A smart ring that generates continuous temperature data may foreshadow COVID-19, even in cases when infection is not suspected.
The device, which may be a better illness indicator than a thermometer, could lead to earlier isolation and testing, curbing the spread of infectious diseases, according to a preliminary study led by UC San Francisco and UC San Diego.
An analysis of data from 50 people previously infected with COVID-19, published online in the peer-reviewed journal Scientific Reports on Dec. 14, 2020, found that data obtained from the commercially available smart ring accurately identified higher temperatures in people with symptoms of COVID-19.
While it is not known how effectively the smart ring can detect asymptomatic COVID-19, which affects between 10 percent to 70 percent of those infected according to the Centers for Disease Control and Prevention, the authors reported that for 38 of the 50 participants, fever was identified when symptoms were unreported or even unnoticed.
Of note, the researchers analyzed weeks of temperature data to determine typical ranges for each of the 50 participants. “Many factors impact body temperature,” said principal investigator and senior author Ashley Mason, Ph.D., assistant professor in the UCSF Department of Psychiatry and faculty at the Osher Center for Integrative Medicine.
“Single-point temperature measurement is not very meaningful. People go in and out of fever, and a temperature that is clearly elevated for one person may not be a major aberration for another person. Continual temperature information can better identify fever.”
According to co-author Frederick Hecht, MD, professor of medicine and director of research at the UCSF Osher Center for Integrative Medicine, this work is “important for showing the potential of wearable devices in early detection of COVID-19, as well as other infectious diseases.”
Asymptomatic Illness or Illness with Unreported/Unnoticed Symptoms?
While the number of study participants was too small to extrapolate for the whole population, the authors said they were encouraged that the smart ring detected illness when symptoms were subtle or unnoticed.
“This raises the question of how many asymptomatic cases are truly asymptomatic and how many might just be unnoticed or unreported,” said first author Benjamin Smarr, Ph.D., an assistant professor in the Department of Bioengineering and the Halicio?lu Data Science Institute at UC San Diego. “By using wearable technology, we’re able to query the body directly.”
To conduct the study, the researchers used the Oura Ring, a wearable sensor made by the Finnish startup Oura, which pairs to a mobile app. The ring continuously measures sleep and wakefulness, heart and respiratory rates, and temperature.
The researchers provided the rings to nearly 3,400 health care workers across the U.S., and worked with Oura to invite existing users to participate in the study via the Oura app, resulting in enrollment of more than 65,000 participants worldwide in a now concluded prospective, observational study, which the UC researchers are preparing for publication.
The participants in the preliminary study reported that they had previously been infected with COVID-19.
A continuous record of their biomonitoring data was still available for analysis from the weeks before their infection, through the time of enrollment until the end of the study.
No-touch thermometers that detect infrared radiation from the forehead are used to quickly screen for fever in airports and offices and are believed to detect some COVID-19 cases, but many studies suggest their value is limited.
The ring records temperature all the time, so each measurement is contextualized by the history of that individual, making relative elevations much easier to spot. “Context matters in temperature assessment,” Smarr emphasized.
Heart Rate, Respiration Rate Provide Other Clues
Other illness-associated changes that the rings detect included increased heart rate, reduced heart rate variability and increased respiration rate, but these changes were not as strongly correlated, the authors noted.
The researchers are using data from the larger, prospective study to develop an algorithm from data collected by wearable devices that can identify when it appears that the user is becoming sick. Mason’s team can then trigger a request for the user to complete with a self-collection COVID-19 test kit.
The researchers will evaluate the algorithm in a new study of 4,000 additional participants.
“The hope is that people infected with COVID will be able to prepare and isolate sooner, call their doctor sooner, notify any folks they’ve been in contact with sooner, and not spread the virus,” Mason said.
The global pandemic requires a global response. The researcher, doctors, engineers are trying their best to stop totally or to reduce the danger of this pandemic [15, 16]. As the vaccine for the novel coronavirus is still under trial, efforts should be focused on preventing the spread of the virus.
In the present era of artificial intelligence (AI) [17–20], the new technologies can play a vital role to assist the world against the pandemic. Wearable technology that can collect a wide range of data such as heart rate, blood pressure, body temperature, ECG, lung sound, blood oxygen saturation (SpO2) level, etc. may help a great extent in preventing the spread of the infectious coronavirus .
The healthcare system with wearable technology allows a surgeon to monitor infected or probable patients, assess the health risk, and forecast future conditions remotely [22, 23]. During the quarantine or self-treatment period, a person/patient can be fully monitored by a doctor with the help of wearable technology.
