Interview with Professor Markus Wirz, Director of Research and Development at the Institute of Physiotherapy, Zurich University of Applied Sciences
After a stroke or as a result of aging, there are many situations when people are impaired in their walking ability and rely on a personal assistant or auxiliary aids and services. The XoSoft Project offers a solution: a soft exoskeleton that can be worn like a pair of leggings and stiffens or softens, depending on the situation.
In this interview with MEDICA-tradefair-com, Professor Markus Wirz explains how the XoSoft system works, when it can be used and who is able to benefit from it the most.
Professor Wirz, what is the objective of the "XoSoft" Project?
Prof. Markus Wirz: The "XoSoft" Project is part of the EU Horizon 2020 research program. The project objective is to develop a support mechanism for patients, who are impaired in their walking ability. You might envision this as a type of splint that is able to compensate for leg muscle weakness. We are already familiar with this concept thanks to exoskeletons. However, they are usually made of rigid materials such as solid metals or rigid composites for example. In this case, the target audience is made up of people, who typically use wheelchairs to be mobile, meaning, they exhibit no leg muscle function. Unlike our XoSoft system, which is aimed at people, who are still able to walk but in a very limited fashion. The goal is to avoid secondary problems stemming from immobility.
What are soft exoskeletons made of?
Wirz: This is a new development. This type of exoskeleton is meant to be made of soft materials that stiffen, depending on the application. You might envision this as a type of tights or leggings made of a somewhat thicker material. It can stiffen and thus ensures stability if a person is standing or in the stance phase of walking for example. At the same time, it can become soft and flexible again if the swing phase of walking or sitting requires the corresponding movement.
XoSoft has integrated sensors. They measure the current state of the exoskeleton or lower extremities, respectively. Any movement you make is being measured. A control unit uses these signals to predict the movement intent. It subsequently activates those actuators or units that make the XoSoft either stiff or flexible, depending on the situation.
What makes this type of exoskeleton different from rigid exoskeletons?
Wirz: The basic idea is not about choosing a rigid or soft exoskeleton. The soft exoskeleton is actually a different concept aimed at those people, who still exhibit walking function. On one side of the spectrum of mobility are those, who are unable to walk and depend on a wheelchair. On the opposite side of this continuum are those people, who can walk without any limitations. And then there is any type of mobility in between these two sides. There is therapeutic walking for example. That means a person is able to walk with the help of an assistant or auxiliary aid but is not fully capable of walking without restrictions. We presently target three types of "primary users" for this system: patients recovering from a stroke, patients with incomplete spinal code injuries or older people, who exhibit limited walking ability due to their age. Our objective with the XoSoft system is to help these people regain independent walking ability and provide intelligent assistance. Rigid exoskeletons have the same purpose, although their target audience is wheelchair users. The long-term goal of rigid exoskeletons is to replace wheelchairs.
How can affected patients benefit from this system?
Wirz: XoSoft is a modular system and consists of three different modules, which can be selected based on the patient's need. There is a module that supports the ankles and reaches just below the knee. Then there is a module for knee joint and another one for hip joint support. The idea behind it is that users put XoSoft on in the mornings like a piece of clothing and wear it discretely under their clothes. This ensures support when they walk.
We are also planning a "connected health module". It records the mobility habits of users. This activity behavior reveals, for example, whether the patient's situation is worsening, ideally before the user is even consciously aware of it. These would be subtle signs of deterioration that could be treated in due time to properly head off any decline. What’s more, the connected health module is also able to monitor the actual system itself and detect when individual components no longer work properly. In doing so, they can be replaced before they fail.
Next to the "primary users", the "secondary users", that being caregivers of patients, also have access to the system. Those might be medical or therapeutic experts but also family caregivers.
Where do you see the benefits of this for physiotherapy and rehabilitation?
Wirz: Physical activity can impact the severity of many chronic non-communicable diseases like excess weight, diabetes or musculoskeletal disorders. When people are physically inactive, they enter a vicious circle and their health keeps deteriorating. Exercise or physical activity is an important intervention in physiotherapy. Our goal is to get people to keep moving in everyday life. Systems like XoSoft help patients to move on their own and don’t enforce actions that add to inactivity.
These new technologies can be roughly distinguished between devices that compensate for the loss of functions, like a prosthesis and those devices that facilitate rehabilitation training, for example. XoSoft is actually a hybrid if you will. On the one hand, it compensates for the loss of functions, while it also enables movement at the same time. Rehabilitation then teaches patients to operate the device and subsequently apply it to daily life.
How far along is your project?
Wirz: We have planned three generations of prototypes called Alpha, Beta, and Gamma. The Alpha prototype pertains to the basic function, for example, ensuring that sensors measure what they are supposed to measure. From the outset, future users are also included in the development process and in every iteration step. Right now, we are on the brink of the first Beta prototype test, which is tested and reviewed at the Movement Laboratory of the Institute of Physiotherapy. We measure where XoSoft comes into play and determine the effect it has on the movement. We test various scenarios, such as straight walking but also walking around corners, getting up or sitting down. The project will ultimately be completed with the Gamma prototype. Testing for this will be conducted in a home environment.
The interview was conducted by Olga Wart and translated from German by Elena O'Meara. MEDICA-tradefair.com