A follow-up study of cognitive function in young adults who had resective epilepsy surgery in childhood.

This study examined cognitive function in young adults who had epilepsy surgery in childhood. Thirty-seven individuals with medically intractable epilepsy with onset at 16 years or younger who had resective epilepsy surgery at least two years in the past (mean follow-up duration of 8.5 years) were assessed; of these, 13 had seizures within the year prior to the study, and the remainder had none. A comparison group of 16 individuals with childhood-onset intractable epilepsy who had not had surgery, all of whom had experienced at least one seizure in the past 12 months, was also included. The cognitive tests included measures of vocabulary, visuoconstructive ability, memory, and concept formation. Group differences were found only for the vocabulary and verbal memory tests, with the surgical group with seizures having the lowest performance. A subset of the surgical patients had preoperative data available on comparable tests, allowing for an examination of performance over time. Vocabulary scores were higher at follow-up, a finding which was present irrespective of seizure status. The results suggest that after epilepsy surgery in childhood or adolescence, few improvements in cognitive skills related to surgery or seizure outcome are to be expected.

Access to surgery for paediatric patients with medically refractory epilepsy: a systems analysis.

PURPOSE: A systems analysis perspective was undertaken to evaluate access to surgery for children with medically refractory epilepsy (MRE) in Ontario, the largest province in Canada. The analysis focused on the assessment of referral patterns, healthcare utilization, time intervals and patient flow to determine surgical candidacy in children with MRE. The purpose of this systems analysis study was to identify rate limiting steps that may lead to delayed surgical candidacy decision and surgery. METHODS: Prolonged video electroencephalography (vEEG) is the common entry point into the process for all potential epilepsy surgery candidates. Therefore, a single centre retrospective chart review of children and adolescents referred to the epilepsy monitoring unit (EMU) for vEEG monitoring at the primary referral centre for paediatric epilepsy surgery in the province. Basic demographic and referral data were abstracted for all screened cases. Included cases were: (1) age <19 years old at time of first EMU admission, (2) date of EMU admission between April 1, 2004 and March 31, 2006 and (3) referral for elective vEEG and/or overnight with vEEG greater than 8h duration. Data were collected on number of seizure conferences, surgical candidacy, surgical outcomes (seizure free and seizure reduction), resource utilization, and recorded time stamps for each event to estimate system delays. RESULTS: During the two-year period, 463 patients were referred to the EMU of whom 349 received prolonged vEEG (>8h). Forty five percent (n=160) of patients came to seizure conference for discussion of their data, of whom 40% (64/160) were considered surgical candidates. Time from first seizure to EMU referral was approximately 4.6 years. Time from referral to admission and admission to first seizure conference were approximately 103 days and 71 days, respectively. From initial EMU referral to surgery ranged from 1.6 to 1.1 years depending on whether the patient required invasive monitoring with intracranial EEG. Overall, 95% of surgical patients had a reduction in seizure frequency, 74% were seizure free after one year post-surgery. SIGNIFICANCE: Referral rates for surgical assessment are low relative to the estimated number of children living with MRE in Ontario, less than 2%. Hence, only a limited number of children with this disorder in the province of Ontario who could benefit from epilepsy surgery are being assessed for surgical candidacy. The majority of Ontario children with MRE are not being provided the potential opportunity to be seizure free and live without functional limitations following surgical intervention. These data document the critical need for health system redesign in Ontario, the goal of which should be to provide more consistent and just access to evidence-based medical and surgical care for those citizens of the province who suffer from epilepsy.

Source localization of interictal spike-locked neuromagnetic oscillations in pediatric neocortical epilepsy.

OBJECTIVE: To evaluate the utility of an event-related beamforming (ERB) algorithm in source localization of interictal discharges. METHODS: We analyzed interictal magnetoencephalography data in 35 children with intractable neocortical epilepsy. We used a spatiotemporal beamforming method to estimate the spatial distribution of source power in individual interictal spikes. We compared ERB results to source localization using the equivalent current dipole model and to the seizure onset zones on intracranial EEG. RESULTS: Focal beamformer localization was observed in 66% of patients and multifocal in the remaining 34%. ERB localized within 2 cm of the equivalent current dipole cluster centroid in 77% of the patients. ERB localization was concordant with the seizure onset zone on intracranial EEG at the gyral level in 69% of patients. Focal ERB localization area was included in the resection margin in 22/23 patients. However, focal ERB localization was not statistically associated with better surgical outcome. CONCLUSIONS: ERB can be used for source localization of interictal spikes and can be predictive of the ictal onset zone in a subset of patients with neocortical epilepsy. SIGNIFICANCE: These results support the utility of beamformer source localization as a fast semi-automated method for source localization of interictal spikes and planning the surgical strategy.

