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.

The relationship between seizures, interictal spikes and antiepileptic drugs

OBJECTIVE

A considerable decrease in spike rate accompanies antiepileptic drug (AED) taper during intracranial EEG (icEEG) monitoring. Since spike rate during icEEG monitoring can be influenced by surgery to place intracranial electrodes, we studied spike rate during long-term scalp EEG monitoring to further test this observation.

METHODS

We analyzed spike rate, seizure occurrence and AED taper in 130 consecutive patients over an average of 8.9days (range 5-17days).

RESULTS

We observed a significant relationship between time to the first seizure, spike rate, AED taper and seizure occurrence (F (3,126)=19.77, p<0.0001). A high spike rate was related to a longer time to the first seizure. Further, in a subset of 79 patients who experienced seizures on or after day 4 of monitoring, spike rate decreased initially from an on- to off-AEDs epoch (from 505.0 to 382.3 spikes per hour, p<0.00001), and increased thereafter with the occurrence of seizures.

CONCLUSIONS

There is an interplay between seizures, spikes and AEDs such that spike rate decreases with AED taper and increases after seizure occurrence.

SIGNIFICANCE

The direct relationship between spike rate and AEDs and between spike rate and time to the first seizure suggests that spikes are a marker of inhibition rather than excitation.

Long-term monitoring of cardiorespiratory patterns in drug-resistant epilepsy

OBJECTIVE

Sudden unexplained death in epilepsy (SUDEP) during inpatient electroencephalography (EEG) monitoring has been a rare but potentially preventable event, with associated cardiopulmonary markers. To date, no systematic evaluation of alarm settings for a continuous pulse oximeter (SpO₂ ) has been performed. In addition, evaluation of the interrelationship between the ictal and interictal states for cardiopulmonary measures has not been reported.

METHODS

Patients with epilepsy were monitored using video-EEG, SpO₂ , and electrocardiography (ECG). Alarm thresholds were tested systematically, balancing the number of false alarms with true seizure detections. Additional cardiopulmonary patterns were explored using automated ECG analysis software.

RESULTS

One hundred ninety-three seizures (32 generalized) were evaluated from 45 patients (7,104 h recorded). Alarm thresholds of 80-86% SpO₂ detected 63-73% of all generalized convulsions and 20-28% of all focal seizures (81-94% of generalized and 25-36% of focal seizures when considering only evaluable data). These same thresholds resulted in 25-146 min between false alarms. The sequential probability of ictal SpO₂ revealed a potential common seizure termination pathway of desaturation. A statistical model of corrected QT intervals (QTc), heart rate (HR), and SpO₂ revealed close cardiopulmonary coupling ictally. Joint probability maps of QTc and SpO₂ demonstrated that many patients had baseline dysfunction in either cardiac, pulmonary, or both domains, and that ictally there was dissociation-some patients exhibited further dysfunction in one or both domains.

SIGNIFICANCE

Optimal selection of continuous pulse oximetry thresholds involves a tradeoff between seizure detection accuracy and false alarm frequency. Alarming at 86% for patients that tend to have fewer false alarms and at 80% for those who have more, would likely result in a reasonable tradeoff. The cardiopulmonary findings may lead to SUDEP biomarkers and early seizure termination therapies.

How reliable is ictal duration to differentiate psychogenic nonepileptic seizures from epileptic seizures?

We sought to investigate (1) differences in ictal duration between psychogenic nonepileptic seizures (PNES) and epileptic seizures (ES), (2) the odds of being PNES when seizures last ≥5min, and (3) the value of ictal duration as a diagnostic test to differentiate PNES from ES. We retrospectively reviewed video-EEG recordings and tabulated ictal durations of all PNES and ES. We estimated the mean ictal durations of PNES and ES using linear mixed models. The odds of being PNES when seizures last ≥5min were estimated using logistic regression. We used receiver operating characteristics (ROC) curves to study the overall diagnostic accuracy of ictal duration in differentiating PNES from ES. We studied 441 ES and 341 PNES recorded from 138 patients. The mean ictal duration of PNES (148.7s, 95% CI: 115.2-191.8) was significantly longer (p<0.001) than that of ES (47.7s, 95% CI: 37.6-60.6). The odds of being PNES was about 24 times higher (Odds ratio: 23.8, 95% CI: 7.9-71.3) when the ictal duration was ≥5min. The ROC curve yielded an area under the curve of 0.80 (95% CI 0.73-0.88). Youden's index identified 123.5s as the optimal threshold to diagnose PNES with 65% sensitivity and 93% specificity. Our results indicate that ictal duration is a useful test to raise suspicion of PNES. When a seizure lasts ≥5min, it is 24 times more likely to be PNES with the potential risk of misdiagnosis as status epilepticus.

