Facilitation of motor evoked potentials after tetanic peripheral nerve stimulation

OBJECTIVE

Tetanic stimulation of a peripheral nerve prior to transcranial electrical stimulation (TES) may enhance motor evoked potential (MEP) amplitudes. The purpose of this study was to investigate the post-tetanic MEP (p-MEP) technique in improving MEP amplitudes.

METHODS

Conventional TES MEPs (c-MEP) and p-MEPs with left upper limb stimulation (p-MEPUL) or left lower limb stimulation (p-MEPLL) were performed in 26 patients. Bilateral hand and foot MEP amplitudes obtained with each protocol were compared. Subgroup comparisons were performed for myelopathy and peripheral neuropathy patients. Within-subject amplitude differences between c-MEP and each p-MEP technique were compared using a Wilcoxon test.

RESULTS

The mean age of the patients was 52.7 years (range, 12-79 years). Overall, p-MEPUL resulted in MEP improvement in 25 of 26 (96%) patients, and p-MEPLL improved MEPs in 19 of 26 (73%) patients. The increase in MEP amplitudes were statistically significant in all muscle groups except left foot. Similar improvements were seen in the myelopathy group; in the neuropathy group, p-MEPUL produced similar results, but p-MEPLL did not.

CONCLUSIONS

The p-MEP technique can improve MEP amplitudes, including in patients with myelopathy. In patients with peripheral neuropathy, the results were mixed.

SIGNIFICANCE

Tetanic stimulation can enhance intraoperative MEP amplitudes.

A novel technique for intraoperative mapping of the somatosensory cortex

OBJECTIVE

Intraoperative mapping of the nervous system is used to identify "eloquent" cortical areas. In this technical report, we describe a novel way of mapping the somatosensory cortex so that injury to those critical pathways can be avoided.

METHODS

An 8 year old female with drug resistant epilepsy presented for resection of a right posterior parietal focal cortical dysplasia. Left median nerve stimulation was used to record somatosensory evoked potentials (SEP) directly from the somatosensory cortex with a strip electrode. A handheld monopolar electrode was also used to record both the median and tibial SEP. Total intravenous anesthesia with propofol and remifentanil was used.

RESULTS

SEP recordings were obtained from a 4-contact strip electrode placed across the central sulcus. A phase reversal was identified and the most likely post central gyrus was noted. With the strip electrode left in place, a monopolar handheld electrode was used to record the median nerve SEPs from different locations on the post central gyrus. The tibial nerve was also stimulated to record where the highest amplitude tibial nerve SEP was present. This map was used delineate functionally "eloquent" areas to avoid during surgery. During resection, the median nerve SEP was recorded from the strip electrode continuously. No significant change in the SEP was noted, and the patient awoke without any sensory deficits.

CONCLUSIONS

Sensory mapping of the cortex is possible with a handheld monopolar electrode. This technique is easy to perform and can help reduce neurological morbidity.

Development of an International Standard Set of Outcomes and Measurement Methods for Routine Practice for Infants, Children, and Adolescents with Epilepsy: The International Consortium for Health Outcomes Measurement Consensus Recommendations

At present, there is no internationally accepted set of core outcomes or measurement methods for epilepsy clinical practice. The International Consortium for Health Outcomes Measurement (ICHOM) convened an international working group of experts in epilepsy, people with epilepsy, and their representatives to develop minimum sets of standardized outcomes and outcome measurement methods for clinical practice. Using modified Delphi consensus methods with consecutive rounds of online voting over 12 months, a core set of outcomes and corresponding measurement tool packages to capture the outcomes were identified for infants, children, and adolescents with epilepsy. Consensus methods identified 20 core outcomes. In addition to the outcomes identified for the ICHOM Epilepsy adult standard set, behavioral, motor, and cognitive/language development outcomes were voted as essential for all infants and children with epilepsy. The proposed set of outcomes and measurement methods will facilitate the implementation of the use of patient-centered outcomes in daily practice.

Development of an International Standard Set of Outcomes and Measurement Methods for Routine Practice for Adults with Epilepsy: The International Consortium for Health Outcomes Measurement Consensus Recommendations

At present, there is no internationally accepted set of core outcomes or measurement methods for epilepsy clinical practice. Therefore, the International Consortium for Health Outcomes Measurement (ICHOM) convened an international working group of experts in epilepsy, people with epilepsy and their representatives to develop minimum sets of standardized outcomes and outcomes measurement methods for clinical practice that support patient-clinician decision-making and quality improvement. Consensus methods identified 20 core outcomes. Measurement tools were recommended based on their evidence of strong clinical measurement properties, feasibility, and cross-cultural applicability. The essential outcomes included many non-seizure outcomes: anxiety, depression, suicidality, memory and attention, sleep quality, functional status, and the social impact of epilepsy. The proposed set will facilitate the implementation of the use of patient-centered outcomes in daily practice, ensuring holistic care. They also encourage harmonization of outcome measurement, and if widely implemented should reduce the heterogeneity of outcome measurement, accelerate comparative research, and facilitate quality improvement efforts.

Dosing and transition characteristics in people with narcolepsy transitioning from sodium oxybate to low-sodium oxybate: Data from the real-world TENOR study

OBJECTIVE

The Transition Experience of persons with Narcolepsy taking Oxybate in the Real-world (TENOR) study assessed the real-world experience of people with narcolepsy switching from sodium oxybate (SXB) to low-sodium oxybate (LXB; 92 % less sodium than SXB).

METHODS

TENOR is a patient-centric, prospective, observational, virtual-format study. Eligible participants included US adults with narcolepsy transitioning from SXB to LXB (±7 days from LXB initiation). Longitudinal data were collected from baseline (taking SXB) through 21 weeks post-transition.

RESULTS

TENOR included 85 participants with narcolepsy (type 1, n = 45; type 2, n = 40). Mean (SD) age was 40.3 (13.0) years; the majority (73 %) were female and White (87 %). At study completion, wake-promoting agents were the most common concomitant medications (47 %). Mean (SD) SXB treatment duration was 57.8 (52.1) months; 96 % took SXB twice nightly. After transitioning, 97 % continued on twice-nightly regimens. Mean (SD) dose of both total nightly SXB (n = 85) and baseline LXB (n = 84) was 7.7 (1.5) g; SXB-LXB dose conversions at baseline were gram-for-gram in 87 % of participants. The mean final total nightly dose of LXB was 7.9 g. The most common participant-reported reasons for transitioning included lower sodium content for improved long-term health (93 %), physician recommendation (47 %), to avoid cardiovascular issues (39 %), to avoid side effects (31 %), and to improve control of narcolepsy symptoms (18 %).

CONCLUSION

Most participants transitioned from SXB to LXB using a gram-for-gram strategy. The most commonly cited reason for transition was long-term health benefits due to lower sodium.

