Changes in local and network brain activity after stereotactic thermocoagulation in patients with drug-resistant epilepsy.

OBJECTIVE: Stereoelectroencephalography-guided radiofrequency thermocoagulation (SEEG-guided RF-TC) aims to reduce seizure frequency by modifying epileptogenic networks through local thermocoagulative lesions. Although RF-TC is hypothesized to functionally modify brain networks, reports of changes in functional connectivity (FC) following the procedure are missing. We evaluated, by means of SEEG recordings, whether variation in brain activity after RF-TC is related to clinical outcome. METHODS: Interictal SEEG recordings from 33 patients with drug-resistant epilepsy (DRE) were analyzed. Therapeutic response was defined as a >50% reduction in seizure frequency for at least 1 month following RF-TC. Local (power spectral density [PSD]) and FC changes were evaluated in 3-min segments recorded shortly before (baseline), shortly after, and 15 min after RF-TC. The PSD and FC strength values after thermocoagulation were compared with baseline as well as between the responder and nonresponder groups. RESULTS: In responders, we found a significant reduction in PSD after RF-TC in channels that were thermocoagulated for all frequency bands (p = .007 for broad, delta and theta, p <.001 for alpha and beta bands). However, we did not observe such PSD decrease in nonresponders. At the network level, nonresponders displayed a significant FC increase in all frequency bands except theta (broad, delta, beta band: p <.001; alpha band: p <.01), although responders showed a significant FC decrease in delta (p <.001) and alpha bands (p <.05). Nonresponders showed stronger FC changes with respect to responders exclusively in TC channels (broad, alpha, theta, beta: p >.05; delta: p = .001). SIGNIFICANCE: Thermocoagulation induces both local and network-related (FC) changes in electrical brain activity of patients with DRE lasting for at least 15 min. This study demonstrates that the observed short-term modifications in brain network and local activity significantly differ between responders and nonresponders and opens new perspectives for studying the longer-lasting FC changes after RF-TC.

Long-term-video monitoring EEG and 18F-FDG-PET are useful tools to detect residual disease activity in anti-LGI1-Abs encephalitis: A case report.

Background: The use of CD20-depleting monoclonal antibodies has shown to improve the long-term outcome of patients with anti-leucine-rich glioma-inactivated protein 1 antibodies (anti-LGI1-Abs) encephalitis after first-line immunotherapy, but currently predictive markers of treatment response and disease activity are lacking. Case presentation: A 75-year-old man presented cognitive impairment and faciobrachial dystonic seizures (FBDS), with mild abnormalities at electroencephalography (EEG), normal brain magnetic resonance and cerebrospinal fluid (CSF) analysis. Anti-LGI1-Abs were detected in serum and CSF, and corticosteroids and intravenous immunoglobulins were administered. Despite partial cognitive improvement, 18F-fluoridesoxyglucose-positron emission tomography (18F-FDG-PET) showed the persistence of temporo-mesial hypermetabolism, and FBDS were still detected by long-term monitoring video EEG (LTMV EEG). Rituximab was therefore administered with FBDS disappearance, further cognitive improvement, and resolution of 18F-FDG-PET temporo-mesial hypermetabolism. Conclusions: Our experience supports the use of 18F-FDG-PET and LTMVEEG as useful tools to measure disease activity, evaluate treatment response and guide therapeutic decisions in the long-term management of anti-LGI1-antibody encephalitis.

Prediction of seizure recurrence risk following discontinuation of antiepileptic drugs.

OBJECTIVE: Discontinuation of antiepileptic drugs (AEDs) in seizure-free patients is an important goal because of possible long-term side effects and the social stigma burden of epilepsy. The purpose of this work was to assess seizure recurrence risk after suspension of AEDs, to evaluate predictors for recurrence, and to investigate the recovery of seizure control after relapse. In addition, the accuracy of a previously published prediction model of seizure recurrence risk was estimated. METHODS: Seizure-free patients with epilepsy who had discontinued AEDs were retrospectively enrolled. The frequency of seizure relapses after AED withdrawal as well as prognosis after recurrence were assessed and the predictive role of baseline clinical-demographic variables was evaluated. The aforementioned prediction model was also validated and its accuracy assessed at different seizure-relapse probability levels. RESULTS: The enrolled patients (n = 133) had been followed for a median of 3 years (range 0.8-33 years) after AED discontinuation; 60 (45%) of them relapsed. Previous febrile seizures in childhood (hazard ratio [HR] 3.927; 95% confidence interval [CI] 1.403-10.988), a seizure-free period on therapy of less than 2 years (HR 2.313; 95% CI 1.193-4.486), and persistent motor deficits (HR 4.568; 95% CI 1.412-14.772) were the clinical features associated with relapse risk in univariate analysis. Among these variables, only a seizure-free period on therapy of less than 2 years was associated with seizure recurrence in multivariate analysis (HR 2.365; 95% CI 1.178-4.7444). Pharmacological control of epilepsy was restored in 82.4% of the patients who relapsed. In this population, the aforementioned prediction model showed an unsatisfactory accuracy. SIGNIFICANCE: A period of freedom from seizure on therapy of less than 2 years was the main predictor of seizure recurrence. The accuracy of the previously described prediction tool was low in this cohort, thus suggesting its cautious use in real-world clinical practice.

