New Wearable Nanodevices Could Revolutionize What We Know About Sleep
Updated: Dec 15, 2022
Written by Jasper Lincoln '25
Edited by Lisa Liong '25
Image from Georgia Tech News 
As we age, our sleep quality deteriorates, and so do our brains. Throughout the day, your brain builds up metabolic waste from its high activity. If left to its own devices, this metabolic waste would damage the brain. However, during the process of sleeping the brain discards the waste and repairs itself for healthy function during the day . This is the reason sleep is so central to our health and why it is important to be aware of sleep quality.
Perhaps you have a Fitbit or Apple watch that notifies you how much sleep you’re getting. But of course, these sleep tracking devices aren’t perfect. Their estimates for the amount of sleep received can be off by multiple hours , and thus you won’t be using one to self diagnose whether you have a chronic sleep issue. For this, you’d have to go to the laboratory, which is equipped with all the instrumentation needed to study your sleep in high resolution. However, a visit to a laboratory is expensive, time consuming, and does not have the capacity to test the millions who have sleeping disorders. Thus, the ability to be diagnosed and treated for sleep disorders disproportionately favors those who can afford it . And in the case of obstructive sleep apnea (OSA), one of the most common sleep disorders, an estimated 80% of the 900 million people afflicted are undiagnosed . Obstructive sleep apnea is caused by the air passages in the throat narrowing or closing during sleep and overtime, like all sleep disorders, it can lead to health complications . In fact, OSA increases risk of stroke by 60%, risk of heart failure by 140%, the risk of coronary heart disease by 30%, and, along with other sleep disorders, has found to increase risk of Alzheimer's Disease and cognitive impairment by a factor between 1.55 and 3.78 compared to a control group .
Diagnosing whether one has a sleep disorder while awake is challenging, especially since its main symptom, loud snoring and exhaustion, can have many other causes. While the FDA has approved sleep apnea at home diagnosis test kits, the devices are difficult for the average consumer to use, have rigid materials that do not make perfect contact with the skin to make measurements, and thus the margins of failed diagnosis are about one in ten .
But soon, you may be able to track your sleep accurately without having to leave your home. Dr. Audrey Duarte and Dr. W. Hong Yeo of Georgia Tech are developing novel sleep tracking devices that use nanotechnology composed of intricate flexible circuitries that conform well with the skin for more accurate measurement and wearability. Professor Yeo developed a device that can be used to diagnose OSA. To use it, it simply needs to be placed on the chest to monitor the heart, respiration, blood oxygen content, and body position . Further, the devices link up with a smartphone just like a Fitbit or Apple watch, and thus with its greater accuracy, affordability, and simplicity over the alternatives may aid in diagnosing the hundreds of millions of undiagnosed cases of OSA.
But perhaps even more notably, Yeo and Duarte collaborated to develop another wireless device that tracks brain waves during sleep. Like the OSA diagnostic device, this device is intended to be commercially available, making it the first at home sleep monitoring system that measures brain waves . They propose to use these measurements in brain activity to allow for a whole new scale of research on the brain to study cognitive diseases like Alzheimer's Disease, that are associated with aging. Furthermore, their study of the sleeping brain may reveal biomarkers to give an early diagnosis of Alzheimer's Disease.
The reason cognitive health of the brain could be gauged by these devices is because of the unique state our brain enters while sleeping. When we are in deep sleep, our brain slips into a state known as slow-wave sleep, which is composed of slow oscillating brian waves. These oscillations are composed of neuronal firing from an “Up” or active state to a low activity silent “Down” state. These cycles are named slow oscillations because they are just that, each cycle lasts about a second, and they are so rudimentary to our brain that they are even observed in slabs of brain in a petri-dish that are entirely separated from the body and in the absence of any stimulation . They are the default state that our brain is in when it has essentially been disconnected from the rest of the world. The essence of detecting and studying Alzheimers through these slow oscillations is that the degeneration of the brain associated with Alzheimers affects the behavior of the oscillations. The long range coherence of the slow oscillations–how synchronized in phase two distance signals within the brain are–is dramatically reduced in brains with Alzheimers, as observed in studies with mice . To take this further, Duarte and Yeo will be studying this in humans with their novel devices.
Because of their simplicity and accuracy of their devices, Duarte and Yeo will be able to study our brains during sleep at a larger scale than before. With enough collected data and research, these devices may function as instruments to diagnose Alzheimers earlier than ever before. Consequently, this gives patients with the early diagnosis the chance to undergo treatment to slow the progress of the disease. Whether it is aiding millions in diagnosing obstructive sleep apnea, studying asleep brain activity at enormous scales, or diagnosing Alzheimers at an earlier stage than ever before, Dr. Duarte and Dr. Yeo may revolutionize how we study sleep, our brains, and preventative care for age related cognitive impairment.
 Catching Z’s, Capturing Data: Researchers Create DIY Device for Monitoring Sleep Patterns | College of Sciences | Georgia Institute of Technology | Atlanta, GA n.d. https://cos.gatech.edu/news/catching-zs-capturing-data-researchers-create-diy-device-monitoring-sleep-patterns (accessed November 13, 2022).
 Giacopuzzi A. Joe Rogan Interviews Sleep Expert Matthew Walker, PHD. SoundOff Sleep Earbuds 2020. https://soundoffsleep.com/joe-rogan-interviews-sleep-expert-matthew-walker-phd/ (accessed November 13, 2022).
 I Wore Six Sleep Trackers for Two Weeks. Here’s What I Learned About Getting Better Sleep. Consumer Reports n.d. https://www.consumerreports.org/sleeping/sleep-trackers-for-better-sleep-what-i-learned-a7533450811/ (accessed November 13, 2022).
 Zavanelli N, Kim H, Kim J, Herbert R, Mahmood M, Kim Y-S, et al. At-home wireless monitoring of acute hemodynamic disturbances to detect sleep apnea and sleep stages via a soft sternal patch. Sci Adv n.d.;7:eabl4146. https://doi.org/10.1126/sciadv.abl4146.
 Obstructive sleep apnea - Symptoms and causes. Mayo Clinic n.d. https://www.mayoclinic.org/diseases-conditions/obstructive-sleep-apnea/symptoms-causes/syc-20352090 (accessed November 13, 2022).
 Andrade A, Bubu OM, Varga AW, Osorio RS. The relationship between Obstructive Sleep Apnea and Alzheimer’s Disease. J Alzheimers Dis 2018;64:S255–70. https://doi.org/10.3233/JAD-179936.
 Sanchez-Vives MV, Massimini M, Mattia M. Shaping the Default Activity Pattern of the Cortical Network. Neuron 2017;94:993–1001. https://doi.org/10.1016/j.neuron.2017.05.015.