"T" Times: Revisiting the Timing of Neuronal Injury in Status Epilepticus

Effects of Epileptiform Activity on Discharge Outcome in Critically Ill Patients in the USA: A Retrospective Cross-Sectional Study Parikh H, Hoffman K, Sun H, Zafar SF, Ge W, Jing J, Liu L, Sun J, Struck A, Volfovsky A, Rudin C, Westover MB. Lancet Digit Health. 2023;5:e495-e502. doi:10.1016/S2589-7500(23)00088-2 Background: Epileptiform activity is associated with worse patient outcomes, including increased risk of disability and death. However, the effect of epileptiform activity on neurological outcome is confounded by the feedback between treatment with antiseizure medications and epileptiform activity burden. We aimed to quantify the heterogeneous effects of epileptiform activity with an interpretability-centred approach. Methods: We did a retrospective, cross-sectional study of patients in the intensive care unit who were admitted to Massachusetts General Hospital (Boston, MA, USA). Participants were aged 18 years or older and had electrographic epileptiform activity identified by a clinical neurophysiologist or epileptologist. The outcome was the dichotomised modified Rankin Scale (mRS) at discharge and the exposure was epileptiform activity burden defined as mean or maximum proportion of time spent with epileptiform activity in 6 h windows in the first 24 h of electroencephalography. We estimated the change in discharge mRS if everyone in the dataset had experienced a specific epileptiform activity burden and were untreated. We combined pharmacological modelling with an interpretable matching method to account for confounding and epileptiform activity-antiseizure medication feedback. The quality of the matched groups was validated by the neurologists. Findings: Between Dec 1, 2011, and Oct 14, 2017, 1514 patients were admitted to Massachusetts General Hospital intensive care unit, 995 (66%) of whom were included in the analysis. Compared with patients with a maximum epileptiform activity of 0 to less than 25%, patients with a maximum epileptiform activity burden of 75% or more when untreated had a mean 22.27% (SD 0.92) increased chance of a poor outcome (severe disability or death). Moderate but long-lasting epileptiform activity (mean epileptiform activity burden 2% to <10%) increased the risk of a poor outcome by mean 13.52% (SD 1.93). The effect sizes were heterogeneous depending on preadmission profile—eg, patients with hypoxic-ischaemic encephalopathy or acquired brain injury were more adversely affected compared with patients without these conditions. Interpretation: Our results suggest that interventions should put a higher priority on patients with an average epileptiform activity burden 10% or greater, and treatment should be more conservative when maximum epileptiform activity burden is low. Treatment should also be tailored to individual preadmission profiles because the potential for epileptiform activity to cause harm depends on age, medical history, and reason for admission.

Effectiveness and tolerability in people with narcolepsy transitioning from sodium oxybate to low-sodium oxybate: Data from the real-world TENOR study

OBJECTIVES

The Transition Experience of persons with Narcolepsy taking Oxybate in the Real-world (TENOR) study was conducted to provide real-world insight into the experience of people with narcolepsy switching from sodium oxybate (SXB) to low-sodium oxybate (LXB; 92% less sodium than SXB).

METHODS

TENOR is a patient-centric, prospective, observational, virtual-format study. Participants were adults with narcolepsy (type 1 or 2) who were transitioning from SXB to LXB treatment (±7 days from LXB initiation). Effectiveness and tolerability data were collected online from baseline (taking SXB) through 21 weeks (taking LXB) via daily and weekly diaries and questionnaires, including the Epworth Sleepiness Scale (ESS), the Functional Outcomes of Sleep Questionnaire, short version (FOSQ-10), and the British Columbia Cognitive Complaints Inventory (BC-CCI).

RESULTS

TENOR participants (N = 85) were 73% female with a mean (SD) age of 40.3 (13.0) years. Mean (SD) ESS scores decreased numerically throughout the transition from SXB to LXB (baseline: 9.9 [5.2]; week 21: 7.5 [4.7]), with 59.5% and 75.0% of participants having scores in the normal range (≤10) at baseline and week 21, respectively. Mean (SD) FOSQ-10 scores (baseline: 14.4 [3.4]; week 21: 15.2 [3.2]) and BC-CCI scores (baseline: 6.1 [4.4]; week 21: 5.0 [4.3]) also remained stable. The most common symptoms related to tolerability reported by participants at baseline were sleep inertia, hyperhidrosis, and dizziness (45.2%, 40.5%, and 27.4%, respectively), which decreased in prevalence by week 21 (33.8%, 13.2%, and 8.8%, respectively).

CONCLUSIONS

Findings from TENOR confirm maintenance of effectiveness and tolerability when transitioning from SXB to LXB treatment.

Impairment in Functioning and Quality of Life in Patients with Idiopathic Hypersomnia: The Real World Idiopathic Hypersomnia Outcomes Study (ARISE)

Purpose

Idiopathic hypersomnia is a debilitating neurologic sleep disorder characterized by excessive daytime sleepiness, sleep inertia, and prolonged sleep. Its impact on patients' quality of life and daily functioning has not been fully elucidated. The Real World Idiopathic Hypersomnia Outcomes Study (ARISE) evaluated the daily functioning, relationships, cognition, emotional well-being, and productivity/employment of participants with idiopathic hypersomnia.

Patients and Methods

ARISE was a US-based virtual cross-sectional survey comprising multiple patient-reported outcome measures (Functional Outcomes of Sleep Questionnaire, short version [FOSQ-10], Quality of Life in Neurological Disorders [Neuro-QoL] Social Roles and Stigma domains, British Columbia Cognitive Complaints Inventory [BC-CCI], Patient Health Questionnaire [PHQ-9], and the Work Productivity and Activity Impairment Questionnaire: Specific Health Problem [WPAI:SHP]). Participants were adults 21-65 years of age with idiopathic hypersomnia. Data were analyzed for all participants and for subgroups with/without long sleep time (LST; self-reported sleep ≥11 hours in 24 hours).

Results

Of 75 participants enrolled, most were female (81.3%) and the mean (SD) age was 34.1 (10.7) years. Participants' scores on the FOSQ-10 (mean [SD] score: 10.7 [2.8]) and the Neuro-QoL Social Roles (43.4 [4.2]) and Stigma (57.3 [5.9]) domains reflected impairments in daily functioning and quality of life. More than half of participants reported moderate to severe cognitive complaints (BC-CCI; 62.7%) and moderate to severe depressive symptoms (PHQ-9; 66.7%). Scores on the WPAI:SHP showed substantial impairments in absenteeism, presenteeism, overall work productivity, and overall regular daily activity (mean percent [SD]: 12.3 [23.6], 47.6 [22.7], 51.4 [24.7], and 64.0 [21.9], respectively). These considerable impairments were found in participants with and without LST.

Conclusion

ARISE participants with idiopathic hypersomnia demonstrated poor quality of life and impaired functioning across multiple symptom domains.

Automated Interpretation of Clinical Electroencephalograms Using Artificial Intelligence

Importance

Electroencephalograms (EEGs) are a fundamental evaluation in neurology but require special expertise unavailable in many regions of the world. Artificial intelligence (AI) has a potential for addressing these unmet needs. Previous AI models address only limited aspects of EEG interpretation such as distinguishing abnormal from normal or identifying epileptiform activity. A comprehensive, fully automated interpretation of routine EEG based on AI suitable for clinical practice is needed.

