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.e., auditory and tactile stimuli). The defining EEG characteristic of absence status epilepticus is the presence of bilateral, synchronous, symmetric, rhythmic paroxysmal activity that shows little or no reactivity to sensory stimulation. On the other hand, in metabolic/toxic or multifactorial encephalopathies, triphasic waves (TWs) are influenced by the level of vigilance. TWs may be transiently abolished when patients increase their level of alertness from a drowsy/lethargic state to a state of wakefulness. This reactivity is only observed when patients can be aroused by a somatosensory or auditory stimulus. This reactivity tends to disappear with increasing severity of the disease and in comatose patients. In patients without preexisting developmental and epileptic encephalopathy, this pattern of stimulus-induced wakefulness with transient improvement of the EEG is a major criterion in determining that the EEG patterns are not ictal. This criterion of reactivity on EEGs, beyond the classical clinical/EEG criteria of NCSE (Salzburg criteria), should now be systematically added.

Enhanced sensitivity of electrocorticography during awake craniotomy using a novel circular grid electrode.

PURPOSE: Awake craniotomy with intraoperative functional brain mapping (FBM) bedside neurological testing is an important technique used to optimize resective brain surgeries near eloquent cortex. Awake craniotomy performed with electrocorticography (ECoG) and direct electrical stimulation (DES) for FBM can delineate eloquent cortex from lesions and epileptogenic regions. However, current electrode technology demonstrates spatial limitations. Our group has developed a novel circular grid with the goal of improving spatial recording of ECoG to enhance detection of ictal and interictal activity. METHODS: This retrospective study was approved by the institutional review board at Mayo Clinic Florida. We analyzed patients undergoing awake craniotomy with ECoG and DES and compared ECoG data obtained using the 22 contact circular grid to standard 6 contact strip electrode. RESULTS: We included 144 cases of awake craniotomy with ECoG, 73 using circular grid and 71 with strip electrode. No significant differences were seen regarding preoperative clinical and demographic data, duration of ECoG recording (p = 0.676) and use of DES (p = 0.926). Circular grid was more sensitive in detecting periodic focal epileptiform discharges (PFEDs) (p = 0.004), PFEDs plus (p = 0.032), afterdischarges (ADs) per case (p = 0.022) at lower minimum (p = 0.012) and maximum (p < 0.0012) intensity stimulation, and seizures (p = 0.048). PFEDs (p < 0.001), PFEDs plus (p < 0.001), and HFOs (p < 0.001) but not ADs (p = 0.255) predicted electrographic seizures. CONCLUSION: We demonstrate higher sensitivity in detecting ictal and interictal activity on ECoG during awake craniotomy with a novel circular grid compared to strip electrode, likely due to better spatial sampling during ECoG. We also found association between PFEDs and intraoperative seizures.

Incidence and risk factors associated with seizures in cerebral amyloid angiopathy.

BACKGROUND AND PURPOSE: Cerebral amyloid angiopathy (CAA) is a common cause of intracranial hemorrhage (ICH), which is a risk factor for seizures. The incidence and risk factors of seizures associated with a heterogeneous cohort of CAA patients have not been studied. METHODS: We conducted a retrospective study of patients with CAA treated at Mayo Clinic Florida between 1 January 2015 and 1 January 2021. CAA was defined using the modified Boston criteria version 2.0. We analyzed electrophysiological and clinical features, and comorbidities including lobar ICH, nontraumatic cortical/convexity subarachnoid hemorrhage (cSAH), superficial siderosis, and inflammation (CAA with inflammation [CAA-ri]). Cognition and mortality were secondary outcomes. Univariate and multivariate analyses were performed to determine risk of seizures relative to clinical presentation. RESULTS: Two hundred eighty-four patients with CAA were identified, with median follow-up of 35.7 months (interquartile range = 13.5-61.3 months). Fifty-six patients (19.7%) had seizures; in 21 (37.5%) patients, seizures were the index feature leading to CAA diagnosis. Seizures were more frequent in females (p = 0.032) and patients with lobar ICH (p = 0.002), cSAH (p = 0.030), superficial siderosis (p < 0.001), and CAA-ri (p = 0.005), and less common in patients with microhemorrhage (p = 0.006). After controlling for age and sex, lobar ICH (odds ratio [OR] = 2.1, 95% confidence interval [CI] = 1.1-4.2), CAA-ri (OR = 3.8, 95% CI = 1.4-10.3), and superficial siderosis (OR = 3.7, 95% CI = 1.9-7.0) were independently associated with higher odds of incident seizures. CONCLUSIONS: Seizures are common in patients with CAA and are independently associated with lobar ICH, CAA-ri, and superficial siderosis. Our results may be applied to optimize clinical monitoring and management for patients with CAA.

