Role of optically pumped magnetometers in presurgical epilepsy evaluation: Commentary of the American Clinical Magnetoencephalography Society.

One of the major challenges of modern epileptology is the underutilization of epilepsy surgery for treatment of patients with focal, medication resistant epilepsy (MRE). Aggravating this distressing failure to deliver optimum care to these patients is the underuse of proven localizing tools, such as magnetoencephalography (MEG), a clinically validated, non-invasive, neurophysiological method used to directly measure and localize brain activity. A sizable mass of published evidence indicates that MEG can improve identification of surgical candidates and guide pre-surgical planning, increasing the yield of SEEG and improving operative outcomes. However, despite at least 10 common, evidence supported, clinical scenarios in MRE patients where MEG can offer non-redundant information and improve the pre-surgical evaluation, it is regularly used by only a minority of USA epilepsy centers. The current state of the art in MEG sensors employs SQUIDs, which require cooling with liquid helium to achieve superconductivity. This sensor technology has undergone significant generational improvement since whole head MEG scanners were introduced around in 1990s, but still has limitations. Further advances in sensor technology which may make ME G more easily accessible and affordable have been eagerly awaited, and development of new techniques should be encouraged. Of late, optically pumped magnetometers (OPMs) have received considerable attention, even prompting some potential acquisitions of new MEG systems to be put on hold, based on a hope that OPMs will usher in a new generation of MEG equipment and procedures. The development of any new clinical test used to guide intracranial EEG monitoring and/or surgical planning must address several specific issues. The goal of this commentary is to recognize the current state of OPM technology and to suggest a framework for it to advance in the clinical realm where it can eventually be deemed clinically valuable to physicians and patients. The American Clinical MEG Society (ACMEGS) strongly supports more advanced and less expensive technology and looks forward to continuing work with researchers to develop new sensors and clinical devices which will improve the experience and outcome for patients, and perhaps extend the role of MEG. However, currently, there are no OPM devices ready for practical clinical use. Based on the engineering obstacles and the clinical tradeoffs to be resolved, the assessment of experts suggests that there will most likely be another decade relying solely on "frozen SQUIDs" in the clinical MEG field.

Comparing electrical stimulation functional mapping with subdural electrodes and stereoelectroencephalography.

OBJECTIVE: Electrical stimulation mapping (ESM) is the clinical standard for functional localization with subdural electrodes (SDE). As stereoelectroencephalography (SEEG) has emerged as an alternative option, we compared functional responses, afterdischarges (ADs), and unwanted ESM-induced seizures (EISs) between the two electrode types. METHODS: Incidence and current thresholds for functional responses (sensory, motor, speech/language), ADs, and EISs were compared between SDE and SEEG using mixed models incorporating relevant covariates. RESULTS: We identified 67 SEEG ESM and 106 SDE ESM patients (7207 and 4980 stimulated contacts, respectively). We found similar incidence of language and motor responses between electrode types; however, more SEEG patients reported sensory responses. ADs and EISs occurred less commonly with SEEG than SDE. Current thresholds for language, face motor, and upper extremity (UE) motor responses and EIS significantly decreased with age. However, they were not affected by electrode type, premedication, or dominant hemispheric stimulation. AD thresholds were higher with SEEG than with SDE. For SEEG ESM, language thresholds remained below AD thresholds up to 26 years of age, whereas this relationship was inverse for SDE. Also, face and UE motor thresholds fell below AD thresholds at earlier ages for SEEG than SDE. AD and EIS thresholds were not affected by premedication. SIGNIFICANCE: SEEG and SDE have clinically relevant differences for functional brain mapping with electrical stimulation. Although evaluation of language and motor regions is comparable between SEEG and SDE, SEEG offers a higher likelihood of identifying sensory areas. A lower incidence of ADs and EISs, and a favorable relationship between functional and AD thresholds suggest superior safety and neurophysiologic validity for SEEG ESM than SDE ESM.

Neuropsychological outcomes after epilepsy surgery: A comparison of stereo electroencephalography and subdural electrodes.