Objective

To develop and validate an AI model (Standardized Computer-based Organized Reporting of EEG-Artificial Intelligence [SCORE-AI]) with the ability to distinguish abnormal from normal EEG recordings and to classify abnormal EEG recordings into categories relevant for clinical decision-making: epileptiform-focal, epileptiform-generalized, nonepileptiform-focal, and nonepileptiform-diffuse.

Design, Setting, and Participants

In this multicenter diagnostic accuracy study, a convolutional neural network model, SCORE-AI, was developed and validated using EEGs recorded between 2014 and 2020. Data were analyzed from January 17, 2022, until November 14, 2022. A total of 30 493 recordings of patients referred for EEG were included into the development data set annotated by 17 experts. Patients aged more than 3 months and not critically ill were eligible. The SCORE-AI was validated using 3 independent test data sets: a multicenter data set of 100 representative EEGs evaluated by 11 experts, a single-center data set of 9785 EEGs evaluated by 14 experts, and for benchmarking with previously published AI models, a data set of 60 EEGs with external reference standard. No patients who met eligibility criteria were excluded.

Main Outcomes and Measures

Diagnostic accuracy, sensitivity, and specificity compared with the experts and the external reference standard of patients' habitual clinical episodes obtained during video-EEG recording.

Results

The characteristics of the EEG data sets include development data set (N = 30 493; 14 980 men; median age, 25.3 years [95% CI, 1.3-76.2 years]), multicenter test data set (N = 100; 61 men, median age, 25.8 years [95% CI, 4.1-85.5 years]), single-center test data set (N = 9785; 5168 men; median age, 35.4 years [95% CI, 0.6-87.4 years]), and test data set with external reference standard (N = 60; 27 men; median age, 36 years [95% CI, 3-75 years]). The SCORE-AI achieved high accuracy, with an area under the receiver operating characteristic curve between 0.89 and 0.96 for the different categories of EEG abnormalities, and performance similar to human experts. Benchmarking against 3 previously published AI models was limited to comparing detection of epileptiform abnormalities. The accuracy of SCORE-AI (88.3%; 95% CI, 79.2%-94.9%) was significantly higher than the 3 previously published models (P < .001) and similar to human experts.

Conclusions and Relevance

In this study, SCORE-AI achieved human expert level performance in fully automated interpretation of routine EEGs. Application of SCORE-AI may improve diagnosis and patient care in underserved areas and improve efficiency and consistency in specialized epilepsy centers.

Symptom Severity and Treatment Satisfaction in Patients with Idiopathic Hypersomnia: The Real World Idiopathic Hypersomnia Outcomes Study (ARISE)

Objective

Idiopathic hypersomnia is a debilitating sleep disorder characterized by excessive daytime sleepiness, sleep inertia, and prolonged sleep duration. The patient burden of idiopathic hypersomnia is poorly understood. The Real World Idiopathic Hypersomnia Outcomes Study (ARISE) evaluated symptoms and treatment effectiveness/satisfaction in participants with idiopathic hypersomnia.

Methods

ARISE was a United States-based virtual cross-sectional survey. Participants were adults 21-65 years of age with idiopathic hypersomnia recruited from social media, the Hypersomnia Foundation website, and a patient panel. Self-assessments included the Epworth Sleepiness Scale (ESS), Idiopathic Hypersomnia Severity Scale (IHSS), Treatment Satisfaction Questionnaire for Medication, version II (TSQM-vII), and additional treatment questions. Data were analyzed for all participants and for subgroups with/without long sleep time (LST; ≥11 hours in 24 hours).

Results

Of 75 participants enrolled, most were female (81.3%). The mean (SD) age was 34.1 (10.7) years and 49% had LST. Most participants took off-label prescription medications (89.3%) and/or used other measures (93.3%) to manage their symptoms. The mean (SD) ESS score was 14.5 (3.5) and the mean IHSS score was 35.2 (7.6). Treatment satisfaction was low (mean [SD] TSQM-vII score: overall, 61.9 [21.2]; with LST, 57.9 [21.4]; without LST, 66.7 [20.3]), primarily driven by dissatisfaction with treatment effectiveness. The most common classes of prescription medications used were stimulants (61.3%), wake-promoting agents (28.0%), and antidepressants (18.7%); non-prescription measures used to manage symptoms included caffeine (73.3%), planned naps (34.7%), and individual accommodations (32.0%).

Conclusion

Overall, participants with idiopathic hypersomnia, with or without LST, had substantial symptom burden despite most of the study population taking off-label medications and using nonprescription measures to manage symptoms.

Intraoperative Electromyography in Awake Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Case Study on Nerve Activation Under the Effects of Local Anesthesia

SUMMARY

With the versatility of lumbar spine surgery continually expanding, intraoperative electromyography (EMG) has become a common adjunct used to reduce risk of nerve injury and postoperative neurologic deficit. EMG monitoring has been deemed particularly useful in the minimally invasive transforaminal lumbar interbody fusion. A more recent evolution of the minimally invasive transforaminal lumbar interbody fusion entails complete percutaneous access to the disc through Kambin's triangle, followed by a percutaneous lumbar interbody fusion. Given the lack of direct visualization of nervous structures with percutaneous entrance into the disc, there is risk of injury to surrounding nervous structures with this approach. In effort to reduce risk of nerve injury, application of triggered EMG to gauge proximity of nervous tissue has been evaluated. Recently, patients presenting with contraindications or concerns for general anesthesia have been offered the alternative to undergo their procedure with spinal anesthesia, allowing them to remain awake. Spinal anesthesia entails intrathecal administration of local anesthetic, which mechanistically acts to reduce overall excitability of surrounding neural structures. However, nerve activation under conditions of local anesthetic is relatively unknown, and the ability of triggered EMG monitoring to reliably detect nerve proximity becomes questionable. This case report demonstrates nerve activation at thresholds comparable with those seen under general anesthesia. Although this has sparked interest in the possibility that local anesthetic may not remarkably affect nerve excitability as measured by triggered EMG activation, further investigation is recommended to reliably apply triggered EMG monitoring in awake spine surgery.

Intravenous ganaxolone for the treatment of refractory status epilepticus: Results from an open-label, dose-finding, phase 2 trial

OBJECTIVE

Patients with refractory status epilepticus (RSE) have failed treatment with benzodiazepines and ≥1 second-line intravenous (IV) antiseizure medication (ASM). Guidelines recommend IV anesthesia when second-line ASMs have failed, but potential harms can outweigh the benefits. Novel treatments are needed to stop and durably control RSE without escalation to IV anesthetics. Ganaxolone is an investigational neuroactive steroid in development for RSE treatment. This study's objective was to determine the appropriate dosing for IV ganaxolone in RSE and obtain a preliminary assessment of efficacy and safety.

