Overcoming traps and pitfalls leading to misinterpretation of normal EEG variants and variation of the background activity.

Normal EEG variants, especially the epileptiform variants, can be challenging to interpret because they often have sharp contours and may be confused with "epileptic" interictal activities. However, they can be recognized by the fact that "most spikes or sharp wave discharges of clinical import are followed by a slow wave or a series of slow deflections" (Maulsby, 1971). If there is no wave after the spike, electroencephalographers should be suspicious of artifacts and normal EEG variants. Most normal EEG variants display a single rhythm with the same frequency within the pattern and the morphology remains stable throughout the entire EEG recording with repetition of the same pattern. In case of doubt or difficulties with a standard EEG, it is recommended to undergo an EEG that includes sleep stages with or without sleep deprivation. Finally, epileptiform is an ambiguous term corresponding to an electroencephalographic trait. Epileptiform does not imply a pathological condition, including epilepsy. The clinical context remains the most paramount in the diagnosis of epilepsy. In this article, we propose a set of rules and guidelines to identify normal EEG variants in EEG tracings and normal variation of the background activity. It is not easy to accurately assign a specific/precise name to all EEG activity, but with an orderly approach to EEG that involves using a set of criteria, nonepileptic activity can be identified.

The role of stand-alone videos in the diagnosis of seizures.

The diagnosis of seizures and seizure mimics relies primarily on the history, but history has well-known limitations. Video recordings of events are a powerful extension of the history because they allow neurologists to view the events in question. In addition, they are readily available in situation, whereas the gold standard of EEG-video is not. That includes underserved or rural areas, and events that are too infrequent to be captured during a few days of EEG-video monitoring. Brief cellphone videos have been shown to be valuable to suggest or guide the correct diagnosis.

Efficacy of highly purified cannabidiol (CBD) in typical absence seizures: A pilot study.

OBJECTIVES: Clinical trials for typical absence seizures are notoriously difficult, because those seizures are clinically subtle and brief, so that seizure counts by caregivers are inaccurate. As a result, treatment options are limited. Currently, there are no published studies on the use of CBD in typical absence seizures. This pilot study aims to evaluate the efficacy of pharmaceutical grade CBD in typical absence seizures. METHODS: We prospectively enrolled 14 patients aged 6 years and older, diagnosed with typical absence seizures. A baseline 24-hour ambulatory EEG was conducted, followed by a second 24-hour EEG after 90 days of treatment. The outcome was an objective measure of spike-wave complexes (SWC) burden change from pre- to post- treatment. RESULTS: After taking CBD for 90 days, 9 (64.3%) patients had an increase in SWC (ranging from 8% to 2876.5%) and 5 (35.7%) had a decrease in SWC (ranging from 62.3% to 98.9%). Of the 5 patients who had a decrease, 3 (60%) were on concomitant ethosuximide (with or without other ASMs). All 3 patients on CBD and ethosuximide improved. CONCLUSIONS: Although based on a small subset of patients, our results suggest that CBD may not be effective for typical absence seizures. However, patients on concomitant ethosuximide or on CBD monotherapy were more likely to improve.

The Yield of Ambulatory Video-EEG: Predictors of Successful Event Capture.

Background and Objectives: The purpose of this study was to assess the likelihood of capturing a patient's typical event in question on ambulatory video-EEG monitoring (AVEM) based on certain baseline patient or event characteristics. Methods: We retrospectively reviewed 300 studies that resulted between June 2021 and August 2022 ordered by adult epileptologists. Patients were included in event analysis if the study was ordered for the purpose of capturing an event (and excluded for all other purposes). Results: A total of 149 studies were included in event analysis. Sixty-eight patients (46%) had their typical events captured on AVEM. Diagnosis was an epileptic seizure in 17 patients (25%), psychogenic nonepileptic seizure in 7 (10%), and other nonepileptic events in 44 (65%). Regarding event frequency, for patients who on average had daily events, 84% had events captured, which corresponds to a significantly increased odds ratio (OR 17.90, 95% CI 7.55-42.44, p < 0.001). For those who had events <1 per week to ≥1 per month, only 9% had events captured (OR 0.06, 95% CI 0.02-0.19, p < 0.001). No patients who had events less frequently than once per month had a diagnostic AVEM. Regarding the number of antiseizure medications (ASMs), the odds ratio was increased for those not on ASMs (OR 2.65, 95% CI 1.17 -6.03, p = 0.02) and decreased for those on 1 ASM (OR 0.28, 95% CI 0.13 -0.60, p = 0.001). There was no statistical significance based on event type (motor vs nonmotor), prior seizure diagnosis, history of psychiatric comorbidity, or presence of a focal brain lesion. Discussion: Certain baseline characteristics can increase or decrease the pretest probability of capturing a typical event on AVEM, particularly the frequency of events and number of ASMs. This can be useful information for clinicians before ordering a study so that resources can be properly allocated.

The Best Seizure Diagnostic Tool Is Not a Medical Device: Why Stand-Alone Video Review Needs a Current Procedural Terminology Code.