Comparison of cardiorespiratory and EEG abnormalities with seizures in adults and children

Cardiopulmonary dysfunction and postictal generalized EEG suppression (PGES) are proposed as possible risk factors for the occurrence of SUDEP. The evolution of cardiorespiratory abnormalities with seizures has not been systematically studied for any age-related findings. Additionally, not many studies have looked into the possible effect of age-related brain maturation on PGES. The purpose of this study was to compare these SUDEP risk factors in adults versus children. We prospectively recorded cardiopulmonary abnormalities during seizures using pulse oximetry, EKG, and respiratory inductance plethysmography. Linear and logistic regression models adjusting for multiple seizures in a single patient were used to compare the cardiorespiratory and EEG findings between adults and children. We recorded 101 seizures in 26 children and 55 seizures in 22 adults. Ictal central apnea and bradycardia occurred more often in children than in adults (p=0.02 and p=0.008, respectively), while ictal tachycardia occurred more often in adults (p=0.001) than in children. Postictal generalized EEG suppression of longer duration occurred more often in adults (p=0.003) than in children. Minimum O2 saturation and seizure duration/generalization/lateralization did not significantly differ between adults and children (p>0.1). Children had more frontal lobe seizures, and adults had more temporal lobe seizures recorded (p=0.01). There may be an age-related effect on cardiorespiratory and EEG abnormalities associated with seizures, with higher rates of apnea and bradycardia in children and a much higher prevalence of PGES of longer duration in adults. This may indicate why, despite lower rates of cardiopulmonary dysfunction, adults die more frequently from SUDEP than children.

Nonconvulsive status epilepticus in patients with brain tumors

PURPOSE

The prevalence of nonconvulsive status epilepticus (NCSE) in brain tumor patients is unknown. Since NCSE has been associated with significant mortality and morbidity, early identification is essential. This study describes the clinical and EEG characteristics, treatment, and outcome in brain tumor patients with NCSE.

METHOD

All patients admitted to Mount Sinai Hospital from 2009 to 2012 with an ICD-9 brain tumor code were cross-referenced with the epilepsy department's database. EEGs from matching patients were reviewed for NCSE. Relevant information from the medical records of the patients with NCSE was extracted.

RESULTS

1101 brain tumor patients were identified, of which 259 (24%) had an EEG and 24 (2%) had NCSE. The vast majority of seizures captured were subclinical with 13 patients (54%) having only subclinical seizures. Treatment resolved the NCSE in 22 patients (92%) with accompanying clinical improvement in 18 (75%) of those patients. Tumor recurrence or progression on MRI was associated with decreased 2-month survival (75% mortality, p=0.035) compared to stable tumors (20% mortality). Patients with metastatic disease had median survival from tumor diagnosis of 1.2 months.

CONCLUSION

NCSE in brain tumor patients may be under diagnosed due to the frequent lack of outward manifestations and highly treatable with improvement in the majority of patients. NCSE patients with progressing brain lesions, tumor recurrence, or metastatic disease are at serious risk of mortality within 2 months. Continuous EEG monitoring in brain tumor patients with recent clinical seizures and/or a depressed level of consciousness may be critical in providing appropriate care.

Depths and grids in brain tumors: implantation strategies, techniques, and complications

Patients with intracranial mass lesions are at increased risk of intractable epilepsy even after tumor resection due to the potential epileptogenicity of lesional and perilesional tissue. Risk factors for tumoral epilepsy include tumor location, histology, and extent of tumor resection. In epilepsy that occurs after tumor resection, the epileptogenic zone often does not correspond precisely with the area of abnormality on imaging, and seizures often arise from a relatively restricted area despite widespread changes on imaging. Invasive monitoring via subdural grids and/or depth electrodes can therefore be helpful to delineate areas of eloquence and localize the epileptogenic zone for subsequent resection. Subdural grids offer excellent contiguous coverage of superficial cortex and allow resection using the same craniotomy, facilitating understanding of anatomic relationships. Depth electrodes offer superior coverage of deep structures, are easier to use in cases where a previous craniotomy is present, are not associated with anatomic distortion due to brain shift, and may be associated with a lower complication rate. We review the biology of focal postoperative epilepsy and invasive diagnostic strategies for the surgical evaluation of medically refractory epilepsy in patients who have undergone resection of intracranial mass lesions.

Comparing spiking and slow wave activity from invasive electroencephalography in patients with and without seizures

OBJECTIVES

To develop quantitative measures for estimating seizure probability, we examine intracranial EEG data from patient groups with three qualitative seizure probabilities: patients with drug resistant focal epilepsy (high), these patients during cortical stimulation (intermediate), and patients who have no history of seizures (low).

METHODS

Patients with focal epilepsy were implanted with subdural electrodes during presurgical evaluation. Patients without seizures were implanted during treatment with motor cortex stimulation for atypical facial pain.

RESULTS

The rate and amplitude of spikes correlate with qualitative seizure probability across patient groups and with proximity to the seizure onset zone in focal epilepsy patients. Spikes occur earlier during the negative oscillation of underlying slow activity (0.5-2 Hz) when seizure probability is increased. Similarly, coupling between slow and fast activity is increased.

CONCLUSIONS

There is likely a continuum of sharply contoured activity between non-epileptiform and epileptiform. Characteristics of spiking and how spikes relate to slow activity can be combined to predict seizure onset zones.

