vEEG Monitoring Research Articles

Pro-Ictal EEG Scheduling Improves the Yield of Epilepsy Monitoring: Validating the Use of Multiday Seizure Cycles to Optimize Video-EEG Timing.

A significant challenge of video-electroencephalography (vEEG) in epilepsy diagnosis is timing monitoring sessions to capture epileptiform activity. In this study, we introduce and validate "pro-ictal EEG scheduling", a method to schedule vEEG monitoring to coincide with periods of increased seizure likelihood as a low-risk approach to enhance the diagnostic yield. A database of long-term ambulatory vEEG monitoring sessions (n = 5,038) of adults and children was examined. Data from linked electronic seizure diaries were extracted (minimum 10 self-reported events) to generate cycle-based estimates of seizure risk. In adults, vEEG monitoring sessions coinciding with periods of estimated high-risk were allocated to the high-risk group (n = 305) and compared to remaining studies (baseline: n = 3,586). Test of proportions and risk-ratios (RR) were applied to index differences in proportions and likelihood of capturing outcome measures (abnormal report, confirmed seizure, and diary event) during monitoring. The impact of clinical and demographic factors (age, sex, epilepsy-type, and medication) was also explored. During vEEG monitoring, the high-risk group was significantly more likely to have an abnormal vEEG report (190/305:62% vs 1,790/3,586:50% [%change = 12%], RR = 1.25, 95% confidence interval [CI] = [1.137-1.370], p < 0.001), present with a confirmed seizure (56/305:18% vs 424/3,586:11% [%change = 7%], RR = 1.63, 95% CI = [1.265-2.101], p < 0.001) and report an event (153/305:50% vs 1,267/3,586:35% (%change = 15%), RR = 1.420, 95% CI = [1.259:1.602], p < 0.001). Similar effects were observed across clinical and demographic features. This study provides the first large-scale validation of pro-ictal EEG scheduling in improving the yield of vEEG. This innovative approach offers a pragmatic and low-risk strategy to enhance the diagnostic capabilities of vEEG monitoring, significantly impacting epilepsy management. ANN NEUROL 2024.

A survey of ictal physical examination during VEEG monitoring in a tertiary epilepsy center

BackgroundIctal examination based on video-based electroencephalography (EEG) is crucial for locating and lateralizing seizures. In this study, we aimed to evaluate the quality of ictal examination in the Comprehensive Epilepsy Center of West China Hospital, Sichuan University, in order to provide information for quality improvement in daily clinical practice.MethodsVideo recordings of 100 patients with epilepsy were retrospectively reviewed. The performance of the ictal examination was independently reviewed by two epileptologists using an ictal examination protocol.ResultsIn this retrospective analysis, 589 seizure episodes from 100 patients with epilepsy were reviewed. The ages of the patients ranged from 3 to 77 years, with a mean age of 25.8 ± 12.8 years. Among the 589 seizure episodes, a majority (93.7%) were focal seizures. For 226 (38.4%) seizures, the medical staff arrived at the bedside. Among them, 153 (153/226, 64.7%) seizure episodes, the medical staff arrival at the bedside within 30 s of onset, and 120 (120/226, 53.1%) seizures were tested by the medical staff. The compliance rates for "safety” and "visibility" reached 80% or higher while “naming”, “retelling”, and “memory testing” only reach less than 3%.ConclusionsOur survey identified the main problems in ictal assessments. It is challenging to complete a standardized examination for new trainees at Epilepsy Monitoring Units. Regularly strengthening training in ictal examination and understanding of semiology may improve patients’ examination ability. However, further study of the implementation of training is necessary.

Alterations in brain network functional connectivity and topological properties in DRE patients.

