Resting-state background features demonstrate multidien cycles in long-term EEG device recordings

Brain stimulation, Journal Year: 2023, Volume and Issue: 16(6), P. 1709 - 1718

Published: Nov. 1, 2023

Longitudinal EEG recorded by implanted devices is critical for understanding and managing epilepsy. Recent research reports patient-specific, multi-day cycles in device-detected epileptiform events that coincide with increased likelihood of clinical seizures. Understanding these could elucidate mechanisms generating seizures advance drug neurostimulation therapies.

Language: Английский

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Direct electrical brain stimulation of human memory: lessons learnt and future perspectives

Brain, Journal Year: 2022, Volume and Issue: 146(6), P. 2214 - 2226

Published: Nov. 21, 2022

Modulation of cognitive functions supporting human declarative memory is one the grand challenges neuroscience, and vast importance for a variety neuropsychiatric, neurodegenerative neurodevelopmental diseases. Despite recent surge successful attempts at improving performance in range tasks, optimal approaches parameters enhancement have yet to be determined. On more fundamental level, it remains elusive as how delivering electrical current given brain area leads enhanced processing. Starting from local distal physiological effects on neural populations, mechanisms encoding, maintenance, consolidation or recall response direct stimulation are only now being unravelled. With advent innovative neurotechnologies concurrent recording intracranially brain, becomes possible study both acute chronic underlying activities. In this review, we summarize various invasive modulating functions. We first outline that were faced initial studies lessons learnt. Electrophysiological biomarkers then reviewed objective measures than behavioural outcomes. Finally, classify into continuous phasic modulation with an open closed loop responsive based analysis recorded Although potential advantage closed-loop over classic open-loop inconclusive, foresee emerging results ongoing longitudinal clinical trials will shed light strategies memory. Adaptive biomarker extended periods time proposed future direction obtaining lasting Chronic tracking activities through adaptive opens tantalizing new avenues continually monitor treat deficits disorders. Brain co-processors created machine-learning tools wireless bi-directional connectivity seamlessly integrate implanted devices smartphones cloud computing poised enable real-time automated large data volumes adaptively tune electrophysiological states. Next-generation implantable high-density activities, technologies distributed brain-computer interfaces presented selected perspectives associated mental processes.

Language: Английский

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Prognostic interictal electroencephalographic biomarkers and models to assess antiseizure medication efficacy for clinical practice: A scoping review

Epilepsia, Journal Year: 2023, Volume and Issue: 64(5), P. 1125 - 1174

Published: Feb. 15, 2023

Abstract Antiseizure medication (ASM) is the primary treatment for epilepsy. In clinical practice, methods to assess ASM efficacy (predict seizure freedom or reduction), during any phase of drug lifecycle, are limited. This scoping review identifies and appraises prognostic electroencephalographic (EEG) biomarkers models that use EEG features, which associated with outcomes following initiation, dose adjustment, withdrawal. We also aim summarize population context in these were identified described, understand how they could be used practice. Between January 2021 October 2022, four databases, references, citations systematically searched studies investigating changes interictal using features outcomes. Study bias was appraised modified Quality Prognosis Studies criteria. Results synthesized into a qualitative review. Of 875 identified, 93 included. Biomarkers classed as (visually by wave morphology) quantitative. Qualitative include identifying hypsarrhythmia, centrotemporal spikes, epileptiform discharges (IED), classifying normal/abnormal/epileptiform, photoparoxysmal response. Quantitative statistics applied IED, high‐frequency activity, frequency band power, current source density estimates, pairwise statistical interdependence between channels, measures complexity. Prognostic Cox proportional hazards machine learning models. There promise some quantitative efficacy, but further research required. insufficient evidence conclude specific biomarker can particular prognosticate efficacy. potential battery biomarkers, combined However, many confounders need addressed translation

Language: Английский

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Biofluid-Permeable and Erosion-Resistant Wireless Neural-Electronic Interfaces for Neurohomeostasis Modulation