The diagnosis of seizures and epilepsy is primarily based on the history, but history-taking is fraught with difficulties and has serious limitations, which is one reason for the common misdiagnosis of seizures. EEG is a very useful tool, but routine EEG has poor sensitivity, and prolonged EEG-video monitoring, the gold-standard for diagnosis, is only useful for patients with frequent events. Smartphones are ubiquitous, and their videos are increasingly used as an extension of the history and a diagnostic tool. Stand-alone videos should be considered a diagnostic tool and treated as such, including with a Current Procedural Terminology (CPT) code, the American uniform nomenclature for medical procedures, which is used for billing and reimbursement.

Normal variants and artifacts: Importance in EEG interpretation.

Overinterpretation of EEG is an important contributor to the misdiagnosis of epilepsy. For the EEG to have a high diagnostic value and high specificity, it is critical to recognize waveforms that can be mistaken for abnormal patterns. This article describes artifacts, normal rhythms, and normal patterns that are prone to being misinterpreted as abnormal. Artifacts are potentials generated outside the brain. They are divided into physiologic and extraphysiologic. Physiologic artifacts arise from the body and include EMG, eyes, various movements, EKG, pulse, and sweat. Some physiologic artifacts can be useful for interpretation such as EMG and eye movements. Extraphysiologic artifacts arise from outside the body, and in turn can be divided into the environments (electrodes, equipment, and cellphones) and devices within the body (pacemakers and neurostimulators). Normal rhythms can be divided into awake patterns (alpha rhythm and its variants, mu rhythm, lambda waves, posterior slow waves of youth, HV-induced slowing, photic driving, and photomyogenic response) and sleep patterns (POSTS, vertex waves, spindles, K complexes, sleep-related hypersynchrony, and frontal arousal rhythm). Breach can affect both awake and sleep rhythms. Normal variants or variants of uncertain clinical significance include variants that may have been considered abnormal in the early days of EEG but are now considered normal. These include wicket spikes and wicket rhythms (the most common normal pattern overread as epileptiform), small sharp spikes (aka benign epileptiform transients of sleep), rhythmic midtemporal theta of drowsiness (aka psychomotor variant), Cigánek rhythm (aka midline theta), 6 Hz phantom spike-wave, 14 and 6 Hz positive spikes, subclinical rhythmic epileptiform discharges of adults (SREDA), slow-fused transients, occipital spikes of blindness, and temporal slowing of the elderly. Correctly identifying artifacts and normal patterns can help avoid overinterpretation and misdiagnosis. This is an educational review paper addressing a learning objective of the International League Against Epilepsy (ILAE) curriculum.

EEG reading with or without clinical information - a real-world practice study.

We sought to investigate electroencephalographers' real-world behaviors and opinions concerning reading routine EEG (rEEG) with or without clinical information. An eight-question, anonymous, online survey targeted at electroencephalographers was disseminated on social media from the authors' personal accounts and emailed to authors' select colleagues. A total of 389 responses were included. Most respondents reported examining clinical information before describing rEEG findings. Nonetheless, only a minority of respondents believe that EEG analysis/description should be influenced by clinical information. We recommend reviewing clinical data only after an unbiased EEG read to prevent history bias and ensure generation of reliable electrodiagnostic information.

Use of new intranasal benzodiazepines at a typical adult epilepsy center.

OBJECTIVE: The aim of this study was to review out-of-hospital use of intranasal diazepam and midazolam for treatment of acute repetitive seizures (ARS) at a typical adult epilepsy center. METHODS: Data were collected through chart review and by telephone calls to either the patient or the caregiver regarding drug effectiveness, overall satisfaction, and adverse events. RESULTS: We identified 96 patients who were prescribed either benzodiazepine. Thirty-nine patients in the diazepam group and 38 patients in the midazolam group were able to be contacted and were included in the study. Sixty-two percent of patients in the diazepam group and 55% of patients in the midazolam group had used the medication at the time of data collection. Of these patients, 83% of patients in the diazepam group and 85% of patients in the midazolam group reported cessation of seizures after either the first or second dose. In comparison of the average patient satisfaction between intranasal diazepam and midazolam, there was no statistical significance (4.25 ± 1.22 vs 3.95 ± 1.35; p = 0.42). Adverse events were minor, included fatigue, nasal discomfort, headache, and dizziness. DISCUSSION: The use of the two new intranasal benzodiazepines was roughly divided equally. Slightly more than half of the patients who were prescribed the medication had used it. The overall satisfaction of the two medications was comparable. These findings highlight the principal usability of intranasal diazepam and midazolam in adults with ARS.

Value of smartphone videos for diagnosis of seizures: Everyone owns half an epilepsy monitoring unit.