The study aimed to find the difference in functional network topology on interictal electroencephalographic (EEG) between patients with drug-resistant epilepsy (DRE) and healthy people. We retrospectively analyzed the medical records as well as EEG data of ten patients with DRE and recruited five sex-age-matched healthy controls (HC group). Each participant remained awake while undergoing video-electroencephalography (vEEG) monitoring. After excluding data that contained abnormal discharges, we screened EEG segments that were free of artifacts and put them together into 20-min segments. The screened data was bandpass filtered to different frequency bands (delta, theta, alpha, beta, and gamma). The weighted phase lag index (wPLI) and the network properties were calculated to evaluate changes in the topology of the functional network. Finally, the results were statistically analyzed, and the false discovery rate (FDR) was used to correct for differences after multiple comparisons. In the full frequency band (0.5-45 Hz), the functional connectivity in the DRE group during the interictal period was significantly lower than that in the HC group (p < 0.05). Compared to the HC group, in the full frequency band, the DRE group exhibited significantly decreased clustering coefficient (CC), node degree (D), and global efficiency (GE), while the characteristic path length (CPL) significantly increased (p < 0.05). In the sub-frequency bands, the functional connectivity of the DRE group was significantly lower than that of the HC group in the delta band but higher in the alpha, beta, and gamma bands (p < 0.05). The statistical results of network properties revealed that in the delta band, the DRE group had significantly decreased values for D, CC, and GE, but in the alpha, beta, and gamma bands, these values were significantly increased (p < 0.05). Additionally, the CPL of the DRE group significantly increased in the delta and theta bands but significantly decreased in the alpha, beta, and gamma bands (p < 0.05). The topology structure of the functional network in DRE patients was significantly changed compared with healthy people, which was reflected in different frequency bands. It provided a theoretical basis for understanding the pathological network alterations of DRE.

Content or context? A study protocol for a three-arm parallel randomised controlled trial of Re-PROGRAM, a brief internet-based intervention for patients with functional seizures

IntroductionFunctional seizures (FS) mimic epilepsy but are not caused by epileptic electrical activity in the brain and are believed to have a psychological origin. There is a well-documented gap between...

Prevalence of ictal injuries in functional (psychogenic nonepileptic) seizures: A systematic review and meta-analysis.

Ictal injuries have long been considered typical signs of epileptic seizures. However, studies have shown that patients with functional seizures (FS)-also named psychogenic nonepileptic seizures-can also present these signs, misleading physicians and delaying a correct diagnosis. This systematic review aimed to assess the prevalence of injuries from FS. A literature search was performed in PubMed, Embase, LILACS (Latin American and Caribbean Health Sciences Literature), Scopus, Web of Science, PsycINFO, Google Scholar, OpenGrey, and ProQuest. Observational studies were included. The risk of bias was assessed using the Joanna Briggs Institute (JBI) checklist for studies reporting prevalence data. RStudio was used for meta-analyses. Cumulative evidence was evaluated according to Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) criteria. From the 2607 identified records, 41 studies were included in the qualitative synthesis, and 28 were included in meta-analyses. A meta-analysis of 13 studies, including 1673 individuals, resulted in an overall lifetime prevalence of injuries due to FS per person of 25% (95% confidence interval [CI] = 19%-32%, I2 = 88%). Considering a limited period (video-electroencephalographic [VEEG] monitoring days), a meta-analysis of 13 studies, including 848 individuals, resulted in an injury prevalence due to FS per person of .7% (95% CI = 0%-3%, I2 = 73%). Also, a meta-analysis of eight studies, including 1000 individuals, resulted in a prevalence of injuries per FS of .1% (95% CI = 0%-.98%, I2 = 49%). The certainty in cumulative evidence assessed by GRADE was rated "very low" for lifetime prevalence of injuries per person, "low" for prevalence per person during VEEG monitoring, and "moderate" for prevalence per number of FS. Overall pooled lifetime prevalence of injuries due to FS per person was 25%. In comparison, the prevalence of injuries per person during VEEG monitoring and per functional seizure was .7% and .1%, respectively. [Correction added on 07 October 2023, after first online publication: In the preceding sentence, 'consecutively' was corrected to 'respectively'.] The evidence of the occurrence of injuries due to FS breaks the paradigm that epileptic seizures can cause injuries but FS cannot.

Inaccuracies in Parental Reporting of Treated Epileptic Spasms: Both Under- and Over-Reporting

