Maxime O Baud

Neurology Department, Inselspital, Universitätsspital Bern · Neurology

Evidence collected from trials of chronic electroencephalographic (EEG) recordings has shown that a cyclical organization of seizures and interictal epileptiform activity is widespread among patients with focal epilepsy. Yet, seizures reported by patients themselves or their family do not always exhibit such regularity. In this review, we discuss v...

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...

Seizures in people with epilepsy were long thought to occur at random, but recent methods for seizure forecasting enable estimation of the likelihood of seizure occurrence over short horizons. These methods rely on days-long cyclical patterns of brain electrical activity and other physiological variables that determine seizure likelihood and that r...

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...

Objective This study was undertaken to determine the effects of antiseizure medications (ASMs) on multidien (multiday) cycles of interictal epileptiform activity (IEA) and seizures and evaluate their potential clinical significance. Methods We retrospectively analyzed up to 10 years of data from 88 of the 256 total adults with pharmacoresistant fo...

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...

This scientific commentary refers to ‘’Chronic intracranial EEG recordings and interictal spike rate reveal multiscale temporal modulations in seizure states” by Schroeder et al. (https://doi.org/10.1093/braincomms/fcad205)

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...

Electroencephalography (EEG) has been the primary diagnostic tool in clinical epilepsy for nearly a century. Its review is performed using qualitative clinical methods that have changed little over time. However, the intersection of higher resolution digital EEG and analytical tools developed in the past decade invites a re‐exploration of relevant...

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...

Objective Epilepsy is characterized by spontaneous seizures that recur at unexpected times. Nonetheless, using years‐long electroencephalographic (EEG) recordings, we previously found that patient‐reported seizures consistently occur when interictal epileptiform activity (IEA) cyclically builds up over days. This multidien (multiday) interictal–ict...

To date, the unpredictability of seizures remains a source of suffering for people with epilepsy, motivating decades of research into methods to forecast seizures. Originally, only few scientists and neurologists ventured into this niche endeavor, which, given the difficulty of the task, soon turned into a long and winding road. Over the past decad...

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...

Epilepsy is among the most dynamic disorders in neurology. A canonical view holds that seizures, the characteristic sign of epilepsy, occur at random, but, for centuries, humans have looked for patterns of temporal organization in seizure occurrence. Observations that seizures are cyclical date back to antiquity, but recent technological advances h...

Objective Intracranial electroencephalography (ICEEG) recordings are performed for seizure localization in medically refractory epilepsy. Signal quantifications such as frequency power can be projected as heatmaps on personalized three‐dimensional (3D) reconstructed cortical surfaces to distill these complex recordings into intuitive cinematic visu...

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...

Importance: Focal epilepsy is characterized by the cyclical recurrence of seizures, but, to our knowledge, the prevalence and patterns of seizure cycles are unknown. Objective: To establish the prevalence, strength, and temporal patterns of seizure cycles over timescales of hours to years. Design, setting, and participants: This retrospective...

Paroxysms are sudden, unpredictable, short-lived events that abound in physiological processes and pathological disorders, from cellular functions (e.g., hormone secretion and neuronal firing) to life-threatening attacks (e.g., cardiac arrhythmia, epileptic seizures, and diabetic ketoacidosis). With the increasing use of personal chronic monitoring...

Purpose There are multidien patterns of seizure occurrence. Predicting seizure risk may be easier with biomarker correlates to multidien patterns. We hypothesize multiday hyper or hypoglycemia contributes to seizure risk. Methods In a type I diabetic (T1D) with focal onset epilepsy with continuous glucose monitoring (CGM) and responsive neurostimu...

Background People with epilepsy are burdened with the apparent unpredictability of seizures. In the past decade, converging evidence from studies using chronic EEG (cEEG) revealed that epileptic brain activity shows robust cycles, operating over hours (circadian) and days (multidien). We hypothesised that these cycles can be leveraged to estimate f...

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...

The cyclical organization of seizures in epilepsy has been described since antiquity. However, historical explanations for seizure cycles—based on celestial, hormonal, and environmental factors—have only recently become testable with the advent of chronic electroencephalography (cEEG) and modern statistical techniques. Here, factors purported over...

Objective Seizure clusters are often encountered in people with poorly controlled epilepsy. Detection of seizure clusters is currently based on simple clinical rules, such as two seizures separated by four or fewer hours or multiple seizures in 24 hours. Current definitions fail to distinguish between statistically significant clusters and those th...

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...

