Wearable medical sensors are playing an increasingly important role in the digitization of healthcare. From heart monitoring to continuous physiological measurements, smart wearables make it possible to collect health data directly from the body, both in the hospital and at home. As this technology is used more frequently for patient care, the importance of reliable signal registration is also increasing.
Researchers at King Abdullah University of Science and Technology (KAUST) have therefore developed a new system that can automatically detect when electrodes from wearable medical sensors become detached from the skin. The study was recently published in Results in Engineering.
Biosensors in healthcare
Sensors worn on the skin are an important building block for modern digital healthcare. They are used for ECG measurements, monitoring vital functions, and long-term observation of patients outside the hospital, among other things. Especially in the case of chronic conditions and home monitoring, such systems can provide valuable data that helps doctors with diagnosis, treatment, and follow-up.
However, the reliability of this data depends entirely on the quality of the signal recorded by the sensors. If electrodes become detached or contact with the skin deteriorates, this can lead to distorted measurements or incorrect interpretations of physiological signals.
Limitations of existing detection methods
Traditionally, the quality of electrode contact is checked using indirect techniques, such as impedance measurements. However, these methods were developed under the assumption that conditions are relatively stable. In practice, this is often not the case.
When people move, perspire, or wear a wearable for long periods of time, the contact between the electrode and the skin can become partially detached or temporarily interrupted. This can cause sensors to record inaccurate data without the system noticing.
According to the researchers, this is particularly problematic when medical wearables are used at home. In such situations, poor electrode contact can go unnoticed for a long time, while the collected data is still used for clinical decisions.
Body part detection mechanism
To address this problem, the research team opted for a different approach. Instead of considering the human body as a disruptive factor in electrical measurements, the body was integrated into the detection mechanism.
Previous research has shown that small electrical signals can be safely conducted through the body. The researchers realized that electrodes can exchange digital signals via the body. The quality of that communication can then provide direct insight into how well the electrodes are connected to the skin. If the contact is good, the digital signal is received clearly. When the contact deteriorates, errors occur in the signal. And if an electrode becomes completely detached, the signal disappears entirely.
Custom chip analyzes electrode contact
For practical implementation, the team developed a system based on a specially designed chip. This chip can send and receive small digital signals between electrodes attached to different places on the body.
A compact processing unit then analyzes how well each signal is received. Clear signals indicate stable skin contact, minor errors indicate incipient contact problems, and missing signals mean that an electrode has become detached.
An additional electronic component manages the control process and ensures that multiple electrodes can be checked automatically. This does not interrupt the medical measurements themselves.
Tests on human skin
In experimental tests, the researchers placed pairs of electrodes on human skin. Various situations were simulated: electrodes that were firmly attached, partially detached, occasionally lost contact, or were completely detached.
The system proved capable of clearly distinguishing between these situations. Notably, the technology also detected early signs of contact deterioration, signals that often go unnoticed with traditional monitoring methods.
According to the researchers, this could offer significant advantages for long-term monitoring, where small changes in electrode contact can have a major impact on the quality of the recorded data.
Integration into future wearables
An important advantage of the system is its low energy consumption. This makes it possible to integrate it into wearable medical devices that need to function continuously, sometimes for days or weeks at a time.
The current research setup still consists of a prototype in the laboratory. The next step is to develop a fully integrated chip that can monitor multiple electrodes simultaneously. This could be used, for example, in multi-channel heart monitors or other medical wearables.
According to the researchers, the technology could ultimately contribute to more reliable digital monitoring, both in hospitals and at home. By automatically checking whether sensors are functioning correctly, the quality of medical data can be improved and confidence in wearables as a clinical tool can be further increased.
