Kaspar Anton Schindler

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• Professor
• Professor at Inselspital, Universitätsspital Bern

Spontaneous neural dynamics manifest across multiple temporal and spatial scales, which are thought to be intrinsic to brain areas and exhibit hierarchical organization across the cortex. In wake, a hierarchy of timescales is thought to naturally emerge from microstructural properties, gene expression, and recurrent connections. A fundamental quest...

All data modalities are not created equal, even when the signal they measure comes from the same source. In the case of the brain, two of the most important data modalities are the scalp electroencephalogram (EEG), and the intracranial electroencephalogram (iEEG). They are used by human experts, supported by deep learning (DL) models, to accomplish...

All data modalities are not created equal, even when the signal they measure comes from the same source. In the case of the brain, two of the most important data modalities are the scalp electroencephalogram (EEG), and the intracra-nial electroencephalogram (iEEG). iEEG benefits from a higher signal-to-noise ratio (SNR), as it measures the electric...

Spontaneous neural dynamics manifest across multiple timescales, which are intrinsic to brain areas and exhibit hierarchical organization across the cortex. In wake, a hierarchy of timescales is thought to naturally emerge from microstructural properties, gene expression, and recurrent connections. A fundamental question is timescales’ organization...

Introduction: In a cohort of adult patients with disturbance of consciousness after TBI, we aimed to explore the relationship of continuous video-EEG (cEEG) and routine EEG (rEEG) with mortality and functional outcome. Methods: Post-hoc analysis of data from a randomized controlled trial (CERTA study), in which adults with disorder of consciousness...

This is an updated and translated version of my tutorial: "Einführung in die EEG Beschreibung". https://medium.com/@kaspar.schindler/a-primer-on-eeg-reading-79da89184308

Epilepsy is defined by the abrupt emergence of harmful seizures, but the nature of these regime shifts remains enigmatic. From the perspective of dynamical systems theory, such critical transitions occur upon inconspicuous perturbations in highly interconnected systems and can be modeled as mathematical bifurcations between alternative regimes. The...

Objective This study evaluates the performance of the novel MRI sequence stimulus‐induced rotary saturation (SIRS) to map responses to interictal epileptic activity in the human cortex. Spin‐lock pulses have been applied to indirectly detect neuronal activity through magnetic field perturbations. Following initial reports about the feasibility of t...

Seizure detection stands as a critical aspect of epilepsy management, which requires continuous monitoring to improve patient care. However, existing monitoring systems face challenges in providing reliable, long–term, portable solutions due to the computational expense and power demands of continuous processing and data transmission. Edge computin...

Background and objectives: Current practice in clinical neurophysiology is limited to short recordings with conventional EEG (days) that fail to capture a range of brain (dys)functions at longer timescales (months). The future ability to optimally manage chronic brain disorders, such as epilepsy, hinges upon finding methods to monitor electrical b...

Unverricht-Lundborg disease (ULD; EPM1) is an inherited neurodegenerative disorder characterized by onset at 6–15 years, stimulus-sensitive, action-activated myoclonus, epilepsy, and progressive neurological deterioration. It is caused by biallelic pathogenic variants in the CSTB gene, encoding a cystatin B. The most common of these is an unstable...

Citation: Duss, S.B.; Vorster, A.P.A.; Urech, A.; Schmitt, W.J.; Beck, J.; Hilt, D.; Gnarra, O.; van der Meer, J.; Tüzün, M.; Berger, T.; et al. The Swiss Sleep House Bern-A New Approach to Sleep Medicine. Clin. Transl. Neurosci. 2024, 8, 14. https://doi. Abstract: Sleep is essential for health, well-being, creativity, and productivity. Sleep loss...

Epilepsy is characterized by the occurrence of epileptic events, ranging from brief bursts of interictal epileptiform brain activity to their most dramatic manifestation as clinically overt bilateral tonic–clonic seizures. Epileptic events are often modulated in a patient-specific way, for example by sleep. But they also reveal temporal patterns no...