SIGNIFICANCE

Intracranial EEG data from patients without seizures represent a unique comparison group and highlight changes seen in spiking and slow wave activity with increased seizure probability. Slow wave activity and related physiology are an important potential biomarker for estimating seizure probability.

Resource efficient data compression algorithms for demanding, WSN based biomedical applications

During the last few years, medical research areas of critical importance such as Epilepsy monitoring and study, increasingly utilize wireless sensor network technologies in order to achieve better understanding and significant breakthroughs. However, the limited memory and communication bandwidth offered by WSN platforms comprise a significant shortcoming to such demanding application scenarios. Although, data compression can mitigate such deficiencies there is a lack of objective and comprehensive evaluation of relative approaches and even more on specialized approaches targeting specific demanding applications. The research work presented in this paper focuses on implementing and offering an in-depth experimental study regarding prominent, already existing as well as novel proposed compression algorithms. All algorithms have been implemented in a common Matlab framework. A major contribution of this paper, that differentiates it from similar research efforts, is the employment of real world Electroencephalography (EEG) and Electrocardiography (ECG) datasets comprising the two most demanding Epilepsy modalities. Emphasis is put on WSN applications, thus the respective metrics focus on compression rate and execution latency for the selected datasets. The evaluation results reveal significant performance and behavioral characteristics of the algorithms related to their complexity and the relative negative effect on compression latency as opposed to the increased compression rate. It is noted that the proposed schemes managed to offer considerable advantage especially aiming to achieve the optimum tradeoff between compression rate-latency. Specifically, proposed algorithm managed to combine highly completive level of compression while ensuring minimum latency thus exhibiting real-time capabilities. Additionally, one of the proposed schemes is compared against state-of-the-art general-purpose compression algorithms also exhibiting considerable advantages as far as the compression rate is concerned.

Interprofessional simulation to improve safety in the epilepsy monitoring unit

OBJECTIVE

Patient safety is critical for epilepsy monitoring units (EMUs). Effective training is important for educating all personnel, including residents and nurses who frequently cover these units. We performed a needs assessment and developed a simulation-based team training curriculum employing actual EMU sentinel events to train neurology resident-nurse interprofessional teams to maximize effective responses to high-acuity events.

METHODS

A mixed-methods design was used. This included the development of a safe-practice checklist to assess team response to acute events in the EMU using expert review with consensus (a modified Delphi process). All nineteen incoming first-year neurology residents and 2 nurses completed a questionnaire assessing baseline knowledge and attitudes regarding seizure management prior to and following a team training program employing simulation and postscenario debriefing. Four resident-nurse teams were recorded while participating in two simulated scenarios. Employing retrospective video review, four trained raters used the newly developed safe-practice checklist to assess team performance. We calculated the interobserver reliability of the checklist for consistency among the raters. We attempted to ascertain whether the training led to improvement in performance in the actual EMU by comparing 10 videos of resident-nurse team responses to seizures 4-8months into the academic year preceding the curricular training to 10 that included those who received the training within 4-8months of the captured video.

RESULTS

Knowledge in seizure management was significantly improved following the program, but confidence in seizure management was not. Interrater agreement was moderate to high for consistency of raters for the majority of individual checklist items. We were unable to demonstrate that the training led to sustainable improvement in performance in the actual EMU by the method we used.

CONCLUSIONS

A simulated team training curriculum using a safe-practice checklist to improve the management of acute events in an EMU may be an effective method of training neurology residents. However, translating the results into sustainable benefits and confidence in management in the EMU requires further study.

A simple clinical score for prediction of nonepileptic seizures

Psychogenic nonepileptic seizures (PNES), often mistaken for epilepsy in community practice, require inpatient video-EEG (VEEG) monitoring for diagnostic confirmation. We developed a simple score designed for use in an outpatient setting to predict the subsequent VEEG diagnosis of PNES. We retrospectively compared fifty-five consecutive patients with VEEG-proven PNES (N₁=55) with a group of randomly selected patients with VEEG-proven epilepsy (N₂=55). Patients were divided into two groups: I) a 'truly retrospective' group of 27 patients with PNES and 27 patients with epilepsy whose data served to develop the score, and II) a 'pseudoprospective' group of 28 patients each with PNES and epilepsy to whom the score was applied. Six features in the history of the Group I cohort appeared more prominent in patients with PNES than patients with epilepsy and were assigned escalating numerical values as follows: number of declared drug allergies (0, 0.5, 1), number of declared comorbidities (0, 0.5, 1), number of previous invasive medical interventions of any type (0, 0.5, 1), and a history of significant psychological or physical trauma (0 or 1). In addition, a score was assigned to verbal description of the seizures themselves as being consistent (=0), atypical (=1), or indeterminate (=0.5) for epilepsy. The values were added to yield an omnibus score ranging from 0 to 6. Scoring of Group II subjects in a blinded fashion revealed that in general patients with PNES had higher scores, and the majority obtained a score >2; most patients with epilepsy scored <1.5. Group difference in the mean between the PNES and epilepsy cohort was highly significant (p<0.0001, Wilcoxon rank-sum test). Our score is a simple clinical instrument based on the patient history that may find use in the triage of patients awaiting hospitalization for VEEG and in pre-VEEG counseling.

