Inclusion Criteria:

• Participant is age 12 and older.
• Participant is male or is a female of childbearing potential who is surgically sterile, 2 years postmenopausal, or practices a reliable method of contraception (hormonal, barrier method or abstention).
• Participant failed treatment with a minimum of two antiseizure medications (used in appropriate doses) with adequate monitoring of compliance and the effects of treatment, as determined by the investigator. • Participant is able to maintain an electronic diary alone or with the assistance of a competent individual.
• Participant is able to attend clinic appointments in accordance with the study schedule.
• Participant or parent(s) or legal representative have signed an IRB approved written informed consent/assent. The informed consent form or specific assent form, where required, will be signed and dated by minors.
• Participant is not currently implanted with an RNS Neurostimulator or NeuroPace Leads.
• In the investigator’s opinion, participant is able to tolerate a neurosurgical procedure.
• Participant with a confirmed diagnosis of idiopathic generalized epilepsy experiencing primary generalized tonic-clonic seizures, with or without myoclonic or absence seizures, consistent with the International League against Epilepsy Revised Classification of Seizures (2017).
• In the Investigator’s opinion, participant is expected to have 2 or more generalized tonic-clonic seizures during the combined two month retrospective and the 1 month prospective baseline. • Participant has had a routine electroencephalogram (EEG) prior to enrollment with electroencephalographic features consistent with idiopathic generalized epilepsy; other concomitant anomalies must be explained by adequate past medical history.
• Participant has been on a stable antiseizure medication (ASM) regimen during the two month retrospective baseline and is willing to remain on a stable ASM regimen during the prospective Baseline and throughout the Effectiveness Evaluation Period, if medically possible; rescue benzodiazepine medications for acute seizure clusters are permitted.
• Participant has undergone computed tomography (CT) or magnetic resonance imaging (MRI) within 10 years prior to enrollment that ruled out a progressive cause of epilepsy or an abnormality likely to be associated with focal-onset seizures.
• Participant does not have a vagus nerve stimulator (VNS, LivaNova) or Participant’s VNS is OFF during the two month retrospective baseline and participant is willing to keep the VNS off during the study.

Exclusion Criteria:

• Participant is pregnant.
• Participant is participating in a therapeutic investigational drug or other device study.
• Participant is implanted with an electronic medical device that delivers electrical energy to the brain.
• Participant requires procedures that are contraindicated based on current RNS System labeling.
• Participant has been diagnosed with active psychosis, major depression or suicidal ideation in the preceding year. Participants with post-ictal psychiatric symptoms need not be excluded.
• In the opinion of the investigator, the participant has a clinically significant or unstable medical condition (including alcohol and/or drug abuse) or a progressive central nervous system disease.
• Participant has a history of partial-onset seizures or EEG findings within the past 2 years indicative of partial-onset or symptomatic generalized abnormalities.
• Participant has been diagnosed with psychogenic or non-epileptic seizures in the preceding year.
• Participant has experienced unprovoked status epilepticus in the preceding year.
• Participant is taking any anticoagulants. Note: For contraindications, refer to current physician labeling (manuals) for the RNS System available at the NeuroPace website (www.neuropace.com).

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 9/27/23. Questions regarding updates should be directed to the study team contact.