METHODS

This was an open-label, phase 2 trial conducted from February 19, 2018 to September 18, 2019, at three sites in the United States. Patients were aged ≥12 years, had convulsive or nonconvulsive SE, and failed to respond to ≥1 second-line IV ASM. Twenty-one patients were screened; 17 were enrolled. Patients received IV ganaxolone added to standard-of-care ASMs. Ganaxolone infusion was initiated as an IV bolus (over 3 min) with continuous infusion of decreasing infusion rates for 48-96 h followed by an 18-h taper. There were three ganaxolone dosing cohorts: low, 500 mg/day; medium, 650 mg/day; and high, 713 mg/day. The primary end point was the number of patients not requiring escalation to IV anesthetic treatment within 24 h of ganaxolone initiation.

RESULTS

Most of the 17 enrolled patients (65%) had nonconvulsive SE, and had failed a median of three prior ASMs, including first-line benzodiazepine and second-line IV ASM therapy. Median time to SE cessation following ganaxolone initiation was 5 min. No patient required escalation to third-line IV anesthetics during the 24-h period following ganaxolone initiation. Two treatment-related serious adverse events (sedation) were reported. Of the three deaths, none was considered related to ganaxolone; all occurred 9-22 days after completing ganaxolone.

SIGNIFICANCE

IV ganaxolone achieved rapid and durable seizure control in patients with RSE, and showed acceptable safety and tolerability.

Association Between Standardized Mortality Ratio and Utilization of Care in US Veterans With Drug-Resistant Epilepsy Compared With All US Veterans and the US General Population

Importance

Drug-resistant epilepsy (DRE) is thought to be associated with increased mortality, but larger population-based studies are lacking. Additionally, the benefit of effective management in DRE lacks evidence.

Objective

To examine the association of utilization of care with mortality in US veterans with DRE.

Design, Setting, and Participants

Observational cohort study conducted between October 1, 2013, and March 31, 2020. Mortality statistics in US veterans with DRE were compared to the US general population and all veterans within the Veterans Health Administration. Epilepsy was defined as use of 1 or more antiseizure medications (ASMs) for 30 days or longer with a seizure diagnosis or 1 inpatient or 2 outpatient encounters with an epilepsy diagnosis. DRE was defined as the use of 2 or more ASMs. Among 9.6 million US veterans, 164 435 (1.7%) had epilepsy, of whom 55 571 (33.8%) had DRE. Epilepsy and DRE were administratively identified based on criteria noted in design. Identified participants were included for analysis.

Exposures

Veterans with DRE.

Main Outcomes and Measures

Standardized mortality ratio (SMR).

Results

Among US veterans with DRE, the mean (SD) age was 58.3 (15.4) years, and 49 430 individuals (88.9%) were male. Of ethnicity data gathered, 3170 individuals (5.7%) were Hispanic or Latino, 50 599 (91.1%) were not Hispanic or Latino, 842 (1.5%) declined to answer, and 960 (1.7%) were recorded as unknown. Of race data gathered, 516 individuals (0.9%) were American Indian or Alaskan Native, 270 (0.5%) were Asian, 11 316 (20.4%) were Black or African American, 587 (1.1%) were of multiple races, 453 (0.8%) were Native Hawaiian or Pacific Islander, 39 543 (71.2%) were White, 1697 (3.1%) declined to answer, and 1189 (2.1%) were recorded as unknown. SMR was 1.50 (95% CI, 1.47-1.53) compared with the US general population and 1.56 (95% CI, 1.53-1.59) compared with all veterans. Utilization rates were 81.1% (n = 45 057) for neurology clinic evaluation, 66.4% (n = 36 905) for magnetic resonance imaging (MRI), and 49.6% (n = 27 546) for electroencephalography (EEG) testing. Only 8350 individuals (15.0%) had comprehensive epilepsy evaluations and 3357 (6.0%) had epilepsy monitoring. Multivariable analysis revealed an association between lower mortality and neurology clinic evaluation, EEG, MRI, epilepsy monitoring, and the use of more than 2 ASMs after adjusting for age and comorbidities.

Conclusions and Relevance

Mortality rates were significantly higher in US veterans with DRE compared to the general population. Better utilization of comprehensive epilepsy care, diagnostic services, and medications were each associated with reduced mortality. These findings indicate that appropriate management of DRE is critical in this population.

Dorsal root entry zone procedure and other surgeries for pain

Pain is a very common symptom that often serves a protective function. It is typically treated medically. When pain becomes chronic and intractable, it no longer serves a protective function and often requires more aggressive forms of treatment. Many types of surgeries can be performed for the management of pain. These surgeries can involve ablation (destruction) or augmentation (stimulation or facilitation) of some part of the nervous system. In many of these surgeries, neurophysiologic intraoperative monitoring (NIOM) is not needed, however, in others neuromonitoring serves a mapping and monitoring purpose. The prototype of pain surgery for this chapter is the dorsal root entry zone (DREZ) procedure. Both mapping and monitoring can help improve lesioning precision and outcomes in this surgery. In this chapter, the DREZ procedures and other surgeries for primarily pain relief in which NIOM is used are discussed. Surgeries, such as spinal stenosis, in which pain relief is important but not the sole purpose, are not discussed here and are covered elsewhere.

Overview of intraoperative neuromonitoring

Intraoperative neuromonitoring (IONM) is used widely to reduce neurologic adverse postoperative outcomes. A variety of techniques are used. Initial techniques were used as far back as the 1930s, and the variety of methods expanded greatly since the 1980s. Many methods monitor baseline findings over time. Other methods test for neurologic function to identify nerves or eloquent cortex. Physicians trained in neurophysiology are key for interpretation of findings, supervision of staff, and making medical recommendations to the surgeon or anesthesiologist. Some neurophysiologists provide the services personally, and in other circumstances well-trained technologist staff help with the techniques. Much IONM is provided by the neurophysiology physician in the operating room, whereas in other cases, the physician may be on-line in real time from a remote site. When monitoring identifies changes, the IONM team must give a clear, timely, and compelling message to the surgeon and anesthesiologist.

Differentiation of Epileptic and Psychogenic Nonepileptic Seizures Using Single-Channel Surface Electromyography

PURPOSE

Epileptic seizures (ES) and psychogenic nonepileptic seizures (PNES) are difficult to differentiate when based on a patient's self-reported symptoms. This study proposes review of objective data captured by a surface electromyography (sEMG) wearable device for classification of events as ES or PNES. This may help clinicians accurately identify ES and PNES.

METHODS

Seventy-one subjects were prospectively enrolled across epilepsy monitoring units at VA Epilepsy Centers of Excellence. Subjects were concomitantly monitored using video EEG and a wearable sEMG epilepsy monitor, the Sensing Portable sEmg Analysis Characterization (SPEAC) System. Three epileptologists independently classified ES and PNES that contained upper extremity motor activity based on video EEG. The sEMG data from those events were automatically processed to provide a seizure score for event classification. After brief training (60 minutes), the sEMG data were reviewed by a separate group of four epileptologists to independently classify events as ES or PNES.