Minimum standards for inpatient long-term video-electroencephalographic monitoring: A clinical practice guideline of the International League Against Epilepsy and International Federation of Clinical Neurophysiology.

The objective of this clinical practice guideline is to provide recommendations on the indications and minimum standards for inpatient long-term video-electroencephalographic monitoring (LTVEM). The Working Group of the International League Against Epilepsy and the International Federation of Clinical Neurophysiology develop guidelines aligned with the Epilepsy Guidelines Task Force. We reviewed published evidence using the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) statement. We found limited high-level evidence aimed at specific aspects of diagnosis for LTVEM performed to evaluate patients with seizures and nonepileptic events. For classification of evidence, we used the Clinical Practice Guideline Process Manual of the American Academy of Neurology. We formulated recommendations for the indications, technical requirements, and essential practice elements of LTVEM to derive minimum standards used in the evaluation of patients with suspected epilepsy using GRADE (Grading of Recommendations Assessment, Development, and Evaluation). Further research is needed to obtain evidence about long-term outcome effects of LTVEM and to establish its clinical utility.

Automated seizure detection using wearable devices: A clinical practice guideline of the International League Against Epilepsy and the International Federation of Clinical Neurophysiology.

The objective of this clinical practice guideline (CPG) is to provide recommendations for healthcare personnel working with patients with epilepsy on the use of wearable devices for automated seizure detection in patients with epilepsy, in outpatient, ambulatory settings. The Working Group of the International League Against Epilepsy (ILAE) and the International Federation of Clinical Neurophysiology (IFCN) developed the CPG according to the methodology proposed by the ILAE Epilepsy Guidelines Working Group. We reviewed the published evidence using The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement and evaluated the evidence and formulated the recommendations following the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. We found high level of evidence for the accuracy of automated detection of generalized tonic-clonic seizures (GTCS) and focal-to-bilateral tonic-clonic seizures (FBTCS) and recommend the use of wearable automated seizure detection devices for selected patients when accurate detection of GTCS and FBTCS is recommended as a clinical adjunct. We also found a moderate level of evidence for seizure types without GTCS or FBTCS. However, it was uncertain whether the detected alarms resulted in meaningful clinical outcomes for the patients. We recommend using clinically validated devices for automated detection of GTCS and FBTCS, especially in unsupervised patients, where alarms can result in rapid intervention (weak/conditional recommendation). At present, we do not recommend clinical use of the currently available devices for other seizure types (weak/conditional recommendation). Further research and development are needed to improve the performance of automated seizure detection and to document their accuracy and clinical utility.

Video quality using outpatient smartphone videos in epilepsy: Results from the OSmartViE study.