Ictal SPECT is an informative seizure imaging technique to tailor epilepsy surgery. However, capturing the onset of unpredictable seizures is a medical and logistic challenge. Here, we sought to image planned seizures triggered by direct stimulation of epileptic networks via stereotactic electroencephalography (sEEG) electrodes. Methods: In this ca...

A growing body of literature demonstrates a critical role for sleep in upregulating diverse biological processes related to protein synthesis, immune function, and cellular housekeeping such as intracellular transport and membrane repair. The energy allocation (EA) hypothesis places sleep in a broader context of resource optimization where sleep–wa...

Introduction: Sleep-wake circadian disorders (SWCDs) are very frequent and linked to major negative effects on the body, mental health, the brain, and on occupational and societal health. The prevention, diagnosis, and treatment of SWCDs and the promotion of sleep health require the sufficient education of general practitioners, specialists, and ot...

Auditory processing and the complexity of neural activity can both indicate residual consciousness levels and differentiate states of arousal. However, how measures of neural signal complexity manifest in neural activity following environmental stimulation and, more generally, how the electrophysiological characteristics of auditory responses chang...

Variable binding is an open problem in both neuroscience and machine learning relating to how neural circuits combine multiple features into a single entity. Emergent Symbols through Binding in External Memory is a recent development tackling variable binding with a compelling solution. An emergent symbolic binding network (ESBN) is able to infer a...

The degree to which unimodal circular data are concentrated around the mean direction can be quantified using the mean resultant length, a measure known under many alternative names, such as the phase locking value or the Kuramoto order parameter. For maximal concentration, achieved when all of the data take the same value, the mean resultant lengt...

Objective: To evaluate the influence of quantitative reports (QReports) on the radiological assessment of hippocampal sclerosis (HS) from MRI of patients with epilepsy in a setting mimicking clinical reality. Methods: The study included 40 patients with epilepsy, among them 20 with structural abnormalities in the mesial temporal lobe (13 with HS...

During rest, intrinsic neural dynamics manifest at multiple timescales, which progressively increase along visual and somatosensory hierarchies. Theoretically, intrinsic timescales are thought to facilitate processing of external stimuli at multiple stages. However, direct links between timescales at rest and sensory processing, as well as translat...

Collaborative efforts between basic scientists, engineers, and clinicians are enabling translational epileptology. In this article, we summarize the recent advances presented at the International Conference for Technology and Analysis of Seizures (ICTALS 2022): (1) novel developments of structural magnetic resonance imaging; (2) latest electroencep...

Auditory processing and the complexity of neural activity can both indicate residual conscious-ness levels and differentiate between states of arousal. However, how measures of neural signal diversity, or complexity, manifest in evoked activity, and, more generally, how the electrophys-iological characteristics of auditory responses change in state...

Epileptic seizures require rapid and safe diagnosis to minimize the time from onset to adequate treatment. Some epileptic seizures can be diagnosed clinically with the respective expertise. For more subtle seizures, imaging is mandatory to rule out treatable structural lesions and potentially life-threatening conditions. MRI perfusion abnormalities...

Background: Digital sensing devices have become an increasingly important component of modern biomedical research, as they help provide objective insights into individuals' everyday behavior in terms of changes in motor and nonmotor symptoms. However, there are significant barriers to the adoption of sensor-enhanced biomedical solutions in terms o...

BACKGROUND Digital sensing devices have become an increasingly important component of modern biomedical research, as they help provide objective insights into individuals’ everyday behavior in terms of changes in motor and nonmotor symptoms. However, there are significant barriers to the adoption of sensor-enhanced biomedical solutions in terms of...

During rest, intrinsic neural dynamics manifest at multiple timescales, which progressively increase along visual and somatosensory hierarchies. Theoretically, intrinsic timescales are thought to facilitate processing of external stimuli at multiple stages. However, direct links between timescales at rest and sensory processing, as well as translat...