BackgroundThe purpose of this study was to evaluate the accuracy of parental reporting of epileptic spasms (ES) after 14 days of appropriate medical therapy for new-onset ES by comparison with extended video electroencephalography (vEEG) monitoring results. MethodsFifty-eight patients were identified from August 2019 to February 2021 with new-onset ES, confirmed on vEEG. Patients were initiated on appropriate treatment (high-dose steroids or vigabatrin). After two weeks of therapy, patients underwent overnight (18 to 24 hours) vEEG monitoring in the epilepsy monitoring unit. Parental reporting of presence or absence of ES on admission was compared with results of vEEG monitoring. ResultsThe 58 patients ranged in age from three to 20 months (average 7.8 months). An underlying etiology was identified in 78%, whereas 22% patients had unknown etiology. The overall accuracy of parental reporting was 74% (43 of 58) when compared with results of vEEG within 14 to 18 days of starting therapy. Of these, 65% (28 of 43) reported ES resolution and 35% (15 of 43) reported continued ES. Of the 26% (15 of 58) families who were incorrect at two-week follow-up, 67% (10 of 15) reported resolution of ES. However, a minority of families, 33% (five of 15), who continued to report spasms clinically, were inaccurate. ConclusionsAlthough a majority of inaccurate parental reports at two weeks of treatment were due to unrecognized ES (a widely known phenomenon), a minority were conversely inaccurate due to persistent over-reporting of ES. This fact highlights the importance of correlating parental history with objective vEEG monitoring, to prevent inappropriate escalation of medication therapy.

Clinical seizure semiology is subtle and identification of seizures by parents is unreliable in infants with tuberous sclerosis complex.

The objectives of this study were to assess the accuracy of parental seizure detection in infants with antenatally diagnosed tuberous sclerosis complex (TSC), and to document the total seizure burden (clinical and subclinical) in those patients who met criteria for prolonged electroencephalography (EEG) recording. Consecutive infants at a single institution with antenatally diagnosed TSC who met criteria for prolonged video-EEG (vEEG) were recruited to this study. The vEEG data were reviewed and when a seizure was identified on EEG, the video and audio recording was assessed for evidence of clinical seizure and, if present, whether there was evidence of parent seizure identification. Nine infants were enrolled, for whom 674 focal seizures were identified in eight of nine patients across 24 prolonged vEEG recordings, with vEEG total duration of 634 h 49 min (average seizure frequency of 1 focal seizure/h). Only 220 of 674 (32.6%) were clinical seizures, 395 of 674 (58.6%) were subclinical seizures, and 59 of 674 seizures could not be classified. Only 63 of 220 clinical seizures (28.6%) were identified by parents, with 157 of 220 (71.4%) not identified. Thirty clusters of epileptic spasms were detected in one patient. At least one clinical epileptic spasm occurred in 2 of 30 clusters (6.7%), 24 of 30 clusters of epileptic spasms (80%) were electrographic only, and classification was uncertain for 4 of 30 clusters (13.3%). No clinical epileptic spasms were detected by parents. Clinical seizure frequency was significantly underestimated by parents for all patients. This study demonstrates that in infants with TSC who met criteria for prolonged vEEG, (1) parents significantly under recognize total clinical seizure count, (2) parents fail to identify epileptic spasms, and (3) seizure frequency is high. This highlights that epilepsy treatment decisions should not be based solely on parental clinical seizure identification. Prolonged vEEG monitoring may have an important role in the routine epilepsy care of infants with TSC, as demonstrating undetected high clinical seizure frequency may allow improved epilepsy management decisions.

VEEG monitoring and electrographic seizures in 232 pediatric patients in ICU at a tertiary hospital in China.

To investigate neonatal electroencephalography (EEG) background activity and electrographic seizures in patients in the pediatric intensive care unit (PICU) who underwent bedside video-electroencephalography (vEEG) monitoring. A total of 232 pediatric patients admitted or transferred to PICU that underwent vEEG monitoring were retrospectively enrolled in this study, and electrographic status epilepticus was observed after vEEG monitoring. The median age was 1.56 years [95% confidence interval (CI) = 1.12-2.44]. Electrographic seizures occurred in 88 patients (37.9%), out of which 36 cases (40.9%) had electrographic status epilepticus. Prior epileptic encephalopathy diagnosis [odds ratio (OR) = 6.57, 95% CI = 1.91-22.59, p = 0.003], interictal epileptiform discharges (OR = 46.82, 95%CI = 5.31-412.86, p = 0.0005), slow disorganized EEG background (OR = 11.92, 95%CI = 1.31-108.71, p = 0.028), and burst-suppression EEG background (OR = 23.64, 95%CI = 1.71-327.57, p = 0.018) were the risk factors for electrographic seizures' occurrence. Of the 232 patients, the condition of 179 (77.2%) patients improved and they were discharged, 34 cases (14.7%) were withdrawn, and 18 cases (7.8%) died. The in-hospital death rate was 47.6% (10 in 21 cases) in patients with attenuated/featureless, compared to 0/23 with normal EEG background. Electrographic status epilepticus occurs in more than one-third of patients with electrographic seizures. vEEG is an efficient method to determine electrographic seizures in children. Abnormal EEG background activity is associated with both electrographic seizures' occurrence and unfavorable in-hospital outcomes.