RESULTS

According to video EEG review, 17 subjects experienced 34 events (15 ES and 19 PNES with upper extremity motor activity). The automated process correctly classified 87% of ES (positive predictive value = 88%, negative predictive value = 76%) and 79% of PNES, and the expert reviewers correctly classified 77% of ES (positive predictive value = 94%, negative predictive value = 84%) and 96% of PNES. The automated process and the expert reviewers correctly classified 100% of tonic-clonic seizures as ES, and 71 and 50%, respectively, of non-tonic-clonic ES.

CONCLUSIONS

Automated and expert review, particularly in combination, of sEMG captured by a wearable seizure monitor (SPEAC System) may be able to differentiate ES (especially tonic-clonic) and PNES with upper extremity motor activity.

Conversational analysis of consciousness during seizures

OBJECTIVE

The objectives of the study were to 1) investigate how patients with epilepsy describe the subjective, conscious experience of having a seizure and 2) determine whether certain themes and descriptions correspond to specific types of epilepsy.

METHODS

We interviewed thirteen patients with electroencephalographically confirmed epilepsy about their subjective experience of having a seizure and used conversational analysis (CA) to analyze the language they used to describe this experience.

RESULTS

Seven patients had focal to bilateral tonic-clonic seizures (FBTCS), 7 had focal impaired awareness seizures (FIAS), 1 had focal aware seizures (FAS), and one had generalized onset tonic-clonic (GTC) seizures. Three had multiple types of seizures. Focal seizure origin was frontal in 2 patients, right hemisphere in 1, parieto-occipital in 1, and temporal in 8. Focal to bilateral tonic-clonic and GTC seizures were most frequently associated with descriptions of a total loss of consciousness (n = 8), whereas FIAS were most frequently associated with a perceived loss of consciousness but able to describe some aspects of being unconscious (n = 5). Temporal seizures most frequently accompanied reports of memory loss/impairment (n = 4). Ten patients provided specific descriptions of the transition between the interictal and ictal state or auras. Descriptions consciousness and unconsciousness ranged significantly, resembling a continuum rather than corresponding to distinct levels.

CONCLUSION

The subjective experience of consciousness for patients with epilepsy may differ by seizure type and origin. These may reflect different involvement of brain regions involved in producing consciousness and arousal. Conversational analysis and narrative approaches can significantly aid clinicians in the diagnosis and management of epilepsy.

Incidence and duration of common, early-onset adverse events occurring during 2 randomized, placebo-controlled, phase 3 studies of sodium oxybate in participants with narcolepsy

STUDY OBJECTIVES

To determine the time course and duration of common, early-onset treatment-emergent adverse events (TEAEs) associated with sodium oxybate (SXB) use in adults with narcolepsy.

METHODS

These were post hoc analyses of two 8-week, randomized, double-blind, placebo-controlled trials. In SXB-15, participants (n = 246) received daily placebo (n = 60) or SXB (n = 186) initiated at 4.5 g. Participants assigned to SXB 6 or 9 g were titrated in 1.5-g increments. In SXB-22, participants entering on modafinil (n = 231) received placebo (n = 56), SXB (n = 55), modafinil (n = 63), or SXB and modafinil (n = 57). SXB was initiated at 6 g for weeks 1-4 and increased to 9 g for weeks 5-8. TEAEs reported more frequently in SXB-treated participants than placebo and in ≥5% of any SXB treatment group during week 1 were examined as TEAEs of interest.

RESULTS

Dizziness and nausea met criteria as TEAEs of interest in both studies; headache also met criteria as a TEAE of interest in SXB-15. Incidence of new or worsened TEAEs was highest at week 1 (SXB-15: dizziness, 7.5%; headache, 7.5%; nausea, 5.9%; SXB-22: dizziness, 5.4%; nausea, 7.1%) and decreased over time in both studies. The longest median duration was reported for dizziness: 9.0 and 17.5 days in SXB-15 and SXB-22, respectively. Dizziness caused discontinuation in 2.2% and 3.6% of participants in SXB-15 and SXB-22, respectively; nausea caused discontinuation in 2.7% and 1.8%.

CONCLUSIONS

Common early-onset TEAEs associated with SXB treatment were generally of short duration and their incidence decreased over time. These TEAEs accounted for few discontinuations overall.

CLINICAL TRIALS REGISTRATION

Registry: ClinicalTrials.gov; Names: Safety and Efficacy of Xyrem Oral Solution (Sodium Oxybate) Compared With Placebo in Narcoleptic Patients; Trial Comparing Effects of Xyrem Taken Orally and Modafinil With Placebo in Treating Daytime Sleepiness in Narcolepsy; URLs: https://clinicaltrials.gov/ct2/show/NCT00049803 and https://clinicaltrials.gov/ct2/show/NCT00066170; Identifiers: NCT00049803 and NCT00066170.

To Wean or Not to Wean: Machine Learning to the Rescue

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The Impact of COVID-19 on Epilepsy Care: A Survey of the American Epilepsy Society Membership

The COVID-19 pandemic has impacted the delivery of care to people with epilepsy (PWE) in multiple ways including limitations on in-person contact and restrictions on neurophysiological procedures. To better study the effect of the pandemic on PWE, members of the American Epilepsy Society were surveyed between April 30 and June 14, 2020. There were 366 initial responses (9% response rate) and 337 respondents remained for analysis after screening out noncompleters and those not directly involved with clinical care; the majority were physicians from the United States. About a third (30%) of respondents stated that they had patients with COVID-19 and reported no significant change in seizure frequency. Conversely, one-third of respondents reported new onset seizures in patients with COVID-19 who had no prior history of seizures. The majority of respondents felt that there were at least some barriers for PWE in receiving appropriate clinical care, neurophysiologic procedures, and elective surgery. Medication shortages were noted by approximately 30% of respondents, with no clear pattern in types of medication involved. Telehealth was overwhelmingly found to have value. Among the limitation of the survey was that it was administered at a single point in time in a rapidly changing pandemic. The survey showed that almost all respondents were affected by the pandemic in a variety of ways.

Barriers and facilitators to implementation of epilepsy self-management programs: a systematic review using qualitative evidence synthesis methods

BACKGROUND

Epilepsy affects nearly 50 million people worldwide. Self-management is critical for individuals with epilepsy in order to maintain optimal physical, cognitive, and emotional health. Implementing and adopting a self-management program requires considering many factors at the person, program, and systems levels. We conducted a systematic review of qualitative and mixed-methods studies to identify facilitators and barriers that impact implementation and adoption of self-management programs for adults with epilepsy.

METHODS

We used established systematic review methodologies for qualitative and mixed-methods studies. We included studies addressing facilitators (i.e., factors that aided) or barriers (i.e., factors that impeded) to implementation and adoption of self-management interventions for adults with epilepsy. We conducted a narrative thematic synthesis to identify facilitators and barriers.

