Singla S, Barot N, Aronson JP. Stereoelectroencephalography-Guided Radiofrequency Thermocoagulation: Diagnostic and Therapeutic Implications. Brain Sci 2024; 14:110. [PMID: 38391685 PMCID: PMC10887298 DOI: 10.3390/brainsci14020110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/15/2024] [Accepted: 01/21/2024] [Indexed: 02/24/2024] Open
Abstract
Despite recent medical therapeutic advances, approximately one third of patients do not attain seizure freedom with medications. This drug-resistant epilepsy population suffers from heightened morbidity and mortality. In appropriate patients, resective epilepsy surgery is far superior to continued medical therapy. Despite this efficacy, there remain drawbacks to traditional epilepsy surgery, such as the morbidity of open neurosurgical procedures as well as neuropsychological adverse effects. SEEG-guided Radiofrequency Thermocoagulation (SgRFTC) is a minimally invasive, electrophysiology-guided intervention with both diagnostic and therapeutic implications for drug-resistant epilepsy that offers a convenient adjunct or alternative to ablative and resective approaches. We review the international experience with this procedure, including methodologies, diagnostic benefit, therapeutic benefit, and safety considerations. We propose a framework in which SgRFTC may be incorporated into intracranial EEG evaluations alongside passive recording. Lastly, we discuss the potential role of SgRFTC in both delineating and reorganizing epilepsy networks.
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Affiliation(s)
- James F Castellano
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Shobhit Singla
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Niravkumar Barot
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Joshua P Aronson
- Department of Neurosurgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
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Kusyk DM, Meinert J, Stabingas KC, Yin Y, Whiting AC. Systematic Review and Meta-Analysis of Responsive Neurostimulation in Epilepsy. World Neurosurg 2022; 167:e70-e78. [PMID: 35948217 DOI: 10.1016/j.wneu.2022.07.147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 10/31/2022]
Abstract
BACKGROUND Neuromodulatory implants provide promising alternatives for patients with drug-resistant epilepsy (DRE) in whom resective or ablative surgery is not an option. Responsive neurostimulation (RNS) operates a unique "closed-loop" system of electrocorticography-triggered stimulation for seizure control. A comprehensive review of the current literature would be valuable to guide clinical decision-making regarding RNS. METHODS Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocols, a systematic PubMed literature review was performed to identify appropriate studies involving patients undergoing RNS for DRE. Full texts of included studies were analyzed and extracted data regarding demographics, seizure reduction rate, responder rate (defined as patients with >50% seizure reduction), and complications were compiled for comprehensive statistical analysis. RESULTS A total of 313 studies were screened, and 17 studies were included in the final review, representative of 541 patients. Mean seizure reduction rate was 68% (95% confidence interval 61%-76%), and the mean responder rate was 68% (95% confidence interval 60%-75%). Complications occurred in 102 of 541 patients, for a complication rate of 18.9%. A strong publication bias toward greater seizure reduction rate and increased responder rate was demonstrated among included literature. CONCLUSIONS A meta-analysis of recent RNS for DRE literature demonstrates seizure reduction and responder rates comparable with other neuromodulatory implants for epilepsy, demonstrating both the value of this intervention and the need for further research to delineate the optimal patient populations. This analysis also demonstrates a strong publication bias toward positive primary outcomes, highlighting the limitations of current literature. Currently, RNS data are optimistic for the treatment of DRE but should be interpreted cautiously.
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Affiliation(s)
- Dorian M Kusyk
- Department of Neurosurgery, Allegheny Health Network, Pittsburgh, Pennsylvania, USA
| | - Justin Meinert
- College of Medicine, Drexel University, Philadelphia, Pennsylvania, USA
| | | | - Yue Yin
- Allegheny-Singer Research Institute, Allegheny Health Network, Pittsburgh, Pennsylvania, USA
| | - Alexander C Whiting
- Department of Neurosurgery, Allegheny Health Network, Pittsburgh, Pennsylvania, USA.