Visual interpretation of electroencephalography (EEG) is time consuming, may lack objectivity, and is restricted to features detectable by a human. Computer-based approaches, especially deep learning, could potentially overcome these limitations. However, most deep learning studies focus on a specific question or a single pathology. Here we explore...

Background Electroencephalography (EEG) is essential to assess prognosis in patients after cardiac arrest (CA). Use of continuous EEG (cEEG) is increasing in critically-ill patients, but it is more resource-consuming than routine EEG (rEEG). Observational studies did not show a major impact of cEEG versus rEEG on outcome, but randomized studies are...

Epilepsy, sleep, and Alzheimer’s disease (AD) are tightly and potentially causally interconnected. The aim of our review was to investigate current research directions on these relationships. Our hope is that they may indicate preventive measures and new treatment options for early neurodegeneration. We included articles that assessed all three top...

Objective To assess, in adults with acute consciousness impairment, the impact of latency between hospital admission and EEG recording start, and their outcome. Methods We reviewed data of the CERTA trial (NCT03129438) and explored correlations between EEG recording latency and mortality, Cerebral Performance Categories (CPC), and modified Rankin...

For patients suffering from neurodegenerative disorders, the behavior and activities of daily living are an indicator of a change in health status, and home-monitoring over a prolonged period of time by unobtrusive sensors is a promising technology to foster independent living and maintain quality of life. The aim of this pilot case study was the d...

Epilepsy surgery can be a very effective therapy in medication refractory patients. During patient evaluation intracranial EEG is analyzed by clinical experts to identify the brain tissue generating epileptiform events. Quantitative EEG analysis increasingly complements this approach in research settings, but not yet in clinical routine. We investi...

Relating brain dynamics acting on time scales that differ by at least an order of magnitude is a fundamental issue in brain research. The same is true for the observation of stable dynamical structures in otherwise highly non-stationary signals. The present study addresses both problems by the analysis of simultaneous resting state EEG-fMRI recordi...

Objectives: To investigate electroencephalogram (EEG) features' relation with mortality or functional outcome after disorder of consciousness, stratifying patients between continuous EEG and routine EEG. Design: Retrospective analysis of data from a randomized controlled trial. Setting: Multiple adult ICUs. Patients: Data from 364 adults wit...

Epilepsy is a severe neurological disorder that affects about 1 % of the world population, and one-third of cases are drug-resistant. Apart from surgery, drug-resistant patients can benefit from closed-loop brain stimulation, eliminating or mitigating the epileptic symptoms. For the closed-loop to be accurate and safe, it is paramount to couple sti...

Neurology is focused on a model where patients receive their care through repeated visits to clinics and doctor’s offices. Diagnostic tests often require expensive and specialized equipment that are only available in clinics. However, this current model has significant drawbacks. First, diagnostic tests, such as daytime EEG and sleep studies, occur...

A central challenge in today's care of epilepsy patients is that the disease dynamics are severely under-sampled in the currently typical setting with appointment-based clinical and electroencephalographic examinations. Implantable devices to monitor electrical brain signals and to detect epileptic seizures may significantly improve this situation...

Objectives Occurrence of EEG spindles has been recently associated with favorable outcome in ICU patients. Available data mostly rely on relatively small patients' samples, particular etiologies, and limited variables ascertainment. We aimed to expand previous findings on a larger dataset, to identify clinical and EEG patterns correlated with spind...

Objective: Neurophysiological exploration of ICU delirium is limited. Here, we examined EEG characteristics of medical-surgical critically ill patients with new-onset altered consciousness state at high risk for ICU delirium. Materials and methods: Pre-planned analysis of non-neurological mechanically ventilated medical-surgical ICU subjects, wh...

Background: Continuous EEG (cEEG) is increasingly used in critically ill patients, but it is more resource-intensive than routine EEG (rEEG). In the US, cEEG generates increased hospitalisation charges. This study analysed hospital-related reimbursement for participants in a Swiss multicentre randomised controlled trial that assessed the relations...