Clinical utility of a video/audio-based epilepsy monitoring system Nelli

OBJECTIVE

The aim of this study was to evaluate the clinical utility of a semi-automated hybrid video/audio-based epilepsy monitoring system (Nelli®) in a home setting.

METHODS

In this retrospective study, 104 consecutive patients underwent Nelli-registration for an average of 29 days at their home. The seizure-related data obtained from the registration were assessed to investigate the utility of the Nelli-registration regarding clinical decision-making.

RESULTS

Of 104 patients, Nelli® hybrid system was able to recognize clinically relevant events in 83 (80%) patients: epileptic seizures in 67 (65%) and nonepileptic events in 16 (15%). A total of 2767 epileptic seizures of different seizure types were captured and identified. These seizures included not only tonic-clonic seizures but also other complex or simple motor seizures. For the outcomes regarding clinical decision-making, a need for a new therapeutic intervention was recognized in 54 (51.9%) patients based on the number and severity of seizures captured by Nelli-registration. In 12 (11.5%) patients, the need to change the treatment plan was excluded because no evidence of suspected epileptic seizures was found. Nelli-registration aided in confirming the therapeutic efficacy of modifications of antiseizure medications (ASMs) or neuromodulation therapies in 13 (12.5%) patients. Nelli-registration enabled to determine the change in seizure classification and facilitated to reach clear diagnostic conclusions in 11 (10.6%) patients. In 14 (13.5%) patients, there was no change in clinical outcome, as Nelli-registration was unable to infer any clinical decision either due to inconclusive results or lack of typical events. Seizures detected during Nelli-registration aided in decision-making for therapeutic interventions in 71 (68%) patients. Altogether, 44 (42%) patients had adjustment of ASMs, and in 9 (9%) patients, Nelli-registrations led to the change in the settings of vagus nerve stimulation (VNS) or deep brain stimulation (DBS) treatment. Additionally, 18 (17%) patients were referred to presurgical evaluation or established a baseline seizure frequency before surgical implantation for neuromodulation treatment with VNS or DBS, while 33 (32%) patients had no change in therapy. Nine patients (8.7%) were referred to video-EEG monitoring (VEM), as Nelli-recorded events highlighted the need for presurgical evaluation in 6 patients or further diagnostic evaluation in 3 patients.

CONCLUSION

This study confirms the clinical utility of the video/audio monitoring system Nelli® in home settings. Home monitoring with Nelli® hybrid system provides a new alternative for the assessment of frequency and type of epileptic seizures as well as for a recognition of nonepileptic events. Thus, Nelli-registration can facilitate the optimization of seizure monitoring and management in clinical practice, complementing existing methods such as VEM and ambulatory EEG recordings.

Sub-scalp electroencephalography: A next-generation technique to study human neurophysiology

Sub-scalp electroencephalography (ssEEG) is emerging as a promising technology in ultra-long-term electroencephalography (EEG) recordings. Given the diversity of devices available in this nascent field, uncertainty persists about its utility in epilepsy evaluation. This review critically dissects the many proposed utilities of ssEEG devices including (1) seizure quantification, (2) seizure characterization, (3) seizure lateralization, (4) seizure localization, (5) seizure alarms, (6) seizure forecasting, (7) biomarker discovery, (8) sleep medicine, and (9) responsive stimulation. The different ssEEG devices in development have individual design philosophies with unique strengths and limitations. There are devices offering primarily unilateral recordings (24/7 EEG^TM SubQ, Neuroview^TM, Soenia® UltimateEEG™), bilateral recordings (Minder™, Epios™), and even those with responsive stimulation capability (EASEE®). We synthesize the current knowledge of these ssEEG systems. We review the (1) ssEEG devices, (2) use case scenarios, (3) challenges and (4) suggest a roadmap for ideal ssEEG designs.

Reasons for prolonged length of stay in the epilepsy monitoring unit

Epilepsy monitoring unit (EMU) admissions are essential for the classification/localization of epileptic seizures (ES) and psychogenic non-epileptic seizures (PNES). However, the duration of admissions is highly variable. Accordingly, we evaluated the duration of 596 EMU admissions and reasons for prolonged (>7 days) lengths of stay (LOS). The average LOS was longer for patients diagnosed with ES (8.0 days, SD 4.1 days) than all others (6.0 days, SD 3.9 days, p<0.001). Of the 596 admissions, 231 (38.8%) had prolonged LOS. The most commonly reported reason for prolonged stay was need to record additional seizures (33%). Other contributors included complications such as seizure clusters (6.9%), status epilepticus (1.6%), test complications (3.7%), psychiatric concerns (4.3%), and medication side effects (1.6%). Our results suggest multiple factors produce prolonged LOS with no factor accounting for the majority. Recording an insufficient number of all habitual seizures was the leading cause, which was over twice the percentage of reported complications (17.6%). However, being able to prolong admissions when necessary resulted in only 14.9% of admissions being inconclusive, potentially justifying the extra expense. Efforts to shorten LOS may be best directed at faster recording of seizures, but this may increase LOS due to complications. Our results may be helpful when assessing whether efforts to shorten LOS are useful in improving the quality and cost of care.

