Clinical Research Directory

Inclusion Criteria: * Focal (partial) onset seizures (based on International League Against Epilepsy (ILAE) 2017 classification) that may or may not evolve to a bilateral tonic-clonic seizure (secondary generalization). The final determination shall be made by the Investigator based on a clinical description of the seizures and previous diagnostic testing that includes, at a minimum, video EEG (inpatient or ambulatory) that captured at least one ictal event * Anticipated average of 6 or more focal (partial) onset seizures per month during CMM phase, with no more than 30 consecutive seizure-free days during the CMM phase * Refractory to at least 3 antiepileptic drugs (AEDs) due to lack of effectiveness * Age 18 or older at the time of enrollment * Willing and able to complete the diary, with or without the assistance of a caregiver, in a reliable way as assessed by the clinical staff * Able to use the Patient Programmer with or without the assistance of a caregiver * Ability of the subject or legal representative to understand and provide signed consent for participating in the study * Willing and available to attend visits as scheduled and to comply with the study protocol Exclusion Criteria: * Generalized onset epilepsy type (based on International League Against Epilepsy (ILAE) 2017 classification) * Seizure frequency is too frequent that subject is unable to provide daily count in order to maintain a reliable seizure diary * Any episode of convulsive status epilepticus within the 12 months prior to the Enrollment Visit * Previous diagnosis of psychogenic/non-epileptic seizures within the 12 months prior to the Enrollment Visit * Surgical candidate for and willing to undergo resective surgery * Evidence of a neurological condition that is likely to progress (e.g., brain tumor, arteriovenous malformations or cavernous angiomas) * Diagnosed with a progressive or degenerative neurological disorder affecting the brain * Significant medical condition that may impact study participation in the opinion of the investigator * Presence of any of the following within 1 year prior to the Enrollment Visit: psychiatric illness hospitalization, suicide attempt or symptoms of psychosis (hallucinations, delusions) unrelated to an ictal state, a post-ictal state or a medication * Malignancy or history of malignancy within 1 year prior to the Enrollment Visit (excluding resected basal cell carcinomas) * Presence of implanted electrical stimulation medical device anywhere in the body (e.g., cardiac pacemakers, spinal cord stimulator, RNS) or any metallic implants in the head (e.g., aneurysm clip, cochlear implant). In the case of an implanted vagus nerve stimulator (VNS), CMM study assessment collection may occur with the device implanted but may not begin until the VNS has been off for at least 30 days. The VNS generator must be explanted prior to or at the time of the DBS neurostimulator implant and the leads removed or trimmed and capped. In the case of a subject who had been previously implanted with a responsive neurostimulator (RNS) but had a full system explant, a subject cannot begin CMM study assessment collection until the RNS has been off for at least 30 days. * Risk factors that would put the participant at risk for intraoperative or postoperative bleeding. This includes administration of any antiplatelet or anticoagulant medication in the 7 days prior to surgery, chronic anticoagulant use, chronic aspirin use of greater than 325 mg/day, and any participant with a history of hemorrhagic stroke * History of drug or alcohol abuse within the past year * Condition or disease that is known to require repeat magnetic resonance imaging (MRIs) * Currently participating, or plans to participate, in another investigational study unless written approval is provided by the Medtronic study team Implant Criteria * Experienced an average of 6 or more focal (partial) onset seizures per month during CMM phase, with no more than 30 consecutive seizure-free days (all seizure types) * Completed a qualifying baseline diary. A qualifying baseline diary meets at least one the following criteria: 1) a study diary with at least 28 completed days; 2) a pre-existing diary with at least 70 completed days. * Completed 3-month CMM visit * No suicide attempt or other self-harm behaviors within past year (assessed by Columbia Suicide Severity Rating Scale (C-SSRS) at 3-month CMM Visit) * For female subjects of child-bearing potential, has negative pregnancy test and if sexually active continues using reliable form of birth control.