Sensing eye mask could provide insight into sleeping patterns
Image credit: Leonidikan/Dreamstime
Researchers in the US have developed a lightweight mask that can unobtrusively capture pulse, eye movement, and sleep signals.
The wearable soft mask was developed by a team at the University of Massachusetts (UMass) Amherst and builds upon a previous project that resulted in physiology-sensing pyjamas. Its creators said being able to track pulse and eye movement in a single wearable device will enable a host of sleep and psycho-social studies, in addition to improving the accuracy and usability of gaming and virtual-reality headsets.
According to Wearable Electronics Lab director Trisha L Andrew, recording health and behaviour signals on or near the face is challenging “because most people are really sensitive and reactive to objects placed on their face or head”. Computer scientist Deepak Ganesan added: “Up to now, integrating many different sensing elements in one garment seemed burdensome, especially when it comes to small eye masks.”
They said their lightweight, tailorable eye mask named 'Chesma' is fitted with two kinds of fabric electrodes that can simply be sewn onto a variety of pre-made garments and further miniaturised, if desired. This capability allows them to integrate electrodes into a lightweight foam mask for recording electro-oculography and cardiac signals. Their design automatically positions the electrodes on the face with no need for custom fitting.
PhD student S Zohreh Homayounfar explained that the mask contains five silver (Ag) thread-based hydrogel electrodes – dubbed tAgTrodes – needed to translate ion-based biological signals into an electric current, among other goals. The researchers also used a vapor-phase deposition process to create the electrodes, including what they call a first-of-its-kind reusable and washable hydrogel component that distinguishes the tAgTrode from other equivalents.
The mask also contains one fabric pressure sensor (PressION) positioned over an artery to monitor pulse as a proxy for cardiac function, with the whole mask linked to two microcontrollers with water-repellant silver threads as connectors.
“The electrode and sensor data need to be communicated once they are acquired,” PhD student Ali Kiaghadi explained. “Our design transmits raw data to the cloud for processing and data visualisation, so that we can reduce the amount of instrumentation that we need to include in the mask itself.”
The team tested the new eye mask on subjects while they were chewing, talking, and during various head and eye movements. They also used the same device for more than a year and after 15 washes found no degradation in performance.
Homayounfar noted that the tAgTrode “overcomes all the drawbacks of commercial wet electrodes such as aesthetic issues, discomfort and wash-stability while maintaining high and constant signal-to-noise ratios during repeated, long-term applications”.
Andrew expects that Chesma’s “unique bimodality” – the combination of electrode network with the pressure sensor – will enable many new cutting-edge studies, not possible until now, for investigating sleep quality, sleep disorders, mental health, neurodegenerative diseases, and schizophrenia, for example.
Sign up to the E&T News e-mail to get great stories like this delivered to your inbox every day.