Abstracts

Rationale: Over 1.2 million people in the US with epilepsy have intractable seizures, which are an immense financial and personal burden to the person with epilepsy and their family. To optimize treatment after initial diagnosis, epileptologists would ideally obtain high-quality, long-term EEG in the hospital with 26-channel wired EEG in the '10-20' montage. This is rarely done because the process is prohibitively expensive, time consuming, and extremely inconvenient for patients.. The current state-of-the-art for recording that seizure activity outside of the hospital is the seizure diary, a home-based, self-reported, incomplete record. Unfortunately, seizure diaries are difficult to maintain accurately, under-report non-convulsive seizures, and importantly, miss any records of seizures that occur during sleep. Thus, the diary can be inaccurate, confounding clinical decisions on appropriate pharmacological treatment. Better clinical decisions could be made if there were an easy-to-use EEG recording technology that enables continuous seizure tracking in the everyday home environment. Methods: Epitel has developed the EEG PatchTM, an inexpensive, waterproof, 1-channel (2-electrode), discrete EEG machine. The EEG Patch is 30x30x6 mm; it transmits and logs continuous EEG data for 7 days on a single charge (3 V, 1.14 mA; 3.42 mW). EEG is amplified and recorded on the device with bandwidth of 0.2 ?" 120 Hz, 8 dB per octave. The EEG Patch is currently being used in a feasibility clinical trial at the University of Colorado Anschutz Medical Center. Patients entering the epilepsy monitoring unit are monitored with video-EEG for 3-7 days. The EEG Patch is placed in four locations between wired EEG electrodes in the standard 10-20 montage where simultaneous recordings are made with the goal of capturing two or more seizures during the patient's stay in the unit. Seizure times from standard-of-care review are used to strip out 5-min epochs of single-channel wired and EEG Patch data along with "catch" trials of random non-seizure epochs. These data are then shuffled and presented serially through a custom user interface to epileptologists blinded to how the data were recorded. Given each 5-min epoch, the epileptologists are asked to identify the epoch as having the electrographic representation of a seizure or no seizure activity. Results: EEG Patch recording from an initial 14 patients have included 30 electrographic seizures from 10 individuals identified through standard-of-care review of video EEG. Data are from 56 individual, single-channel EEG Patches. We will present the results of single-channel analysis of wired and EEG Patch data using these identified seizure epochs as the "gold standard". Our initial, limited blinded "test" of the first generation single-channel review interface from a single epileptologist resulted in 80% correct seizure identification. These data will be run again after 20, 40, and 60 patients have been enrolled using multiple epileptologists blinded to the single-channel data. Conclusions: In this feasibility study, we have initial evidence that a single-channel of EEG can be used to identify electrographic seizure activity. The EEG Patch is capable of recording seizure activity as well as wired EEG and is tolerable for entirety of the patient's stay in the epilepsy monitoring unit. The next step, following feasibility, is to take the EEG Patch out of the clinic to be used alongside ambulatory EEG in the user's home environment. We will compare seizure diaries with electrographic seizure activity identified on the wired ambulatory EEG, as well as, the EEG Patch. This study will determine the suitability of the EEG Patch as a seizure counting tool capable of augmenting seizure diaries. Funding: The Epilepsy Foundation