Skin Irritation during Video-EEG Monitoring

OBJECTIVES

Video-EEG (VEEG) monitoring, indicated to characterize and diagnose seizures, is recorded over several days with electrodes glued to the patient's scalp. Our investigation was designed to determine the incidence of electrode-related skin irritation during VEEG in the epilepsy monitoring unit (EMU) and implement a series of interventions to reduce the incidence of moderate to severe irritation.

METHODS

Between May 2012 and March 2015, EMU patients were assessed for skin lesions before electrode placement and at discharge. Prospectively gathered demographic data included: age, gender, race/ethnicity, length of monitoring (LOM), skin prep medium (SPM) used, self-reported skin sensitivity, history of skin diseases, and skin products used on the day of admission. When present, electrode-related skin irritation was graded as mild, moderate, or severe. Data were collected before any intervention (baseline-group) and thereafter with each intervention: standardization (single SPM, raising awareness, monitoring for electrode-related discomfort); face washing; applying skin barrier; replacing tape with gauze; and using disposable electrodes.

RESULTS

Data from 861 patients were analyzed (104-146 per group). At baseline, any skin irritation occurred in 27.3% of patients; it was moderate or severe in 19.1%. LOM ≥4 days and electrode position on facial skin were associated with significantly higher risk. All interventions reduced rates of skin irritation, but only the standardization intervention was statistically significant.

CONCLUSIONS

During VEEG admissions, electrode-related skin irritation occurred in about one-third of patients; it was moderate to severe in one-fifth. A standardized care process with regular monitoring for discomfort led to significant improvement in the rate of irritation.

Antiepileptic drug withdrawal and seizure severity in the epilepsy monitoring unit

OBJECTIVE

The goal of this study was to identify a strategy for antiepileptic drug (AED) reduction to allow efficient recording of focal seizures (FS) in patients undergoing video-electroencephalography (EEG) in an epilepsy monitoring unit (EMU) while avoiding the risk of complications associated with more severe seizure types.

METHODS

We retrospectively reviewed consecutive patients admitted to our institution's EMU from July 1, 2016 to December 31, 2017. We included 114 presurgical patients who had AEDs reduced and at least one seizure during the admission. We compared AED dosages at which FS versus focal to bilateral tonic-clonic seizures (f-BTCS), seizure clusters, and lorazepam administration occurred. We also examined rate of AED reduction and seizure types. We used a receiver-operating characteristic (ROC) curve to identify a dose maximizing FS and minimizing other seizure types.

RESULTS

Antiepileptic drug withdrawal rates ranged from 0 to 100% in the first 24 h (mean: 20%, standard deviation: 20%). Focal to bilateral tonic-clonic seizures and lorazepam administration occurred at a lower median AED dose than did FS (0%, 7.2%, and 43.8%, respectively, expressed as a percentage of the patient's outpatient daily AED dose; p < 0.001). A daily EMU-administered dose of one-third of the patient's outpatient AED dose allowed 55.0% of FS to occur while avoiding 82.0% of more severe seizure types. The seizure types had no difference in rate of AED withdrawal in the first 24 h of EMU stay.

CONCLUSIONS

Focal seizures occurred at a higher AED dose than did f-BTCS. This may imply that a low minimally effective dose of AED could allow FS to be recorded while providing protection against f-BTCS. This strategy could improve efficacy and safety in the EMU.

Health care resource utilization and costs before and after epilepsy surgery

OBJECTIVE

To describe the demographics of epilepsy surgery utilization and its impact on health care resource use.

METHODS

Retrospective descriptive study using the MarketScan commercial claims database. We studied children and adults who underwent epilepsy surgery in the USA in the period 2006-2019. Our main outcome was health care resource utilization.

RESULTS

Among the 87,368 patients with refractory epilepsy, 2,011 (2.3%) patients underwent resective epilepsy surgery, 188 (0.2%) patients underwent partial or total hemispherectomy, and 183 (0.2%) patients underwent corpus callosotomy. The proportion of patients undergoing epilepsy surgery has barely increased in the period 2006 to 2019. The year of resective epilepsy surgery was associated with high healthcare costs per person-year [median (p₂₅-p₇₅): $140,322 ($88,749-$225,862)], but healthcare costs per person-year substantially decreased in the 5 years after compared to the 5 years before the year of resective epilepsy surgery [$7,691 ($2,738-$22,092) versus $18,750 ($7,361-$47,082), p-value < 0.0001]. This result held in all resective epilepsy surgery subgroups: children, adults, temporal, extratemporal, subdural EEG monitoring, stereoEEG monitoring, and no intracranial monitoring. Similarly, the year of hemispherectomy was associated with high healthcare costs per person-year [$260,983 ($154,791-$453,986)], but healthcare costs per person-year substantially decreased in the 5 years after compared to the 5 years before the year of hemispherectomy [$26,834 ($12,842-$52,627) versus $54,596 ($19,547-$136,412), p-value < 0.0001]. In contrast, the year of corpus callosotomy was associated with high healthcare costs per person-year [$162,399 ($108,150-$253,156)], but healthcare costs per person-year did not substantially decrease in the 5 years after than in the 5 years before the year of corpus callosotomy [$25,464 ($10,764-$69,338) versus $36,221 ($12,841-$85,747), p-value = 0.2142].

