'Smart' pajamas give new insight into sleep habits

Known as "Phyjama", the jersey can be used to monitor the quality of the wearer's sleep, such as the amount of REM sleep they get, which occurs occasionally during the night and is characterized by quick eye movements, dreams and body movements or if they have breathing problems during the night.

Five light sensors are sewn into the lining of the shirt. Four of them detect constant pressure, such as that of a body pressed against a bed. The fifth, placed on the chest, detects rapid changes in pressure, providing information on heart rate and breathing.

The sensors are connected by threads finely coated with silver. "They are sewn on the seams of the shirt, so you will not see them," said Dr. Trisha Andrew, director of UMass Amherst's Wearable Electronics Lab.

The signals collected from the five patches are sent to a tiny circuit board resembling an ordinary pajama button. The button has a built-in Bluetooth transmitter that sends wireless data to a computer for analysis.

"Smart clothing with built-in self-powered sensors can revolutionize the monitoring of human behavior by using everyday clothing as a sensing substrate," said Andrew.

"Our smart pajamas faced a lot of technical challenges," she added. "We had to discreetly integrate sensing elements and portable power supplies into everyday clothing, while maintaining the weight, feel, comfort, functionality and robustness of familiar clothing and fabrics." .

"We have also worked with computer scientists and electrical engineers to process the myriad signals from sensors to provide clear, easy-to-understand information."

According to the US National Institutes of Health, getting enough sleep can help protect people from stress, infections and multiple diseases, such as heart and kidney disease, high blood pressure and diabetes.

Previous studies have shown that sleep quality also increases mental acuity and strengthens decision-making abilities. However, most people do not sleep enough or are not the type.

Some smart mattress manufacturers claim that products can detect movement and induce sleep posture. However, these mattresses do not provide detailed information about the bed and are not portable for travel.

To overcome this problem, commercially available electronic tapes, such as Fitbit or Apple Watch, worn on the wrist provide information on heart rate and control the total sleep time of the user.

The UMass Amherst team, however, is developing its own solutions.

"We are using a reactive vapor-phase coating to turn fabric, thread or standard fabricated garments into a plethora of easy-to-wear electronic devices," said Dr. Andrew.

These novel patches are used in different parts of the pajamas, so that the researcher can determine the sleep posture. In addition, the patches detect rapid changes in pressure, such as the physical pumping of the heart, which provides heart rate information, which is the first time that a sensor of this type detects tiny signals from the heart .

The pajama shirt is still in its infancy and has been tested overnight on only eight people. In addition, the team always ensures that sensors are accurate for different body shapes and heights.

Andrew says that the jersey can not yet be used to diagnose medical problems, but the goal is to eventually replace sleep studies in the laboratory where participants are connected to different machines overnight, using the pajamas as an alternative to testing.

The technology is being extended to include portable electronic sensors to detect gait and send information to a monitor to prevent falls among residents of care facilities and sheltered accommodations.