This also provides an opportunity for remote treatment and puts the healthcare workers at a lesser risk of infection. Furthermore, a study related to coronavirus transmission with skilled nursing facilities indicated that the asymptotic rate of transmission was 56% (27 out of 57), among them, 90% shows symptoms subsequently.
From this scenario, it is obvious that the symptom-based screening method may fail to detect more than 50% of people affected by COVID-19. The continuous data monitoring generated by wearable technology can overcome these challenges.
The wearable technology has to be enriched for the following reasons:
- (i) to monitor remotely the status of the health of a coronavirus infected patients or self-quarantined individuals who are taking treatment in a personal room.
- (ii) Forecasting the risk of the vulnerable people who are under the critical zone regarding COVID-19. The early screening will assist in reducing the infection rate significantly.
- (iii) To decrease the transmission rate of infectious COVID-19 among the surgeons, caregivers, and hospital management personnel and patients of other diseases as wearable technology allows the surgeons and caregivers to check patients in real-time.
- (iv) To ensure service delivery of telehealth and Internet of Medical Thing (IoMT) technologies to fight against COVID-19 as without the patient data produced by wearable technology, the telehealth system, or IoMT or any other intelligent medical system cannot perform effectively.
This paper aims to describe the impact of the relevant wearable technology that helps to fight against the pandemic COVID-19. The entire review work is categorized in two directions:
- (i) initial symptoms monitoring systems for COVID-19
- (ii) respiratory support systems for COVID-19 infected patients.
All the developed systems are demonstrated in terms of types of services, working functionalities, relative cost as well as merits and demerits of the current systems. The challenges faced by existing systems as well as potential future works are also drawn.
The rest of the paper is as follows. The supportive wearable devices for assisting COVID-19 patients are reviewed in Sect. “Supportive Wearable Devices for COVID-19 Patients”. Section “Discussions” discusses the reviewed systems, their limitations, and some future directions. Finally, Sect. “Conclusion” presents the concluding remarks.
Basic Symptoms Monitoring Systems for COVID-19
The term wearable technology represents the intelligent electronic devices that are worn on the body for assessing, evaluating, and transferring different types of data. The data can be, for example, different types of signals related to the body and physical activity.
The wearable technology performs a substantial role in the detection of COVID-19 symptoms to assist the patients infected by this novel virus.
There are three signs which are considered as primary coronavirus symptoms:
- (i) respiratory distress/difficulty
- (ii) fever and
- (iii) coughing  which are universal to all the clinical demonstrations of COVID-19.
The person who is infected by this virus has a respiratory rate (RR) ≥ 20 breaths/min (bpm), body temperature ≥ 38 °C, (iv) pulse rate > 100 beats/min in general [25, 26].
Hence, it is crucial to assess respiratory, cardiovascular monitoring, and evaluation of other parameters such as body temperature, oxygen saturation (SpO2). Using wearable sensors, the necessary assessment, monitoring, and evaluation of parameters are performed very easily, effectively, and cost-efficiently. The systems that are developed for basic signs monitoring for COVID-19 infected patients are described as follows.
Respiration Rate Monitoring
Respiration rate for respiratory assessment is one of the most crucial parameters in COVID-19 infection detection as the virus has a severe effect on the lungs area. COVID-19 shows a lower-respiratory tract infection that causes disorder in lung tissue, shortness of breath, and coughing .
The patient who has serious respiratory difficulty has a respiration rate ≥ 30 breaths/min that can lead to acute respiratory distress syndrome (ARDS) . Real-time and continuous assessment of RR is very important for monitoring the current condition, progression, and treatment of the patients infected with COVID-19.
A group of researchers has already proposed wearable devices that are mounted on the chest  or put on the skin  to measure the RR and these devices are useful for monitoring COVID-19 patients. Accelerometer-based sensors, triboelectric sensors, and wearable strain gauge sensors are used to measure the RR and provides satisfactory results.
But patients may not feel comfortable wearing these types of belts. RR can be assessed by monitoring the variations in body temperature, humidity, and CO2 using wearable devices. Using the airflow-sensing method, researchers have proposed many wearable devices that used nasal or oronasal thermistor, a humidity sensor and a CO2 sensor that identifies the temperature/humidity/CO2 changes between the inhaled and exhaled air.
For instance, Liu et al.  proposed a RR system that is used to be placed on the upper lip which is mainly a flexible epidermal respiratory system based on the thermal convection. Dai et al.  introduced a polyelectrolyte humidity sensor, a particular type of humidity sensor that can be attached to a facial mask which is widely used during the COVID-19 pandemic.