CONCLUSION

In privately insured patients in the USA, resective epilepsy surgery and hemispherectomy substantially decrease healthcare utilization in subsequent years. Epilepsy surgery may help contain costs in the field of epilepsy.

Decreasing SUDEP incidence in a tertiary epilepsy center between 1981 and 2016: Effects of better patient supervision

OBJECTIVE

The objective of this study was to investigate the incidence of sudden unexpected death in epilepsy (SUDEP) in a tertiary epilepsy center in the years 1981-2016 with an emphasis on patient supervision and nursing intervention in different departments.

METHODS

We identified 14 SUDEP cases (probable, definite, definite plus). Patient-years (PY) and incidence were calculated for the periods of six years for the general epileptology wards (adults and children) and, in addition, for the epilepsy monitoring unit (EMU) since 1990.

RESULTS

The incidence of SUDEP showed a decreasing trend over time (r = -0.81; p = 0.053, two-sided; Pearson correlation coefficient). This is especially true in children (no SUDEP occurred in pediatric general epileptology since 1992). Additionally, in the EMU (314 PY since the start of 1990), no SUDEP occurred. Sudden unexpected death in epilepsy incidence was highest (6.8/1000 PY) in the early time periods (1981-1992) and lowest (1.7/1000 PY) in the later time periods (1999-2010). In the general epileptology wards (3579 PY), the overall incidence was 3.9 per 1000 PY (95% confidence interval (CI): 2.1-6.6).

CONCLUSIONS

We assume that the decreased SUDEP incidence is an effect of better supervision by the use of technical means (e.g., video cameras, pulse oximeters, seizure detection systems) and rooming-in of parents or family.

Seizures by the clock: Temporal patterns of psychogenic nonepileptic seizures

We hypothesized that (1) the occurrence of psychogenic nonepileptic seizures (PNES) is modulated by the interaction between the 24-hour clock and the sleep-wake cycle and (2) the pattern of modulation in PNES differs from epileptic seizures (ES). We sought to test our hypotheses in a cohort of patients diagnosed with PNES or ES in the setting of an epilepsy monitoring unit (EMU). We retrospectively reviewed consecutive video-EEG (VEEG) recordings of patients who underwent monitoring at the EMU of a tertiary hospital. The seizure type (PNES vs ES), onset time, and the state (sleep vs awake) were tabulated. The relationship between the onset time, the state of arousal, and the occurrence of PNES was determined using logistic regression analysis. To determine if the nature of the relationship between the state of arousal and PNES differed according to the onset time, an interaction between the onset time and the state of arousal was also fitted to the model. We studied a total of 754 seizures (ES, 437; PNES, 317) from 135 patients consisting of 71 (52.6%) females and 64 (47.4%) males with the median age of 39years (range, 18-91). We found a significant association between the state of arousal and PNES with the odds of being PNES four times higher when patients were awake (OR: 4.27, 95% CI: 2.44-7.48; p<0.0001) compared with when they were asleep. The analysis further revealed a significant interaction between the onset time and the state of arousal (p=0.004). The odds of being PNES were significantly higher if the seizure occurred when the patient was awake at night. These patterns possibly indicate the complex interaction between the sleep-wake cycle and the 24-hour time cycle in the generation of PNES.

Characterizing women veterans receiving seizure care in the veterans affairs healthcare system

OBJECTIVE

The number and proportion of women served by the Veterans Health Administration (VHA) is rapidly expanding, necessitating better characterization of factors unique to this population. While nascent literature has begun to better characterize women within the broader seizure population, women Veterans remain an understudied sample. To expand our clinical understanding of women with seizures, we assessed demographic and clinical characteristics, as well as psychiatric/military histories in women receiving care from an Epilepsy Center of Excellence within the VA Healthcare System.

METHODS

The sample included 90 women with psychogenic nonepileptic seizures (PNES) and 28 women with epileptic seizures (ES) as the final diagnosis after epilepsy monitoring at a large VA medical center between 2010 and 2020. Retrospective chart review gathered demographics, including age, marital status, and work status; clinical characteristics, including history of traumatic brain injury (TBI) or migraines, gynecological history, and use of anti-seizure medications (ASM); psychiatric information, including trauma history, psychiatric diagnoses, and treatment; and military history related to service or service connection. Group differences were assessed between women with PNES and ES.