ACS Nano, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 17, 2025

Neural-electronic interfaces through delivering electroceuticals to lesions and modulating pathological endogenous electrical environments offer exciting opportunities treat drug-refractory neurological disorders. Such an interface should ideally be compatible with the neural tissue aggressive biofluid environment. Unfortunately, no specifically designed for is available so far; instead, simply stacking encapsulation layer on silicon-based substrates makes them susceptible leakage, device malfunction, foreign-body reactions. Here, we developed a biofluid-permeable erosion-resistant wireless neural-electronic (BNEI) that composed of flexible 3D interconnected poly(l-lactide) fibrous network dense axially aligned piezoelectrical molecular chain arrangement architecture. The organized structure enhances tortuous pathway longitudinal piezoelectric coefficient fibers, improves their water barrier properties, enables efficient conversion low-intensity acoustic vibrations transmitted in biofluids into signals, achieving long-term stable neuromodulation. A 3-month clinical trial demonstrated BNEI can effectively accelerate cascade peripheral neuropathy nerve regeneration transcranially modulate cerebellar-cerebral circuit dynamics, suppressing seizures temporal lobe epilepsy. clinically scalable approach neuromodulation broadly applicable modulation neurohomeostasis both central nervous systems.

Language: Английский

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Evaluating the accuracy of monitoring seizure cycles with seizure diaries

Epilepsia, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 24, 2025

Abstract Objective Epileptic seizures occurring in cyclical patterns is increasingly recognized as a significant opportunity to advance epilepsy management. Current methods for detecting seizure cycles rely on intrusive techniques or specialized biomarkers, thereby limiting their accessibility. This study evaluates non‐invasive cycle detection method using diaries and compares its accuracy with identified from intracranial electroencephalography (iEEG) interictal epileptiform discharges (IEDs). Methods Using data previously published first in‐human iEEG device trial ( n = 10), we analyzed through diary reports, seizures, IEDs. Cycle similarities across IEDs were evaluated at periods of 1 45 days spectral coherence, accuracy, precision, recall, the false‐positive rate. Results A coherence analysis raw signals showed moderately similar periodic components between seizures/day (median .43, IQR .68). In contrast, there was low IEDs/day .11, .18) .12, .19). Accuracy, recall scores, rates significantly higher than chance all participants (accuracy (mean ± standard deviation): .95 .02; precision: .56 .19; recall: rate: .02 .01). However, scores IED both did not perform above chance, average. Recall compared good reporters, under‐reporters, over‐reporters, generally performing better reporters under‐reporters over‐reporters. Significance These findings suggest that can be even individuals who under‐ over‐report seizures. approach offers an accessible alternative monitoring more invasive methods.

Language: Английский

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Signatures of Electrical Stimulation Driven Network Interactions in the Human Limbic System

Journal of Neuroscience, Journal Year: 2023, Volume and Issue: 43(39), P. 6697 - 6711

Published: Aug. 24, 2023

Stimulation-evoked signals are starting to be used as biomarkers indicate the state and health of brain networks. The human limbic network, often targeted for stimulation therapy, is involved in emotion memory processing. Previous anatomic, neurophysiological, functional studies suggest distinct subsystems within network (Rolls, 2015). Studies using intracranial electrical stimulation, however, have emphasized similarities evoked waveforms across network. We test whether these stimulation-driven signatures. In eight patients (four male, four female) with drug-resistant epilepsy, we stimulated system single-pulse stimulation. Reliable corticocortical potentials (CCEPs) were measured between hippocampus posterior cingulate cortex (PCC) amygdala anterior (ACC). However, CCEP waveform PCC after hippocampal showed a unique reliable morphology, which term "limbic Hippocampus-Anterior nucleus thalamus-Posterior cingulate, HAP-wave." This HAP-wave was visually separately decoded from ACC Diffusion MRI data show that end points overlap parolfactory cingulum bundle rather than parahippocampal cingulum, suggesting may travel through fornix, mammillary bodies, thalamus (ANT). further confirmed by stimulating ANT, same but an earlier latency. Limbic stimulation-evoked signatures future help pathology diagnosis.

Language: Английский

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Acute to long-term characteristics of impedance recordings during neurostimulation in humans

Journal of Neural Engineering, Journal Year: 2024, Volume and Issue: 21(2), P. 026022 - 026022

Published: March 14, 2024

Abstract Objective. This study aims to characterize the time course of impedance, a crucial electrophysiological property brain tissue, in human thalamus (THL), amygdala-hippocampus, and posterior hippocampus over an extended period. Approach. Impedance was periodically sampled every 5–15 min several months five subjects with drug-resistant epilepsy using investigational neuromodulation device. Initially, we employed descriptive piecewise continuous mathematical models impedance response for approximately three weeks post-electrode implantation. We then explored temporal dynamics during periods when electrical stimulation temporarily halted, observing monotonic increase (rebound) before it stabilized at higher value. Lastly, assessed stability amplitude phase 24 h cycle throughout multi-month recording. Main results. Immediately post-implantation, decreased, reaching minimum value all regions within two days, increased monotonically about 14 d stable The accounted variance short-term changes. Notably, THL most epileptogenic hemisphere significantly lower than other regions. During gaps stimulation, rebound decreased around 200 days post-implant, likely indicative foreign body fibrous tissue encapsulation electrodes. oscillation remained recording, circadian variation dominating long-term measures. Significance. Our findings illustrate complex implanted electrodes impact stimulation. discuss these context known biological data suggest that are dependent on anatomical location epileptogenicity. These insights may offer additional guidance delivery therapeutic various points post-implantation therapy.