The diagnosis of epilepsy is primarily based on the history and the verbal description of the events in question. Smartphone videos are increasingly used to assist in the diagnosis. The purpose of this study is to evaluate their value for the diagnosis of seizures. We prospectively collected smartphone videos from patients who presented to our epilepsy center over two years. The video-based diagnosis was then compared to the eventual diagnosis based on video-electroencephalographic (EEG) monitoring with recorded episodes. Video-EEG studies and smartphone videos were reviewed by two separate physicians, each blinded to the other's interpretation. Fifty-four patients were included in the final analysis (mean age = 34.7 years, SD = 17 years). Data (either smartphone video or video-EEG monitoring) were inconclusive in 18 patients. Of the 36 patients with conclusive data, 34 (94%) were in agreement. Smartphone video interpretation can be a useful adjunctive tool in the diagnosis of seizure-like events.

Intracranial recordings for non-lesional mesiotemporal epilepsy? Almost always, but not quite always.

•The majority of patients with non-lesional mesial TLE needs intracranial recordings.•This rule should not be rigid and there are some exceptions. Decisions should be individualized.•For bilateral mesial temporal lobe epilepsy, chronic ECoG with RNS may be preferable over "traditional" short-term intracranial recording.

Fish soup for the falling sickness: Tracing epilepsy through Hmong and Western beliefs.

Hmong communities originated in China but today are located across the globe. Salvation, health, and well-being in Hmong tradition are contingent upon pleasing spirits and ancestors. While most diseases are believed to reflect the displeasure of spirits and ancestors, epilepsy is unique in that it portends a heightened capacity for achieving an elevated level of spirituality, which has led it to be deemed honorable by Hmong society members. This stands in stark contrast to some contexts within which epilepsy has been historically understood in the West in which the disease was believed to originate from sin and evil. If and how societal response toward persons with epilepsy (PWE) in Hmong communities differ from that in other Western communities in a way that parallels these differences in beliefs regarding the etiology and significance of the seizures is unknown. Understanding this may have implications that guide efforts in combatting stigma affecting PWE.

The Yield of Ambulatory EEG-Video Monitoring.

INTRODUCTION: The availability of ambulatory EEG-video monitoring gives an alternative to traditional inpatient EEG-video, but its yield and diagnostic value are not well known. This study evaluates the yield of ambulatory EEG-video for the diagnosis of epilepsy. METHODS: We retrospectively reviewed the ambulatory EEG-video monitoring data from 200 consecutive and unselected patients aged 12 years and older performed by a single company (RSC Diagnostic Services) between January 2018 and May 2018. Studies were processed by two senior certified long-term monitoring EEG technologists and interpreted by neurologists. RESULTS: Of the 200 patients, 130 (65%) were women, mean age was 45 years. Mean duration of studies were 76.6 hours (range 23-175 hours). There were 110 studies (55%) with events recorded and 101 (92%) were captured on video. Epileptic events accounted for 17.8% (18/101) of the events captured and 9% (18/200) of our total cohort. Nonepileptic diagnosis accounted for 38% of the total number of patients in study (76/200). CONCLUSION: Ambulatory EEG-video monitoring may be a useful alternative to inpatient epilepsy monitoring unit, particularly with high clinical suspicion for nonepileptic events.

Driving a motor vehicle and psychogenic nonepileptic seizures: ILAE Report by the Task Force on Psychogenic Nonepileptic Seizures.

OBJECTIVES: This International League Against Epilepsy (ILAE) Report: (a) summarizes the literature about "driving and psychogenic nonepileptic seizures (PNES)"; (b) presents the views of international experts; and (c) proposes an approach to assessing the ability of persons with PNES (PwPNES) to drive. METHODS: Phase 1: Systematic literature review. Phase 2: Collection of international expert opinion using SurveyMonkey®. Experts included the members of the ILAE PNES Task Force and individuals with relevant publications since 2000. Phase 3: Joint analysis of the findings and refinement of conclusions by all participants using email. As an ILAE Report, the resulting text was reviewed by the Psychiatry Commission, the ILAE Task Force on Driving Guidelines, and Executive Committee. RESULTS: Eight studies identified by the systematic review process failed to provide a firm evidence base for PNES-related driving regulations, but suggest that most health professionals think restrictions are appropriate. Twenty-six experts responded to the survey. Most held the view that decisions about driving privileges should consider individual patient and PNES characteristics and take account of whether permits are sought for private or commercial driving. Most felt that those with active PNES should not be allowed to drive unless certain criteria were met and that PNES should be thought of as "active" if the last psychogenic seizure had occurred within 6 months. SIGNIFICANCE: Recommendations on whether PwPNES can drive should be made at the individual patient level. Until future research has determined the risk of accidents in PwPNES a proposed algorithm may guide decisions about driving advice.

The role of EEG in patients with suspected epilepsy.

Despite the advances in imaging, EEG remains a critical test for the diagnosis of epilepsy. Not only can it confirm the diagnosis, but it can also clarify the type of epilepsy. There are many different types of EEG recordings depending on duration, the presence of video, and inpatient or outpatient setting, each with its pros and cons. Interictal epileptiform abnormalities are very specific to epilepsy, but they can be over-interpreted by inexperienced readers. In addition to diagnosis of epilepsy, EEG also has a role in the decision to discontinue treatment in seizure-free patients, and in assessing critically ill patients for possible status epilepticus and encephalopathies. EEG reports should be relatively standardized and clear to the clinician who requested the EEG.