Effects of Botulinum Toxin Injection on Reducing Myogenic Artifacts during Video-EEG Monitoring: A Longitudinal Study

ABSTRACT Medically refractory seizures affect one-third of patients with epilepsy (PwE), for whom epilepsy surgery is considered. Video electroencephalography (vEEG) monitoring is a fundamental tool for pre-operative seizure localization. Facial and cranial myogenic artifacts can obscure vEEG findings, thus interfering with seizure localization. Studies have shown the beneficial effects of botulinum toxin type A (BTX-A) injection into cranial muscles for reducing myogenic artifacts. This longitudinal study aimed to assess the effects of BTX-A injection on these artifacts. Twenty-two patients with medically refractory hypermotor seizures with daily seizure frequency and undetermined epilepsy localization were included in this study and underwent Dysport® injection (200 units) into the frontotemporal region. vEEG recordings were performed at baseline (one week before the injection), and at three days and six days post-injection. Before and after the injection, the amplitudes of myogenic artifacts were compared during various states (ictal, blinking, chewing, bruxism, head lateralization, scowling, talking, and yawning). BTX-A injection significantly reduced the amplitudes of EEG myogenic artifacts, except during blinking (day three) and talking (days three and six). On day six, significant reduction in EEG myogenic artifacts were noted during blinking, chewing, and bruxism for the greatest number of patients (95.5%, 90.9%, 81.8%), while significant reductions in EEG myogenic artifacts during talking, head lateralization, and ictal phase were associated with the least number of patients (22.7%, 36.3%, and 40.9%). Therefore, BTX-A injection could be a convenient method for filtering myogenic contamination, improving EEG interpretation, and facilitating seizure localization in patients with medically refractory seizures.

A retrospective study of the correlation between duration of monitoring in the epilepsy monitoring unit and diagnostic yield

ObjectiveLong-term video-electroencephalographic (LTVEM) monitoring is a valuable tool in the evaluation of paroxysmal clinical events. However, vEEG itself is costly. Hence, we aimed to establish if longer duration of monitoring (DOM) is associated with higher diagnostic yield. MethodA retrospective review of patients admitted into the epilepsy monitoring unit (EMU) for the diagnostic evaluation of paroxysmal events was performed. Patients’ demographic, clinical characteristics, and vEEG data were analyzed. In the cohort of patients with DOM > 7 days, the reasons for prolonged DOM were identified and the differences in clinical characteristics and vEEG data between conclusive and inconclusive studies were analyzed. ResultA total of 501 patients were included. Four hundred and thirty-six (87 %) patients had conclusive studies. Of these patients, 67.9 % patients with conclusive studies received diagnosis within the first 7 days of monitoring with the highest on day 7. The likelihood of conclusive studies decreased beyond 7 days. A total of 175 had DOM > 7 days, of which 140 (80 %) had conclusive studies. In the cohort with DOM > 7 days, patients with previous abnormal routine EEG, previous vEEG monitoring, first event recorded before day 5 of admission and ≥1 events recorded during vEEG monitoring were more likely to have conclusive studies. The most common reason for prolonging DOM beyond 7 days was to adequately record multiple semiologically distinctive events (76 %). ConclusionOur study supports that longer DOM is associated with an increase in diagnostic yield. More than one-third of our cohort were monitored beyond 7 days with majority (80 %) being conclusive. Our findings may guide clinicians in planning the DOM and predicting the likelihood of conclusive vEEG studies in patients with prolonged DOM based on the clinical characteristics and vEEG data.

Autoimmune parkinsonism with faciobrachiocrural dystonic seizures: a new phenotype of leucine-rich glioma-inactivated 1 (LGI1) autoimmunity.