BACKGROUND AND PURPOSE: We analyzed the association of neuropsychological outcomes after epilepsy surgery with the intracranial electrode type (stereo electroencephalography [SEEG] and subdural electrodes [SDE]), and electrical stimulation mapping (ESM) of speech/language. METHODS: Drug-resistant epilepsy patients who underwent comprehensive neuropsychological evaluation before and 1 year after epilepsy surgery were included. SEEG and SDE subgroups were matched by age, handedness, operated hemisphere, and seizure freedom. Postsurgical neuropsychological outcomes (adjusted for presurgical scores) and reliable change indices were analyzed as functions of electrode type and ESM. RESULTS: Ninety-nine patients aged 6-29 years were included with similar surgical resection/ablation volumes in the SEEG and SDE subgroups. Most of the neuropsychological outcomes were comparable between SEEG and SDE subgroups; however, Working Memory and Processing Speed were significantly improved in the SEEG subgroup. Undergoing language ESM was associated with significant improvements in Spelling, Letter-Word Identification, Vocabulary, Verbal Comprehension, Verbal Learning, and Story Memory scores, but a decline in Calculation scores. CONCLUSIONS: Intracranial evaluations with SEEG and SDE are comparable in terms of long-term postsurgical neuropsychological outcomes. Our data suggest that SEEG may be associated with improvements in working memory and processing speed, representing cognitive domains served by spatially distributed networks. Our study also supports wider use of language ESM before epilepsy surgery, preferably using other language tasks in addition to visual naming. Rather than the type of electrode, postsurgical neuropsychological outcomes are driven by whether language ESM was performed or not, with beneficial effects of language mapping.

Pilot randomized controlled clinical trial of an adherence social norms intervention for adolescents with epilepsy.

OBJECTIVE: Non-adherence to anti-seizure medications (ASMs) is common for adolescents with epilepsy, with potentially devastating consequences. Existing adherence interventions in epilepsy do not meet the unique challenges faced by adolescents. Leveraging social norms capitalizes on the increased importance of peer influence while simultaneously targeting the low motivation levels of many adolescents. The current study examined the feasibility, acceptability, and satisfaction of a social norms adherence intervention in adolescents with epilepsy. METHODS: A pilot RCT of a mHealth social norms intervention was conducted with adolescents with epilepsy who demonstrated non-adherence (≤95% adherence) during baseline. Adolescents were randomized to either (1) mHealth social norms (reminders, individualized and social norms adherence feedback) or (2) control (reminders and individualized adherence feedback). Primary outcomes included feasibility, acceptability, and satisfaction. Exploratory outcomes included electronically monitored adherence, seizure severity, and health-related quality of life (HRQOL). RESULTS: One hundred four adolescents were recruited (53% female; Mage = 15.4 ± 1.4 years; 81% White: Non-Hispanic; 5% Black, 10% Bi/Multiracial; 2% White: Hispanic; 1% Other: Hispanic; 1% Bi/Multiracial-Hispanic). Forty-five percent screen-failed due to high adherence, 16% withdrew, and 38% were randomized to treatment (n = 19) or control (n = 21). Recruitment (75%), retention (78%), and treatment satisfaction were moderately high. Engagement with the intervention was moderate, with 64% of participants engaging with intervention notifications. Exploratory analyses revealed that after controlling for COVID-19 impact, the social norms intervention group maintained higher adherence over time compared to the control group. Small to moderate effect sizes were noted for seizure severity and HRQOL between groups. CONCLUSION: This pilot intervention appeared feasible and acceptable. Increases in adherence in the treatment versus control group were modest, but a future larger more adequately powered study is needed to detect effects. Notably, it appeared the COVID pandemic influenced adherence behaviors during our trial.

Predictors of objective treatment adherence in adolescents with epilepsy: The important role of motivation.

OBJECTIVE: Adolescents with epilepsy are at heightened risk for suboptimal anti-seizure medication (ASM) adherence; however, there is a paucity of adherence interventions for this age group. The current study aimed to identify a comprehensive and novel set of predictors of objective, electronically-monitored ASM adherence in adolescents with epilepsy. METHODS: Participants included 104 adolescents (13-17 years old; M = 15.36 ± 1.40), diagnosed with epilepsy and their caregivers. Cross-sectional data were collected from adolescents, caregivers, healthcare providers, and medical chart reviews, including demographics (i.e., age, race/ethnicity, sex, insurance status), the COVID-19 pandemic (i.e., participation before versus during), seizure characteristics (i.e., presence and severity), ASM side effects (Pediatric Epilepsy Side Effects Questionnaire), adherence motivation (1-item 6-point Likert scale item), and adherence barriers (Pediatric Epilepsy Medication Self-Management Questionnaire). Electronically-monitored adherence data was collected via the AdhereTechTM pill bottle or the Vaica SimpleMedTM pillbox over 30 days. RESULTS: Adolescents demonstrated suboptimal adherence at 78 ± 31.6%, despite high ASM adherence motivation (M = 4.43 ± .94) and minimal adherence barriers (M = 35.64 ± 3.78). Hierarchical multiple regression, which included non-modifiable sociodemographic and medical variables (Block 1) and behaviorally modifiable psychosocial variables (Block 2) was significant, F(12,87) = 3.69, p < .001. Specifically, having private insurance (versus Medicaid or public insurance; t = -2.11, p = .038) and higher adherence motivation (t = 2.91, p = .005) predicted higher objective ASM adherence. CONCLUSION: Routine assessment of adherence predictors is vital for the promotion of adherence among adolescents with epilepsy. Adolescent adherence motivation may be an important element of multi-component interventions focused on improving ASM adherence in adolescents with epilepsy.

