myBrain: a novel EEG embedded system for epilepsy monitoring

Abstract

The World Health Organisation has pointed that a successful health care delivery, requires effective medical devices as tools for prevention, diagnosis, treatment and rehabilitation. Several studies have concluded that longer monitoring periods and outpatient settings might increase diagnosis accuracy and success rate of treatment selection. The long-term monitoring of epileptic patients through electroencephalography (EEG) has been considered a powerful tool to improve the diagnosis, disease classification, and treatment of patients with such condition. This work presents the development of a wireless and wearable EEG acquisition platform suitable for both long-term and short-term monitoring in inpatient and outpatient settings. The developed platform features 32 passive dry electrodes, analogue-to-digital signal conversion with 24-bit resolution and a variable sampling frequency from 250 Hz to 1000 Hz per channel, embedded in a stand-alone module. A computer-on-module embedded system runs a Linux operating system that rules the interface between two software frameworks, which interact to satisfy the real-time constraints of signal acquisition as well as parallel recording, processing and wireless data transmission. A textile structure was developed to accommodate all components. Platform performance was evaluated in terms of hardware, software and signal quality. The electrodes were characterised through electrochemical impedance spectroscopy and the operating system performance running an epileptic discrimination algorithm was evaluated. Signal quality was thoroughly assessed in two different approaches: playback of EEG reference signals and benchmarking with a clinical-grade EEG system in alpha-wave replacement and steady-state visual evoked potential paradigms. The proposed platform seems to efficiently monitor epileptic patients in both inpatient and outpatient settings and paves the way to new ambulatory clinical regimens as well as non-clinical EEG applications.

Comparison between a wireless dry electrode EEG system with a conventional wired wet electrode EEG system for clinical applications

“…The recording system consists of dry electrodes with two spring-loaded silver pins per electrode (see also 19,22,32 for similar solutions), The pins are available in two different lengths (12 and 15 mm) to accommodate different head shapes and hair volume, thereby avoiding the need of a chin strap. The two-pins per electrode set up is in line with findings of a previous study 32 that systematically evaluated various dry electrode designs differing in the number of pins (referred to as 'fingers' in their paper) per electrode.…”

“…(2020) 10:5218 | https://doi.org/10.1038/s41598-020-62154-0www.nature.com/scientificreports www.nature.com/scientificreports/ by the aforementioned criteria and omitting the high pass and notch filtering mentioned above. Absolute spectral band power values were computed for the following frequency bands, which are typically reported in clinical EEG settings: Delta (1.5-4 Hz), Theta (4-8 Hz), Alpha (8-13 Hz), Beta(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30).…”

Systematic comparison between a wireless EEG system with dry electrodes and a wired EEG system with wet electrodes

“…In parallel, the appeal of dry electrodes has initiated considerable development of this technology in recent years. Several of the commercially available dry EEG systems used sensors comprised of metal pins (Guger et al, 2012; Käthner et al, 2017; Lo et al, 2016; Pinho et al, 2017; Toyama et al, 2012). Other materials, including silicon (Taheri et al, 1996; Yu et al, 2014) and foam (Lin et al, 2011) based sensors, have been proposed and are reported in recent reviews of EEG systems using dry electrodes (Liao et al, 2012; Lopez-Gordo et al, 2014).…”

Diagnostic and therapeutic yield of a patient-controlled portable EEG device with dry electrodes for home-monitoring neurological outpatients—rationale and protocol of the HOMEONE pilot study

“…Traditional EEG devices are not intended to be used in the home environment of patients, especially due to their immobility. To meet medical and technical requirements and the needs and expectations of patients and professionals, Pinho et al [ 1 ] summarize that EEG systems for outpatient care shall have the following features: “wireless connectivity, dry electrodes, signal resolution, sampling frequency, comfort, portability, signal artefact attenuation, event detection and event prediction” (p. 565). For the purposes of realizing the HOME project, we expand the list of necessary features by adding two additional needs: (1) an integrated and structured reporting system and (2) the full coverage of the 10–20 system for electrode placement.…”

“…For the purposes of realizing the HOME project, we expand the list of necessary features by adding two additional needs: (1) an integrated and structured reporting system and (2) the full coverage of the 10–20 system for electrode placement. There are several EEG devices on the market that meet (at least some of) these demands (e.g., [ 2 – 5 ]); other devices are in the developing process (e.g., [ 1 , 6 , 7 ]). The “Fourier One” 1 was developed to fulfill all demands and is, to the best of our knowledge, the first that meets all legal requirements (particularly with regard to CE certification) for the use in routine medical care and for home-monitoring.…”