Extrapyramidal symptoms are seen in patients with leucine-rich glioma-inactivated 1 (LGI1) antibody-positive patients infrequently and this can be successfully treated with immunotherapy. This is a retrospective hospital-based study from 2013 to 2021 at a tertiary care referral hospital in South India. LGI1 antibody-positive cases with Faciobrachio-crural dystonic seizures [FBCDS] were identified by reviewing electronic medical records and Neuroimmunology laboratory register. Clinical and laboratory details and treatment outcomes were analysed. There was a total of 23 patients who were positive for LGI1 antibody. Of these, three cases had FBCDS (2 males, age range 30-76years). Upon reviewing the records they had additional asymmetric parkinsonian features. All had similar presentations with progressive slowness of activities and gait and later went on to have paroxysmal events of sudden falls with vocalization. Prolonged VEEG monitoring captured the habitual event, which were confirmed to be FBCDS. MRI did not show significant structural abnormalities, CSF showed elevated proteins and normal cell in two and lymphocytic pleocytosis in one, PET scans ruled out malignancy. Of the three patients, two were completely relieved of FBCDS with immunosuppression and there was complete resolution of extrapyramidal features in all. Thus, the patients in our series of FBCDS showed additional features of parkinsonism which responded well to immunotherapy. Involvement of basal ganglia can explain all the manifestations of this phenotype. This series reveals a unique phenotype of the LGI1 antibody.

Seizure Susceptibility and Sleep Disturbance as Biomarkers of Epileptogenesis after Experimental TBI.

Objectives: We investigated whether seizure susceptibility increases over weeks–months after experimental traumatic brain injury (TBI), and whether seizure susceptibility in rats predicts the development of post-traumatic epilepsy (PTE) or epileptiform activity. We further investigated whether rats develop chronic sleep disturbance after TBI, and whether sleep disturbance parameters—alone or in combination with pentylenetetrazol (PTZ) test parameters—could serve as novel biomarkers for the development of post-traumatic epileptogenesis. Methods: TBI was induced in adult male Sprague-Dawley rats with lateral fluid-percussion injury. Sham-operated experimental controls underwent craniectomy without exposure to an impact force. Seizure susceptibility was tested with a PTZ test (30 mg/kg, intraperitoneally) on day (D) 30, D60, D90, and D180 after TBI (n = 28) or sham operation (n = 16) under video electroencephalogram (vEEG). In the 7th post-injury month, rats underwent continuous vEEG monitoring to detect spontaneous seizures and assess sleep disturbances. At the end of the experiments, rats were perfused for brain histology. Results: In the TBI group, the percentage of rats with PTZ-induced seizures increased over time (adjusted p < 0.05 compared with D30). Combinations of three PTZ test parameters (latency to the first epileptiform discharge (ED), number of EDs, and number of PTZ-induced seizures) survived the leave-one-out validation for differentiating rats with or without epileptiform activity, indicating an area under the receiver operating curve (AUC) of 0.743 (95% CI 0.472–0.992, p = 0.05) with a misclassification rate of 36% on D90, and an AUC of 0.752 (95% CI 0.483–0.929, p < 0.05) with a misclassification rate of 32% on D180. Sleep analysis revealed that the number of transitions to N3 or rapid eye movement (REM) sleep, along with the total number of transitions, was increased in the TBI group during the lights-on period (all p < 0.05). The sleep fragmentation index during the lights-on period was greater in the TBI rats than in sham-operated rats (p < 0.05). A combination of sleep parameters showed promise as diagnostic biomarkers of prior TBI, with an AUC of 0.792 (95% CI 0.549–0.934, p < 0.01) and a misclassification rate of 28%. Rats with epilepsy or any epileptiform activity had more transitions from N3 to the awake stage (p < 0.05), and the number of N3–awake transitions differentiated rats with or without epileptiform activity, with an AUC of 0.857 (95% CI 0.651–1.063, p < 0.01). Combining sleep parameters with PTZ parameters did not improve the biomarker performance. Significance: This is the first attempt to monitor the evolution of seizure susceptibility over months in a well-described rat model of PTE. Our data suggest that assessment of seizure susceptibility and sleep disturbance can provide diagnostic biomarkers of prior TBI and prognostic biomarkers of post-traumatic epileptogenesis.

Extent of EEG monitoring for detecting epileptic spasms.