For persons with epilepsy, much suffering stems from the apparent unpredictability of seizures. Historically, efforts to predict seizures have sought to detect changes in brain activity in the seconds to minutes preceding seizures (pre-ictal period), a timeframe that limits preventative interventions. Recently, converging evidence from studies usin...

The current paradigm for treatment of epilepsy begins with trials of antiepileptic drugs, followed by evaluation for resective brain surgery in drug-resistant patients. If surgery is not possible or fails to control seizures, some patients benefit from implanted neurostimulation devices. In addition to their therapeutic benefit, some of these devic...

Objective: Resective surgery is effective in treating drug-resistant focal epilepsy, but it remains unclear whether improved diagnostics influence postsurgical outcomes. Here, we compared practice and outcomes over 2 periods 15 years apart. Methods: Sixteen European centers retrospectively identified 2 cohorts of children and adults who underwen...

BACKGROUND AND PURPOSE Surgery is the first choice therapeutic approach in case of drug‐resistant epilepsy. Unfortunately, up to 43% of patients referred for presurgical assessment do not have a lesion detectable by routine 3T magnetic resonance imaging (MRI) (MRI‐negative), although most of them likely have an underlying epileptogenic lesion. Thus...

Epilepsy is defined by the seemingly random occurrence of spontaneous seizures. The ability to anticipate seizures would enable preventative treatment strategies. A central but unresolved question concerns the relationship of seizure timing to fluctuating rates of interictal epileptiform discharges (here termed interictal epileptiform activity, IEA...

Objective The mechanism of hypoglycorrhachia—low CSF glucose—in meningitis remains unknown. We sought to evaluate the relative contribution of CSF inflammation vs microorganisms (bacteria and fungi) in lowering CSF glucose levels. Methods We retrospectively categorized CSF profiles into microbial and aseptic meningitis and analyzed CSF leukocyte c...

Background: Interictal epileptiform discharges are an important biomarker for localization of focal epilepsy, especially in patients who undergo chronic intracranial monitoring. Manual detection of these pathophysiological events is cumbersome, but is still superior to current rule-based approaches in most automated algorithms. Objective: To dev...

Supplementary Figures 1-10 and Supplementary Table 1.

Humans are adept at understanding speech despite the fact that our natural listening environment is often filled with interference. An example of this capacity is phoneme restoration, in which part of a word is completely replaced by noise, yet listeners report hearing the whole word. The neurological basis for this unconscious fill-in phenomenon i...

Sleep is viewed as a fundamental restorative function of the brain, but its specific role in neural energy budget remains poorly understood. Sleep deprivation dampens brain energy metabolism and impairs cognitive functions. Intriguingly, sleep fragmentation, despite normal total sleep duration, has a similar cognitive impact, and in this paper we a...

Frontal lobe epilepsy (FLE) frequently leads to secondary generalized tonic-clonic seizures (SGTCS). However, little is known about the clinical, electrophysiologic, and radiologic correlates of SGTCS and whether these could influence diagnosis and treatment. A cohort of 48 patients with confirmed FLE was retrospectively identified and dichotomized...

Cocaine use is associated with multiple neurovascular complications, including ischemic and hemorrhagic strokes. Intracerebral hemorrhage is especially prevalent in patients with acute cocaine intoxication as defined by positive urine toxin assays.1 In addition, intracerebral hemorrhage in patients with cocaine intoxication are more severe, often a...

A 61-year-old man presented with orthostatic headaches and asymmetric sensorineural hearing loss (ASNHL) 8 years after cervical laminoplasty. Percussion of his cervical spine elicited Lhermitte sign. Brain MRI demonstrated trace intraventricular blood and mild superficial siderosis (figure 1); digital subtraction angiogram had normal results. CT my...

Study objectives: Sleep fragmentation (SF) is an integral feature of sleep apnea and other prevalent sleep disorders. Although the effect of repetitive arousals on cognitive performance is well documented, the effects of long-term SF on electroencephalography (EEG) and molecular markers of sleep homeostasis remain poorly investigated. To address t...

Sleep fragmentation is present in numerous sleep pathologies and constitutes a major feature of patients with obstructive sleep apnea. A prevalence of metabolic syndrome, diabetes and obesity has been shown to be associated to obstructive sleep apnea. While sleep fragmentation has been shown to impact sleep homeostasis, its specific effects on meta...

The quality of sleep has recently come to the forefront of public health concerns in industrialized nations. Indeed, voluntary sleep curtailment is widespread, sleep disorders are increasingly recognized and both correlate with the current epidemiology of diabetes and obesity (Van Cauter and Knutson, 2008). Sleep fragmentation (SF) is a periodic di...