Changes in epileptogenicity biomarkers after stereotactic thermocoagulation.

OBJECTIVE: Stereo-electroencephalography (SEEG)-guided radiofrequency thermocoagulation (RF-TC) aims at modifying epileptogenic networks to reduce seizure frequency. High-frequency oscillations (HFOs), spikes, and cross-rate are quantifiable epileptogenic biomarkers. In this study, we sought to evaluate, using SEEG signals recorded before and after thermocoagulation, whether a variation in these markers is related to the therapeutic effect of this procedure and to the outcome of surgery. METHODS: Interictal segments of SEEG signals were analyzed in 38 patients during presurgical evaluation. We used an automatized method to quantify the rate of spikes, rate of HFOs, and cross-rate (a measure combining spikes and HFOs) before and after thermocoagulation. We analyzed the differences both at an individual level with a surrogate approach and at a group level with analysis of variance. We then evaluated the correlation between these variations and the clinical response to RF-TC and to subsequent resective surgery. RESULTS: After thermocoagulation, 19 patients showed a clinical improvement. At the individual level, clinically improved patients more frequently had a reduction in spikes and cross-rate in the epileptogenic zone than patients without clinical improvement (p = .002, p = .02). At a group level, there was a greater decrease of HFOs in epileptogenic and thermocoagulated zones in patients with clinical improvement (p < .05) compared to those with no clinical benefit. Eventually, a significant decrease of all the markers after RF-TC was found in patients with a favorable outcome of resective surgery (spikes, p = .026; HFOs, p = .03; cross-rate, p = .03). SIGNIFICANCE: Quantified changes in the rate of spikes, rate of HFOs, and cross-rate can be observed after thermocoagulation, and the reduction of these markers correlates with a favorable clinical outcome after RF-TC and with successful resective surgery. This may suggest that interictal biomarker modifications after RF-TC can be clinically used to predict the effectiveness of the thermocoagulation procedure and the outcome of resective surgery.

Intravenous brivaracetam in status epilepticus: A multicentric retrospective study in Italy.

PURPOSE: to evaluate the use, effectiveness, and adverse events of intravenous brivaracetam (BRV) in status epilepticus (SE). METHODS: a retrospective multicentric study involving 24 Italian neurology units was performed from March 2018 to June 2020. A shared case report form was used across participating centres to limit biases of retrospective data collection. Diagnosis and classification of SE followed the 2015 ILAE proposal. We considered a trial with BRV a success when it was the last administered drug prior the clinical and/or EEG resolution of seizures, and the SE did not recur during hospital observation. In addition, we considered cases with early response, defined as SE resolved within 6 h after BRV administration. RESULTS: 56 patients were included (mean age 62 years; 57 % male). A previous diagnosis of epilepsy was present in 21 (38 %). Regarding SE etiology classification 46 % were acute symptomatic, 18 % remote and 16 % progressive symptomatic. SE episodes with prominent motor features were the majority (80 %). BRV was administered as first drug after benzodiazepine failure in 21 % episodes, while it was used as the second or the third (or more) drug in the 38 % and 38 % of episodes respectively. The median loading dose was 100 mg (range 50-300 mg). BRV was effective in 32 cases (57 %). An early response was documented in 22 patients (39 % of the whole sample). The use of the BRV within 6 h from SE onset was independently associated to an early SE resolution (OR 32; 95 % CI 3.39-202; p = 0.002). No severe treatment emergent adverse events were observed. CONCLUSION: BRV proved to be useful and safe for the treatment of SE. Time to seizures resolution appears shorter when it is administered in the early phases of SE.