Epileptic spasms (ES) are the ictal manifestation of West syndrome. Due to poor interrater reliability in diagnosing hypsarrhythmia, identification of ES - ideally on video EEG monitoring - is important to start proper treatment. We retrospectively analyzed inpatient video EEG recordings of 42 patients with new onset ES and calculated the time needed to capture the first ES, along with time to first sleep epoch, among other data. The average time to capture ES was 188.36min with a 95 percent confidence interval from 116.95 to 259.76min. The average onset of sleep occurred at 30.8min with 95% Confidence interval between 19.9 and 41.9min. There was no significant correlation between duration of symptoms and etiology and the time needed to detect first spasm on EEG. Routine or short duration EEGs are not sufficient to capture ES in most patients. 4-5-hour VEEG monitoring duration should be considered to capture ictal data in patients suspected of having ES.

Characterising seizure development, behavioural comorbidities and neuroinflammation in a self-sustained electrical status epilepticus model of mesial temporal lobe epilepsy in C57BL/6J mice

ObjectiveStatus epilepticus (SE) models in rodents are commonly used to research mesial temporal lobe epilepsy (mTLE) in translational epilepsy research. However, due to differences in susceptibility of mice strains to chemoconvulsants, developing this model in mice is challenging. Mice offer experimental advantages; in particular, the ability to use transgenic strains could provide novel insights about neurobiological mechanisms or ease of genetic modification to test potential therapeutic targets. This study aimed to characterise the neuroinflammation, epileptic seizures and behavioural comorbidities after self-sustained Electrical Status Epilepticus (SSSE) in C57BL/6J mice. MethodsSSSE was induced in C57BL/6J mice via prolonged electrical stimulation through a bipolar electrode implanted in the ventral hippocampus. Video electroencephalography (vEEG) monitoring was then performed between 1st month (acute timepoint) and 4th month (chronic timepoint). Brain tissues were collected at two timepoints for gene expression and immunohistochemical analysis: 7-days and 16-weeks post-SE. Additionally, at the chronic timepoint, animals underwent a series of neurobehavioural tests. ResultsSixty percent of animals that underwent SSSE developed spontaneous seizures within the first month, and an additional 25% developed seizures at the chronic timepoint. The number of seizures per week during the chronic period ranged from 0.2 to 15.7. Mortality rate was ~9% during or after SSSE. SSSE animals displayed significant spatial memory impairment and depression-like behaviour compared to sham animals. mRNA expression of inflammatory cytokines was upregulated at 7-days following SE, but equal to sham levels at 16-weeks. SignificanceThis study provides evidence that SSSE in C57BL/6J mice induces epileptic seizures consistent with those seen in patients with mTLE, along with cognitive and behavioural comorbidities. This model therefore has the potential to be used experimentally to uncover mechanisms to target against epileptogenesis, or to test novel treatment approaches.

Bilateral temporal lobe epilepsy: How many seizures are required in chronic ambulatory electrocorticography to estimate the laterality ratio?

This study was undertaken to measure the duration of chronic electrocorticography (ECoG) needed to attain stable estimates of the seizure laterality ratio in patients with drug-resistant bilateral temporal lobe epilepsy (BTLE). We studied 13 patients with drug-resistant BTLE who were implanted for at least 1year with a responsive neurostimulation device (RNS System) that provides chronic ambulatory ECoG. Bootstrap analysis and nonlinear regression were applied to model the relationship between chronic ECoG duration and the probability of capturing at least one seizure. Laterality of electrographic seizures in chronic ECoG was compared with the seizure laterality ratio from Phase 1scalp video-electroencephalographic (vEEG) monitoring. The Kaplan-Meier estimator was used to evaluate time to seizure laterality ratio convergence. Seizure laterality ratios from Phase 1scalp vEEG monitoring correlated poorly with those from RNS chronic ECoG (r=.31, p=.30). Across the 13 patients, average electrographic seizure frequencies ranged from 1.4seizures/month to 5.1seizures/day. A 50% probability of recording at least one electrographic seizure required 9.1days of chronic ECoG, and 90% probability required 44.3days of chronic ECoG. A median recording duration of 150.9days (5months), corresponding to a median of 16seizures, was needed before confidence intervals for the seizure laterality ratio reliably contained the long-term value. The median recording duration before the point estimate of the seizure laterality ratio converged to a stationary value was 236.8days (7.9months). RNS chronic ECoG overcomes temporal sampling limitations intrinsic to inpatient Phase 1 vEEG evaluations. In patients with drug-resistant BTLE, approximately 8months of chronic RNS ECoG are needed to precisely estimate the seizure laterality ratio, with 75% of people with BTLE achieving convergence after 1 year of RNS recording. For individuals who are candidates for unilateral resection based on seizure laterality, optimized recording duration may help avert morbidity associated with delay to definitive treatment.

