The value of linear and non-linear quantitative EEG analysis in paediatric epilepsy surgery: a machine learning approach.

Epilepsy surgery is effective for patients with medication-resistant seizures, however 20-40% of them are not seizure free after surgery. Aim of this study is to evaluate the role of linear and non-linear EEG features to predict post-surgical outcome. We included 123 paediatric patients who underwent epilepsy surgery at Bambino Gesù Children Hospital (January 2009-April 2020). All patients had long term video-EEG monitoring. We analysed 1-min scalp interictal EEG (wakefulness and sleep) and extracted 13 linear and non-linear EEG features (power spectral density (PSD), Hjorth, approximate entropy, permutation entropy, Lyapunov and Hurst value). We used a logistic regression (LR) as feature selection process. To quantify the correlation between EEG features and surgical outcome we used an artificial neural network (ANN) model with 18 architectures. LR revealed a significant correlation between PSD of alpha band (sleep), Mobility index (sleep) and the Hurst value (sleep and awake) with outcome. The fifty-four ANN models gave a range of accuracy (46-65%) in predicting outcome. Within the fifty-four ANN models, we found a higher accuracy (64.8% ± 7.6%) in seizure outcome prediction, using features selected by LR. The combination of PSD of alpha band, mobility and the Hurst value positively correlate with good surgical outcome.

Phase-amplitude coupling between low- and high-frequency activities as preoperative biomarker of focal cortical dysplasia subtypes.

OBJECTIVE: To evaluate whether ictal phase-amplitude coupling (PAC) between high-frequency activity and low-frequency activity could be used as a preoperative biomarker of Focal Cortical Dysplasia (FCD) subtypes. We hypothesize that FCD seizures present unique PAC characteristics that may be linked to their specific histopathological features. METHODS: We retrospectively examined 12 children with FCD and refractory epilepsy who underwent successful epilepsy surgery. We identified ictal onsets recorded with stereo-EEG. We estimated the strength of PAC between low-frequencies and high-frequencies for each seizure by means of modulation index. Generalized mixed effect models and receiver operating characteristic (ROC) curve analysis were used to test the association between ictal PAC and FCD subtypes. RESULTS: Ictal PAC was significantly higher in patients with FCD type II compared to type I, only on SOZ-electrodes (p < 0.005). No differences in ictal PAC were found on non-SOZ electrodes. Pre-ictal PAC registered on SOZ electrodes predicted FCD histopathology with a classification accuracy > 0.9 (p < 0.05). CONCLUSIONS: The correlations between histopathology and neurophysiology provide evidence for the contribution of ictal PAC as a preoperative biomarker of FCD subtypes. SIGNIFICANCE: Developed into a proper clinical application, such a technique may help improve clinical management and facilitate the prediction of surgical outcome in patients with FCD undergoing stereo-EEG monitoring.

Neurophysiological Findings in Neuronal Ceroid Lipofuscinoses.

Neuronal ceroid lipofuscinoses (NCLs) are a heterogeneous group of neurodegenerative diseases, characterized by progressive cerebral atrophy due to lysosomal storage disorder. Common clinical features include epileptic seizures, progressive cognitive and motor decline, and visual failure, which occur over different time courses according to subtypes. During the latest years, many advances have been done in the field of targeted treatments, and in the next future, gene therapies and enzyme replacement treatments may be available for several NCL variants. Considering that there is rapid disease progression in NCLs, an early diagnosis is crucial, and neurophysiological features might have a key role for this purpose. Across the different subtypes of NCLs, electroencephalogram (EEG) is characterized by a progressive deterioration of cerebral activity with slowing of background activity and disappearance of spindles during sleep. Some types of heterogeneous abnormalities, diffuse or focal, prevalent over temporal and occipital regions, are described in many NCL variants. Photoparoxysmal response to low-frequency intermittent photic stimulation (IPS) is a typical EEG finding, mostly described in CLN2, CLN5, and CLN6 diseases. Visual evoked potentials (VEPs) allow to monitor the visual functions, and the lack of response at electroretinogram (ERG) reflects retinal neurodegeneration. Taken together, EEG, VEPs, and ERG may represent essential tools toward an early diagnosis of NCLs.

