Concurrent electroencephalography (EEG) and new tripolar EEG (tEEG) will be recorded from adult and pediatric patients. In some patients stereo EEG (sEEG) will also be recorded concurrently.

This study is a prospective observational study of the clinical utility (usability + accuracy) and safety of a novel EEG diagnostic device, the Tripolar Concentric Ring Electrode (TCE), that will be used to record the tripolar electroencephalogram (tEEG). The major objectives of the proposed studies will be to compare the recording qualities of the standard scalp EEG and intracranial stereo-EEG (sEEG), in preparation for obtaining FDA clearance for the TCRE and the tEEG technique. tEEG resolves the fundamental drawbacks of conventional EEG, providing significant improvement in signal fidelity, spatial resolution, and registering of higher frequency brain activities. In this project, a comparison of the safety, ease of use, and accuracy of the TCRE device to standard EEG and intracranial sEEG recordings in patients with epilepsy will be performed. An overview of the proposed studies are as follows:

Milestone 1: Simultaneous tEEG and EEG will be recorded in the outpatient clinical EEG lab. Per recording, tEEG and gold standard scalp EEG will be compared in 30-minute studies, examining a) usability (i.e., ease of application, time for electrode application, and subject ratings of comfort), b) EEG data quality, and c) accuracy of blinded analysis of common EEG patterns, including epileptiform activity.

Milestone 2: Data collected will be analyzed in Milestone 2, to assess the ability of tEEG to suppress commonly encountered EEG artifacts, by comparing blinded analysis of tEEG to the gold standard scalp EEG.

Milestone 3: Simultaneous tEEG and EEG will be collected in the inpatient epilepsy monitoring unit. It is anticipated that recordings will last 24-120 hours. From these data, a comparison of the sensitivity and accuracy of tEEG and scalp EEG for detection of seizures and high-frequency oscillations (HFOs) will be performed in long-term (24 hours to 120 hours) studies in subjects undergoing continuous video-EEG monitoring in the Epilepsy Monitoring Unit.

Milestone 4: A comparison of the accuracy of tEEG, to gold standard intracranial sEEG for seizure and high frequency oscillation (HFO) localization, will be performed in patients undergoing invasive diagnostic evaluation for epilepsy surgery.

In all instances, tEEG and EEG data will be interpreted by board-certified clinical neurophysiologists. This project is a collaborative project where data will be collected separately from pediatric and adult participants. The project leadership team are; study PI, Dr. Walter Besio from CREmedical, Boston Children's Hospital site PI, Dr. Alexander Rotenberg, and Barrow Neurological Institute (Phoenix, AZ) site PI, Dr. Susan Herman.

Inclusion Criteria:

• Pediatric (BCH): Age ≥ 6 years and < 18 years
• Adult (BNI): Age ≥ 18 years
• Able to provide written informed consent or have a legally authorized representative able to provide consent; pediatric patients to provide assent when appropriate
• Scheduled for routine outpatient EEG for clinical diagnosis
• Able to participate in a post-EEG telemedicine video visit
• Clinical diagnosis of epilepsy with epileptiform discharges on prior routine EEG
• Scheduled for inpatient video-EEG monitoring for clinical diagnosis
• MRI of brain available for co-registration
• Confirmed diagnosis of focal epilepsy by prior video-EEG monitoring interpreted by board-certified epileptologist or clinical neurophysiologist
• Scheduled for inpatient video-EEG monitoring with intracranial stereo-EEG electrodes for epilepsy presurgical evaluation
• MRI of brain available for co-registration

Exclusion criteria

• Presence of a condition or abnormality that in the opinion of the Investigator would compromise the safety of the subject or the integrity of the data
• Any clinical suspicion of prion disease
• History of allergy or adverse reaction to EEG electrode paste or gel
• Scalp lesions or infections
• Severe intellectual disability or behavioral disorders with inability to cooperate with EEG application or recording

Pediatric and adult patients either suspected of, or having epilepsy.

Once we publish our results we will make the data from the study available to other researchers.

Once we publish the results.

We intend to post the data on the BRAIN Initiative data sharing website. Researchers that have access to the website can access the data.