BACKGROUND AND PURPOSE: The aim of this study was to evaluate the quality of smartphone videos (SVs) of neurologic events in adult epilepsy outpatients. The use of home video recording in patients with neurological disease states is increasing. Experts interpretation of outpatient smartphone videos of seizures and neurological events has demonstrated similar diagnostic accuracy to inpatient video-electroencephalography (EEG) monitoring. METHODS: A prospective, multicenter cohort study was conducted to evaluate SV quality in patients with paroxysmal neurologic events from August 15, 2015 through August 31, 2018. Epileptic seizures (ESs), psychogenic nonepileptic attacks (PNEAs), and physiologic nonepileptic events (PhysNEEs) were confirmed by video-EEG monitoring. Experts and senior neurology residents blindly viewed cloud-based SVs without clinical information. Quality ratings with regard to technical and operator-driven metrics were provided in responses to a survey. RESULTS: Forty-four patients (31 women, age 45.1 years [r = 20-82]) were included and 530 SVs were viewed by a mean of seven experts and six residents; one video per patient was reviewed for a mean of 133.8 s (r = 9-543). In all, 30 patients had PNEAs, 11 had ESs, and three had PhysNEEs. Quality was suitable in 70.8% of SVs (375/530 total views), with 36/44 (81.8%) patient SVs rated as adequate by the majority of reviewers. Accuracy improved with the presence of convulsive features from 72.4% to 98.2% in ESs and from 71.1% to 95.7% in PNEAs. An accurate diagnosis was given by all reviewers (100%) in 11/44 SVs (all PNEAs). Audio was rated as good by 86.2% of reviewers for these SVs compared with 75.4% for the remaining SVs (p = 0.01). Lighting was better in SVs associated with high accuracy (p = 0.06), but clarity was not (p = 0.59). Poor video quality yielded unknown diagnoses in 24.2% of the SVs reviewed. Features hindering diagnosis were limited interactivity, restricted field of view and short video duration. CONCLUSIONS: Smartphone video quality is adequate for clinical interpretation in the majority of patients with paroxysmal neurologic events. Quality can be optimized by encouraging interactivity with the patient, adequate duration of the SV, and enlarged field of view during videography. Quality limitations were primarily operational though accuracy remained for SV review of ESs and PNEAs.

Injection of prophylactic lorazepam versus antiseizure drugs on the localization value of ictal SPECT studies and treatment-emergent adverse events: A single-center prospective study.

OBJECTIVE: We aimed to examine the impact of resumption of home antiseizure drugs alone (ASD-) compared with adjunct administration of scheduled intravenous (IV) lorazepam 2 mg every 6 h (ASD+) following ictal single-photon emission computed tomography (SPECT) injection on the localization value of SPECT studies and treatment-emergent adverse events (TEAEs). METHODS: We conducted a prospective study at Mayo Clinic inpatient epilepsy monitoring unit (EMU) between January 2018 and May 2020 in Jacksonville, Florida. The ASD- and ASD+ groups were compared for concordance of SPECT studies with the epilepsy surgical conference (ESC) consensus or intracranial electroencephalography (icEEG) findings as reference. Treatment-emergent adverse events, obtained from surveys at 24 h and one week postictal SPECT injection, were also compared between both groups. RESULTS: Twenty-two consecutive patients with temporal (eight patients, 36%) and extratemporal (14 patients, 64%) epilepsy were included: 12 ASD+ and 10 ASD-. The two groups were well matched with regard to clinical and ictal SPECT injection characteristics including the occurrence of seizure between ictal and interictal SPECT injections. The localization value of SPECT studies was similar in the two groups. Patients in the ASD+ group reported higher rates of dizziness and excessive sedation at 24 h (p-value = 0.008). Fourteen patients (64%) underwent icEEG monitoring. For the entire cohort, the localization concordance of SPECT analysis by statistical parametric mapping (SPM) was superior to raw ictal SPECT (p-value = 0.003) and subtraction ictal SPECT coregistered to magnetic resonance imaging (MRI) (SISCOM; p-value = 0.021). Eventually, seven patients (31.8%) underwent resective brain surgery of whom four (57.1%) became seizure-free (median follow-up = 22 months). CONCLUSIONS: Our findings suggest that resuming home ASDs without the addition of scheduled IV lorazepam following inpatient ictal SPECT injection is equally efficacious for seizure onset zone (SOZ) localization on SPECT studies, especially SPM. This approach is also associated with fewer transient TEAEs and lower financial cost with no difference in preventing seizure between ictal and interictal SPECT injections.

Potential differences between monolingual and bilingual patients in approach and outcome after awake brain surgery.