Epilepsy and cysticercosis in Northwest Cameroon: a serological study.

PURPOSE: The prevalence of epilepsy in Cameroon is higher than that of the industrialized world and other developing countries. Neurocysticercosis due to Taenia solium infestation has been reported as a major cause of epilepsy in some parts of Cameroon although there are some conflicting data. The prevalence of epilepsy is especially high in the Momo division of the North-West Province of Cameroon. We hypothesized that individuals with epilepsy in this region have a higher percentage of seropositivity to T. solium than matched controls. METHODS: We conducted a case-control study in the Momo subdivision of Ngie. Individuals with epilepsy were recruited from the health centers in Ngie. Control subjects were selected from 19 Ngie villages. Potential cases of people with epilepsy (PWE) were identified through a questionnaire applied by trained field workers, using history of epileptic seizures as a key indicator. Blood samples were taken from all consenting individuals by finger prick, stored in StabilZyme Select, and assayed for antibodies to T. solium in an Atlanta based reference laboratory. RESULTS: We accrued 249 patients with epilepsy, of whom 237 met the inclusion criteria, and 245 age-matched controls. There was no significant difference in seropositivity to T. solium between those individuals with epilepsy (5%) and controls (4.9%). CONCLUSIONS: Our data do not support the hypothesis that epilepsy is associated with seropositivity to T. solium. It is highly unlikely that cysticercosis plays a causative role in the high prevalence of epilepsy in this region of Cameroon.

Determinants of quality of life in children with chronic somatic disease: pilot data from the GapS Questionnaire.

PURPOSE: Quality of life (QoL) is a ubiquitous yet poorly defined concept; the precise determinants of QoL are rarely identified. We used pilot data from the GapS Questionnaire to investigate the most important determinants of QoL in children with chronic somatic illness. METHODS: We enrolled 92 participants including 60 parents and 32 of their children. The sample comprised rheumatology, diabetes, epilepsy, gastroenterology, cystic fibrosis, and day unit patients. Trained interviewers administered the GapS Questionnaire to parents, and to children if ≥ 10 years. We determined the relative importance of different items for QoL. RESULTS: Child participants had a mean age of 14.7 years. Children identified "having good friendships", "being happy most days", and "getting along with parents" as most important. Parents ranked most highly "being allowed to do all the things you like doing", "getting told you have done a good job at something", and "being physically able to do everything you enjoy doing". CONCLUSIONS: Physical health items were not as important as social and psychological determinants of QoL in our pilot sample.

Quality of life in young adults who underwent resective surgery for epilepsy in childhood.

PURPOSE: This study investigated quality of life (QOL) in young adults who had undergone epilepsy surgery before the age of 16 years. The contribution to QOL of seizure status in the prior year, sex, number of antiepileptic drugs, and mood were evaluated. METHODS: Sixty-nine young adults who had undergone surgery were subdivided into those who were seizure-free in the past year (n = 38) and those who had seizures (n = 31) in that time. A nonsurgical comparison group of young adults (n = 29) with childhood-onset medically intractable epilepsy was also studied. All groups completed measures of QOL and mood. KEY FINDINGS: After accounting for mood, sex, and number of antiepileptic drugs, the seizure-free group reported better cognitive and physical function and overall QOL, experienced less seizure worry, and had better self-perception. Mood was the most consistently predictive covariate, and was independently predictive of many aspects of QOL. SIGNIFICANCE: Seizure freedom associated with surgery in childhood is associated with improved QOL in certain domains. Findings highlight the importance of mood in determining self-perception of QOL.

High kurtosis of intracranial electroencephalogram as a marker of ictogenicity in pediatric epilepsy surgery.

