Rhythmic EEG patterns: The oldest idea in the EEG world, but without an obvious definition.

The word "rhythmic" was quickly introduced in the vocabulary of the electroencephalographers with the discovery of the alpha rhythm and typical discharges of spike-and-waves at 3 Hz in childhood absence epilepsy, but without any definition until recently. In its last revision (2017), the International Federation of Clinical Neurophysiology proposed a specific definition. The word "rhythmic" is "applied to regular waves occurring at a constant period and of relatively uniform morphology.

Nonconvulsive status epilepticus in patients under intensive care: Should we view epilepsy as a sleep disorder?

Nonconvulsive status epilepticus (NCSE) was initially described in patients with typical and atypical absence status epilepticus (ASE) characterized by states of confusion varying in severity and in focal epilepsies with or without alteration of consciousness. Continuous EEG monitoring of critically ill patients has further refined the classification of NCSE into two main categories: with coma and without coma. Hypnotic, soporific or somniferous epileptic seizures do not exist.

When patients with Creutzfeldt-Jakob disease are misdiagnosed as having nonconvulsive status epilepticus.

Contemporary studies report nonconvulsive status epilepticus (NCSE) in Creutzfeldt-Jakob disease (CJD), based on benzodiazepine (BZP)-responsive epileptiform discharges on the electroencephalogram (EEG), with the following false syllogism: (1) intravenous (IV) administration of BZPs usually suppress ictal activity in NCSE; (2) in CJD, periodic sharp wave complexes (PSWCs) are suppressed by IV BZPs; (3) therefore, these patients have NCSE. This is a simplistic and invalid conclusion, because authors of 20th-century science reports have clearly shown that IV BZPs, short-acting barbiturates, and drugs with no antiseizure effects, such as chloral hydrate and IV naloxone, suppress PSWCs, but patients fall asleep with no clinical improvement. In contrast, IV methylphenidate transiently improves both the EEG and clinical states.

Stimulus-induced arousal with transient electroencephalographic improvement distinguishes nonictal from ictal generalized periodic discharges.

In the case of suspicion of nonconvulsive status epilepticus (NCSE), reactivity on electroencephalograms (EEGs) can provide valuable diagnostic information. Reactivity refers to responses to auditory or somatosensory stimulation, with changes in amplitude and frequency of background activity. Because of self-perpetuating processes and the failure of self-terminating mechanisms, status epilepticus is unlikely to cease when patients spontaneously move, and it cannot typically be stopped by external stimulation (i.

Epilepsy with eyelid myoclonia (Jeavons syndrome): Generalized, focal, or combined generalized and focal epilepsy syndrome?

Epilepsy with eyelid myoclonia (EM) or Jeavons syndrome (JS) is an epileptic syndrome related to the spectrum of genetic generalized epilepsies (GGE). We report two untreated children on which EEGs were performed several hours after a generalized tonic-clonic seizure (GTCS). These showed a unilateral, nearly continuous posterior slowing.

Bilateral and synchronous "dents de scie" spikes: A highly specific EEG pattern of young adult Dravet syndrome.

Background: In Dravet syndrome (DS), EEGs evolve over time.

Objective: To describe a peculiar EEG pattern in two adults with a de novo SCN1A gene mutation, in exon 5 (case 1) and 9 (case 2).

Methods: Two female patients underwent a prolonged video EEG (24 h) as part of their epilepsy assessment.

Prognostic factors in epilepsy with eyelid myoclonia (Jeavons syndrome).

Purpose: To describe the prognostic factors of drug resistance in 40 patients with epilepsy with eyelid myoclonia or Jeavons syndrome.

Method: Retrospective analysis from two French tertiary centers.

Results: Forty patients were enrolled (31 females and 9 males; mean age at epilepsy onset: 6.

Determining ICU EEG periodic patterns and why it matters.

Historically, periodic EEG patterns were described as any pattern with stereotyped paroxysmal complexes occurring at regular intervals, i.e., the period (T).

Frontal Intermittent Rhythmic Delta Activity Is a Useful Diagnostic Tool of Neurotoxicity After CAR T-Cell Infusion.

Background And Objectives: Chimeric antigen receptor (CAR) T-cell therapies have dramatically improved the prognosis of patients with relapsed or refractory hematologic malignancies; however, cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome (ICANS) occur in ∼100 and 50% of patients, respectively. This study aimed to determine whether EEG patterns may be considered as diagnostic tools for ICANS.

Methods: Patients who received CAR T-cell therapy at Montpellier University Hospital between September 2020 and July 2021 were prospectively enrolled.

Microendoscopic transventricular deep brain stimulation of the anterior nucleus of the thalamus as a safe treatment in intractable epilepsy: A feasibility study.

