Surgical Treatments for Epilepsy

PURPOSE OF REVIEW

More than 20 new antiseizure medications have been approved by the US Food and Drug Administration (FDA) in the past 3 decades; however, outcomes in newly diagnosed epilepsy have not improved, and epilepsy remains drug resistant in up to 40% of patients. Evidence supports improved seizure outcomes and quality of life in those who have undergone epilepsy surgery, but epilepsy surgery remains underutilized. This article outlines indications for epilepsy surgery, describes the presurgical workup, and summarizes current available surgical approaches.

RECENT FINDINGS

Class I evidence has demonstrated the superiority of resective surgery compared to medical therapy for seizure control and quality of life in patients with drug-resistant epilepsy. The use of minimally invasive options, such as laser interstitial thermal therapy and stereotactic radiosurgery, are alternatives to resective surgery in well-selected patients. Neuromodulation techniques, such as responsive neurostimulation, deep brain stimulation, and vagus nerve stimulation, offer a suitable alternative, especially in those where resective surgery is contraindicated or where patients prefer nonresective surgery. Although neuromodulation approaches reduce seizure frequency, they are less likely to be associated with seizure freedom than resective surgery.

SUMMARY

Appropriate patients with drug-resistant epilepsy benefit from epilepsy surgery. If two well-chosen and tolerated medication trials do not achieve seizure control, referral to a comprehensive epilepsy center for a thorough presurgical workup and discussion of surgical options is appropriate. Mounting Class I evidence supports a significantly higher chance of stopping disabling seizures with surgery than with further medication trials.

AiED: Artificial intelligence for the detection of intracranial interictal epileptiform discharges

OBJECTIVE

Deep learning provides an appealing solution for the ongoing challenge of automatically classifying intracranial interictal epileptiform discharges (IEDs). We report results from an automated method consisting of a template-matching algorithm and convolutional neural network (CNN) for the detection of intracranial IEDs ("AiED").

METHODS

1000 intracranial electroencephalogram (EEG) epochs extracted randomly from 307 subjects with refractory epilepsy were annotated independently by two expert neurophysiologists. These annotated epochs were divided into 1062 two-second epochs with IEDs and 1428 two-second epochs without IEDs, which were transformed into spectrograms prior to training the neural network. The highest performing network was validated on an annotated external test set.

RESULTS

The final network had an F1-score of 0.95 (95% CI: 0.91-0.98) and an average Area Under the Receiver Operating Characteristic of 0.98 (95% CI: 0.96-1.00). For the external test set, it showed an overall F1-score of 0.71, correctly identifying 100% of all high-amplitude IED complexes, 96.23% of all high-amplitude isolated IEDs, and 66.15% of all IEDs of atypical morphology.

CONCLUSIONS

Template-matching combined with a CNN offers a fast, robust method for detecting intracranial IEDs.

SIGNIFICANCE

"AiED" is generalizable and achieves comparable performance to human reviewers; it may support clinical and research EEG analyses.

Simulation-Based Assessments and Graduating Neurology Residents' Milestones: Status Epilepticus Milestones

BACKGROUND

The American Board of Psychiatry and Neurology and the Accreditation Council for Graduate Medical Education (ACGME) developed Milestones that provide a framework for residents' assessment. However, Milestones do not provide a description for how programs should perform assessments.

OBJECTIVES

We evaluated graduating residents' status epilepticus (SE) identification and management skills and how they correlate with ACGME Milestones reported for epilepsy and management/treatment by their program's clinical competency committee (CCC).

METHODS

We performed a cohort study of graduating neurology residents from 3 academic medical centers in Chicago in 2018. We evaluated residents' skills identifying and managing SE using a simulation-based assessment (26-item checklist). Simulation-based assessment scores were compared to experience (number of SE cases each resident reported identifying and managing during residency), self-confidence in identifying and managing these cases, and their end of residency Milestones assigned by a CCC based on end-of-rotation evaluations.

RESULTS

Sixteen of 21 (76%) eligible residents participated in the study. Average SE checklist score was 15.6 of 26 checklist items correct (60%, SD 12.2%). There were no significant correlations between resident checklist performance and experience or self-confidence. The average participant's level of Milestone for epilepsy and management/treatment was high at 4.3 of 5 (SD 0.4) and 4.4 of 5 (SD 0.4), respectively. There were no significant associations between checklist skills performance and level of Milestone assigned.