RESULTS

The literature search identified 2700 citations; 13 studies met eligibility criteria. Our synthesis identified five themes that categorize facilitators and barriers to successful implementation epilepsy self-management: (1) relevance, intervention content that facilitates acquisition of self-management skills; (2) personalization, intervention components that account for the individual's social, physical, and environmental characteristics; (3) intervention components, components and dosing of the intervention; (4) technology considerations, considerations that account for individual's use, familiarity with, and ownership of technology; and (5) clinician interventionist, role and preparation of the individual who leads intervention. We identified facilitators in 11 of the 13 studies and barriers in 11 of the 13 studies and classified these by social-ecological level (i.e., patient/caregiver, program, site/system).

CONCLUSION

Identification of facilitators and barriers at multiple levels provides insight into disease-specific factors that influence implementation and adoption of self-management programs for individuals with epilepsy. Our findings indicate that involving individuals with epilepsy and their caregivers in intervention development, and then tailoring intervention content during the intervention, can help ensure the content is relevant to intervention participants. Our findings also indicate the role of the clinician (i.e., the individual who provides self-management education) is important to intervention implementation, and key issues with clinicians were identified as barriers and opportunities for improvement. Overall, our findings have practical value for those seeking to implement and adopt self-management interventions for epilepsy and other chronic illnesses.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number is CRD42018098604.

Finally, Some Neurophysiologic Good News-Favorable Prognosis in Coma

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Randomized trial of lacosamide versus fosphenytoin for nonconvulsive seizures

OBJECTIVE

The optimal treatment of nonconvulsive seizures in critically ill patients is uncertain. We evaluated the comparative effectiveness of the antiseizure drugs lacosamide (LCM) and fosphenytoin (fPHT) in this population.

METHODS

The TRENdS (Treatment of Recurrent Electrographic Nonconvulsive Seizures) study was a noninferiority, prospective, multicenter, randomized treatment trial of patients diagnosed with nonconvulsive seizures (NCSs) by continuous electroencephalography (cEEG). Treatment was randomized to intravenous (IV) LCM 400mg or IV fPHT 20mg phenytoin equivalents/kg. The primary endpoint was absence of electrographic seizures for 24 hours as determined by 1 blinded EEG reviewer. The frequency with which NCS control was achieved in each arm was compared, and the 90% confidence interval (CI) was determined. Noninferiority of LCM to fPHT was to be concluded if the lower bound of the CI for relative risk was >0.8.

RESULTS

Seventy-four subjects were enrolled (37 LCM, 37 fPHT) between August 21, 2012 and December 20, 2013. The mean age was 63.6 years; 38 were women. Seizures were controlled in 19 of 30 (63.3%) subjects in the LCM arm and 16 of 32 (50%) subjects in the fPHT arm. LCM was noninferior to fPHT (p = 0.02), with a risk ratio of 1.27 (90% CI = 0.88-1.83). Treatment emergent adverse events (TEAEs) were similar in both arms, occurring in 9 of 35 (25.7%) LCM and 9 of 37 (24.3%) fPHT subjects (p = 1.0).

INTERPRETATION

LCM was noninferior to fPHT in controlling NCS, and TEAEs were comparable. LCM can be considered an alternative to fPHT in the treatment of NCSs detected on cEEG. Ann Neurol 2018;83:1174-1185.

Self-management of Epilepsy: A Systematic Review

BACKGROUND

Although self-management is recommended for persons with epilepsy, its optimal strategies and effects are uncertain.

PURPOSE

To evaluate the components and efficacy of self-management interventions in the treatment of epilepsy in community-dwelling persons.

DATA SOURCES

English-language searches of MEDLINE, Cochrane Central Register of Controlled Trials, PsycINFO, and CINAHL in April 2018; the MEDLINE search was updated in March 2019.

STUDY SELECTION

Randomized and nonrandomized comparative studies of self-management interventions for adults with epilepsy.

DATA EXTRACTION

An investigator assessed study characteristics; intervention details, including 6 components of self-management; and outcomes, which were verified by a second reviewer. Risk of bias (ROB) was assessed independently by 2 investigators.

DATA SYNTHESIS

13 randomized and 2 nonrandomized studies (2514 patients) evaluated self-management interventions. Interventions were delivered primarily in group settings, used a median of 4 components, and followed 2 general strategies: 1 based on education and the other on psychosocial therapy. Education-based approaches improved self-management behaviors (standardized mean difference, 0.52 [95% CI, 0.0 to 1.04]), and psychosocial therapy-based approaches improved quality of life (mean difference, 6.64 [CI, 2.51 to 10.77]). Overall, self-management interventions did not reduce seizure rates, but 1 educational intervention decreased a composite of seizures, emergency department visits, and hospitalizations.

LIMITATION

High ROB in most studies, incomplete intervention descriptions, and studies limited to English-language publications.

CONCLUSION

There is limited evidence that self-management strategies modestly improve some patient outcomes that are important to persons with epilepsy. Overall, self-management research in epilepsy is limited by the range of interventions tested, the small number of studies using self-monitoring technology, and uncertainty about components and strategies associated with benefit.

PRIMARY FUNDING SOURCE

U.S. Department of Veterans Affairs. (PROSPERO: CRD42018098604).

Did This Patient Have Cardiac Syncope?: The Rational Clinical Examination Systematic Review

IMPORTANCE

Syncope can result from a reduction in cardiac output from serious cardiac conditions, such as arrhythmias or structural heart disease (cardiac syncope), or other causes, such as vasovagal syncope or orthostatic hypotension.

OBJECTIVE

To perform a systematic review of studies of the accuracy of the clinical examination for identifying patients with cardiac syncope.

STUDY SELECTION

Studies of adults presenting to primary care, emergency departments, or referred to specialty clinics.

DATA EXTRACTION AND SYNTHESIS

Relevant data were abstracted from articles in databases through April 9, 2019, and methodologic quality was assessed. Included studies had an independent comparison to a reference standard.

MAIN OUTCOMES AND MEASURES

Sensitivity, specificity, and likelihood ratios (LRs).