Can Presurgical Interhemispheric EEG Connectivity Predict Outcome in Hemispheric Surgery? A Brain Machine Learning Approach.

OBJECTIVES: Hemispherotomy (HT) is a surgical option for treatment of drug-resistant seizures due to hemispheric structural lesions. Factors affecting seizure outcome have not been fully clarified. In our study, we used a brain Machine Learning (ML) approach to evaluate the possible role of Inter-hemispheric EEG Connectivity (IC) in predicting post-surgical seizure outcome. METHODS: We collected 21 pediatric patients with drug-resistant epilepsy; who underwent HT in our center from 2009 to 2020; with a follow-up of at least two years. We selected 5-s windows of wakefulness and sleep pre-surgical EEG and we trained Artificial Neuronal Network (ANN) to estimate epilepsy outcome. We extracted EEG features as input data and selected the ANN with best accuracy. RESULTS: Among 21 patients, 15 (71%) were seizure and drug-free at last follow-up. ANN showed 73.3% of accuracy, with 85% of seizure free and 40% of non-seizure free patients appropriately classified. CONCLUSIONS: The accuracy level that we reached supports the hypothesis that pre-surgical EEG features may have the potential to predict epilepsy outcome after HT. SIGNIFICANCE: The role of pre-surgical EEG data in influencing seizure outcome after HT is still debated. We proposed a computational predictive model, with an ML approach, with a high accuracy level.

The Role of KRAS Mutations in Cortical Malformation and Epilepsy Surgery: A Novel Report of Nevus Sebaceous Syndrome and Review of the Literature.

The rare nevus sebaceous (NS) syndrome (NSS) includes cortical malformations and drug-resistant epilepsy. Somatic RAS-pathway genetic variants are pathogenetic in NS, but not yet described within the brain of patients with NSS. We report on a 5-year-old boy with mild psychomotor delay. A brown-yellow linear skin lesion suggestive of NS in the left temporo-occipital area was evident at birth. Epileptic spasms presented at aged six months. EEG showed continuous left temporo-occipital epileptiform abnormalities. Brain MRI revealed a similarly located diffuse cortical malformation with temporal pole volume reduction and a small hippocampus. We performed a left temporo-occipital resection with histopathological diagnosis of focal cortical dysplasia type Ia in the occipital region and hippocampal sclerosis type 1. Three years after surgery, he is seizure-and drug-free (Engel class Ia) and showed cognitive improvement. Genetic examination of brain and skin specimens revealed the c.35G > T (p.Gly12Val) KRAS somatic missense mutation. Literature review suggests epilepsy surgery in patients with NSS is highly efficacious, with 73% probability of seizure freedom. The few histological analyses reported evidenced disorganized cortex, occasionally with cytomegalic neurons. This is the first reported association of a KRAS genetic variant with cortical malformations associated with epilepsy, and suggests a possible genetic substrate for hippocampal sclerosis.

Early Onset Epilepsy Caused by Low-Grade Epilepsy-Associated Tumors and Focal Meningeal Involvement.

Background: Low-grade epilepsy-associated neuroepithelial tumors (LEATs) are a frequent etiology in pediatric patients with epilepsy undergoing surgery. Objective: To identify differences in clinical and post-surgical follow-up between patients with focal meningeal involvement (MI) and those without MI within our cohort of pediatric patients with LEATs. Methods: We retrospectively reviewed all pediatric patients (<18 y) who underwent epilepsy surgery between 2011 and 2017 at our hospital. Cohort inclusion required histological diagnosis of LEATs and post-surgical follow-up of ≥2 y. We subsequently stratified patients according to presence of neuroradiological MI. Results: We identified 37 patients: five with MI and 32 without. Half of patients (19) were drug sensitive at surgery; similar between groups. The group with MI differed mainly for age of epilepsy-onset (0.6 vs. 7.0 y) but not for epilepsy duration (0.9 vs. 1.5 y). Post-surgery radiological follow-up (median 4.0 y; IQR 2.8-5.0 y) did not indicate disease progression. Seizure outcome was excellent in both groups, with 34 patients overall being both drug- and seizure-free. Conclusions: Our study identified a new subgroup of LEATs with focal MI and excellent post-surgical outcome. Moreover, this highlights the effectiveness of early surgery in pediatric LEATs.