CONCLUSIONS

Simulated SE skills performance of graduating neurology residents was poor. Our study suggests that end-of-rotation evaluations alone are inadequate for assigning Milestones for high-stakes clinical skills such as identification and management of SE.

Interictal Epileptiform Discharges are Task Dependent and are Associated with Lasting Electrocorticographic Changes

The factors that control the occurrence of interictal epileptiform discharges (IEDs) are not well understood. We suspected that this phenomenon reflects an attention-dependent suppression of interictal epileptiform activity. We hypothesized that IEDs would occur less frequently when a subject viewed a task-relevant stimulus compared with viewing a blank screen. Furthermore, IEDs have been shown to impair memory when they occur in certain regions during the encoding or recall phases of a memory task. Although these discharges have a short duration, their impact on memory suggests that they have longer lasting electrophysiological effects. We found that IEDs were associated with an increase in low-frequency power and a change in the balance between low- and high-frequency oscillations for several seconds. We found that the occurrence of IEDs is modified by whether a subject is attending to a word displayed on screen or is observing a blank screen. In addition, we found that discharges in brain regions in every lobe impair memory. These findings elucidate the relationship between IEDs and memory impairment and reveal the task dependence of the occurrence of IEDs.

Immunologic Treatments of Seizures and Status Epilepticus

An autoimmune etiology for seizures, epilepsy, and status epilepticus is becoming increasingly recognized. The role of autoimmunity in epilepsy has been highlighted in the literature and the International League Against Epilepsy now recognizes autoimmune epilepsy as a distinct entity. An appropriate and thorough work-up of all new-onset seizures and status epilepticus is paramount in determining the likely efficacy of immunotherapeutic agents in treating seizures and status epilepticus. Criteria for the clinical diagnosis of autoimmune mediated epilepsy and encephalitis have been published by expert consensus and validated models to predict response to immunotherapy exist. These guidelines should guide clinicians about when to promptly start immunotherapy. Immunotherapy has been shown to improve outcomes and may reduce relapse rates in autoimmune encephalitis. Treatment algorithms with immunotherapeutic agents have been established by expert opinion and multiple observational retrospective trials in the past 10 years. However, future prospective randomized controlled trials are still needed to better understand the optimal regimen, dosing schedule, and duration of treatment with immunotherapeutic agents.

Use of a simulation-based mastery learning curriculum for neurology residents to improve the identification and management of status epilepticus

BACKGROUND

Appropriate and timely treatment of status epilepticus (SE) decreases morbidity and mortality. Therefore, skill-based training in the identification and management of SE is crucial for clinicians.

OBJECTIVE

The objective of the study was to develop and evaluate the impact of a simulation-based mastery learning (SBML) curriculum to train neurology residents on the identification and management of SE.

METHODS

We used pretest-posttest design with a retention test on SE skills for this study. Neurology residents in the second postgraduate year (PGY-2) were eligible to participate in the SE SBML curriculum. Learners completed a baseline-simulated SE skills assessment (pretest) using a 26-item dichotomous skills checklist. Next, they participated in a didactic session about the identification and management of SE, followed by deliberate skills practice. Subsequently, participants completed another skills assessment (posttest) using the same 26-item checklist. All participants were required to meet or exceed a minimum passing standard (MPS) determined by a panel of 14 SE experts using the Mastery Angoff standard setting method. After meeting the MPS at posttest, participants were reassessed during an unannounced in situ simulation session on the medical wards. We compared pretest with posttest simulated SE skills performance and posttest with reassessment in situ performance.

RESULTS

The MPS was set at 88% (23/26) checklist items correct. Sixteen neurology residents participated in the intervention. Participant performance improved from a median of 44.23% (Interquartile range (IQR): 34.62-55.77) at pretest to 94.23% (IQR: 92.13-100) at the posttest after SBML (p < .001). There was no significant difference in scores between the posttest and in situ test up to 8 months later (94.23%; IQR: 92.31-100 vs. 92.31%; IQR: 88.46-96.15; p = .13).

CONCLUSIONS

Our SBML curriculum significantly improved residents' SE identification and management skills that were largely retained during an unannounced simulated encounter in the hospital setting.