Development of an Integrated EEG/fNIRS Brain Function Monitoring System

Abstract

In this study, a fully integrated electroencephalogram/functional near-infrared spectroscopy (EEG/fNIRS) brain monitoring system was designed to fulfill the demand for a miniaturized, light-weight, low-power-consumption, and low-cost brain monitoring system as a potential tool with which to screen for brain diseases. The system is based on the ADS1298IPAG Analog Front-End (AFE) and can simultaneously acquire two-channel EEG signals with a sampling rate of 250 SPS and six-channel fNIRS signals with a sampling rate of 8 SPS. AFE is controlled by Teensy 3.2 and powered by a lithium polymer battery connected to two protection circuits and regulators. The acquired EEG and fNIRS signals are monitored and stored using a Graphical User Interface (GUI). The system was evaluated by implementing several tests to verify its ability to simultaneously acquire EEG and fNIRS signals. The implemented system can acquire EEG and fNIRS signals with a CMRR of −115 dB, power consumption of 0.75 mW/ch, system weight of 70.5 g, probe weight of 3.1 g, and a total cost of USD 130. The results proved that this system can be qualified as a low-cost, light-weight, low-power-consumption, and fully integrated EEG/fNIRS brain monitoring system.

Monitoring the Impact of Spaceflight on the Human Brain

“…This hybrid system can acquire and analyze multiple brain signals and provide a comprehensive picture of brain function that cannot be obtained with only one of the components. Combining two methods that represent two different physiological processes (neuronal electrical activity and the hemodynamic activity of the brain) allows to draw conclusions from the simultaneous real-time data [ 44 ].…”

“…In the clinical setting, measurement of cerebral oxygenation and autoregulation can be performed with fNIRS, although other applications of fNIRS are also transferable to deep space [ 44 , 83 ]. Technology has been developed that combines the use of an fNIRS device with that of an EEG for simultaneous brain monitoring.…”

“…Although this integrated EEG/fNIRS monitoring system is also low-cost and lightweight, it is fairly new, and it has not been tested for the purposes of spaceflight [ 45 ]. Conventional fNIRS is more established in analog and pre- and post-flight studies, though its ability to analyze different brain signals simultaneously may prove to be a useful tool for deep space research in the future [ 44 , 82 ].…”

“…Although NASA studies suggest that better designed headgear will reduce the variability in collected data, more work must be carried out to test fNIRS in deep space radiation environments [82]. In the clinical setting, measurement of cerebral oxygenation and autoregulation can be performed with fNIRS, although other applications of fNIRS are also transferable to deep space [44,83]. Technology has been developed that combines the use of an fNIRS device with that of an EEG for simultaneous brain monitoring.…”

Tablet-Based Wearable Patch Sensor Design for Continuous Cardiovascular System Monitoring in Postoperative Settings

“…To acquire the ECG signal, various lead systems can be used such as a single-lead system, a three-lead system, and a twelve-lead ECG system. Short distance ECG measurement using a three-lead system has been proven for its effectiveness and high-quality data acquisition [ 19 ], in which three electrodes are used and placed on the chest around the heart, two electrodes form a three-lead ECG system, and the third one is the right leg drive (RLD) electrode, which is used to improve the common mode rejection ratio (CMRR) by rejecting noise and interferences from external sources [ 20 ]. After sensing the signal from the electrodes, an acquisition circuit is required to amplify the signal to a level that can be detected by the controller and filtered from the noise that may corrupt the signal.…”