Towards network-guided neuromodulation for epilepsy

Brain, Journal Year: 2022, Volume and Issue: 145(10), P. 3347 - 3362

Published: June 30, 2022

Abstract Epilepsy is well-recognized as a disorder of brain networks. There growing body research to identify critical nodes within dynamic epileptic networks with the aim target therapies that halt onset and propagation seizures. In parallel, intracranial neuromodulation, including deep stimulation responsive neurostimulation, are well-established expanding reduce seizures in adults focal-onset epilepsy; there emerging evidence for their efficacy children generalized-onset seizure disorders. The convergence these advancing fields driving an era ‘network-guided neuromodulation’ epilepsy. this review, we distil current literature on network mechanisms underlying neurostimulation We discuss modulation key ‘propagation points’ epileptogenic network, focusing primarily thalamic nuclei targeted clinical practice. These include (i) anterior nucleus thalamus, now clinically approved site open loop stimulation, increasingly neurostimulation; (ii) centromedian both epilepsies. briefly associated other neuromodulation targets, such pulvinar piriform cortex, septal area, subthalamic nucleus, cerebellum others. report synergistic findings garnered from multiple modalities investigation have revealed structural functional points — scalp invasive EEG, diffusion MRI. also recordings implanted devices which provide us data aiming modulate. Finally, review continuing evolution network-guided epilepsy accelerate progress towards two translational goals: use pre-surgical analyses determine patient candidacy by providing biomarkers predict efficacy; deliver precise, personalized effective antiepileptic prevent arrest through mapping each patients’ individual

Language: Английский

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The Interictal Suppression Hypothesis in focal epilepsy: network-level supporting evidence

Brain, Journal Year: 2023, Volume and Issue: 146(7), P. 2828 - 2845

Published: Feb. 1, 2023

Abstract Why are people with focal epilepsy not continuously having seizures? Previous neuronal signalling work has implicated gamma-aminobutyric acid balance as integral to seizure generation and termination, but is a high-level distributed brain network involved in suppressing Recent intracranial electrographic evidence suggested that seizure-onset zones have increased inward connectivity could be associated interictal suppression of activity. Accordingly, we hypothesize actively suppressed by the rest during states. Full testing this hypothesis would require collaboration across multiple domains neuroscience. We focused on partially at level within 81 individuals drug-resistant undergoing presurgical evaluation. used resting-state neurostimulation recordings evaluate onset, early propagation non-involved zones. then diffusion imaging acquire estimates white-matter structure–function coupling effects findings. Finally, generated classification model assist clinicians detecting without need for ictal recordings. Our findings indicate onset demonstrate markedly inwards decreased outwards using both (one-way ANOVA, P-value = 3.13 × 10−13) analyses evoked responses 2.5 10−3). When controlling distance between regions, difference remained stable up 80 mm connections (two-way repeated measures group effect 2.6 10−12). Structure–function revealed exhibit abnormally enhanced (hypercoupling) surrounding regions compared presumably healthy tissue interaction 9.76 10−21). Using these observations, our support vector models achieved maximum held-out set accuracy 92.0 ± 2.2% classify These results suggest segregated widespread network. Furthermore, electrographically observed functional disproportionate any structural alterations implications identification only brief reduce patient morbidity augment evaluation epilepsy. Further can provide insight into potential new resective, ablative neuromodulation approaches improve surgical success rates those suffering from

Language: Английский

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Quantitative approaches to guide epilepsy surgery from intracranial EEG

Brain, Journal Year: 2023, Volume and Issue: 146(6), P. 2248 - 2258

Published: Jan. 8, 2023

Over the past 10 years, drive to improve outcomes from epilepsy surgery has stimulated widespread interest in methods quantitatively guide intracranial EEG (iEEG). Many patients fail achieve seizure freedom, part due challenges subjective iEEG interpretation. To address this clinical need, quantitative analytics have been developed using a variety of approaches, spanning studies seizures, interictal periods, and their transitions, encompass range techniques including electrographic signal analysis, dynamical systems modeling, machine learning graph theory. Unfortunately, many generalize new data are sensitive differences pathology electrode placement. Here, we critically review selected literature on computational identifying epileptogenic zone iEEG. We highlight shared methodological common field propose ways that they can be addressed. One fundamental pitfall is lack open-source, high-quality data, which specifically by sharing centralized high-quality, well-annotated, multicentre dataset consisting >100 support larger more rigorous studies. Ultimately, provide road map help these tools reach trials hope lives future patients.

Language: Английский

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Generalisability of epileptiform patterns across time and patients

Scientific Reports, Journal Year: 2024, Volume and Issue: 14(1)

Published: March 15, 2024

Abstract The complexity of localising the epileptogenic zone (EZ) contributes to surgical resection failures in achieving seizure freedom. distinct patterns epileptiform activity during interictal and ictal phases, varying across patients, often lead suboptimal localisation using electroencephalography (EEG) features. We posed two key questions: whether neural signals reflecting epileptogenicity generalise from time windows within each patient, patients. Utilising an intracranial EEG dataset 55 we extracted a large battery simple complex features stereo-EEG (SEEG) electrocorticographic (ECoG) windows. Our (n = 34) quantified many aspects including statistical moments, complexities, frequency-domain cross-channel network attributes. Decision tree classifiers were then trained tested on patients evaluate generalisability respectively. Evidence strongly supported particularly signal power high-frequency network-based Consistent observed most regions generalised with higher window. Signal contributory cross-patient generalisation These findings offer insights into generalisable epileptic implications for future automated approaches supplement other EZ methods.