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Boddeti U, McAfee D, Khan A, Bachani M, Ksendzovsky A. Responsive Neurostimulation for Seizure Control: Current Status and Future Directions. Biomedicines 2022; 10:2677. [PMID: 36359197 PMCID: PMC9687706 DOI: 10.3390/biomedicines10112677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/13/2022] [Accepted: 10/15/2022] [Indexed: 10/29/2023] Open
Abstract
Electrocorticography (ECoG) data are commonly obtained during drug-resistant epilepsy (DRE) workup, in which subdural grids and stereotaxic depth electrodes are placed on the cortex for weeks at a time, with the goal of elucidating seizure origination. ECoG data can also be recorded from neuromodulatory devices, such as responsive neurostimulation (RNS), which involves the placement of electrodes deep in the brain. Of the neuromodulatory devices, RNS is the first to use recorded ECoG data to direct the delivery of electrical stimulation in order to control seizures. In this review, we first introduced the clinical management for epilepsy, and discussed the steps from seizure onset to surgical intervention. We then reviewed studies discussing the emergence and therapeutic mechanism behind RNS, and discussed why RNS may be underperforming despite an improved seizure detection mechanism. We discussed the potential utility of incorporating machine learning techniques to improve seizure detection in RNS, and the necessity to change RNS targets for stimulation, in order to account for the network theory of epilepsy. We concluded by commenting on the current and future status of neuromodulation in managing epilepsy, and the role of predictive algorithms to improve outcomes.
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Affiliation(s)
- Ujwal Boddeti
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Darrian McAfee
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Anas Khan
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Muzna Bachani
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Alexander Ksendzovsky
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Buch VP, Mirro EA, Purger DA, Zeineh M, Wilmer-Fierro K, Razavi B, Halpern CH. Magnetic resonance imaging–guided laser interstitial thermal therapy for refractory focal epilepsy in a patient with a fully implanted RNS system: illustrative case. JOURNAL OF NEUROSURGERY: CASE LESSONS 2022; 3:CASE22117. [PMID: 35734233 PMCID: PMC9204920 DOI: 10.3171/case22117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 03/28/2022] [Indexed: 11/24/2022]
Abstract
BACKGROUND The resective surgery plus responsive neurostimulation (RNS) system is an effective treatment for patients with refractory focal epilepsy. Furthermore, the long-term intracranial electroencephalography data provided by the system can inform a future resection or ablation procedure. RNS patients may undergo 1.5-T magnetic resonance imaging (MRI) under the conditions specified in the RNS system MRI guidelines; however, it was unknown if the MRI artifact would limit intraoperative laser interstitial thermal therapy (LITT) in a patient with a fully implanted RNS system. OBSERVATIONS The authors were able to complete a successful awake LITT of epileptogenic tissue in a 1.5-T MRI scanner on the ipsilateral side to an implanted RNS system. LESSONS If a future LITT procedure is probable, the neurostimulator should be placed contralateral to the side of the potential ablation. Using twist drill holes versus burr holes for depth lead placement may assist in future laser bone anchor seating. Before a LITT procedure in a patient with the neurostimulator ipsilateral to the ablation, 1.5-T MRI thermography scanning should be scheduled preoperatively to assess artifact in the proposed ablation zone. Per the RNS system MRI guidelines, the patient must be positioned supine and awake, with no more than 30 minutes of active scan time before a 30-minute pause.
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Affiliation(s)
| | | | | | | | | | - Babak Razavi
- Neurology and Neurological Sciences, Stanford University, Stanford, California
| | - Casey H. Halpern
- Department of Neurosurgery, Perelman School of Medicine of the University of Pennsylvania, Pennsylvania Hospital, Philadelphia, Pennsylvania
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Fan JM, Lee AT, Kudo K, Ranasinghe KG, Morise H, Findlay AM, Kirsch HE, Chang EF, Nagarajan SS, Rao VR. Network connectivity predicts effectiveness of responsive neurostimulation in focal epilepsy. Brain Commun 2022; 4:fcac104. [PMID: 35611310 PMCID: PMC9123848 DOI: 10.1093/braincomms/fcac104] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/23/2022] [Accepted: 04/21/2022] [Indexed: 11/13/2022] Open
Abstract
Responsive neurostimulation is a promising treatment for drug-resistant focal epilepsy; however, clinical outcomes are highly variable across individuals. The therapeutic mechanism of responsive neurostimulation likely involves modulatory effects on brain networks; however, with no known biomarkers that predict clinical response, patient selection remains empiric. This study aimed to determine whether functional brain connectivity measured non-invasively prior to device implantation predicts clinical response to responsive neurostimulation therapy. Resting-state magnetoencephalography was obtained in 31 participants with subsequent responsive neurostimulation device implantation between 15 August 2014 and 1 October 2020. Functional connectivity was computed across multiple spatial scales (global, hemispheric, and lobar) using pre-implantation magnetoencephalography and normalized to maps of healthy controls. Normalized