Sensor-based wearable motion tracking

Sensor-based wearable motion tracking – boosting patient wellbeing

At imec we have extensive experience in developing sensor-based technology to monitor cardiorespiratory diseases and support patient wellbeing. Moving forward, we recently have been looking into applying wearable sensor technology for so-called motion analysis, specifically in the case of post-operative knee rehabilitation. Working in close collaboration with orthopaedic specialists from Sports Medical centre TopSupport*, we have now successfully taken our wearable sensor technology to a next level: providing orthopaedic surgeons and physiotherapists the tools to acquire measurable insights into rehabilitation outcomes.

The potential for applying sensor technology in rehabilitation is huge. All surgery or injuries require rehabilitation to a smaller or larger extent. Increasingly, improving health care means ensuring patients get the best care, not only in the sense of successful operations, but as in improving his or her quality of life. This also includes outcomes of operations and patients' well-being in the long term.

Wearable devices that enable long-term monitoring

"At imec we already have a wealth of experience in using sensor technology for cardiorespiratory diseases. What we observe, is that early identification of problems or close follow-up during rehabilitation helps to prevent diseases or enhance recovery of the patient. As such, remote monitoring potentially also reduces the cost of care and helps address the shortage of healthcare providers. Our focus at imec is on developing sensor technology for patient-friendly and wearable smart devices, to monitor health over a longer period of time, in real-life conditions," explains Heleen Boers, Biomedical R&D Engineer at imec.


"So, it's a logical step to apply our knowledge in the field of rehabilitation. We found an ideal partner in the orthopaedic department of the St Anna Hospital, with its specialist physiotherapy centre: Medical Sports centre TopSupport. They are the go-to experts for research and treatment of post-operative orthopaedic rehabilitation and sports-related injuries. They had, for some time already, been looking into the possibilities of wearable sensors for data collection, to support their physiotherapists in their work."


Turning data into actionable insights

"Of course, collecting reliable data using connected health solutions is a first step to improving health outcomes. But, once you've captured your data, how do you turn it into actionable insights? You can have piles of data, but that is only of value if you have algorithms in place that can perform different data processing steps and mine the data. Without such algorithms, data is simply a pile of data. That's where we come in. And it's also where we came in to support researchers and specialists at Sports Medical centre TopSupport."


"For motion analysis, we were able to relate the output of body movement sensors to the progress in patient's individual rehabilitation. Importantly, the sensors help us identify the quality of the patient's movement. For instance, to what extent is someone able to bend his knee when carrying out daily activities?"


Monitoring patient wellbeing

Orthopaedic surgeon Rob Bogie at the St. Anna Hospital Geldrop and its orthopaedic and sports centre TopSupport in Eindhoven explains: "We had been busy with sensor technology, to see how such technology could possibly support our therapies. We wanted to use wearable sensor technology to create a more patient-friendly and smarter monitoring solution for use during rehabilitation. This could provide us with real, measured rehabilitation progress before and after knee surgery. And do so over a longer period of time and in everyday situations."


"Our enthusiasm was soon curtailed by our success. We were getting loads of potentially valuable data. The only downside was that we didn't have the know-how to access and manage it all."


"So, we were extremely happy when the opportunity arose to do further research in collaboration with imec. They provided the insights and know-how that we were lacking. Conversely, we provided the opportunity for them to validate their sensor technology."


What imec did

Imec developed and validated algorithms using data from wearable motion sensors. These motion sensors measure the movement of several body segments (e.g. lower leg, upper leg, pelvis). The output of these sensors and algorithms can help to monitor physical function and progress of total knee replacement patients during daily activities in natural surroundings, such as: strolling through the supermarket, walking up and down stairs, getting out of bed or standing up from a chair.


"Our algorithms now accurately characterize the collected mass of raw data. They carry out different data processing steps, from filtering to feature extraction. Once you have such filtered and reliable data sets, they can be mined for actionable insights," Heleen Boers explains.


Bogie on current rehabilitation: "Basically, we tell patients to do a set of exercises. Of course, they also get extensive support from our physiotherapists. But every patient and every knee is different. The use of sensor technology will enable us to move away from a one-size-fits-all recovery plan to made-to-measure therapy that – based on sensor data – can be constantly adjusted as needs be. Data that we gather during therapy sessions and during normal everyday situations will provide value-adding insights. Without doubt, all these advancements will mean an enormous boost in positive outcomes and, by extension, patient wellbeing."

Helping improve quality of life

"What we see is that the outcome of so-called Patient Reported Outcome Measures (PROMs) questionnaires is increasingly important. The PROMs are standardised questionnaires about the effect of the pathology on quality of life. We use them to monitor outcomes and also to reach out to patients with a below average score," Bogie points out.


"The thing is, though, that data acquired by PROMs regards aspects of health that are not 'objectively' perceptible. For example, symptoms and complaints such as pain or anxiety, how one functions at work, during sports activities or at home are very subjective. Such aspects of health are often described as 'quality of life'. But how do you monitor and measure something that is inherently subjective; a patient's quality of life?"


"Solutions with wearable sensors will enable us to derive the quality of movement, which is related to the quality of life. What are the measurable improvements and progress? For example, does the patient's knee flex sufficiently to be able to get into the car. Once we can measure this, everybody concerned in the rehabilitation trajectory stands to benefit: surgeons, physiotherapists, above all, the patient. Not only will we be able to improve our healthcare based on measurable outcomes, such information will also become invaluable in maintaining an affordable and effective health service," Bogie concludes.


Smart brace

"We're now also looking into applying this technology for ankle rehabilitation," Eva Wentink, Principal Scientist and Bio-Medical Engineer at imec points out. "We're developing sensors with multiple parameters to integrate into a brace. In first instance, such a brace will be used for knees or ankles, but there is a huge potential for other body parts as well."


"Parameters like temperature, swelling and range of motion give insight into the healing status of an injury or post-surgery rehabilitation. In fact, parameters measured could provide valuable insights and direct, real-time feedback to the patient on what activities can be performed and when to stop. There is no doubt that such immediate feedback can boost rehabilitation and, by extension, patient wellbeing," Eva concludes.


* Sports Medical centre TopSupport is located in Eindhoven. This expert centre is part of the St. Anna Hospital in Geldrop, the Netherlands.

Share this page