Refractory Status Epilepticus in Genetic Epilepsy-Is Vagus Nerve Stimulation an Option?

Refractory and super-refractory status epilepticus (RSE, SRSE) are severe conditions that can have long-term neurological consequences with high morbidity and mortality rates. The usefulness of vagus nerve-stimulation (VNS) implantation during RSE has been documented by anecdotal cases and in systematic reviews; however, the use of VNS in RSE has not been widely adopted. We successfully implanted VNS in two patients with genetic epilepsy admitted to hospital for SRSE; detailed descriptions of the clinical findings and VNS parameters are provided. Our patients were implanted 25 and 58 days after status epilepticus (SE) onset, and a stable remission of SE was observed from the seventh and tenth day after VNS implantation, respectively, without change in anti-seizure medication. We used a fast ramp-up of stimulation without evident side effects. Our results support the consideration of VNS implantation as a safe and effective adjunctive treatment for SRSE.

Pediatric status epilepticus: Identification of prognostic factors using the new ILAE classification after 5 years of follow-up.

OBJECTIVE: Status epilepticus (SE) is the most common neurologic emergency in childhood. This study aimed to report on a large cohort of pediatric patients with SE, applying the International League Against Epilepsy (ILAE) Classification for SE to identify prognostic factors. METHODS: We included 173 children treated at "Bambino Gesù" Children's Hospital in Rome for SE exceeding 30 minutes (mean age 4.43 ± 4.93 years old, median 2.28, interquartile range [IQR] 0.41-7.32; follow-up for a mean of 4.9 ± 3.4 years, median 8.75, IQR 4,58-12.63). A multivariate model was constructed to predict neurocognitive outcome, recurrence of SE, development of epilepsy, and mortality. Adjusted odds ratios [ORs] were calculated with 95% confidence interval (OR, 95% CIs). RESULTS: We observed a different prevalence of etiologies for the different semiologies (P < .05) and for each age group (P < .05), overlapping only in part with the recent ILAE classification. After SE, patients showed 69.9% epilepsy (drug-resistant in half of them), 23.1% worsening of neurologic findings on examination, 28.9% cognitive deficit, and 28.3% recurrent SE. At multivariate analysis: superrefractory SE was correlated to an increased risk of developing cognitive (OR 6.00, 95% CI 2.09, 17.31) or neurologic sequelae (OR 4.9, 95% CI 1.75, 19.77). A similar finding was observed for patients with onset in the neonatal period for cognitive (OR 4.84, 95% CI 1.13, 17.3) and neurologic sequelae (OR 9.03, 95% CI 2.40, 34.04). Recurrence of SE was associated with unknown etiology (OR 6.15, 95% CI 1.43, 26.76), and myoclonic semiology (OR 6.1, 95% CI 1.23, 29.3). Patients with acute symptomatic etiology (OR 0.12, 95% CI 0.04, 0.40) had a lower risk for developing epilepsy. SIGNIFICANCE: Age at onset and duration of SE were critical independent variables associated with worse neurocognitive outcome. The risk of developing epilepsy was lower after acute symptomatic and febrile SE. Semiology and age at onset correlate with etiology of SE. For this reason, ILAE classification with respect to four axes seems an appropriate advancement.

Purified Cannabidiol for Treatment of Refractory Epilepsies in Pediatric Patients with Developmental and Epileptic Encephalopathy.