Language: Английский

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Aperiodic activity as a biomarker of seizures and neuromodulation

Brain stimulation, Journal Year: 2025, Volume and Issue: unknown

Published: April 1, 2025

Mounting evidence suggests the efficacy of neuromodulation for epilepsy is mediated by network remodeling and neural state. Epilepsy related pathophysiology has been associated with variation in aperiodic exponent, which describes inverse relationship between frequency power linked to synaptic-level processes. This study sought assess relationships periodic activity, disease state, responsive stimulation. Chronic intracranial EEG was recorded from 13 patients undergoing neurostimulation epilepsy. Recordings containing clinician-annotated seizures, stimulation triggered device-detected interictal epileptiform activity (IEA), stimulation-free periods were analyzed. Multidien IEA cycles identified, recordings classified cycle phase. Power spectra parameterized into components using an established algorithm. The exponent larger during seizures pre-stimulation intervals than recordings, decreased following A rise observed 12 hours preceding seizures. Larger rising phase multidien cycles. Periodic alpha beta intervals, high-risk (rising and/or peak) phases, whereas theta gamma exhibited variable relationships. did not change after or before any studied band. positively instantaneous state severity negatively therapeutic Aperiodic may emerge as a practical biomarker treatment response guide

Language: Английский

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Epileptiform Activity and Seizure Risk Follow Long‐Term Non‐Linear Attractor Dynamics

Advanced Science, Journal Year: 2025, Volume and Issue: unknown

Published: April 7, 2025

Abstract Many biological systems display circadian and slow multi‐day rhythms, such as hormonal cardiac cycles. In patients with epilepsy, these cycles also manifest cyclical fluctuations in seizure propensity. However, symptoms are consequences of the complex interactions between underlying physiological, pathophysiological, external causes. Therefore, identifying an accurate model system that governs rhythms allows for a more reliable risk forecast targeted interventions. The primary aim is to develop personalized strategy inferring long‐term trajectories epileptiform activity and, consequently, individual undergoing ECoG sampling via implantable neurostimulation devices. To achieve this goal, Hankel alternative view Koopman (HAVOK) analysis adopted approximate linear representation nonlinear propensity dynamics. HAVOK framework leverages theory delay‐embedding decompose chaotic dynamics into leading delay‐embedded coordinates driven by low‐energy coordinate (i.e., forcing). findings reveal topology attractors cycles, showing seizures tend occur regions manifold strongly Moreover, it demonstrated identified forcings short periods up few days accurately predicts patients' slower which improves forecasting.

Language: Английский

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Chronobiology of epilepsy and sudden unexpected death in epilepsy

Frontiers in Neuroscience, Journal Year: 2022, Volume and Issue: 16

Published: Sept. 7, 2022

Epilepsy is a neurological disease characterized by spontaneous, unprovoked seizures. Various insults render the brain hyperexcitable and susceptible to seizure. Despite there being dozens of preventative anti-seizure medications available, these drugs fail control seizures in nearly 1 3 patients with epilepsy. Over last century, large body evidence has demonstrated that internal external rhythms can modify seizure phenotypes. Physiologically relevant shorter periodic rhythms, such as endogenous circadian sleep-state, well longer periodicity, including multidien menses, influence timing through poorly understood mechanisms. The purpose this review discuss findings from both human animal studies consider effect biologically on epilepsy seizure-associated death. Patients medically refractory are at increased risk sudden unexpected death (SUDEP). role some play nocturnal susceptibility SUDEP will also be discussed. While involvement been known for over applying rhythmic nature phenomenon management, particularly mitigating SUDEP, underutilized. As our understanding physiological improves, technology chronic intracranial epileptiform monitoring becomes more widespread, smaller less invasive, novel seizure-prediction technologies time-dependent chronotherapeutic management strategies realized.

Language: Английский

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