RESULTS

The ES group was significantly older than the PNES group (47.8 v. 41.9 years, p = 0.02) and had a non-significantly longer diagnosis duration (12.3 vs. 8.6 years, p = 0.17). Clinically, the PNES group had a significantly higher rate of migraines (76.7% v. 57.1%, p = 0.04) and hysterectomy (40% v. 17.9%, p = 0.03). Many psychiatric factors differentiated the two groups, with significantly higher rates of psychotropic medication use (86.7% v. 60.7%, p = 0.002), psychiatric hospitalization (42.2% v. 21.4%, p = 0.047), and suicide attempts (42.2% v. 14.3%, p = 0.005), alongside trends toward higher rates of military sexual trauma (47.8% vs. 28.6%, p = 0.07) and childhood sexual trauma (37.8% vs. 17.9%, p = 0.05) among those with PNES.

SIGNIFICANCE

This is the largest study to date characterizing women veterans with seizures seeking comprehensive seizure care and provides an update to previously published information on Veteran samples with seizures. Several characteristics differ between women Veterans with PNES and ES, spanning demographic, clinical, and psychiatric factors. Understanding the unique profile of women Veterans with epilepsy seeking care through the VA system is a crucial step in providing optimal care, including making informed diagnosis and providing appropriate treatment.

Social determinants do not affect access to specialized epilepsy care in veterans

INTRODUCTION

It is well established that sociodemographic and neighborhood determinants impact access to healthcare. Veterans with epilepsy (VWE) face unique challenges that may limit access to specialized epilepsy care, though institutional initiatives have aimed to minimize disparities. We assessed the extent to which surrogate markers of access to quality care in VWE were impacted by sociodemographic and neighborhood determinants.

METHODS

The sample included 180 VWE. Surrogate markers included time between initial diagnosis and admission to epilepsy monitoring unit (EMU) (time to referral, TTR), and the number of CT, MRI, and EEGs conducted prior to initial EMU evaluation. Sociodemographic and neighborhood determinants included age, sex, race, education, neighborhood advantage, rural status, distance from home to the nearest VAMC, and number of service connection (SC) conditions. Significant correlations across variables of interest were entered into a linear regression. Group differences between social factors were assessed for early and late TTR groups (based on 1st and 4th quartiles).

RESULTS

The mean TTR was 12 years (SD ± 13.18). Longer TTR was correlated to older age (p < 0.001) and fewer SC conditions (p = 0.03). None of the other factors were significantly correlated to TTR. Older age significantly predicted longer TTR on regression. The earlier TTR group was younger, had more SC conditions, lived closer to a VAMC, and was more likely to be female. Greater geographic distance was correlated with fewer CT scans (p = 0.01). A greater number of MRIs was correlated with older age (p = 0.04). Younger age (p < 0.01) and greater education (p = 0.01) were correlated with more SC.

CONCLUSION

Access to epilepsy care among VWE was largely unimpacted by social determinants, with the exception of older age leading to longer TTR. The TTR in VWE was considerably shorter than has been reported in the literature for civilian patients. The Veterans Health Administration model of care may harbor certain advantages in epilepsy treatment.

Pathology of bilateral pulvinar degeneration following long duration status epilepticus

PURPOSE

To define the neuropathological findings of pulvinar degeneration seen in long duration status epilepticus.

METHODS

We review the clinical, radiologic, neurophysiologic, investigational and neuropathological findings on a 27 year old woman who died after 162 days of prolonged refractory status epilepticus.

RESULTS

Continuous EEG monitoring confirmed recurrent uncontrolled seizure activity bilaterally and independently, most frequent in the right fronto-temporal region. Initial MRI of the brain was normal. Repeat study until on day 127 of admission showed advanced changes, with bilateral pulvinar T2/FLAIR hyperintensities. The autopsy revealed sharply defined, grey, soft, granular nodules in each medial pulvinar nucleus. Microscopically these consisted of sharply defined paucicellular areas with loss of neurons and myelin and with numerous macrophages in their centers, surrounded by reactive astrocytes with relatively spared of axons. The spinal cord at cervical and thoracic levels showed symmetric spongy vacuolation in the central part of the dorsal columns and lateral corticospinal tracts, with mild myelin loss, relatively preserved axons. The pathological lesions found in this case in thepulvinar are somewhat similar to the pathologic lesions described in Wernicke's encephalopathy. Those found in the spinal cord of our patient resemble characteristic features of B12 related subacute combined degeneration.

CONCLUSION

Characteristic pulvinar degeneration may be found as an acquired phenomenon in prolonged refractory status epilepticus. We hypothesize that the neuropathological findings result from an excessive focal metabolic demand, secondary to neuronal network over activation in the setting of prolonged, frequent bi-temporal seizures.

Can seizure-related heart rate differentiate epileptic from psychogenic nonepileptic seizures?

OBJECTIVES

We aimed to (1) determine if seizure-related heart rate (HR) differentiates epileptic seizures (ES) from psychogenic nonepileptic seizures (PNES); (2) define the most useful point of the following HR measurements: preictal, ictal-onset, maximal-ictal, or postictal; and (3) delineate the optimal HR cutoff points (absolute HR and relative HR increase) to differentiate ES from PNES.