BACKGROUND: A pharmaceutical grade formulation of cannabidiol (CBD) has been approved for the treatment of Dravet syndrome and Lennox-Gastaut syndrome; however, this formulation is not yet available to patients outside the USA. In addition, CBD is thought to have broad anti-seizure properties that may be beneficial for other types of intractable epilepsy. OBJECTIVE: The aim of this study was to evaluate the efficacy, safety and tolerability of artisanal medical CBD oil in patients with developmental and epileptic encephalopathy (DEE) at the tertiary epilepsy center of Bambino Gesù Children's Hospital in Rome, Italy. METHODS: This was a single-center, prospective, open-label study. Patients aged from 1 to 18 years with DEE and seizures refractory to appropriate antiepileptic drugs (AEDs) and other alternative treatments (i.e., vagal nerve stimulator and ketogenic diet) were included. Crystalline extract CBD powder (98-99% pure) in an oil artisanal formulation was added to the baseline AED regimen at a dosage of 2-5 mg/kg/day divided for twice-daily administration, then up-titrated until intolerance or a maximum dosage of 25 mg/kg/day was reached. Patients were treated for at least 6 months. Efficacy, safety and tolerability of CBD treatment were assessed through the evaluation of seizure frequency and reports of adverse effects. RESULTS: Twenty-nine patients were enrolled in this study (41.4% male). The mean duration of exposure to artisanal CBD was 11.2 months [range 6-25 months; standard deviation (SD) ± 4.4 months]. Mean age at study enrollment was 9.3 years (range 1.9-16.3 years; SD ± 4.7 years). Eleven out of 29 patients (37.9%) had a ≥ 50% improvement in seizure frequency; one patient became seizure free. None of the patients reported worsening seizure frequency; however, 18 patients (62.1%) experienced no beneficial effect regarding seizure frequency. Adverse effects were reported in seven patients (24.14%), most commonly somnolence, decreased appetite and diarrhea. Adverse events were mild and transient, and no dose modification of CBD or other AEDs was required. CONCLUSIONS: These data suggest that CBD may have beneficial effects in patients with DEE and an acceptable safety profile. Placebo-controlled randomized trials should be conducted to formally assess the safety and efficacy of CBD in patients with DEE.

Outcome after hemispherotomy in patients with intractable epilepsy: Comparison of techniques in the Italian experience.

OBJECTIVE: The objective of the study was to evaluate clinical characteristics and outcome of hemispherotomy in children and adolescents with hemispheric refractory epilepsy in an Italian cohort of patients. METHODS: We retrospectively evaluated the clinical course and outcome of 92 patients with refractory epilepsy who underwent hemispherotomy in three Italian epilepsy centers between 2006 and 2016. Three different approaches for hemispherotomy were used: parasagittal, modified parasagittal, and lateral. RESULTS: Mean age at epilepsy onset was 1.8 ±â€¯2.51 years, and mean duration of epilepsy prior to surgery was 7.4 ±â€¯5.6 years. Mean age at surgery was 9.2 ±â€¯8.0 years. After a mean follow-up of 2.81 ±â€¯2.4 years, 66 of 90 patients (two lost from follow-up, 73.3%) were seizure-free (Engel class I). The etiology of epilepsy was related to acquired lesions (encephalomalacia or gliosis) in 44 patients (47.8%), congenital malformations (cortical dysplasia, hemimegalencephaly, other cortical malformations) in 38 (41.3%), and progressive conditions (Rasmussen or Sturge-Weber syndrome) in 10 patients (10.9%). Regarding seizure outcome, we could not identify statistically significant differences between vertical and lateral approaches (p = 0.154). Seizure outcome was not statistically different in patients with congenital vs acquired or progressive etiologies (p = 0.43). Acute postoperative seizures (APOS) correlated with poor outcome (p < 0.05). On multivariate analysis, presurgical focal to bilateral tonic-clonic seizures (Odds Ratio (OR) = 3.63, 95% Confidence Interval (CI): 1.86-15.20, p = 0.048) independently predicted seizure recurrence. Twenty-one patients (22.8%) exhibited postoperative complications, with no unexpected and persistent neurological deficit. More than 50% of the patients completely tapered drugs. SIGNIFICANCE: Our data confirm hemispherotomy to be a safe and effective procedure in patients with drug resistant epilepsies due to hemispheric lesions. Presurgical focal to bilateral tonic-clonic seizures are the strongest predictor of seizure recurrence after surgery, independently from the type of hemispherotomy.