Comparison of outcomes after stereoelectroencephalography and subdural grid monitoring in pediatric tuberous sclerosis complex.

OBJECTIVE: Patients with tuberous sclerosis complex (TSC) epilepsy present with unique clinical challenges such as early seizure onset and high rates of intractability and multifocality. Although there are numerous studies about the safety and efficacy of stereoelectroencephalography (SEEG), this topic has not been studied in TSC patients who have distinct epilepsy profiles. The authors investigated subdural grid (SDG) and SEEG monitoring to determine whether these procedures lead to similar seizure and safety outcomes and to identify features unique to this pediatric population. METHODS: TSC patients who underwent SDG or SEEG placement and a second epilepsy surgery during the period from 2007 to 2021 were included in this single-center retrospective cohort analysis. Various patient, hospitalization, and epilepsy characteristics were collected. RESULTS: A total of 50 TSC patients were included in this study: 30 were included in the SDG cohort and 20 in the SEEG cohort. Baseline weekly seizure count did not significantly differ between the 2 groups (p = 0.412). The SEEG group had a greater mean baseline number of antiepileptic drugs (AEDs) (3.0 vs 2.0, p = 0.003), higher rate of previous surgical interventions (25% vs 0%, p = 0.007), and larger proportion of patients who underwent bilateral monitoring (50% vs 13.3%, p = 0.005). Despite this, there was no significant difference in seizure freedom between the SDG and SEEG cohorts. The mean reduction in seizure count was 84.9% and 47.8% of patients were seizure free at last follow-up (mean 79.4 months). SEEG trended toward being a safer procedure than SDG monitoring, with a shorter mean ICU stay (0.7 days vs 3.9 days, p < 0.001), lower blood transfusion rate (0% vs 13.3%, p = 0.140), and lower surgical complication rate (0% vs 10%, p = 0.265). CONCLUSIONS: In the comparison of the SDG and SEEG cohorts, the SEEG group included patients who appeared to receive more aggressive management and have a higher rate of multifocality, more prior surgical interventions, more AEDs at baseline, and a higher rate of bilateral invasive monitoring. Despite this, the SEEG cohort had similar seizure outcomes and a trend toward increased safety. Based on these findings, SEEG appears to allow for monitoring of a wider breadth of TSC patients given its minimally invasive nature and its relative simplicity for monitoring numerous regions of the brain.

Subtraction ictal SPECT co-registered to MRI (SISCOM) patterns in children with temporal lobe epilepsy.

OBJECTIVE: We evaluated SISCOM patterns and their relationship with surgical outcome in children with temporal lobe epilepsy (TLE) who had undergone a temporal lobe surgery. METHODS: This was an observational study evaluating SISCOM patterns in 40 children with TLE. We classified SISCOM patterns into 4 categories; (i) unilateral anteromesial and/or anterolateral temporal pattern; (ii) unilateral anteromesial and/or anterolateral temporal plus posterior extension pattern; (iii) bilateral anteromesial and/or anterolateral temporal pattern; and (iv) atypical pattern. Determinants of SISCOM pattern and correlation between postoperative outcomes and SISCOM patterns were evaluated. RESULTS: Pattern (i), (ii), (iii), and (iv) were identified in 10 (25%), 14 (35%), 0 (0%), and 16 (40%) patients, respectively. There was no significant correlation between patterns and postoperative outcomes. SISCOM patterns significantly associated with the presence of hippocampal sclerosis and type of focal cortical dysplasia (p-value = 0.048 and 0.036, respectively). Patients with HS had 5 times the odds of having unilateral temporal pattern, compared to patients with other neuropathology (OR = 5, 95% CI 0.92 to 27.08). Patients with FCD type 2 had 9.71 times the odds of having atypical pattern, compared to patients with other types of FCD (OR = 9.71, 95% CI 0.92 to 103.04). Lobar concordance of SISCOM and ictal and interictal scalp EEG significantly correlated with postoperative outcomes (p-value = 0.018 and 0.013, respectively). CONCLUSION: Three SISCOM patterns were seen. Patients with HS had increased odds of having unilateral temporal pattern while patients with FCD type 2 had increased odds of having atypical pattern. However, there was no significant correlation between SISCOM patterns and postoperative outcomes. Lobar concordance of SISCOM and ictal and interictal scalp EEG significantly correlated with postoperative outcome. SIGNIFICANCE: This study shows that the distribution of SISCOM patterns and their relationship with postoperative outcomes in children with TLE are different from adult population. Besides, SISCOM may add only limited diagnostic and prognostic information in children with drug-resistant TLE undergoing epilepsy surgery. Further evaluation to identify patient populations that may benefit from SISCOM is desirable.