Cortical excitability, the variable response to a given cortical input, is widely studied in neuroscience, from slice experiments and in silico modeling work to human clinical settings. However, a unifying definition and a translational approach to the phenomenon are currently lacking. For example, at the onset of epileptic seizures, cortical excit...

In Reply We thank Gaspard et al for their letter, which raises several relevant issues, some of which were already discussed in the article (eg, the imitated generalizability to patients without recent seizures or status epilepticus¹). They point to the median latency of electroencephalography (EEG) recordings (57.5 hours in the continuous EEG [cEE...

Background Neurophysiological exploration of ICU delirium is limited. Here, we examined EEG characteristics of medical-surgical critically ill patients with new onset altered consciousness state at high risk for ICU delirium. Methods Pre-planned analysis of non-neurological mechanically ventilated medical-surgical ICU subjects, who underwent a pro...

Background Early prognostication in patients with acute consciousness impairment is a challenging but essential task. Current prognostic guidelines vary with the underlying etiology. In particular, electroencephalography (EEG) is the most important paraclinical examination tool in patients with hypoxic ischemic encephalopathy (HIE), whereas it is n...

Objective The 2014 update of the Swiss law on research increases patients' protection; it adds specific requirements for emergency situations, implying an active search for patients' wishes regarding research participation; the possibility of consent waivers is not clearly stated. We explored its practical impact in a RCT on critically ill adults....

The cyclical structure of epilepsy was recently (re)-discovered through years-long intracranial electroencephalography (EEG) obtained with implanted devices. In this review, we discuss how new revelations from chronic EEG relate to the practice and interpretation of conventional EEG. We argue for an electrographic definition of seizures and highlig...

Sleep spindle generation classically relies on an interplay between the thalamic reticular nucleus (TRN), thalamo-cortical (TC) relay cells and cortico-thalamic (CT) feedback during non-rapid eye movement (NREM) sleep. Spindles are hypothesized to stabilize sleep, gate sensory processing and consolidate memory. However, the contribution of non-sens...

Epilepsie ist eine häufige neurologische Erkrankung, die zunehmend besser behan-delbar ist. Epileptische Anfälle treten in Zyklen auf, weshalb eine dynamische und personalisierte Behandlung sinnvoll ist. Dank der Fortschritte im Bereich des Neu-roengineering wird es in den folgenden zehn Jahren zahlreiche neue Entwicklungen geben, die den Patienten...

We propose an intracranial electroencephalography (iEEG) based algorithm for detecting epileptic seizures with short latency, and with identifying the most relevant electrodes. Our algorithm first extracts three features, namely mean amplitude, line length, and local binary patterns that are fed to an ensemble of classifiers using hyperdimensional...

Importance In critically ill patients with altered consciousness, continuous electroencephalogram (cEEG) improves seizure detection, but is resource-consuming compared with routine EEG (rEEG). It is also uncertain whether cEEG has an effect on outcome. Objective To assess whether cEEG is associated with reduced mortality compared with rEEG. Desig...

Diagnosis of epilepsy after a first unprovoked seizure is possible according to the guidelines by the International League Against Epilepsy, if the risk recurrence of a second unprovoked seizure is exceeding 60%. However, this cutoff constitutes only a proxy depending on the patients’ history, magnetic resonance imaging (MRI), and electroencephalog...

Dieses Kapitel beschreibt wie die elektrische Aktivität der Nervenzellen im Gehirn von aussen gemessen werden kann. Die Messung nennt sich Elektroenzephalographie (EEG) und beruht auf der Registrierung sehr kleiner Stromveränderungen auf der Kopfoberfläche die durch aktive Nervenzellen verursacht werden. Das Kapitel beschreibt zuerst die neurophysi...

Purpose of review: Epilepsy is a dynamical disorder of the brain characterized by sudden, seemingly unpredictable transitions to the ictal state. When and how these transitions occur remain unresolved questions in neurology. Recent findings: Modelling work based on dynamical systems theory proposed that a slow control parameter is necessary to e...