But the system may not be suitable for the patients and the movement of the sensor may influence the accuracy. RR can also be measured by electrocardiography (ECG) and photoplethysmogram (PPG) which can be easily obtained by wearable devices. Charlton et al.  proposed a system for RR estimation from ECG and PPG  which increased the estimation accuracy.
The benefit of the system is that it can be incorporated into commercial wearable devices, thus adding RR monitoring functionality in existing systems. Hence, this technology would be very efficient for COVID-19 patients to monitor their RR during this current pandemic situation.
Heart Rate Monitoring
COVID-19 can significantly affect heart function and lead to myocardial injury which may irreparably damage the cardiovascular system . Viral illness due to the COVID-19 increases physiological stress on the body which typically manifests as an overall increase in heart rate (HR). Wearable devices are used to monitor the HR of COVID-19 patients as they are very convenient and cost-effective.
A piezoresistive sensor based wearable device for monitoring heart rate was proposed by Quy et al. . The device monitors the heart rate in real-time. It is very cost-effective, small, and has high accuracy. Besides other clinical uses, this device can be used for COVID-19 patients. Shahshahani et al.  developed an ultrasound sensor based wearable device for heart rate monitoring.
But the piezo sensor of the device is supposed to place perpendicular to the heart for achieving better accuracy. This device monitors the heart rate in real-time as well as ECG signals which is very helpful for COVID-19 patients nursing. Tamilselvi et al.  proposed a system for health monitoring that can monitor primary metrics of a patient such as body temperature, heart rate, eye movement, and percentage of oxygen saturation.
For this purpose, the system integrated heartbeat, SpO2, temperature, and eye blink sensors for data collection and Arduino-UNO as a processing device. As this system is IoT based, doctors can monitor the COVID-19 patients remotely. Banerjee et al.  proposed a non-invasive technique based pulse rate detection system.
The system applied the plethysmography process and consistently exhibited the result digitally in a real-time monitoring device. The device provides a reliable heart rate monitoring system for COVID-19 patients as it is better than other contemporary invasive techniques based devices.
Temperature measurement is exceptionally essential for COVID-19 detection and has been broadly used by many countries as an instant test to determine if travellers or citizens have been infected with COVID-19. While quarantining people with fever may prevent spread to some point, this method for body temperature monitoring is not adequate as COVID-19 can be spread before the fever grows.
The continuous monitoring of skin temperature can be a good approach in this regard which is currently used by some hospitals . Wearable devices are considered as an efficient solution for this purpose. Many researchers have already proposed wearable devices for continuous body temperature monitoring which can be used for COVID-19 patients.
Song et al.  proposed a wearable system based on multiple artificial neural networks which monitors the body temperature very precisely with shorter reaction time. Liu et al.  proposed a wearable device as a physiological monitoring system that monitors body temperature, ECG, blood glucose, blood pressure, and some other physiological parameters.
The device is very small in size, easy to use, and specially developed for home application which can be used for COVID-19 patients. During this pandemic, infants can also be infected by the COVID-19. Zakaria et al.  developed an IoT based body temperature monitoring, especially for infants.
The device is very small in size, lightweight, and continuously monitors the body temperature and comfortably used by the baby. Another IoT based device named Health Companion using wearable computing was proposed by Kulkarni et al.  which monitors the temperature and pulse.
This device aims to measure and collect different parameters of the human body, assist the users to monitor their physical condition, and facilitates the doctors to closely investigate the patients’ ailments. This device can be used for fever tracking during illness. The device also alerts users as well as the clinical staff of sharp changes in temperature or high fever.
Oxygen Saturation (SpO2) Monitoring
Respiratory illness of a patient can be assessed by measuring the level of blood oxygen saturation (SpO2). It measures the percentage of hemoglobin saturated with oxygen which is an indication of the overall physical condition of the human body. SpO2 level of an overall healthy person is 95–100%.
It decreases if someone has respiratory distress  or any other health issues. This SpO2 is a crucial factor for monitoring the progression and acuteness of disease in COVID-19 infected patients. In addition, the resting SpO2 rate is significantly lower in patients who are in a severe stage.
Xue et al.  developed a wearable device that continuously monitors SpO2 and body temperature in real-time. This device can be used for COVID-19 patients as its power consumption is very low and compact in design. A wearable device for Heart Rate Variability (HRV) and SpO2 estimation was proposed by Jarchi et al.  which used commercial wrist-worn pulse oximeter for achieving accurate results. Son et al.  developed a light reflection based wearable SpO2 measurement device for real-time monitoring.
