Children's Adaptive Deep Brain Stimulation for Epilepsy Trial (CADET): Pilot

INCLUSION CRITERIA: Children enrolled in this study must: 1. Be 5-14 years of age at consent. 2. Have a diagnosis of Lennox-Gastaut Syndrome, as determined by: * Slow (\<3.0Hz) spike-and-wave pattern and/or fast wave pattern (tonic seizures) on EEG for at least six-months months prior to the enrolment into the baseline period * History of drop seizures (tonic, atonic, or tonic-clonic) for at least six-months prior to the enrolment into the baseline period 3. Experience at least 10 seizures per month. 4. Have tried and not responded to two or more antiseizure medications prior to enrolment. 5. Be taking one or more anti-seizure medication(s) at a stable dose for at least the four weeks prior and have a parent/guardian(s) who is willing for their child's maintenance anti-seizure drugs to be unaltered for the trial duration. 6. If on a ketogenic diet, have been established on a stable ketogenic diet for at least 12 weeks prior to screening and the parent/guardian(s) to be willing for child to stay on a stable ketogenic for the duration of the trial. 7. Have a parent/guardian(s) who is willing and able to comply with all the requirements of the study, including the completion of the seizure diary and periodic device charging. \------------------------------- EXCLUSION CRITERIA: Children enrolled in this study must not: 1. Have had prior deep brain stimulation insertion. 2. Have an active ('on') vagus nerve stimulator (or active within the six months prior to the baseline period). 3. Have abnormal thalamic anatomy detected on imaging that would render DBS either unsafe or unfeasible. 4. Have a bleeding disorder. 5. Have medical conditions/factors that would increase their anaesthetic risk to an unacceptable level. 6. Have a nickel allergy 7. Be pregnant 8. Participate in contact sports