Aim: Multimodal prognostication in comatose patients after cardiac arrest (CA) is complicated by the fact that different modalities are usually not independent. Here we set out to systematically correlate early EEG and MRI findings. Methods: 89 adult patients from a prospective register who underwent at least one EEG and one MRI in the acute pha...

High frequency oscillations (HFOs) are traditional biomarkers to identify the epileptogenic tissue during presurgical evaluation in pharmacoresistant epileptic patients. Recently, the resection of brain tissue exhibiting coupling between the amplitude of HFOs and the phase of low frequencies demonstrated a more favorable surgical outcome. Here we c...

Resection of the seizure generating tissue can be highly beneficial in patients with drug‐resistant epilepsy. However, only about half of all patients undergoing surgery get permanently and completely seizure free. Investigating the dependences between intracranial EEG signals adds a multivariate perspective largely unavailable to visual EEG analys...

Network models of brain dynamics provide valuable insight into the healthy functioning of the brain and how this breaks down in disease. A pertinent example is the use of network models to understand seizure generation (ictogenesis) in epilepsy. Recently, computational models have emerged to aid our understanding of seizures and to predict the outc...

Theta phase modulates gamma amplitude in hippocampal networks during spatial navigation and rapid eye movement (REM) sleep. This cross-frequency coupling has been linked to working memory and spatial memory consolidation, however, its spatial and temporal dynamics remains unclear. Here, we first investigate the dynamics of theta-gamma interactions...

Objective: We develop a fast learning algorithm combining symbolic dynamics and brain-inspired hyperdimensional computing for both seizure onset detection and identification of ictogenic (seizure generating) brain regions from intracranial electroencephalography (iEEG). Methods: Our algorithm first transforms iEEG time series from each electrode...

Network models of brain dynamics provide valuable insight into the healthy functioning of the brain and how this breaks down in disease. A pertinent example is the use of network models to understand seizure generation (ictogenesis) in epilepsy. Recently, computational models have emerged to aid our understanding of seizures and to predict the outc...

Genetic generalized epilepsies (GGEs) are a group of seizure syndromes that start in childhood and adolescence. Although generally viewed as benign, large-scale epidemiological studies suggest that a significant proportion of GGE patients suffer from drug-resistant seizures, cognitive impairment and social problems. This motivates further research...

Epilepsy is a cyclical brain disorder par excellence: Single or clusters of spontaneous seizures recur with relatively fixed symptom-free intervals. This temporal structure of epilepsy is a fascinating phenomenon that likely has an endogenous basis. Over the past decades, seizure prediction has been a niche endeavor for a few epileptologists and sc...

About thirty percent of patients with focal epilepsy continue to have seizures despite best possible treatment with seizure suppressive drugs. For these patients, epilepsy surgery is currently the best chance to attain seizure freedom. Pre-surgical evaluation is a highly specialized task, and aims at a) delineating the brain area responsible for se...

The identification of effective targets for resection is a crucial requirement for the surgical treatment of epilepsy. Quantitative methods have the potential to provide beneficial information in this regard and might in the future reduce the necessary time and effort for physicians. The approach described here uses a distributional clustering fram...

August 2024: An English version can be found at: https://medium.com/@kaspar.schindler/a-primer-on-eeg-reading-79da89184308

Since the discovery of electrical activity of the brain electroencephalographic recordings (EEG) constitute one of the most popular techniques of brain research. However, EEG-signals are highly non-stationary and one should expect that averages of the cross-correlation coefficient, which may take positive and negative values with equal probability,...

This paper presents an efficient binarized algorithm for both learning and classification of human epileptic seizures from intracranial electroencephalography (iEEG). The algorithm combines local binary patterns with brain-inspired hyperdimensional computing to enable end-to-end learning and inference with binary operations. The algorithm first tra...

We study two-layer networks of identical phase oscillators. Each individual layer is a ring network for which a non-local intra-layer coupling leads to the formation of a chimera state. The number of oscillators and their natural frequencies is in general different across the layers. We couple the phases of individual oscillators in one layer to th...