RESULTS

Eleven studies of cardiac syncope (N = 4317) were included. Age at first syncope of at least 35 years was associated with greater likelihood of cardiac syncope (n = 323; sensitivity, 91% [95% CI, 85%-97%]; specificity, 72% [95% CI, 66%-78%]; LR, 3.3 [95% CI, 2.6-4.1]), while age younger than 35 years was associated with a lower likelihood (LR, 0.13 [95% CI, 0.06-0.25]). A history of atrial fibrillation or flutter (n = 323; sensitivity, 13% [95% CI, 6%-20%]; specificity, 98% [95% CI, 96%-100%]; LR, 7.3 [95% CI, 2.4-22]), or known severe structural heart disease (n = 222; range of sensitivity, 35%-51%, range of specificity, 84%-93%; range of LR, 3.3-4.8; 2 studies) were associated with greater likelihood of cardiac syncope. Symptoms prior to syncope that were associated with lower likelihood of cardiac syncope were mood change or prodromal preoccupation with details (n = 323; sensitivity, 2% [95% CI, 0%-5%]; specificity, 76% [95% CI, 71%-81%]; LR, 0.09 [95% CI, 0.02-0.38]), feeling cold (n = 412; sensitivity, 2% [95% CI, 0%-5%]; specificity, 89% [95% CI, 85%-93%]; LR, 0.16 [95% CI, 0.06-0.64]), or headache (n = 323; sensitivity, 3% [95% CI, 0%-7%]; specificity, 80% [95% CI, 75%-85%]; LR, 0.17 [95% CI, 0.06-0.55]). Cyanosis witnessed during the episode was associated with higher likelihood of cardiac syncope (n = 323; sensitivity, 8% [95% CI, 2%-14%]; specificity, 99% [95% CI, 98%-100%]; LR, 6.2 [95% CI, 1.6-24]). Mood changes after syncope (n = 323; sensitivity, 3% [95% CI, 0%-7%]; specificity, 83% [95% CI, 78%-88%]; LR, 0.21 [95% CI, 0.06-0.65]) and inability to remember behavior prior to syncope (n = 323; sensitivity, 5% [95% CI, 0%-9%]; specificity, 82% [95% CI, 77%-87%]; LR, 0.25, [95% CI, 0.09-0.69]) were associated with lower likelihood of cardiac syncope. Two studies prospectively validated the accuracy of the multivariable Evaluation of Guidelines in Syncope Study (EGSYS) score, which is based on 6 clinical variables. An EGSYS score of less than 3 was associated with lower likelihood of cardiac syncope (n = 456; range of sensitivity, 89%-91%, range of specificity, 69%-73%; range of LR, 0.12-0.17; 2 studies). Cardiac biomarkers show promising diagnostic accuracy for cardiac syncope, but diagnostic thresholds require validation.

CONCLUSIONS AND RELEVANCE

The clinical examination, including the electrocardiogram as part of multivariable scores, can accurately identify patients with and without cardiac syncope.

Continuous EEG Monitoring-The Neurologist's Crystal Ball

Time to Epileptiform Activity and EEG Background Recovery Are Independent Predictors After Cardiac Arrest

Westhall E, Rose I, Rundgren M, Bro-Jeppesen J, Kjaergaard J, Hassager C, Lindehammar H, Horn J, Ullen S, Nielsen N, Friberg H, Cronberg T. Clin Neurophysiol. 2018;129:1660-1668. doi:10.1016/j.clinph.2018.05.016

Objective: To investigate the temporal development of electroencephalogram (EEG) and prognosis. Methods: Prospective observational substudy of the Target Temperature Management trial. Six sites performed simplified continuous EEG monitoring (cEEG) on comatose patients after cardiac arrest, blinded to treating physicians. We determined time points of recovery of a normal-voltage continuous background activity and the appearance of an epileptiform EEG, defined as abundant epileptiform discharges, periodic/rhythmic discharges, or electrographic seizure activity. Results: One hundred thirty-four patients were included, of which 65 had a good outcome. Early recovery of continuous background activity (within 24 hours) occurred in 72 patients and predicted good outcome since 55 (76%) had good outcome, increasing the odds for a good outcome 7 times compared to a late background recovery. Early appearance of an epileptiform EEG occurred in 38 patients and 34 (89%) had a poor outcome, increasing the odds for a poor outcome 6 times compared to a late debut. The time to background recovery and the time to epileptiform activity were highly associated with outcome and levels of neuron-specific enolase. Multiple regression analysis showed that both variables were independent predictors. Conclusions: Time to epileptiform activity and background recovery are independent prognostic indicators. SIGNIFICANCE: Patients with early background recovery combined with late appearance of epileptiform activity may have a good outcome.

Lower Extremity Somatosensory Evoked Potential P37 Waveform Optimization

Somatosensory evoked potentials (SEPs) using tibial nerve stimulation are used during neurophysiologic intraoperative monitoring (NIOM). These SEPs produce a P37 waveform that is recorded from scalp electrodes. In this study, we attempted to determine the best derivation for recording the P37 waveform. Surgical cases using tibial nerve SEP NIOM were reviewed. Only cases in which the P37 was recorded using all of the following derivations were analyzed: centroparietal ipsilateral-centroparietal contralateral (CPi-CPc), centroparietal midline-frontopolar midline (CPz-Fpz), and CPz-CPc. The amplitude of the P37 waveform was measured in each derivation. Descriptive statistics were obtained for the P37 waveform amplitude. The mean amplitude in each of the derivations was compared using a chi-square test. Data from 39 patients (78 lower limbs) were available for analysis. The mean age of the patients was 49.64 years (range: 4-87 years); 18 were female. The highest amplitude P37 waveform was recorded from the CPz-Fpz derivation in 29 (35.4%) limbs, whereas the CPz-CPc and CPi-CPc derivations showed the highest amplitude in 29 (35.4%) and 20 (24.4%) limbs, respectively. The mean amplitudes were not significantly different between the various derivations. In only 10 (24.4%) of patients was the best derivation the same for both left and right limbs. A single best derivation was not found for recording the P37 waveform. Multiple derivations should be used to record cortical channels whenever possible. If the number of available channels is limited, using at least the CPz-Fpz and CPz-CPc derivations is recommended.

Loss of Vestibular Ocular Reflex in Nonconvulsive Status Epilepticus

BACKGROUND

Electroencephalogram (EEG) findings of generalized periodic discharges (GPDs) with triphasic morphology were introduced as a metabolic phenomenon, but more recently have been associated with epileptic phenomenon. Resolution of EEG findings along with clinical improvement from treatment is diagnostic. The known causes of reversible, isolated loss of OVR include medication toxicity, lead exposure, and thiamine deficiency, but its association with nonconvulsive status epilepticus (NCSE) has never been published. Medication induced loss of OVR resolves after a 24-hour washout period. We report a case of reversible, isolated loss of vestibular ocular reflex (VOR) associated with epileptic phenomenon.

METHODS

This is a case report of a single patient.

RESULTS

A 74-year-old male with a history of complex partial seizures admitted for a pneumonectomy had a post-operative course complicated by two instances of coma, the latter associated with an isolated loss of VOR. EEG revealed GPDs with triphasic morphology initially interpreted as a metabolic phenomenon. The patient's mental status, exam and EEG findings improved after low dose infusion of propofol for tracheostomy, and he was eventually discharged at baseline neurological function. Due to this response, his coma, loss of VOR and EEG were later interpreted as a consequence of NCSE.

CONCLUSION

The interpretation of GPDs with triphasic wave morphology range from metabolic phenomenon to NCSE. NCSE should be highly considered on the differential for encephalopathy regardless of the circumstances. NCSE may be a potential cause of reversible, isolated loss of the VOR and an AED trial in the appropriate clinical context should be considered. This is the first report of loss of VOR possibly associated with NCSE.