OBJECTIVE: We determined whether kurtosis analysis of intracranial electroencephalogram (EEG) can estimate the localization of the epileptogenic zone. METHODS: We analyzed 29 pediatric epilepsy patients who underwent intracranial EEG before focal resective surgery. We localized the brain regions with high kurtosis, the seizure onset zone (SOZ) and the regions with high-rate, high-amplitude and long-duration interictal paroxysms ≥20 Hz. We tested correlations between the surgical resection of those regions and post-surgical seizure outcome, and correlations between kurtosis and the rate/amplitude/duration of interictal paroxysms. RESULTS: The resection of the regions with high kurtosis correlated with 1-year post-surgical seizure outcome (p=0.028) but not with 2-year outcome. Kurtosis showed more significant correlation with 1-year seizure outcome than the SOZ and the rate/amplitude/duration of interictal paroxysms. Kurtosis showed positive, independent correlations with the amplitude and duration of interictal paroxysms (p<0.0001) but not with the rate (p=0.4). CONCLUSIONS: The regions with high kurtosis provide more reliable information to predict seizure outcome than the SOZ and the regions with high-rate/amplitude and long-duration interictal paroxysms. Kurtosis reflects combined effects of the amplitude and duration of the interictal paroxysms. SIGNIFICANCE: High kurtosis suggests the regions with acquired ictogenicity within the irritative zone.

Ethical issues in surgical decision making concerning children with medically intractable epilepsy.

The widespread inclusion of surgical strategies in the treatment of medically intractable epilepsy is largely justified by the medical and psychosocial burden of the illness. Performing these procedures in pediatric populations is associated with distinct challenges ranging from unique seizure etiologies to issues surrounding brain development and functional plasticity. As the trend toward more aggressive surgical intervention continues, the ethical foundation of current and emerging practices must be increasingly scrutinized. Here, we present the first article discussing ethical issues in the surgical management of medically intractable epilepsies in children. We discuss principles of informed consent, harm reduction, and justice in this vulnerable patient population. We also highlight the unique ethical challenge of surgical decision making concerning developmentally delayed children. The recognition of these issues is essential to providing patient-centered, responsible, and ethical care.

Focal resection of fast ripples on extraoperative intracranial EEG improves seizure outcome in pediatric epilepsy.

PURPOSE: High-frequency oscillations (HFOs), termed ripples at 80-200 Hz and fast ripples (FRs) at >200/250 Hz, recorded by intracranial electroencephalography (EEG), may be a valuable surrogate marker for the localization of the epileptogenic zone. We evaluated the relationship of the resection of focal brain regions containing high-rate interictal HFOs and the seizure-onset zone (SOZ) determined by visual EEG analysis with the postsurgical seizure outcome, using extraoperative intracranial EEG monitoring in pediatric patients and automated HFO detection. METHODS: We retrospectively analyzed 28 pediatric epilepsy patients who underwent extraoperative intracranial video-EEG monitoring prior to focal resection. Utilizing the automated analysis, we identified interictal HFOs during 20 min of sleep EEG and determined the brain regions containing high-rate HFOs. We investigated spatial relationships between regions with high-rate HFOs and SOZs. We compared the size of these regions, the surgical resection, and the amount of the regions with high-rate HFOs/SOZs within the resection area with seizure outcome. KEY FINDINGS: Ten patients were completely seizure-free and 18 were not at 2 years after surgery. The brain regions with high-rate ripples were larger than those with high-rate FRs (p = 0.0011) with partial overlap. More complete resection of the regions with high-rate FRs significantly correlated with a better seizure outcome (p = 0.046). More complete resection of the regions with high-rate ripples tended to improve seizure outcome (p = 0.091); however, the resection of SOZ did not influence seizure outcome (p = 0.18). The size of surgical resection was not associated with seizure outcome (p = 0.22-0.39). SIGNIFICANCE: The interictal high-rate FRs are a possible surrogate marker of the epileptogenic zone. Interictal ripples are not as specific a marker of the epileptogenic zone as interictal FRs. Resection of the brain regions with high-rate interictal FRs in addition to the SOZ may achieve a better seizure outcome.

Self-reported symptoms of psychological well-being in young adults who underwent resective epilepsy surgery in childhood.