Network oscillations in the brain are routinely recorded in the clinic and in the research lab. Here we outline a new paradigm in which network oscillations serve as treatment targets for noninvasive brain stimulation. We show how transcranial alternating current stimulation (tACS) can be used to modulate network oscillations that are impaired in d...

Background: Quantitative analysis of intracranial EEG is a promising tool to assist clinicians in the planning of resective brain surgery in patients suffering from pharmacoresistant epilepsies. Quantifying the accuracy of such tools, however, is nontrivial as a ground truth to verify predictions about hypothetical resections is missing. New meth...

Introduction Experimental studies suggested a role for sleep in the reorganization of neuronal connectivity map and brain plasticity during stroke recovery. Here, we investigate the role of Slow Waves (SW) oscillations during sleep on brain plasticity following ischemic stroke using optogenetic tools and in vivo electrophysiology in mice. Methods...

Zusammenfassung Die Theorie der Netzwerke hat sich zu einem bedeutsamen Werkzeug bei der Analyse komplexer Systeme entwickelt und ihre Methoden werden erfolgreich angewendet, um die Dynamik epileptischer Anfälle zu verstehen. In diesem Artikel wird eine nicht-technische Einführung in die Konzepte der Netzwerktheorie gegeben. Ausgehend von intrakran...

Objective Large-scale connectivity, especially interhemispheric connections, plays a crucial role for recovery after stroke. Here we used methods from information theory to characterize interhemispheric information flow in wake- and sleep-EEG after cerebral ischemia. Methods 33 patients with unilateral ischemic stroke were included. Symbolic Trans...

Recent studies have shown that mathematical models can be used to analyze brain networks by quantifying how likely they are to generate seizures. In particular, we have introduced the quantity termed brain network ictogenicity (BNI), which was demonstrated to have the capability of differentiating between functional connectivity (FC) of healthy ind...

Continuous video-EEG is recommended for patients with altered consciousness; as compared to routine EEG (lasting <30 minutes), it improves seizure detection, but is time- and resource-consuming. Although North American centers increasingly implement continuous video-EEG, most other (including European) hospitals have insufficient resources. Only on...

A correction to this article has been published and is linked from the HTML version of this paper. The error has been fixed in the paper.

Volumetric and morphometric studies have demonstrated structural abnormalities related to chronic epilepsies on a cohort- and population-based level. On a single-patient level, specific patterns of atrophy or cortical reorganization may be widespread and heterogeneous but represent potential targets for further personalized image analysis and surgi...

Background: Sleepwalking (SW) is found to affect children predominantly, but it can persist or appear de novo even among adults. In this study, we assessed the demographic, clinical and polysomnographic profile, trigger factors and associated comorbidities of adult-onset (AO-SW) and childhood-onset (CO-SW) adult sleepwalkers. Methods: In adult s...

Theta phase modulates gamma amplitude during spatial navigation and rapid eye movement sleep (REMs). Although the REMs theta rhythm has been linked to spatial memory consolidation, the underlying mechanism remains unclear. We investigate dynamics of theta-gamma interactions across multiple frequency and temporal scales in simultaneous recordings fr...

Surgery is a therapeutic option for people with epilepsy whose seizures are not controlled by anti-epilepsy drugs. In pre-surgical planning, an array of data modalities, often including intra-cranial EEG, is used in an attempt to map regions of the brain thought to be crucial for the generation of seizures. These regions are then resected with the...

NI of different directed network topologies in the CM. Each row corresponds to a different network topology: (a)-(c) random network; (d)-(f) scale-free network (SF) (γ = 3); (g)-(i) small-world network (SW); (j)-(l) rich-club (RC) network. In the first column the nodes are sorted by their NI, so that NI is monotonically increasing; in the second co...

Interictal spikes (IS) are one of the major hallmarks of epilepsy. Understanding the factors promoting or suppressing IS would increase our comprehension of epilepsy and possibly open new avenues for therapy. Sleep strongly influences epileptic activity, and the modulatory effects of the different sleep stages on IS have been studied for decades. H...