Flexible EEG Headband with Artifact Reduction and Continuous Electrode Skin Impedance Monitoring for Neurological Disorders

For the treatment and early diagnosis of complex neurological disorders, continuous 24/7 electroencephalogram (EEG) monitoring is necessary. However, present neural recording systems are cumbersome, contain complex leads and rigid electrodes, need rigorous preparatory procedures, require skin preparation, and lack the electrode skin impedance (ESI) measuring unit. To overcome these issues, we present a novel flexible headband for acquiring EEG continuously via active dry electrodes (flexible). It is a four differential channel EEG measurement system and is composed of four flexible polyimide layers. The top layer consists of an EEG measurement circuit while the bottom layer incorporates the gold-printed electrodes along with the middle layers comprising active shielding and ground plane layers, achieving the smallest possible form factor resulting in active electrode topology. The presented EEG head-band contains an Analog Front End for acquiring filtered EEG, a Back End for digitizing and transmitting data wirelessly, and ESI measuring circuitry. Off-the-shelf components were used to develop a fully functioning flex PCB prototype having dimensions of 160mm by 24mm and weighing only 0.3 ounces. Along with ESI measurement, various EEG verification tests such as saccade eye movement, visual evoked potential, and eye blinks were performed to verify the acquired EEG data from the headband.