Epilepsy-Work-Up and Management in Children.

Pediatric epilepsy is a highly variable condition due to age-related expression of syndromes that require specific diagnosis, evaluations, and treatments. Children with epilepsy differ from their adult counterparts in many important ways, mostly related to the age-related expression of specific epilepsy syndromes. This results in many important considerations related to the epilepsy diagnosis, classification, evaluations to determine an etiology, as well as treatment guidelines. A good understanding of these factors will help to establish an accurate epilepsy diagnosis, which in turn will guide appropriate testing and treatment decisions. In this way, patients will have improved seizure outcomes, and families will be educated appropriately and provided with the most accurate prognostic information available. The purpose of this article is to review the diagnosis, work-up, and management of pediatric epilepsy.

Reading in children with drug-resistant epilepsy was related to functional connectivity in cognitive control regions.

AIM: This study aimed to define whether individuals with drug-resistant focal epilepsy also used regions related to cognitive control to facilitate reading. METHODS: We focused on patients with drug-resistant focal epilepsy in 2011-2014, who were aged 8-20 years and were being treated at the Cincinnati Children's Hospital, USA. They performed a verb generation functional magnetic resonance imaging task known to involve language and cognitive control, as well as a formal reading assessment. The reading scores were correlated with functional connectivity of the anterior cingulate cortex (ACC) using seed-to-voxel analysis. RESULTS: There were 81 potential patients and 13 (seven females) met the inclusion criteria. Their age at seizure onset was 0-13 years, and they had a mean age of 12.66 ± 3.17 years at the time of the study. Individuals with epilepsy demonstrated average intelligence and word reading ability. Their reading scores were positively correlated with functional connectivity between the ACC and regions related to emotional processing (right amygdala), learning and language processing (left cerebellum) and visual processing. CONCLUSION: Our results support the role that the ACC plays in proficient reading among children with drug-resistant epilepsy, even in those with epileptogenic foci in areas related to language.

Ictal connectivity in childhood absence epilepsy: Associations with outcome.

OBJECTIVE: The understanding of childhood absence epilepsy (CAE) has been revolutionized over the past decade, but the biological mechanisms responsible for variable treatment outcomes are unknown. Our purpose in this prospective observational study was to determine how pretreatment ictal network pathways, defined using a combined electroencephalography (EEG)-functional magnetic resonance imaging (EEG-fMRI) and magnetoencephalography (MEG) effective connectivity analysis, were related to treatment response. METHODS: Sixteen children with newly diagnosed and drug-naive CAE had 31 typical absence seizures during EEG-fMRI and 74 during MEG. The spatial extent of the pretreatment ictal network was defined using fMRI hemodynamic response with an event-related independent component analysis (eICA). This spatially defined pretreatment ictal network supplied prior information for MEG-effective connectivity analysis calculated using phase slope index (PSI). Treatment outcome was assessed 2 years following diagnosis and dichotomized to ethosuximide (ETX)-treatment responders (N = 11) or nonresponders (N = 5). Effective connectivity of the pretreatment ictal network was compared to the treatment response. RESULTS: Patterns of pretreatment connectivity demonstrated strongest connections in the thalamus and posterior brain regions (parietal, posterior cingulate, angular gyrus, precuneus, and occipital) at delta frequencies and the frontal cortices at gamma frequencies (P < .05). ETX treatment nonresponders had pretreatment connectivity, which was decreased in the precuneus region and increased in the frontal cortex compared to ETX responders (P < .05). SIGNIFICANCE: Pretreatment ictal connectivity differences in children with CAE were associated with response to antiepileptic treatment. This is a possible mechanism for the variable treatment response seen in patients sharing the same epilepsy syndrome.