Clinical Neurophysiology in the Treatment of Disease

Clinical neurophysiology has a long-standing history and value in the diagnosis of neurologic diseases. Because of their unique ability to assess physiology and function of the nervous system, electroencephalography (EEG), evoked potentials, electromyography (EMG), and polysomnography have long been used in the diagnostic evaluation of epilepsies, demyelinating disorders, neuromuscular disorders, sleep disorders, and other diseases affecting the central and peripheral nervous systems. The role of these tests and clinical neurophysiology in general has usually ended upon diagnosis. New applications of these trusted techniques are changing old perceptions. Continuous EEG monitoring has found new value in not only diagnosis but also in treatment of nonconvulsive seizures and status epilepticus. Visual evoked potentials have been shown to be a biomarker for assessment of demyelination and remyelination associated with treatment of multiple sclerosis. Various EMG techniques can be used to independently assess improvement or otherwise of many neuromuscular diseases. The use of these techniques in the treatment of various neurologic disorders is the next frontier for clinical neurophysiology.

Magnesium Sulfate-Induced Motor Evoked Potential Changes

Motor evoked potentials (MEPs) are commonly used during neurophysiologic intraoperative monitoring. Anesthetic, homeostatic, surgical, and technical factors can cause a change in MEPs. The authors describe a case in which a bolus of magnesium sulfate resulted in a loss of amplitude of MEPs. Responses returned to near baseline about 20 minutes later. The patient did not have any new postoperative deficits. When MEP changes occur, in addition to evaluating other causes, magnesium sulfate administration should be considered.

Brexanolone as adjunctive therapy in super-refractory status epilepticus

Objective

Super‐refractory status epilepticus (SRSE) is a life‐threatening form of status epilepticus that continues or recurs despite 24 hours or more of anesthetic treatment. We conducted a multicenter, phase 1/2 study in SRSE patients to evaluate the safety and tolerability of brexanolone (USAN; formerly SAGE‐547 Injection), a proprietary, aqueous formulation of the neuroactive steroid, allopregnanolone. Secondary objectives included pharmacokinetic assessment and open‐label evaluation of brexanolone response during and after anesthetic third‐line agent (TLA) weaning.

Methods

Patients receiving TLAs for SRSE control were eligible for open‐label, 1‐hour brexanolone loading infusions, followed by maintenance infusion. After 48 hours of brexanolone infusion, TLAs were weaned during brexanolone maintenance. After 4 days, the brexanolone dose was tapered. Safety and functional status were assessed over 3 weeks of follow‐up.

Results

Twenty‐five patients received open‐label study drug. No serious adverse events (SAEs) were attributable to study drug, as determined by the Safety Review Committee. Sixteen patients (64%) experienced ≥1 SAE. Six patient deaths occurred, all deemed related to underlying medical conditions. Twenty‐two patients underwent ≥1 TLA wean attempt. Seventeen (77%) met the response endpoint of weaning successfully off TLAs before tapering brexanolone. Sixteen (73%) were successfully weaned off TLAs within 5 days of initiating brexanolone infusion without anesthetic agent reinstatement in the following 24 hours.

Interpretation

In an open‐label cohort of limited size, brexanolone demonstrated tolerability among SRSE patients of heterogeneous etiologies and was associated with a high rate of successful TLA weaning. The results suggest the possible development of brexanolone as an adjunctive therapy for SRSE requiring pharmacological coma for seizure control. Ann Neurol 2017;82:342–352

First-in-man allopregnanolone use in super-refractory status epilepticus

Super‐refractory status epilepticus (SRSE) is associated with high morbidity and mortality. Treatment of SRSE is complicated by progressive cortical hyperexcitability believed to result in part from synaptic GABA receptor internalization and desensitization. Allopregnanolone, a neurosteroid that positively modulates synaptic and extrasynaptic GABA_A receptors, has been proposed as a novel treatment. We describe the first two patients with SRSE who were each successfully treated with a 120‐h continuous infusion of allopregnanolone. Both patients recovered from prolonged SRSE with good cognitive outcomes.

Neurophysiological Intraoperative Monitoring During Aortic Arch Surgery

Circulatory management during replacement of the aortic arch is complex and involves a period of circulatory arrest to provide a bloodless field during arch vessel anastomosis. To guard against ischemic brain injury, tissue metabolic demand is reduced by systemically cooling the patient prior to circulatory arrest. Neurophysiological intraoperative monitoring (NIOM) is often used during the course of these procedures to provide contemporaneous assessment of brain status to help direct circulatory management decisions and detect brain ischemia. In this review, we discuss the characteristics of electrocerebral activity through the process of cooling, circulatory arrest, and rewarming as depicted through commonly used NIOM modalities, including electroencephalography and peripheral nerve somatosensory-evoked potentials. Attention is directed toward the role NIOM has traditionally played during deep hypothermic circulatory arrest, where it is used to define the point of electrocerebral inactivity or maximal cerebral metabolic suppression prior to initiating circulatory arrest while also discussing the evolving utility of NIOM when systemic circulatory arrest is initiated at more moderate degrees of hypothermia in conjunction with regional brain perfusion. The use of cerebral tissue oximetry by near-infrared spectroscopy as an alternative NIOM modality during surgery of the aortic arch is addressed as well. Finally, special considerations for NIOM and the detection of spinal cord ischemia during hybrid aortic arch repair and emerging operative techniques are also discussed.

Lacosamide in status epilepticus: Update on the TRENdS study

Many patients with critical illness have been noted to have nonconvulsive seizures (NCSs) and nonconvulsive status epilepticus (NCSE). How aggressively these seizures should be treated is unclear. Many investigators feel that the morbidity of NCSs and NCSE is different from that of generalized convulsive status epilepticus (GCSE), so treatment should be less urgent. Consequently, many nonsedating AEDs have been used to treat NCSs and NCSE in patients with critical illness. Randomized, controlled trials demonstrating the efficacy of AEDs in NCSs and NCSE are lacking. The Treatment of Recurrent Electrographic Nonconvulsive Seizures (TRENdS) study compared lacosamide to fosphenytoin in the treatment of NCSs. An update of the study is presented. This article is part of a Special Issue entitled "Status Epilepticus".

Nonconvulsive seizure control in the intensive care unit

OPINION STATEMENT

Nonconvulsive seizures (NCS) occur in as many as 20 % of comatose critically ill patients. These seizures need to be treated; however, the urgency with which this must be done and the medications that should be used are unclear. Often, data from treatment of convulsive status epilepticus (SE) is used to determine the best therapy for NCS. This may lead to "overtreatment" with sedating medications that prolongs hospitalization and worsens outcome. Nonsedating antiepileptic drug (AED) use is favored by many neurologists as the side effect profile is superior to sedating medications. Though limited, the available data suggests that valproic acid and lacosamide may be preferable to phenytoin/fosphenytoin and levetiracetam based on efficacy and side effect profiles. Other AEDs such as topiramate and pregabalin have also been used, but their data is even more limited, and they do not have an intravenous formulation. Clinical trials that have recently been completed and those that are ongoing will further inform our decisions about which drugs to use in the future.