INTRODUCTION: 20.8% of the United States population and 67% of the European population speak two or more languages. Intraoperative different languages, mapping, and localization are crucial. This investigation aims to address three questions between BL and ML patients: (1) Are there differences in complications (i.e. seizures) and DECS techniques during intra-operative brain mapping? (2) Is EOR different? and (3) Are there differences in the recovery pattern post-surgery? METHODS: Data from 56 patients that underwent left-sided awake craniotomy for tumors infiltrating possible dominant hemisphere language areas from September 2016 to June 2019 were identified and analyzed in this study; 14 BL and 42 ML control patients. Patient demographics, education level, and the age of language acquisition were documented and evaluated. fMRI was performed on all participants. RESULTS: 0 (0%) BL and 3 (7%) ML experienced intraoperative seizures (P = 0.73). BL patients received a higher direct DECS current in comparison to the ML patients (average = 4.7, 3.8, respectively, P = 0.03). The extent of resection was higher in ML patients in comparison to the BL patients (80.9 vs. 64.8, respectively, P = 0.04). The post-operative KPS scores were higher in BL patients in comparison to ML patients (84.3, 77.4, respectively, P = 0.03). BL showed lower drop in post-operative KPS in comparison to ML patients (- 4.3, - 8.7, respectively, P = 0.03). CONCLUSION: We show that BL patients have a lower incidence of intra-operative seizures, lower EOR, higher post-operative KPS and tolerate higher DECS current, in comparison to ML patients.

The impact of stereotactic laser ablation at a typical epilepsy center.

PURPOSE: Stereotactic laser ablation (SLA) is a novel form of epilepsy surgery for patients with drug-resistant focal epilepsy. We evaluated one hundred consecutive surgeries performed for patients with epilepsy to address the impact of SLA on our therapeutic approach, as well as patient outcomes. METHODS: A retrospective, single center analysis of the last one hundred neurosurgeries for epilepsy was performed from 2013 to 2015. Demographics, surgical procedures, and postoperative measures were assessed up to 5years to compare the effect of SLA on outcome. Confidence intervals (CI) and comparative tests of proportions compared outcomes for SLA and resective surgery. Procedural categorical comparison used Chi-square and Kaplan-Meier curves. Student t-test was utilized for single variables such as age at procedure and seizure onset. RESULTS: One hundred surgeries for epilepsy yielded thirty-three SLAs and twenty-one resections with a mean of 21.7-month and 21.3-month follow-up, respectively. The temporal lobe was the most common target for SLA (92.6%) and resection (75%). A discrete lesion was present on brain magnetic resonance imaging (MRI) in 27/32 (84.4%) of SLA patients compared with 7/20 (35%) of resection patients with a normal MRI. Overall, 55-60% of patients became seizure-free (SF). Four of five patients with initial failure to SLA became SF with subsequent resection surgery. Complications were more frequent with resection although SF outcomes did not differ (Chi square; p=0.79). Stereotactic laser ablation patients were older than those with resections (47.0years vs. 35.4years, p=0.001). The mean length of hospitalization prior to discharge was shorter for SLA (1.18days) compared with open resection (3.43days; SD: 3.16 days) (p=0.0002). CONCLUSION: We now use SLA as a first line therapy at our center in patients with lesional temporal lobe epilepsy (TLE) before resection. Seizure-free outcome with SLA and resection was similar but with a shorter length of stay. Long-term follow-up is recommended to determine sustained SF status from SLA.

Detection of generalized tonic-clonic seizures using surface electromyographic monitoring.