The device has small dimensions, accessible measurements, location tracking, and IoT support. Using the device, doctors can monitor the level of SpO2 of COVID-19 patients remotely. To measure the SpO2 of the patients experiencing obstructive sleep apnea (OSA), a telemedicine system was proposed by Rostami et al. .
The system allows real-time monitoring of the SpO2 level for the detection of apnea episodes in patients with OSA and helps them to track their health conditions. This telemedicine system can be very helpful for remote monitoring of the SpO2 level of COVID-19 patients. In addition, Oxitone 1000 M can be used for this purpose as it is the world’s first FDA-approved wrist-sensor pulse oximetry monitor with high accuracy. The SpO2 measurement error rate for this device is within 3% . The device can also be worn on the different places of the body for example on the head or in the chest area.
Respiratory Support Systems
There are many assistive respiratory support systems  that are used to assist COVID-19 patients in their recovery process. The systems that are developed based on wearable technology for the respiration support of COVID-19 patients are outlined as follows.
Ventilators as Respiratory Support
Open source positive pressure ventilation device (OSPPVD) was developed in response to the shortage of ventilation capacity in hospitals for COVID-19 patients . The OSPPVD assistive respiratory support system was designed in accordance with a health care professional descriptions and observation of COVID-19 infection rather than recreating existing technologies .
Most of the assistive breathing support systems for COVID-19 patients are very expensive. Hence, in response to this expensiveness of the systems, a preliminary investigation design for easy development, simple, innovative, and portable ventilator for COVID-19 patients was carried out in the study of .
The proposed ventilator would be developed in accordance with proper medical standards such as IEC 62304, ISO 5367, and ISO 80601, and the system will facilitate the monitoring of expiratory/inspiratory ratio of COVID-19 patients via an LCD screen.
CPAP Devices for Breathing Assistant
The guidelines for the management of COVID-19 patients with respiratory failure are the use of continuous positive airway pressure (CPAP) and non-invasive ventilation (NIV) assistive respiratory support systems; provided appropriate personal protective equipment is worn.
The CPAP and NIV devices have the potential to minimize the risk of airborne transmission from COVID-19 patients. According to , CPAP provides the application of a stable level of positive airway pressure throughout the entire respiratory cycle. The Formula One Company in collaboration with mechanical engineers from the University College London and clinicians at College London Hospital produced CPAP assistive respiratory support systems for COVID-19 patients which can easily be reproduced .
The system has already been approved by the medicines and health product regularly agency and it has been widely used for COVID-19 patients in Italy and China, respectively. The system is very effective while being less invasive and does not require healthcare workers or intensive monitoring because patients can be weaned off and put the bank on again if needed .
Nishkantha et al.  recommended the use of the helmet device for CPAP and pressure support ventilation (PSV) which are also respiratory support systems to limit the spread of the virus into the ambient air. A helmet is a reusable single interface made up of a plastic hood on a hard plastic ring with a multi-size silicon polyvinyl chloride soft collar to fit a wide range of neck’s dimensions [58, 59].
An alternative Continuous Positive Airway Pressure system (ACPAP) assistive respiratory support system for COVID-19 was proposed to include an anesthesia reservoir bag to enable COVID-19 patients’ spontaneous ventilation to be manually assisted and the system proved to be invaluable in generating larger breaths .
The ACPAP respiratory support system was developed by engineers from the Innovation Department of Hospital Sant Joan de Deu, Spain supported by researchers who developed a CPAP respiratory support system with positive end-expiratory pressure (PEEP) valve and a Venturi connector fitted to a facial snorkel interface . The system offers an alternative frontal interface which reduces droplet dispersion that reduces the risk of infection to health workers.
Oxygen Therapy for Respiration
High flow nasal cannula (HFNC) is one of the respiratory support systems that support patients infected with COVID-19. COVID-19 infected patients were successfully discharged from the negative pressure intensive care unit (ICU) after treatment with HFNC respiratory support system .
HFNC respiratory support system allows COVID-19 patients to turn into the prone position three times a day, thus a manoeuvre that helps the patients in improving oxygenation. Non-invasive ventilation (NIV) and high flow nasal oxygen (HFO) breathing assistants have been used to manage acute hypoxemic respiratory failure caused by COVID-19 [63, 64].
reference link : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7528718/
More information: Feasibility of continuous fever monitoring using wearable devices, Scientific Reports (2020).