PURPOSE: This study investigated the relationship of childhood resective surgery for lesional epilepsy and recent seizure history on self-reported symptoms of mood and psychological distress in young adults (aged 18-30). METHODS: Ninety-eight individuals with epilepsy of childhood onset were divided into three groups: a seizure-free surgical group (n = 39), a surgical group still experiencing seizures (n = 31), and a nonsurgical epilepsy comparison group (n = 28). Participants completed two standardized questionnaires about current mood state and psychological and psychiatric symptoms: the Profile of Mood States (POMS) and the Symptom Checklist-90 Revised (SCL-90R). KEY FINDINGS: Forty-eight percent of all participants reported a history of psychological problems. The percentage of the seizure-free surgical group who met the SCL-90R criteria for current clinically significant distress was statistically less than in the other groups. Those who were seizure free also reported significantly fewer total symptoms on the SCL-90R. The current number of antiepileptic medications was related to scores on a number of the scales. SIGNIFICANCE: These results provide modest support for the contention that seizure freedom after pediatric epilepsy surgery is associated with reduced risk for psychological distress during early adulthood.

Topographic movie of intracranial ictal high-frequency oscillations with seizure semiology: epileptic network in Jacksonian seizures.

PURPOSE: We developed a technique to produce images of dynamic changes in ictal high-frequency oscillations (HFOs) >40 Hz recorded on subdural electroencephalography (EEG) that are time-locked to the ictal EEG and ictal semiology video. We applied this technique to Jacksonian seizures to demonstrate ictal HFO propagation along the homunculus in the primary sensory-motor cortex to visualize the underlying epileptic network. METHODS: We analyzed intracranial ictal EEGs from two patients with intractable Jacksonian seizures who underwent epilepsy surgery. We calculated the degrees of increase in amplitude within 40-80, 80-200, and 200-300 Hz frequency bands compared to the interictal period and converted them into topographic movies projected onto the brain surface picture. We combined these data with the ictal EEGs and video of the patient demonstrating ictal semiology. KEY FINDINGS: The ictal HFOs began in the sensory cortex and appeared concomitantly with the sensory aura. They then propagated to the motor cortex at the same time that focal motor symptoms evolved. As the seizure progressed, the ictal HFOs spread or reverberated in the rolandic region. However, even when the seizure became secondarily generalized, the ictal HFOs were confined to the rolandic region. In both cases, there was increased amplitude of higher frequency bands during seizure initiation compared to seizure progression. SIGNIFICANCE: This combined movie showed the ictal HFO propagation corresponding to the ictal semiology in Jacksonian seizures and revealed the epileptic network involved in seizure initiation and progression. This method may advance understanding of neural network activities relating to clinical seizure generation and propagation.

Patient-reported outcome of pediatric epilepsy surgery: social inclusion or exclusion as young adults?

PURPOSE: The purpose of this study was to examine the social relationships and participation in educational, vocational, and community life in young adults who had undergone epilepsy surgery during childhood or adolescence. METHODS: This was a retrospective, cross-sectional, case-controlled, and multisite design study. Findings were compared between young adults who had undergone epilepsy surgery and were seizure-free in the previous 12 months (n = 38), those who had undergone epilepsy surgery and were not seizure-free (n = 33), and a group of individuals with epilepsy who had not undergone surgery (n = 31). RESULTS: The surgical seizure-free group had significantly better general social well-being than the other two groups. Specifically, these participants were employed for more months over the past year, were less likely to report that epilepsy had affected their employment, and were more likely to belong to at least one community organization. However, these participants were not any more likely to be involved in a relationship than those in the other two groups. In addition, there were no group differences in the reported number of friends or the frequency of visits with friends, or in what participants described as their principal activity (i.e., student, employed or unemployed). DISCUSSION: There are a number of benefits to social functioning associated with having had epilepsy surgery and being seizure-free in the past year. Further research is recommended to increase our understanding of the mechanisms involved in the social and personal challenges that these individuals face.

Self-perceptions of social function 2 years after pediatric epilepsy surgery.

The present qualitative study explored how participants perceive their quality of life within the social domain 2 years following epilepsy surgery. Semistructured, open-ended interviews were conducted with 27 participants (11-21 years old), 2 years following epilepsy surgery. Thirteen of the 27 participants were seizure free. Data were transcribed and coded inductively to allow for the identification of salient themes. Many of the seizure-free participants reported greater independence following surgery. However, most participants, irrespective of seizure status, continued to report some problems with peer relations and isolation. These findings suggest that self-perceived improvements in social function among seizure-free participants may require longer than 2 years to develop.

Sex differences in episodic memory among children with intractable epilepsy.

