Noninvasive Neural Prostheses Using Mobile and Wireless EEG

Abstract

Neural prosthetic technologies have helped many patients by restoring vision, hearing, or movement and relieving chronic pain or neurological disorders. While most neural prosthetic systems to date have used invasive or implantable devices for patients with inoperative or malfunctioning external body parts or internal organs, a much larger population of Bhealthy[ people who suffer episodic or progressive cognitive impairments in daily life can benefit from noninvasive neural prostheses. For example, reduced alertness, lack of attention, or poor decision-making during monotonous, routine tasks can have catastrophic consequences. This study proposes a noninvasive mobile prosthetic platform for continuously monitoring high-temporal resolution brain dynamics without requiring application of conductive gels on the scalp. The proposed system features dry microelectromechanical system electroencephalography sensors, low-power signal acquisition, amplification and digitization, wireless telemetry, online artifact cancellation, and signal processing. Its implications for neural prostheses are examined in two sample studies: 1) cognitive-state monitoring of participants performing realistic driving tasks in the virtualreality-based dynamic driving simulator and 2) the neural correlates of motion sickness in driving. The experimental results of these studies provide new insights into the understanding of complex brain functions of participants actively performing ordinary tasks in natural body positions and situations within real operational environments.

Knowledge-based identification of sleep stages based on two forehead electroencephalogram channels

“…Experimental results demonstrate the feasibility of using the proposed system as the preliminary screening results for a preclinical diagnosis to assist clinicians in making a diagnosis (rather having a depth testing with PSG system in a sleep laboratory) to reduce time for the procedure. Moreover, the proposed system only uses two forehead EEG signals, allowing us to apply the wearable and wireless EEG recording device (Lin et al, 2008; Liao et al, 2012) [e.g., Mindo-4S (Mindo, Hsinchu, Taiwan) and MindWave Mobile (NeuroSky, CA, USA)] in order to record the patient's EEG signals at home. Importantly, the proposed system provides an easier way for large population studies, long-term sleep monitoring, and home-based daily care.…”

“…FP1 and FP2 have the following advantages: the physiological data include information from sleep brain electrical activity and eye movement; and adopting the forehead EEGs makes it feasible for self-application for a self-operating user. With the portable EEG device (Lin et al, 2008) and dry sensors (Lin et al, 2011), home-based users can easily to wear the EEG headband to record the sleep forehead EEG signals by self-applicable. Furthermore, we can further analyze with the collected data can be analyzed further, even leading to the development of on-line sleep stage classification software.…”

“…A subject's sleep position may interfere with the wire, thereby degrading the EOG and ECG signal quality. Despite the persistent hair and conductive gel problems associated with EEG measurement, recent developments to resolve these problems include a headband and portable EEG recording device, as well as a dry polymer foam electrode for long-term EEG measurement (Lin et al, 2008, 2011). Additionally, physiological characteristics during sleep are more easily identified by EEG than by EOG and ECG, explaining why the former is preferred when classifying sleep stages.…”

“…Importantly, the proposed system provides preliminary results for diagnostic assistance and automatic ambulant scoring to determine whether a patient requires detailed testing with the PSG system in a sleep laboratory. Furthermore, the headband and portable EEG device as well as dry EEG electrodes (Lin et al, 2008, 2011) greatly facilitate the implementation of the proposed system in homecare setting for long-term monitoring of sleep quality, as well as for large-scale population studies.…”

Wearable Electroencephalography

“…These electrodes require no special preparation of the subject, are simply placed on the scalp, and can be easily held in place by a hat, readily accepted in social situations. Multiple potential methods have been investigated, e.g., ä stainless steel with various coatings for capacitive coupling of the EEG [25], [26] ä hybrid resistive-capacitive coupling of the EEG [27] ä carbon nanotube and micro electro mechanical systems electrodes based on piercing the outer layers of skin for better electrical conductivity [28], [29]. Undoubtedly, these electrodes have a big future, but there would still be the issue of keeping the electrodes in place over a long period of time: a hat cannot be worn 24 hours a day, seven days a week.…”