Real-World Preliminary Experience With Responsive Neurostimulation in Pediatric Epilepsy: A Multicenter Retrospective Observational Study

BACKGROUND

Despite the well-documented utility of responsive neurostimulation (RNS, NeuroPace) in adult epilepsy patients, literature on the use of RNS in children is limited.

OBJECTIVE

To determine the real-world efficacy and safety of RNS in pediatric epilepsy patients.

METHODS

Patients with childhood-onset drug-resistant epilepsy treated with RNS were retrospectively identified at 5 pediatric centers. Reduction of disabling seizures and complications were evaluated for children (<18 yr) and young adults (>18 yr) and compared with prior literature pertaining to adult patients.

RESULTS

Of 35 patients identified, 17 were <18 yr at the time of RNS implantation, including a 3-yr-old patient. Four patients (11%) had concurrent resection. Three complications, requiring additional surgical interventions, were noted in young adults (2 infections [6%] and 1 lead fracture [3%]). No complications were noted in children. Among the 32 patients with continued therapy, 2 (6%) achieved seizure freedom, 4 (13%) achieved ≥90% seizure reduction, 13 (41%) had ≥50% reduction, 8 (25%) had <50% reduction, and 5 (16%) experienced no improvement. The average follow-up duration was 1.7 yr (median 1.8 yr, range 0.3-4.8 yr). There was no statistically significant difference for seizure reduction and complications between children and young adults in our cohort or between our cohort and the adult literature.

CONCLUSION

These preliminary data suggest that RNS is well tolerated and an effective off-label surgical treatment of drug-resistant epilepsy in carefully selected pediatric patients as young as 3 yr of age. Data regarding long-term efficacy and safety in children will be critical to optimize patient selection.

Prospective observational study: Fast ripple localization delineates the epileptogenic zone

OBJECTIVE

To investigate spatial correlation between interictal HFOs and neuroimaging abnormalities, and to determine if complete removal of prospectively identified interictal HFOs correlates with post-surgical seizure-freedom.

METHODS

Interictal fast ripples (FRs: 250-500 Hz) in 19 consecutive children with pharmacoresistant focal epilepsy who underwent extra-operative electrocorticography (ECoG) recording were prospectively analyzed. The interictal FRs were sampled at 2000 Hz and were visually identified during 10 min of slow wave sleep. Interictal FRs, MRI and FDG-PET were delineated on patient-specific reconstructed three-dimensional brain MRI.

RESULTS

Interictal FRs were observed in all patients except one. Thirteen out of 18 patients (72%) exhibited FRs beyond the extent of neuroimaging abnormalities. Fifteen of 19 children underwent resective surgery, and survival analysis with log-rank test demonstrated that complete resection of cortical sites showing interictal FRs correlated with longer post-operative seizure-freedom (p < 0.01). Complete resection of seizure onset zones (SOZ) also correlated with longer post-operative seizure-freedom (p = 0.01), yet complete resection of neuroimaging abnormalities did not (p = 0.43).

CONCLUSIONS

Prospective visual analysis of interictal FRs was feasible, and it seemed to accurately localize epileptogenic zones.

SIGNIFICANCE

Topological extent of epileptogenic region may exceed what is discernible by multimodal neuroimaging.

Limited efficacy of the ketogenic diet in the treatment of highly refractory epileptic spasms

PURPOSE

Numerous studies have suggested that the ketogenic diet is effective in the treatment of epileptic spasms, even in refractory cases. However, there has been very limited demonstration of prompt and complete (video-EEG confirmed) response. We set out to describe our center's experience with the ketogenic diet in the treatment of children with highly refractory epileptic spasms, with rigorous seizure outcome assessment.

METHOD

Children treated with the ketogenic diet for epileptic spasms between April, 2010 and June, 2014 were retrospectively identified. Seizure burden was tabulated at baseline and after 1, 3, 6, and 12-months of ketogenic diet exposure. Adverse events were similarly ascertained.

RESULTS

We identified a cohort of 22 consecutive patients who received ketogenic diet therapy, with median age of onset of epileptic spasms of 5.2 (IQR 2.0-9.0) months, with diet initiation beginning a median of 26.4 (12.5-38.7) months after onset, and following a median of 7 (IQR 5-7) treatment failures. Only 2 patients exhibited a complete response during ketogenic diet exposure, and response was more reasonably attributed to alternative therapies in both cases. A modest early reduction in seizure frequency was not sustained beyond 1 month of diet exposure. The diet was well tolerated, and continued in 6 patients with subjective and/or partial response.

CONCLUSION

In contrast to prior studies reporting substantial efficacy of the ketogenic diet, our findings suggest limited efficacy, albeit in a highly refractory cohort. Prospective studies in both refractory and new-onset populations, with both video-EEG confirmation of response and rigorous cognitive outcome assessment, would be of great value to more clearly define the utility of the ketogenic diet in the treatment of epileptic spasms.

The ketogenic diet as broad-spectrum treatment for super-refractory pediatric status epilepticus: challenges in implementation in the pediatric and neonatal intensive care units

Refractory status epilepticus carries significant morbidity and mortality. Recent reports have promoted the use of the ketogenic diet as an effective treatment for refractory status epilepticus. We describe our recent experience with instituting the ketogenic diet for 4 critically ill children in refractory status epilepticus, ranging in age from 9 weeks to 13.5 years after failure of traditional treatment. The ketogenic diet allowed these patients to be weaned off continuous infusions of anesthetics without recurrence of status epilepticus, though delayed ketosis and persistently elevated glucose measurements posed special challenges to effective initiation, and none experienced complete seizure cessation. The ease of sustaining myocardial function with fatty acid energy substrates compares favorably over the myocardial toxicity posed by anesthetic doses of barbiturates and contributes to the safety profile of the ketogenic diet. The ketogenic diet can be implemented successfully and safely for the treatment of refractory status epilepticus in pediatric patients.