This study investigated whether children with epilepsy exhibit sex differences in episodic memory. Fifty-one children and adolescents (26 boys and 25 girls) with intractable epilepsy were administered two verbal-auditory tasks (learning and recall of a word list and story recall) and two visual tasks (design recall and face recognition). Girls exhibited an advantage on the delayed recall of stories and on the learning phase of the word list task. No significant differences were observed on the delayed recall of words or the visual tasks. These results identify a particular risk for cognitive impairment in boys that could have an important impact on their academic performance.

Long-term seizure and social outcomes following temporal lobe surgery for intractable epilepsy during childhood.

PURPOSE: Studies of adults who underwent temporal lobectomy for intractable temporal lobe epilepsy (TLE) demonstrated declining seizure free rates over time. Using seizure and social parameters, we followed patients who had temporal lobe surgery (TLS) in childhood to determine long-term outcomes. METHODS: We identified 42 patients who underwent TLS for medically intractable epilepsy during childhood. Follow-up data were collected from 10 to 20 years after surgery (median, 12 years). We studied histopathology, seizure outcome, employment, school enrolment, and driver's licensing. Patients or parents graded their satisfaction with TLS. RESULTS: Number of Engel class I patients was 34 (81%) after 6 months; 32 (76%) after 1 year; 30 (71%) after 5 years; and 28 (67%) at last >or=10 years follow-up. Nineteen (79%) of 24 children with tumors or cavernous angioma achieved class I outcomes in contrast to 9 (50%) of 18 children with other pathologies (p<0.05). Ten (56%) of 18 recurrent seizure patients experienced seizures within the first year; 4 required reoperation for seizure freedom. More seizure free patients (24, 86%) than residual seizure patients (8, 57%) were employed or in school (p=0.05). Twelve (63%) of 19 eligible patients obtained driver's licenses. Twenty-three (82%) of 28 seizure free patients discontinued anticonvulsants. Surgery grading averaged "satisfied." Class I patients reported greater satisfaction than class III/IV patients (p<0.001). CONCLUSION: Two-thirds of children who underwent TLS achieved seizure freedom at >or=10 year follow-up. Children with tumors or cavernous angiomas achieved better long-term outcomes than those with other histopathologies. Long-term seizure free patients were most often satisfied with surgery and employed or in school.

Psychosocial outcomes in children two years after epilepsy surgery: has anything changed?

PURPOSE: We prospectively explored psychosocial outcomes in children (7-18 years) 2 years after epilepsy surgery. This study built on our previous one that examined these children 1 year after surgery. METHODS: Twenty children were studied using the Child Behavior Checklist (CBCL; a parent report instrument of potential behavioral and social problems) preoperatively, 1 year and 2 years after surgery. A comparison group of 12 children with medically refractory seizures was examined at comparable times. We conducted mixed factorial ANOVAs to determine group, time, and interaction effects, and regression analyses to assess factors driving significant (p

Utility of magnetoencephalography in the evaluation of recurrent seizures after epilepsy surgery.

PURPOSE: To study the role of magnetoencephalography (MEG) in the surgical evaluation of children with recurrent seizures after epilepsy surgery. METHODS: We studied 17 children with recurrent seizures after epilepsy surgery using interictal and ictal scalp EEG, intracranial video EEG (IVEEG), MRI, and MEG. We analyzed the location and distribution of MEG spike sources (MEGSSs) and the relationship of MEGSSs to the margins of previous resections and surgical outcome. RESULTS: Clustered MEGSSs occurred at the margins of previous resections within two contiguous gyri in 10 patients (group A), extended spatially from a margin by < or =3 cm in three patients (group B), and were remote from a resection margin by >3 cm in six patients (group C). Two patients had concomitant group A and C clusters. Thirteen patients underwent second surgeries. IVEEG was used in four patients. Six of seven patients with group A MEGSS clusters did not require IVEEG for second surgeries. Follow-up periods ranged from 0.6 to 4.3 years (mean: 2.6 years). Eleven children, including eight who became seizure-free, achieved Engel class I or II. CONCLUSION: Our data demonstrate the utility of MEG for evaluating patients with recurrent seizures after epilepsy surgery. Specific MEGSS cluster patterns delineate epileptogenic zones. Removing cluster regions adjacent to the margins of previous resections, in addition to removing recurrent lesions, achieves favorable surgical outcome. Cluster location and extent identify which patients require IVEEG, potentially eliminating IVEEG for some. Patients with remotely located clusters require IVEEG for accurate assessment and localization of the entire epileptogenic zone.