functional connectivity was investigated as a predictor of clinical response, defined as percent change in self-reported seizure frequency in the most recent year of clinic visits relative to pre-responsive neurostimulation baseline. Area under the receiver operating characteristic curve quantified the performance of functional connectivity in predicting responders (≥50% reduction in seizure frequency) and non-responders (<50%). Leave-one-out cross-validation was furthermore performed to characterize model performance. The relationship between seizure frequency reduction and frequency-specific functional connectivity was further assessed as a continuous measure. Across participants, stimulation was enabled for a median duration of 52.2 (interquartile range, 27.0-62.3) months. Demographics, seizure characteristics, and responsive neurostimulation lead configurations were matched across 22 responders and 9 non-responders. Global functional connectivity in the alpha and beta bands were lower in non-responders as compared with responders (alpha, pfdr < 0.001; beta, pfdr < 0.001). The classification of responsive neurostimulation outcome was improved by combining feature inputs; the best model incorporated four features (i.e. mean and dispersion of alpha and beta bands) and yielded an area under the receiver operating characteristic curve of 0.970 (0.919-1.00). The leave-one-out cross-validation analysis of this four-feature model yielded a sensitivity of 86.3%, specificity of 77.8%, positive predictive value of 90.5%, and negative predictive value of 70%. Global functional connectivity in alpha band correlated with seizure frequency reduction (alpha, P = 0.010). Global functional connectivity predicted responder status more strongly, as compared with hemispheric predictors. Lobar functional connectivity was not a predictor. These findings suggest that non-invasive functional connectivity may be a candidate personalized biomarker that has the potential to predict responsive neurostimulation effectiveness and to identify patients most likely to benefit from responsive neurostimulation therapy. Follow-up large-cohort, prospective studies are required to validate this biomarker. These findings furthermore support an emerging view that the therapeutic mechanism of responsive neurostimulation involves network-level effects in the brain.
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Affiliation(s)
- Joline M Fan
- Department of Neurology and Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
| | - Anthony T Lee
- Department of Neurosurgery, University of California San Francisco, San Francisco, CA, USA
| | - Kiwamu Kudo
- Medical Imaging Center, Ricoh Company, Ltd., Kanazawa, Japan.,Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, USA
| | - Kamalini G Ranasinghe
- Department of Neurology and Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
| | - Hirofumi Morise
- Medical Imaging Center, Ricoh Company, Ltd., Kanazawa, Japan.,Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, USA
| | - Anne M Findlay
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, USA
| | - Heidi E Kirsch
- Department of Neurology and Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA.,Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, USA
| | - Edward F Chang
- Department of Neurosurgery, University of California San Francisco, San Francisco, CA, USA
| | - Srikantan S Nagarajan
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, USA
| | - Vikram R Rao
- Department of Neurology and Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA, USA
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Rao VR. Chronic electroencephalography in epilepsy with a responsive neurostimulation device: current status and future prospects. Expert Rev Med Devices 2021; 18:1093-1105. [PMID: 34696676 DOI: 10.1080/17434440.2021.1994388] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Implanted neurostimulation devices are gaining traction as therapeutic options for people with certain forms of drug-resistant focal epilepsy. Some of these devices enable chronic electroencephalography (cEEG), which offers views of the dynamics of brain activity in epilepsy over unprecedented time horizons. AREAS COVERED This review focuses on clinical insights and basic neuroscience discoveries enabled by analyses of cEEG from an exemplar device, the NeuroPace RNS® System. Applications of RNS cEEG covered here include counting and lateralizing seizures, quantifying medication response, characterizing spells, forecasting seizures, and exploring mechanisms of cognition. Limitations of the RNS System are discussed in the context of next-generation devices in development. EXPERT OPINION The wide temporal lens of cEEG helps capture the dynamism of epilepsy, revealing phenomena that cannot be appreciated with short duration recordings. The RNS System is a vanguard device whose diagnostic utility rivals its therapeutic benefits, but emerging minimally invasive devices, including those with subscalp recording electrodes, promise to be more applicable within a broad population of people with epilepsy. Epileptology is on the precipice of a paradigm shift in which cEEG is a standard part of diagnostic evaluations and clinical management is predicated on quantitative observations integrated over long timescales.
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Affiliation(s)
- Vikram R Rao
- Associate Professor of Clinical Neurology, Chief, Epilepsy Division, Department of Neurology and Weill Institute for Neurosciences, University of California, San Francisco, CA, USA
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