Not many people fancy the idea of spending the night in a sleep clinic with multiple electrodes stuck to their skin. That's why scientists have developed a smart pajama top that assesses sleep disorders while its wearer comfortably slumbers at home.
When it comes to diagnosing sleep problems, the gold standard is a process known as polysomnography. It typically requires the patient to sleep through the night on a bed in a laboratory, while wired up with electrodes that monitor body functions such as brain activity, eye movements, heart rhythm and muscle activity.
Needless to say, this is a hassle for the patient, who may not sleep as they normally do due to the uncomfortable electrodes and unfamiliar setting. Additionally, the sleep data is only collected over one or just a few nights.
One alternative involves utilizing portable sleep-monitoring systems that can be used over the course of many nights in the patient's own home. These are typically optimized for detecting and assessing sleep apnea, however, so they may miss other disorders.
Wearable devices such as specialized smartwatches or wristbands are another alternative, but they often don't capture as much physiological data as the other two options. That brings us to the smart PJ top.
Developed by Prof. Luigi Occhipinti and colleagues at the University of Cambridge, the washable garment features an array of graphene strain sensors printed onto its collar. Those sensors detect the subtle vibrations that are transmitted to the extrinsic laryngeal muscles (in the neck) from other anatomical locations including the velum, oropharynx, tongue, and epiglottis.
That data is wirelessly transmitted to a nearby device such as a smartphone, where it's processed by the machine-learning-based SleepNet program.
The software is in turn able to identify six healthy, sub-healthy and unhealthy sleep states including nasal breathing, mouth breathing, snoring, teeth grinding, central sleep apnea and obstructive sleep apnea. When SleepNet was used to process pajama-top data gathered from seven healthy volunteers and two with sleep apnea, it proved to be 98.6% accurate at detecting the different sleep states.
Importantly, the system is not thrown off by the regular tossing and turning motions that wearers make throughout the night. Additionally, its collar fits relatively loosely around the neck, so it's not uncomfortably tight.
"Sleep is so important to health, and reliable sleep monitoring can be key in preventative care," says Occhipinti. "Since this garment can be used at home, rather than in a hospital or clinic, it can alert users to changes in their sleep that they can then discuss with their doctor."
A paper on the research, which also involved scientists from Capital Medical University (Beijing) and Beihang University, was recently published in the journal PNAS.
Source: University of Cambridge