METHODS

All video-electroencephalography (VEEG) recorded at an Australian tertiary hospital from May 2009 to November 2015 were retrospectively reviewed. Baseline (during rest and wakefulness), 1-min preictal, ictal-onset, maximal-ictal, and 1-min postictal HR were measured for each ES and PNES event. Events lasting <10 s or with uninterpretable electrocardiogram (ECG) due to artifacts were excluded. Receiver operating characteristic curve analysis was performed to assess the diagnostic accuracy of HR reflected by the area under the curve (AUC).

RESULTS

Video-electroencephalography of 341 ES and 265 PNES from 130 patients were analyzed. The AUC for preictal, ictal-onset, maximal-ictal, and postictal HR were found to have poor differentiation between all types of ES and PNES. However, comparing bilateral tonic-clonic ES and PNES, AUC for absolute maximal-ictal HR was 0.84 (95% confidence interval [CI]: 0.73-0.95) and for absolute postictal HR was 0.90 (95% CI: 0.81-1.00) indicating good diagnostic discrimination. Using Youden's index to diagnose tonic-clonic ES, the optimal cutoff point for absolute maximal-ictal HR was 114 bpm (sensitivity: 84%, specificity: 82%) and for absolute postictal HR was 90 bpm (sensitivity: 91%, specificity: 82%).

CONCLUSION

These findings suggest that seizure-related HR is useful in differentiating bilateral tonic-clonic ES from PNES. Based on the AUC, the best diagnostic measurements are maximal-ictal and postictal HR.

Cardiac-based detection of seizures in children with epilepsy

INTRODUCTION

We evaluated a multi-parametric approach to seizure detection using cardiac and activity features to detect a wide range of seizures across different people using the same model.

METHODS

Electrocardiogram (ECG) and accelerometer data were collected from a chest-worn sensor from 62 children aged 2-17 years undergoing video-electroencephalogram monitoring for clinical care. ECG data from 5 adults aged 31-48 years who experienced focal seizures were also analyzed from the PhysioNet database. A detection algorithm was developed based on a combination of multiple heart rhythm and motion parameters.

RESULTS

Excluding patients with multiple seizures per hour and myoclonic jerks, 25 seizures were captured from 18 children. Using cardiac parameters only, 11/12 generalized seizures with clonic or tonic activity were detected as well as 7/13 focal seizures without generalization. Separately, cardiac parameters were evaluated using electrocardiogram data from 10 complex partial seizures in the PhysioNet database of which 7 were detected. False alarms averaged one per day. Movement-based parameters did not identify any seizures missed by cardiac parameters, but did improve detection time for 4 of the generalized seizures.

CONCLUSION

Our data suggest that cardiac measures can detect seizures with bilateral motor features with high sensitivity, while detection of focal seizures depends on seizure duration and localization and may require customization of parameter thresholds.

Characterizing differences in psychiatric profiles between male and female veterans with epilepsy and psychogenic non-epileptic seizures

OBJECTIVE

While previous studies have described psychiatric profiles in patients with psychogenic non-epileptic seizures (PNES) and epileptic seizures (ES), a well-matched comparison between males and females has been lacking. To address this shortcoming, the present study sought to explore sex differences between male and female Veterans with ES and PNES in terms of psychiatric diagnoses, trauma histories, and psychiatric treatment.

METHODS

A male Veteran sample (PNES n = 87, ES n = 28) was identified matching age and seizure diagnosis with our previously-gathered female Veteran sample (PNES n = 90, ES n = 28). Retrospective chart review was used to obtain demographic, psychiatric, and seizure-related variables. Group differences between PNES and ES were first assessed among males followed by differences between males and females.

RESULTS

Males with PNES were more likely to receive psychiatric treatment (82.6 % vs. 60.7 %, p = 0.017), be prescribed more psychotropics (1.6 vs. 0.9, p = 0.003), and more likely to have childhood physical abuse (27.9 % vs. 3.6 %, p = 0.007) than those with ES. Compared to PNES, males with ES presented to the epilepsy monitoring unit (EMU) significantly later (12.8 years vs. 6.1 years, p = 0.009), and were prescribed more anti-seizure medications (ASMs) previously (2.1 vs. 0.8, p = 0.009) and currently (1.6 vs. 1.0, p = 0.001). Between males and females with PNES, females evidenced more depression (76.7 % vs. 26.3 %, p < 0.001), borderline personality disorder (18.9 % vs. 4.7 %, p = 0.004), suicidality (65.6 % vs. 33.7 %, p < 0.001), and childhood sexual abuse (37.8 % vs. 11.6 %, p < 0.001), while males had higher rates of substance use disorders (37.2 % vs. 8.9 %, p < 0.001).

SIGNIFICANCE

A greater psychiatric burden is seen among females compared to males with PNES, especially diagnoses of borderline personality disorder and depression. Higher rates of suicidality and inpatient psychiatric hospitalization may warrant particular consideration in screening and intervention efforts among female Veterans with PNES.