Diagnostic Yield of 8-Hour Video-EEG in Detecting Psychogenic Non-Epileptic Seizures (PNES)

ABSTRACT To evaluate the diagnostic yield of the first 8 hours of video-EEG (vEEG) monitoring in detecting Psychogenic Non-Epileptic Seizures (PNES) during the Epilepsy Monitoring Unit (EMU) admission. We performed a retrospective chart review of patients ages ≥4 years who were admitted to the EMU between 2011 and 2018 (n = 616). We calculated the proportion of patients diagnosed with PNES within the first 8 hours of EEG recording and studied the associated risk factors for patients diagnosed with PNES and patients with epileptic seizures (ES). Out of the total 616 patients, 24% (149) patients had an EMU diagnosis of PNES. Of these, 44.3% had at least one typical event within the first 8 hours of vEEG monitoring. A higher incidence was seen within the pediatric subgroup (54.8% had an event within 8 hours). A diagnosis of chronic pain disorder was more common with PNES compared to ES (48.3% versus 16.5%, p < 0.001). A suspicion for PNES documented during an office visit was noted in a high proportion of patients (68.5%) who eventually had a PNES event during EMU. Our study suggests that in a well-selected group of patients (such as a high suspicion of PNES during a physician/neurology office visit), an outpatient 8-hour vEEG could open new avenues for a prompt diagnosis. This could especially be beneficial in hospital settings where there is either a lack of an EMU or a delay in admission to the EMU.

O-EG002. 8-Year experience of stereoelectroencephalography at Westmead Hospital and the Children’s Hospital at Westmead

Introduction . We report our surgical series of intractable epilepsies investigated with stereoelectroencephalography (SEEG) at Westmead Hospital and The Children’s Hospital at Westmead; evaluating the methodology, complication rate and seizure outcome from an 8-year program. Methods . 82 SEEG were performed in 80 patients (males, n = 45) at Westmead Hospital and The Children’s Hospital at Westmead from 2012 to 2019. All SEEG were performed using frame-based stereotaxy with CRW (Integra, Plainsboro, NJ, USA) frame systems. Clinical demographics, methodology, outcomes and complications were collected and analysed. Results . Mean age of patients was 22 years old (range 4–49 years old). Two patients had two SEEG implantations because the initial implantation did not provide sufficient information to inform resection. Fifty-six patients had normal MRI. A total of 1132 electrodes were inserted in 82 SEEG procedures (mean number of electrodes per SEEG = 14, range 8–21; total number of electrode contact = 14611). Majority of patients had unilateral implantation (left = 24, right = 32, bilateral = 24). Complications occurred in four patients (subdural haemorrhage = 3, fractured electrode = 1). All patients were able to proceed with VEEG monitoring after electrode implantation. Seizures were recorded in 81 SEEG studies. One patient did not have any seizures during the evaluation. 72% of patients underwent resective surgery following SEEG. Two patients were offered resective surgery but had declined. 26% of patients were not localised. 13 patients were awaiting surgery or pending conference decision. 74% became seizure free after resective surgery. Conclusion . SEEG can be a relative safe and effective methodology for defining the epileptogenic zone.

Readmission after epilepsy monitoring unit discharge in a nationally representative sample

ObjectiveTo determine the 30-day readmission rate after Epilepsy Monitoring Unit (EMU) discharge in a nationally representative sample, as well as patient, clinical, and hospital characteristics associated with readmission. MethodsThis is a retrospective cohort study of adults discharged from an elective hospitalization with continuous video electroencephalography (vEEG) monitoring, sampled from the Healthcare Cost and Utilization Project’s 2014 Nationwide Readmissions Database. Descriptive statistics were used to quantify and characterize readmission within 30 days and logistic regression models were built to examine factors associated with readmission. Results6869 admissions met inclusion criteria, with 292 people (4.2 %) readmitted within 30 days. 79.5 % (n = 232/292) of all readmissions were non-elective. Patient characteristics associated with readmission included a higher Elixhauser comorbidity score [adjusted odds ratio (AOR) 1.03, 95 % confidence interval (CI) 1.02–1.04 per 1 point increase in Elixhauser score], a longer length of stay [AOR 1.05, 95 % CI 1.02–1.09 per one day increase in length], non-routine discharge [AOR 1.85, 95 %CI 102−3.38], and comorbid brain tumor diagnosis [AOR 2.55, 95 %CI 1.46–4.46]. Female sex was inversely associated with 30-day readmission [AOR 0.68, 95 % CI 0.54−0.85]. The most common reason for readmission was epilepsy or convulsion (27.6 %), followed by sepsis (5.8 %) and complications of surgical procedures or medical care (5.5 %). ConclusionsPatients electively admitted for continuous vEEG monitoring are infrequently readmitted. These data provide a preliminary national readmission benchmark for patients with elective admissions for vEEG monitoring.