Dynamic changes of ictal high-frequency oscillations in neocortical epilepsy: using multiple band frequency analysis.

PURPOSE: To characterize the spatial and temporal course of ictal high-frequency oscillations (HFOs) recorded by subdural EEG in children with intractable neocortical epilepsy. METHODS: We retrospectively studied nine children (four girls, five boys; 4-17 yr) who presented with intractable extrahippocampal localization-related epilepsy and who underwent extraoperative video subdural EEG (1000 Hz sampling rate) and cortical resection. We performed multiple band frequency analysis (MBFA) to evaluate the frequency, time course, and distribution of ictal HFOs. We compared ictal HFO changes before and after clinical onset and postsurgical seizure outcomes. RESULTS: Seventy-eight of 79 seizures showed HFOs. We observed wide-band HFOs ( approximately 250 Hz, approximately 120 electrodes) in six patients either with partial seizures alone (three patients) or with epileptic spasms (three patients). Three patients with partial seizures that secondarily generalized had wide-band HFOs ( approximately 170 Hz) before clinical onset and sustained narrow-band HFOs (60-164 Hz) with electrodecremental events after clinical onset ( approximately 28 electrodes). In four postoperatively seizure-free patients, more electrodes recorded higher-frequency HFOs inside the resection area than outside before and after clinical seizure onset. In five patients with residual seizures, electrodes recorded more HFOs that were of higher or equal frequency outside the surgical area than inside after clinical onset. CONCLUSION: For partial seizures alone and epileptic spasms, more electrodes recorded only wide-band HFOs; for partial seizures that secondarily generalized, fewer electrodes recorded wide-band HFOs, but in these seizures electrodes also recorded subsequent sustained narrow-band ictal HFOs. Resection of those brain regions having electrodes with ictal, higher HFOs resulted in postsurgical seizure-free outcomes.

Memory outcome after pediatric epilepsy surgery: objective and subjective perspectives.

Memory was investigated in 27 children and adolescents in a longitudinal study before and at one and two years after epilepsy surgery. A comparison group with intractable epilepsy (n = 15), matched in age, sex, age of seizure onset, and IQ, was studied at comparable points in time. Methods included administration of standardized measures of story recall and face recognition, and qualitative interviews to probe the participants' perceptions of their memory function over time. There was no significant change over time in either group on the standardized measures. Site and laterality of excision, age at surgery, and seizure outcome were not predictive of change within the surgical group. The narratives revealed facets of memory that were problematic in daily life. The objective and subjective results showed low concordance regarding change, possibly due to limitations in the objective measures for capturing semantic and autobiographical memory.

Efficacy of dexamathasone on cerebral swelling and seizures during subdural grid EEG recording in children.

PURPOSE: To evaluate the impact of steroid treatment on cerebral swelling and seizures during subdural grid EEG (SGEEG) monitoring. METHODS: We reviewed data from 37 pediatric patients with intractable epilepsy who underwent SGEEG monitoring and divided the patients into those who received dexamethasone and those who did not. We then correlated administration of steroids to incidence of cerebral swelling on computed tomography (CT) scans and to frequency of seizures during SGEEG. RESULTS: Twenty-three patients received dexamethasone prophylactically every 6 hours (dosage range, 1-7.5 mg; mean, 3.2 mg) from the first day of SGEEG placement (group A); 14 patients received no dexamethasone (group B). Eight (21.6%) of 37 patients experienced cerebral swelling on CT: two (9%) were in group A, and six (42.9%) were in group B (p < 0.05). SGEEG monitoring time for recording habitual seizures that localized cortical areas for surgical excision was longer in group A (1-6 days; mean, 3.0) than it was in group B (1-3 days; mean, 2.2), (p < 0.05). Habitual seizures were recorded in 36 patients. One group A patient experienced obtundation due to cerebral swelling, and monitoring in this patient was discontinued. CONCLUSIONS: The prophylactic administration of steroids to pediatric patients during SGEEG monitoring is efficacious for reducing cerebral swelling. Although it decreases the frequency of habitual seizures and increases seizure-monitoring time, dexamethasone reduces the risk of complications from cerebral swelling during the SGEEG procedure.