Language: Английский

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Normative intracranial EEG maps epileptogenic tissues in focal epilepsy

Brain, Journal Year: 2021, Volume and Issue: 145(6), P. 1949 - 1961

Published: Dec. 21, 2021

Abstract Planning surgery for patients with medically refractory epilepsy often requires recording seizures using intracranial EEG. Quantitative measures derived from interictal EEG yield potentially appealing biomarkers to guide these surgical procedures; however, their utility is limited by the sparsity of electrode implantation as well normal confounds spatiotemporally varying neural activity and connectivity. We propose that comparing recordings a normative atlas connectivity can reliably map abnormal regions, identify targets invasive treatment increase our understanding human epilepsy. Merging data Penn Epilepsy Center public database Montreal Neurological Institute, we aggregated retrospectively across 166 subjects comprising >5000 channels. For each channel, calculated normalized spectral power coherence in canonical frequency band. constructed an mapping distribution feature brain tested against novel generating z-score channel. demonstrate seizure onset zones within mesial temporal lobe, abnormality provide greater distinguishing value than univariate activity. also find longer diagnosis have abnormalities By integrating both single-channel inter-regional functional connectivity, better accuracy predicting versus (area under curve = 0.77) compared either group features alone. aggregating centres into provides rigorous, quantitative method epileptic networks therapy. publicly share data, infrastructure methods, international framework leveraging big planning

Language: Английский

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The role of quantitative markers in surgical prognostication after stereoelectroencephalography

Annals of Clinical and Translational Neurology, Journal Year: 2023, Volume and Issue: 10(11), P. 2114 - 2126

Published: Sept. 21, 2023

Stereoelectroencephalography (SEEG) is the reference method in presurgical exploration of drug-resistant focal epilepsy. However, prognosticating surgery on an individual level difficult. A quantified estimation most epileptogenic regions by searching for relevant biomarkers can be proposed this purpose. We investigated performances ictal (Epileptogenicity Index, EI; Connectivity EI, cEI), interictal (spikes, high-frequency oscillations, HFO [80-300 Hz]; Spikes × HFO), and combined (Spikes cEI) predicting surgical outcome searched prognostic factors based SEEG-signal quantification.Fifty-three patients operated following SEEG were included. compared, using precision-recall, zone different (EZq ) against visual analysis (EZC ). Correlations between EZ resection rates or extent prognosis analyzed.EI EI showed best precision EZc (0.74; 0.70), followed cEI cEI, whereas markers lower precision. The greater seizure-free than non-seizure-free defined correlated with EI. No such correlation was found markers. did not correlate prognosis.Ictal ictal-interictal overperformed both detecting seizure freedom. Combining epileptogenicity improves detection accuracy. Resection only statistically significant determinants prognosis.

Language: Английский

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Developmental atlas of phase-amplitude coupling between physiologic high-frequency oscillations and slow waves

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Oct. 13, 2023

We investigated the developmental changes in high-frequency oscillation (HFO) and Modulation Index (MI) - coupling measure between HFO slow-wave phase. generated normative brain atlases, using subdural EEG signals from 8251 nonepileptic electrode sites 114 patients (ages 1.0-41.5 years) who achieved seizure control following resective epilepsy surgery. observed a higher MI occipital lobe across all ages, increased notably during early childhood. The cortical areas exhibiting co-growth were connected via vertical fasciculi posterior callosal fibers. While rate showed no significant age-association, temporal, frontal, parietal lobes exhibited an age-inversed rate. Assessment of 1006 onset revealed that z-score normalized at versus sites. have publicly shared our intracranial data to enable investigators validate HFO-centric presurgical evaluations identify epileptogenic zone.

Language: Английский

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MEG abnormalities and mechanisms of surgical failure in neocortical epilepsy

Epilepsia, Journal Year: 2023, Volume and Issue: 64(3), P. 692 - 704

Published: Jan. 8, 2023

Epilepsy surgery fails to achieve seizure freedom in 30%-40% of cases. It is not fully understood why some surgeries are unsuccessful. By comparing interictal magnetoencephalography (MEG) band power from patient data normative maps, which describe healthy spatial and population variability, we identify patient-specific abnormalities relating surgical failure. We propose three mechanisms contributing poor outcome: (1) resecting the epileptogenic (mislocalization), (2) failing remove all (partial resection), (3) insufficiently impacting overall cortical abnormality. Herein develop markers these mechanisms, validating them against outcomes.

Language: Английский

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Passive and active markers of cortical excitability in epilepsy

Epilepsia, Journal Year: 2023, Volume and Issue: 64(S3)

Published: March 10, 2023

Abstract Electroencephalography (EEG) has been the primary diagnostic tool in clinical epilepsy for nearly a century. Its review is performed using qualitative methods that have changed little over time. However, intersection of higher resolution digital EEG and analytical tools developed past decade invites re‐exploration relevant methodology. In addition to established spatial temporal markers spikes high‐frequency oscillations, novel involving advanced postprocessing active probing interictal are gaining ground. This provides an overview EEG‐based passive cortical excitability techniques facilitate their identification. Several different emerging discussed context specific applications barriers we must overcome translate these into practice.

Language: Английский

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Vagus nerve stimulation for epilepsy: A narrative review of factors predictive of response

Epilepsia, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 16, 2024

Abstract Vagus nerve stimulation (VNS) is an established therapy for drug‐resistant epilepsy. However, there a lack of reliable predictors VNS response in clinical use. The identification factors predictive important patient selection and stratification as well tailored programming. We conducted narrative review the existing literature on prognostic markers using clinical, demographic, biochemical, modality‐specific information such from electroencephalography (EEG), magnetoencephalography, magnetic resonance imaging (MRI). No individual marker demonstrated sufficient power patients, although several have been suggested, with some promising initial findings. Combining underresearched modalities T1‐weighted MRI morphometrics EEG may provide better strategies treatment optimization.

Language: Английский

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