PMDs are helping to revolutionise patient care by enabling remote monitoring, early detection of health conditions, and personalised treatment plans.
The nature and quality of the data from PMDs allows them to be used in a fundamentally different way from the first wave of wearables, meriting the creation of the new product category.
Devices in the first wave of wearables monitored phenomena that users could interpret as indicators of exertion. The data rendered was strictly for the personal use of wearers, enabling them to track and evaluate their health and fitness activity, which is why these devices are generally referred to as fitness trackers. The limitation to personal use had to do with what the sensor technology was originally able to measure, and the quality of the data rendered.
From the beginning, fitness trackers could deliver relatively precise pulse rate data. From a medical standpoint, however, pulse rate typically needs to be considered along with other health indicators to indicate a specific condition. Meanwhile, the other most common measurement provided – steps – is only an approximate gauge indicating that some activity has occurred; it does not correlate to physiological condition.
Refinements made to the sensors used in PMDs have made them accurate enough to meet the strict standards necessary to be used for medical monitoring. The data collected and reported is now so reliable that medical professionals can use it to make diagnoses and deliver therapies. These refinements allow for the recategorization of the new generation of PMDs from simple fitness products to medical devices.
PMD applications
The market for PMDs is still relatively new and is expected to continue to experience appreciable growth for many years to come. This growth is partially driven by ongoing technology innovation, the inclusion of more physiological conditions that can be monitored, and by broadening the application scope to encompass a wider range of post-acute, rehabilitation, and chronic cases.
The PMD market can be segmented into two broad categories. One segment includes devices used to monitor a physiological condition or combination of conditions. These devices include
- digital thermometers
- blood glucose meters (BGM) and continuous glucose monitors (CGM)
- blood pressure monitors
- pulse oximeters
- cardiac monitoring systems (electrocardiograms – ECGs/EKGs)
More and more PMDs of this nature are being developed. For example, there is research into devices that might be able to help with epilepsy management. There are several different causes of seizures. Researchers are developing products that can not only detect the conditions leading up to a seizure but also determine which type of seizure it is so that it can be treated appropriately.
In this same category of PMDs are a growing number of monitors, frequently in the form of patches, used to simply determine if and when medications have been taken or delivered.
A different segment of PMDs includes devices that can administer a therapy, rather than only monitor physiological conditions. Insulin pumps are an example of this.
Above: A typical design of a portable medical device with wireless SoC, analogue front end, sensors/actuator interface and display capabilities
Sensor technology
The latest trends in PMDs include the integration of advanced sensors, AI-powered analytics, efficient processing, and secure wireless connectivity, often powered by comprehensive solutions from a growing number of companies.
Sensor technology continues to evolve, and developers keep producing sensors capable of increasingly precise measurements of temperature, blood pressure, blood glucose levels, blood oxygenation levels, and more.
Ongoing miniaturisation serves several purposes. More highly integrated electronics generally draw less power, and developers of PMDs can take advantage of this in several ways. Drawing less power translates into extended battery life, so PMDs could be used longer before needing to be recharged or replaced. CGMs used to last days; they now can last for weeks.
Alternatively, using a lower-power device could make it possible to use a smaller battery. It will also become increasingly possible to consider energy harvesting to supplement or even replace batteries.
Miniaturisation of the electronic components and the development of increasingly compact batteries also contribute to the reduction in the size and weight of the PMDs themselves, which tends to make them more comfortable and less obtrusive to use.
Connectivity
Sensor innovation is the main driver of the PMD trend, but it is also dependent on the growing reliability and expanding reach of broadband connectivity coupled with data security technology.
It is common to be able to view health and fitness data through an app on a computer, smartphone or smartwatch, usually through a Bluetooth connection, sometimes via WiFi. The same is true for PMDs, Bluetooth Low Energy is the most deployed wireless technology for portable medical devices.
When people have access to accurate medical information, it empowers them to better manage their own conditions. For example, some wearable blood glucose monitors can be tapped at any point for a reading, while wearable CGMs can provide a continuous stream of readings in real-time. Both types allow diabetics to more closely monitor and better manage their condition.
Security
With PMDs, there can also be provisions for sharing data with medical professionals at remote facilities. There are compelling reasons to protect all personal data, but medical data is commonly subject to much higher standards of legal protection. Security must be fundamental in PMD design.
There are many security technologies for protecting PMDs (and other connected devices) that include both hardware and software approaches. Different combinations of these measures can be adopted. They include:
- data encryption
- secure key management, including the use of physically unclonable functions (PUF)
- anti-tampering
- secure boot
- secure debug
A number of companies can now offer custom manufacturing service that makes it possible to adopt additional security measures, such as numbering every part for tracking purposes. At Silicon Labs its suite of security measures is called SecureVault.
Artificial intelligence
Artificial intelligence (AI) has great promise for PMDs. One avenue of exploration is how to use AI at the edge for data-driven insights to improve device or patient outcomes.
Researchers are also examining how AI can be used to help guide the use of PMDs. Is the PMD being placed optimally? Are there physiological differences between users that should be considered when using a PMD? Can the data collected by the PMD be personalized to make it more applicable to each specific end user?
Conclusion
Evolutionary advances in sensor technology, in connectivity technology, in security, and in AI are enabling a revolution in medical care. Technological innovations are empowering patients to take charge of their health while providing healthcare providers with valuable insights for proactive intervention and improved outcomes.
Improving PMDs and creating new ones are both extraordinary challenges, from both the technological and regulatory perspectives. Choosing to work with an experienced development partner is the first step in the process of creating a successful product. Choose a partner with experience with ultra-low power electronics including processors, a variety of security technologies, RF technology & wireless protocols, and AI.
Author details: Fritz Werder, Senior Product Line Director, Life at Silicon Labs
