Contactless health monitoring

Radar is already being used successfully in the automotive sector. Together with lidar and camera, it forms the basis for modern driver assistance systems. For autonomous driving, radar is known for monitoring outside the vehicle. But the vehicle interior also offers various application possibilities.

In the future, as soon as the assistance systems reach their limits, radar will be used to quickly determine whether the driver is ready to take the wheel again. Fraunhofer IDMT are already planning test measurements for the use of radar vital sign detection in vehicles for people in a seated position in order to monitor the vital parameters of the driver, e. g. for professional drivers or, in perspective, in autonomous vehicles. In the future, this should make it possible to assess the driver's condition quickly and robustly. For this application, it is conceivable to position the radar in the vehicle ceiling.

After just a few minutes in a closed car in the sun, the situation can become life-threatening for children and animals. Young children are particularly vulnerable to heat, as they sweat less than adults. The radar can be used to detect more than just the driver's vital signs. The pulse and movement measurements can also detect the presence of children or animals in vehicles. This is therefore of particular interest to the automotive industry.

Sleep apnoea syndrome is one of the most common sleep disorders, characterized by repeated pauses in breathing during sleep. Typical symptoms include snoring, pauses in breathing during sleep, daytime sleepiness, difficulty concentrating and morning headaches. The interruptions in sleep caused by sleep apnoea lead to serious secondary diseases, including cardiovascular diseases such as high blood pressure and heart failure, strokes, type 2 diabetes and depression. It is estimated that around 4% of middle-aged men and 2% of middle-aged women are affected¹. A full diagnosis is typically made by an examination in a sleep laboratory with complex sensor technology. This examination requires an initial suspicion. To prevent secondary diseases, screening with an easy-to-use sensor system in the home environment would be advantageous.

In this context, the Evangelical Hospital in Oldenburg, the University of Oldenburg, and the Fraunhofer IDMT in Oldenburg are researching the “Identification of biosignals for mobile sleep screening with a special focus on apnoea” in the “IdA” project. The aim of the project is to identify the risk of apnoea in stroke patients using mobile sensor technology. For this purpose, a polysomnography (PSG) is conducted to measure respiratory data, ECG, pulse oximetry and brain activity via an EEG (electroencephalogram). An innovative, radio-frequency-based sensor system from IDMT was included as a further component. The IDMT's sensor system can be used to record breathing and heartbeat without contact to the patient and identify apnoea events. Since mid-2024, the prototype designed for this purpose has been in use in the stroke unit of the Evangelical Hospital in Oldenburg for exploratory research.

The IDMT sensor system is attached to the foot end of the patient's bed by the medical staff. The medical staff start and end the measurements independently and can easily remove the device at any time if necessary. The design is space-saving, robust and easy to operate. It can also be synchronized with the polysomnography device so that data analysis can be carried out in relation to the medical reference. This integration of novel sensor technology is relevant in the context of early evaluations and is made possible by the Fraunhofer IDMT as sensor data fusion.

¹Young, T., Palta, M., Dempsey, J., Skatrud, J., Weber, S., & Badr, S. (1993). The occurrence of sleep-disordered breathing among middle-aged adults. New England journal of medicine, 328(17), 1230-1235

Most of the time, breathing is not continuously monitored in nursing or in hospital, especially during sleep. As a result, a change for the worse in the patient's condition is noticed late. Continuous recording of respiratory parameters with discret, external sensors can be a solution. The recorded respiratory data provide information about the general state of health and can be used for an early alarm in case of deterioration. The measurement is enabled by a radar that measures without contact and is therefore particularly user-friendly and hygienic.

Sleep problems can become a health risk. This is because poor sleep increases the risk of daytime sleepiness. This is especially the case with breathing-related sleep problems, such as chronic obstructive pulmonary disease (COPD) or sleep apnea. The nocturnal breathing pauses in sleep apnea also carry a high risk of cardiovascular degradations and additional diseases. The contactless respiratory monitoring, developed at the Oldenburg Branch for Hearing, Speech and Audio Technology HSA, is aimed at companies in the consumer health sector as well as markets for medical devices for vital data recording. In our Connected Health work area, we develop solutions for health services that can be used flexibly from anywhere and function contactless.

Various neurological diseases, such as Parkinson's or epilepsy, are associated with movement disorders. For example, tremors, persistent muscle tension or balance disorders. These can be depicted in the radar data. Radar technology can also be combined with other solutions, such as mobile EEG systems, to improve the detection of epileptic seizures.

Sudden infant death syndrome (SIDS) refers to the sudden death of a healthy-appearing infant for no known medical reason. The sleeping position on the back, the use of a sleeping bag instead of pillows and blankets and a separate bed ensure a safer sleeping environment for infants. In addition to these preventative measures, the use of a radar to monitor vital functions is also conceivable here. In this way, irregularities in breathing, pulse or an unsafe sleeping position of the child can be identified at an early stage.