OBJECTIVE: A prospective multicenter phase III trial was undertaken to evaluate the performance and tolerability in the epilepsy monitoring unit (EMU) of an investigational wearable surface electromyographic (sEMG) monitoring system for the detection of generalized tonic-clonic seizures (GTCSs). METHODS: One hundred ninety-nine patients with a history of GTCSs who were admitted to the EMU in 11 level IV epilepsy centers for clinically indicated video-electroencephalographic monitoring also received sEMG monitoring with a wearable device that was worn on the arm over the biceps muscle. All recorded sEMG data were processed at a central site using a previously developed detection algorithm. Detected GTCSs were compared to events verified by a majority of three expert reviewers. RESULTS: For all subjects, the detection algorithm detected 35 of 46 (76%, 95% confidence interval [CI] = 0.61-0.87) of the GTCSs, with a positive predictive value (PPV) of 0.03 and a mean false alarm rate (FAR) of 2.52 per 24 h. For data recorded while the device was placed over the midline of the biceps muscle, the system detected 29 of 29 GTCSs (100%, 95% CI = 0.88-1.00), with a detection delay averaging 7.70 s, a PPV of 6.2%, and a mean FAR of 1.44 per 24 h. Mild to moderate adverse events were reported in 28% (55 of 199) of subjects and led to study withdrawal in 9% (17 of 199). These adverse events consisted mostly of skin irritation caused by the electrode patch that resolved without treatment. No serious adverse events were reported. SIGNIFICANCE: Detection of GTCSs using an sEMG monitoring device on the biceps is feasible. Proper positioning of this device is important for accuracy, and for some patients, minimizing the number of false positives may be challenging.

Neuropsychological outcomes following stereotactic laser amygdalohippocampectomy.

OBJECTIVE: The objective was to analyze neuropsychological testing data from 15 patients before and after stereotactic laser ablation surgery for temporal lobe epilepsy and to describe the seizure outcomes after stereotactic laser ablation surgery. METHODS: A retrospective review of 15 patients who underwent stereotactic laser ablation and who also underwent neuropsychological testing before and after surgery was performed. Verbal and visual memory was assessed in all 15 patients using California Verbal Learning Test and Wechsler Memory Scale IV. Naming was assessed in 9 of 15 patients using the Boston Naming Test. Statistical analysis was performed to determine clinically significant changes using previously validated reliable change indices and proprietary Advanced Clinical Solutions software. Seizure outcome data were evaluated using Engel classification. RESULTS: Postsurgery neuropsychological evaluation demonstrated that all 15 patients experienced at least 1 clinically significant decline in either verbal or visual memory. Ten patients in this series, including five with dominant-hemisphere surgery, demonstrated decline in delayed memory for narrative information (Logical Memory II). By contrast, the Boston Naming Test demonstrated more favorable results after surgery. Two of nine patients demonstrated a clinically significant increase in naming ability, and only one of nine patients demonstrated a clinically significant decline in naming ability. With at least 6months of follow-up after surgery, 33% reported seizure freedom. CONCLUSION: Stereotactic laser ablation can result in clinically significant and meaningful decline in verbal and visual memory when comparing patients to their own presurgical baseline. Naming ability, conversely, is much less likely to be impacted by stereotactic laser ablation and may improve after the procedure.

Index-finger pointing in generalized tonic-clonic seizures.

OBJECTIVE: Most patients with localization-related epilepsy (LRE) and genetic generalized epilepsy (GGE) are classified based on semiology and video-EEG, but both features occasionally fail to provide a definitive diagnosis. Several reliable lateralizing signs have been described, although hand and finger posturing has received little attention. We sought to investigate the frequency of index-finger pointing (IFP) during generalized motor convulsions as a lateralizing semiology in LRE. METHODS: We retrospectively analyzed 98 videos of generalized convulsions in 64 consecutive patients who were admitted for diagnostic video-EEG (vEEG). Demographics were recorded, and IFP ipsilateral, contralateral, and bilateral to vEEG ictal correlate was compared between LRE, GGE, and nonepileptic attacks (NEAs). The angle of IFP was measured to quantify the mean degree of IFP in "pointers" versus "nonpointers". Statistical analysis was completed using JMP 9.0. RESULTS: Index-finger pointing was more common in epileptic GTC seizures than in convulsive NEAs (83.6% vs 12.0%; p<0.001) and was more common in LRE compared with GGE (96% vs 56.6%; p≤0.001). The frequency of contralateral, ipsilateral, or bilateral IFP did not differ between LRE and GGE. The average angle at the MCP joint in "pointers" was 35.8° (SD 22.0°) and in "nonpointers" 3.0° (SD 7.2°). SIGNIFICANCE: This is the first study to examine hand and finger postures as a clinical sign to help classify epilepsy type. The presence of IFP was more common in patients with LRE than in patients with GGE and very rarely occurred in NEA. Index-finger pointing and other hand semiologies are potentially quantifiable localizing signs to aid in the characterization of patients with GTC seizures.