Introduction: Deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) is proposed in patients with severe intractable epilepsy. When used, the transventricular approach increases the risk of bleeding due the anatomy around the entry point in the thalamus. To avoid such a complication, we used a transventricular microendoscopic technique.

Genotype-phenotype correlations in SCN8A-related disorders reveal prognostic and therapeutic implications.

We report detailed functional analyses and genotype-phenotype correlations in 392 individuals carrying disease-causing variants in SCN8A, encoding the voltage-gated Na+ channel Nav1.6, with the aim of describing clinical phenotypes related to functional effects. Six different clinical subgroups were identified: Group 1, benign familial infantile epilepsy (n = 15, normal cognition, treatable seizures); Group 2, intermediate epilepsy (n = 33, mild intellectual disability, partially pharmaco-responsive); Group 3, developmental and epileptic encephalopathy (n = 177, severe intellectual disability, majority pharmaco-resistant); Group 4, generalized epilepsy (n = 20, mild to moderate intellectual disability, frequently with absence seizures); Group 5, unclassifiable epilepsy (n = 127); and Group 6, neurodevelopmental disorder without epilepsy (n = 20, mild to moderate intellectual disability).

An EEG Voyage in Search of Triphasic Waves-The Sirens and Corsairs on the Encephalopathy/EEG Horizon: A Survey of Triphasic Waves.

Generalized periodic discharges with triphasic wave (TW) morphology, long referred to as TWs, are typical of many toxic, metabolic, infectious, and cerebral structural problems, often in concert. Identifying TWs has been challenging for the electroencephalographer and clinician, as has been their cause, significance, prognosis, and treatment. This review highlights the many different patterns of TWs with commentary on their various causes and etiologies, characteristics, different morbidities, differentiation from nonconvulsive status epilepticus, and their prognosis.

Stimulus-Induced Rhythmic or Periodic Intermittent Discharges (SIRPIDs) in patients with triphasic waves and Creutzfeldt-Jakob disease.

Since the term Stimulus-Induced Rhythmic, Periodic, or Ictal Discharges (SIRPIDs) was introduced into the vocabulary of electrophysiologists/neurologists, there has been an ongoing debate about its significance, as well as its correlation with outcomes. SIRPIDs are frequently seen in patients who are critically ill from various causes. The literature reflects the findings of triphasic morphology, with the generalized periodic discharge (GPD) classification in many patients with SIRPIDs: toxic/metabolic encephalopathies, septic, and hypoxemic/hypercapnic encephalopathies, but also sharp periodic complexes in Creutzfeldt-Jakob disease and advanced Alzheimer's disease.

Lateralized Periodic Discharges: Which patterns are interictal, ictal, or peri-ictal?

There is an ongoing debate if Lateralized Periodic Discharges (LPDs) represent an interictal pattern reflecting non-specific but irritative brain injury, or conversely, is an ictal pattern. The challenge is: how to correctly manage these patients? Between this apparent dichotomous distinction, there is a pattern lying along the interictal-ictal continuum (IIC) that we may call "peri-ictal". Peri-ictal means that LPDs are temporally associated with epileptic seizures (although not necessarily in the same recording).

Benign EEG variants in the sleep-wake cycle: A prospective observational study using the 10-20 system and additional electrodes.

Objectives: To study the prevalence of benign EEG variants (BEVs) in the sleep-wake cycle among 1163 consecutive patients.

Methods: Prospective, observational EEG study using the 10-20 system with systematically two additional anterior-temporal electrodes. Depending on clinical indications, other electrodes were added.

Epilepsy with eyelid myoclonias (Jeavons syndrome): An electro-clinical study of 40 patients from childhood to adulthood.

Purpose: To describe the typical and atypical clinical and electroencephalographic (EEG) features of 40 patients with Jeavons syndrome (JS).

Method: Retrospective analysis from two French tertiary centers.

Results: Forty patients were enrolled (31 females and 9 males; sex ratio F/M = 3.

Will MRI replace the EEG for the diagnosis of nonconvulsive status epilepticus, especially focal?

Magnetic resonance imaging (MRI) can now be used to diagnose or to provide confirmation of focal nonconvulsive status epilepticus (NCSE). Approximately half of patients with status epilepticus (SE) have signal changes. MRI can also aid in the differential diagnosis with generalized NCSE when there is a clinical or EEG doubt, e.

Failure to recognize muscular artifacts on the EEG may cause a wrong diagnosis of myoclonic status epilepticus.

•Quetiapine may cause myoclonus.•Usually, no muscular artifact on the midline EEG electrodes•The EEG pattern of myoclonic jerks is rather polyspike-waves and not only polyspikes.•Failure to recognize muscular artifacts may cause a wrong diagnosis of polyspikes.