closed-loop system using transcranial direct current stimulation (tdcs) for epilepsy

Conditions: Epilepsy; Seizures

Summary: in this pilot study, the researchers investigated the feasibility of a closed-loop electroencephalography (eeg) / transcranial direct current stimulation (tdcs) system for treatment of epilepsy. they looked to see the feasibility of triggering tdcs stimulation within 10 seconds of a detected eeg partial-onset seizure, and also a proof-of-principle determination of whether tdcs applied during this vulnerable period may be feasible to prevent the oncoming seizure. this study required 5 visits over the course of approximately 8 weeks. each visit was separated by at least 2 weeks. two of the visits had 24-hour eeg monitoring sessions. during these two sessions, the eeg and tdcs were hooked into a closed loop system, such that when seizure activity wasdetected, the tdcs was triggered to deliver stimulation. subjects received active stimulation or sham stimulation sessions during the first 24-hour visit, and the opposite during the second. the subjects were randomized and counterbalanced. we have also added a healthy subjects cohort to assess the feasibility of the closed loop system. in order to test the proof-of-concept of this system, the experiment will focus on detecting and acting upon alpha- and beta-band changes traced in the eeg activity that is being recorded, and provide tdcs stimulation based upon those changes. we will enroll 6 subjects who will have 2 visits each. during these two visits subjects will be randomized to active or sham stimulation sessions and receive the opposite during their second visit.


Eligibility criteria:
inclusion criteria (epileptics) * disabling motor simple partial seizures, complex partial seizures, and/or secondarily generalized seizures. disabling refers to seizures that are severe enough to significantly impair functional abilities in areas such as employment, psychological or social wellbeing, education or mobility. * failed treatment with a minimum of two antiepileptic medications. * experienced an average of three or more disabling simple weekly partial seizures, complex partial seizures and/or secondarily generalized seizures. * between the ages of 18 and 70 years. * no more than two epileptogenic regions in the brain. * must be able to provide informed consent themselves. exclusion criteria * has a progressive neurological or systemic disease. * has a history of nonepileptic seizures. * has an implanted metallic device, aneurysm clips, cochlear implants, or spinal cord stimulator. * has suffered a severe traumatic brain injury with skull fracture. * contraindications to tdcs * metal in the head * implanted brain medical devices * pregnancy * any implanted electrical medical device, including pacers and implanted cardiac defibrillators inclusion criteria (healthy subjects) - healthy subjects age 18 and older exclusion criteria: * existence of major neurologic or psychiatric condition (i.e. epilepsy, severe depression) * history of head injury resulting in more than a momentary loss of consciousness * previous neurosurgery * a history of significant alcohol or drug abuse in the prior 6 months * presence of unstable medical conditions, such as; uncontrolled diabetes mellitus, cardiac pathology, cancer, kidney insufficiency, acute thrombosis * contraindication to tdcs * metal in the head * implanted electronic medical devices * pregnancy

Keywords: transcranial direct current stimulation electroencephalography