Cortical processing during smartphone text messaging.

OBJECTIVE: The objective of this study was to report the EEG features of text messaging using smartphones. METHODS: One hundred twenty-nine patients were prospectively evaluated during video-EEG monitoring (VEM) over 16months. A reproducible texting rhythm (TR) present during active text messaging with a smartphone was compared with passive and forced audio telephone use, thumb/finger movements, cognitive testing/calculation, scanning eye movements, and speech/language tasks in patients with and without epilepsy. Statistical significance was set at p<0.05. RESULTS: Twenty-seven patients with a TR were identified from a cohort of 129 (93 female, mean age: 36; range: 18-71) unselected VEM patients. Fifty-three out of 129 patients had epileptic seizures (ES), 74/129 had nonepileptic seizures (NES), and 2/129 were dual-diagnosed. A reproducible TR was present in 27/129 (20.9%) specific to text messaging (p<0.0001) and present in 28% of patients with ES and 16% of patients with NES (p=NS). The TR was absent during independent tasks and audio cellular telephone use (p<0.0001). Age, gender, epilepsy type, MRI results, and EEG lateralization in patients with focal seizures were unrelated (p=NS). CONCLUSIONS: Our results suggest that the TR on scalp EEG represents a novel technology-specific neurophysiological alteration of brain networks. We propose that cortical processing in the contemporary brain is uniquely activated by the use of PEDs. SIGNIFICANCE: These findings have practical implications that could impact industry and research in nonverbal communication.

Neurocognitive outcome following stereotactic laser ablation in two patients with MRI-/PET+ mTLE.

The most effective treatment for drug-resistant seizures associated with mesial temporal lobe epilepsy (mTLE) is surgical resection. Neurocognitive sequelae may occur and are especially likely to occur after left temporal lobectomy. Smaller resections observed with selective amygdalohippocampectomy have resulted in a more favorable neurocognitive outcome in some cases when compared to standard anterior temporal lobectomy. Specifically, MRI-guided interstitial laser thermal ablation (MRgLITT) uses a superselective stereotactic amygdalohippocampotomy that has been reported to preserve object recognition and naming abilities compared with standard temporal lobe resection. We report two patients with drug-resistant mTLE and a normal high-resolution 3-T brain MRI who underwent neuropsychological assessment pre- and postleft temporal MRgLITT. Both patients demonstrated preserved visual naming ability following surgery. Semantic verbal fluency declined after surgery, but the magnitude of decline did not reach the statistical threshold for reliable change. Both patients demonstrated statistically significant and clinically meaningful declines in memory, but abilities across other nonmemory neurocognitive domains (i.e., visuospatial ability, attention) were preserved.

Refractory and super-refractory status epilepticus--an update.

Status epilepticus is a medical emergency with a high mortality. Early recognition and initiation of treatment leads to a better response and may improve outcomes. Refractory status epilepticus is defined as recurrent seizure activity despite two appropriately selected and dosed antiepileptic drugs including a benzodiazepine. The term "super-refractory status epilepticus" was introduced during the London-Innsbruck Colloquium on status epilepticus in 2011 and refers to status epilepticus that continues or recurs 24 h or more after the initiation of treatment with anesthetic antiepileptic drugs. This includes cases in which seizure control is attained after induction of anesthesia but recurs on weaning the patient off the anesthetic agent. This article reviews the approach to refractory status epilepticus and super-refractory status epilepticus, including management as well as common pathophysiological causes of these entities.

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.

Early Postoperative Seizures Following Awake Craniotomy and Functional Brain Mapping for Lesionectomy.

