Development of a discrete, wearable, EEG device for counting seizures
December 06, 2015
Mark Lehmkuhle, Michael Elwood, Jean Wheeler, John Fisher, F. Edward Dudek
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. Optimal treatment depends on identifying the full extent of a patient’s convulsive and non-convulsive seizure activity. 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: Towards this goal, we have developed an inexpensive, waterproof, 1-channel (2-electrode), discrete EEG monitoring device called the EEG PatchTM. The waterproof design provides users with freedom of mobility in daily activities such as bathing, sports, and sleep during continuous EEG monitoring. The EEG Patch is discrete, unobtrusive, and disposable with electrode spacing based on the classic wired EEG in the ’10-20’ montage. The EEG Patch simultaneously logs and transmits EEG in real time. The EEG can be downloaded off of the device at any time for review in the standard European Data Format. A small handheld device can be used to wirelessly observe the EEG signal in real time as a means to spot-check signal quality.Results: 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 compact technology reduces electrical and movement artifacts, common in wired, “ambulatory” EEG. The device is placed on the scalp by an epileptologist at a selected location where seizures are known to manifest in the wired EEG record during a traditional diagnosis of epilepsy.Conclusions: We have developed a self-contained, EEG-based device that is capable of continuously tracking seizures for 7 days and is robust enough for at-home use. The device will be validated against the gold-standard wired EEG in the EEG long-term monitoring unit. Armed with 7 day, location-specific EEG data, an epileptologist will have a robust record of quantitative seizure counts to better treat patients, revolutionizing therapy.