Twenty-four-hour patterns in electrodermal activity recordings of patients with and without epileptic seizures.

Daytime and nighttime patterns affect the dynamic modulation of brain and body functions and influence the autonomic nervous system response to seizures. Therefore, we aimed to evaluate 24-hour patterns of electrodermal activity (EDA) in patients with and without seizures. We included pediatric patients with (a) seizures (SZ), including focal impaired awareness seizures (FIAS) or generalized tonic-clonic seizures (GTCS), (b) no seizures and normal electroencephalography (NEEG), or (c) no seizures but epileptiform activity in the EEG (EA) during vEEG monitoring. Patients wore a device that continuously recorded EDA and temperature (TEMP). EDA levels, EDA spectral power, and TEMP levels were analyzed. To investigate 24-hour patterns, we performed a nonlinear mixed-effects model analysis. Relative mean pre-ictal (-30min to seizure onset) and post-ictal (I: 30min after seizure offset; II: 30 to 60min after seizure offset) values were compared for SZ subgroups. We included 119 patients (40 SZ, 17 NEEG, 62 EA). EDA level and power group-specific models (SZ, NEEG, EA) (h=1; P<.01) were superior to the all-patient cohort model. Fifty-nine seizures were analyzed. Pre-ictal EDA values were lower than respective 24-hour modulated SZ group values. Post hoc comparisons following the period-by-seizure type interaction (EDA level: =18.50; P<.001, and power: =6.73; P=.035) revealed that EDA levels were higher in the post-ictal period I for FIAS and GTCS and in post-ictal period II for GTCS only compared to the pre-ictal period. Continuously monitored EDA shows a pattern of change over 24 hours. Curve amplitudes in patients with recorded seizures were lower as compared to patients who did not exhibit seizures during the recording period. Sympathetic skin responses were greater and more prolonged in GTCS compared to FIAS. EDA recordings from wearable devices offer a noninvasive tool to continuously monitor sympathetic activity with potential applications for seizure detection, prediction, and potentially sudden unexpected death in epilepsy (SUDEP) risk estimation.

Home video prediction of epileptic vs. nonepileptic seizures in US veterans

ObjectiveUsing video-EEG (v-EEG) diagnosis as a gold standard, we assessed the predictive diagnostic value of home videos of spells with or without additional limited demographic data in US veterans referred for evaluation of epilepsy. Veterans, in particular, stand to benefit from improved diagnostic tools given higher rates of PNES and limited accessibility to care. MethodsThis was a prospective, blinded diagnostic accuracy study in adults conducted at the Houston VA Medical Center from 12/2015–06/2019. Patients with a definitive diagnosis of epileptic seizures (ES), psychogenic nonepileptic seizures (PNES), or physiologic nonepileptic events (PhysNEE) from v-EEG monitoring were asked to submit home videos. Four board-certified epileptologists blinded to the original diagnosis formulated a diagnostic impression based upon the home video review alone and video plus limited demographic data. ResultsFifty patients (30 males; mean age 47.7 years) submitted home videos. Of these, 14 had ES, 33 had PNES, and three had PhysNEE diagnosed by v-EEG. The diagnostic accuracy by video alone was 88.0%, with a sensitivity of 83.9% and specificity of 89.6%. Providing raters with basic patient demographic information in addition to the home videos did not significantly improve diagnostic accuracy when comparing to reviewing the videos alone. Inter-rater agreement between four raters based on video was moderate with both videos alone (kappa = 0.59) and video plus limited demographic data (kappa = 0.60). SignificanceThis study demonstrated that home videos of paroxysmal events could be an important tool in reliably diagnosing ES vs. PNES in veterans referred for evaluation of epilepsy when interpreted by experts. A moderate inter-rater reliability was observed in this study.