OBJECTIVE: Awake craniotomy with electrocorticography (ECoG) and direct electrical stimulation (DES) facilitates lesionectomy while avoiding adverse effects. Early postoperative seizures (EPS), occurring within 7 days following surgery, can lead to morbidity. However, risk factors for EPS after awake craniotomy including clinical and ECoG data are not well defined. METHODS: We retrospectively studied the incidence and risk factors of EPS following awake craniotomy for lesionectomy, and report short-term outcomes between January 1, 2020, and December 31, 2022. RESULTS: We included 138 patients (56 female) who underwent 142 awake craniotomies, average age was 50.78 ± 15.97 years. Eighty-eight (63.7%) patients had a preoperative history of tumor-related epilepsy treated with antiseizure medication (ASM), 12 (13.6%) with drug-resistance. All others (36.3%) received ASM prophylaxis with levetiracetam perioperatively and continued for 14 days. An equal number of cases (71) each utilized a novel circle grid or strip electrodes for ECoG. There were 31 (21.8%) cases of intraoperative seizures, 16 with EPS (11.3%). Acute abnormality on early postoperative neuroimaging (P = 0.01), subarachnoid hemorrhage (P = 0.01), young age (P = 0.01), and persistent postoperative neurologic deficits (P = 0.013) were associated with EPS. Acute abnormality on neuroimaging remained significant in multivariate analysis. Outcomes during hospitalization and early outpatient follow up were worse with EPS. CONCLUSIONS: We report novel findings using ECoG and clinical features to predict EPS, including acute perioperative brain injury, persistent postoperative deficits and young age. Given worse outcomes with EPS, clinical indicators for EPS should alert clinicians of potential need for early postoperative EEG monitoring and perioperative ASM adjustment.

Brain tumor-related epilepsy management: A Society for Neuro-oncology (SNO) consensus review on current management.

Tumor-related epilepsy (TRE) is a frequent and major consequence of brain tumors. Management of TRE is required throughout the course of disease and a deep understanding of diagnosis and treatment is key to improving quality of life. Gross total resection is favored from both an oncologic and epilepsy perspective. Shared mechanisms of tumor growth and epilepsy exist, and emerging data will provide better targeted therapy options. Initial treatment with antiseizure medications (ASM) in conjunction with surgery and/or chemoradiotherapy is typical. The first choice of ASM is critical to optimize seizure control and tolerability considering the effects of the tumor itself. These agents carry a potential for drug-drug interactions and therefore knowledge of mechanisms of action and interactions is needed. A review of adverse effects is necessary to guide ASM adjustments and decision-making. This review highlights the essential aspects of diagnosis and treatment of TRE with ASMs, surgery, chemotherapy, and radiotherapy while indicating areas of uncertainty. Future studies should consider the use of a standardized method of seizure tracking and incorporating seizure outcomes as a primary endpoint of tumor treatment trials.

Radiologic Classification of Hippocampal Sclerosis in Epilepsy.

Temporal lobe epilepsy is a common form of epilepsy that is often associated with hippocampal sclerosis (HS). Although HS is commonly considered a binary assessment in radiological evaluation, it is known that histopathological changes occur in distinct clusters. Some subtypes of HS only affect certain subfields, resulting in minimal changes to the overall volume of the hippocampus. This is likely a major reason why whole hippocampal volumetrics have underperformed versus expert readers. With recent advancements in MRI technology, it is now possible to characterize the substructure of the hippocampus more accurately. However, this is not consistently addressed in radiographic evaluations. The histological subtype of HS is critical for prognosis and treatment decision making, necessitating improved radiological classification of HS. The International League Against Epilepsy (ILAE) has issued a consensus classification scheme for subtyping HS histopathological changes. This review aims to explore how the ILAE subtypes of HS correlate with radiographic findings, introduce a grading system that integrates radiological and pathological reporting in HS, and outline an approach to detecting HS subtypes using MRI. This framework will not only benefit current clinical evaluations, but also enhance future studies involving high-resolution MRI in temporal lobe epilepsy.ABBREVIATIONS: CA = cornu ammonis; DG = dentate gyrus; HS = hippocampal sclerosis; ILAE = International League Against Epilepsy; SRLM = strata radiatum, lacunosum, and moleculare layers; TLE = temporal lobe epilepsy.