NeuroCIMT Project 6: Stiffness as needed

Stiffness as needed

Intelligent brace unstiffens feet

Neurological diseases such as strokes or cerebral palsy often result in the shortening of muscles, loss of muscle strength and increased stiffness of tissue surrounding joints. In some cases, this leads to stiffened ankle joints. The patient is unable to move his or her foot upwards in a controlled way increasing the risk of falling. As a therapy, these patients are injected with botulinum toxin relaxing the muscle, completed with an orthosis to fix the ankle in a more desired pose.

Supporting brace with training perspective
This project aims at developing a revolutionary brace for CVA and cerebral palsy patients suffering from mobility loss due to stiffness of the ankle joint. Instead of giving passive support, the new system will appeal to the available neuromuscular rest capacity of the patient. The brace introduces compensating stiffness to restore the joint stiffness to the desired value. Instead of fixating the foot in a desired position, this way the foot’s tissue and muscles are trained to move in a near natural way. By training the foot this way, the patients’ walking pattern should improve importantly.

Large force in small volume
At the moment there is a similar product available which can be used in an experimental setting. In a simulation, it is shown that this kind of application can indeed improve the motor function of the ankle joint. The next step is to develop a practical, daily wearable orthosis based on this method. That is a major challenge, since the device should be able to apply rather large forces, and at the same time still be small enough to be worn inside a normal shoe.

Application perspective
Rogier Barents, general manager Intespring
‘Our company is specialised in balancing and suspension systems. We have for example developed a technology capable of balancing large forces in small volumes. For another application, we have developed a system to compensate stiffness, with the aid of special materials. For us, this research project is the perfect opportunity to combine the two: the challenge is to develop a small, low weight system which can counteract large stiffness in a wearable application. By participating in this project, we can advance our technology, and perhaps by doing so, enter a whole new market.’

Delft University of Technology, Intespring, Leiden University Medical Center, OIM Orthopaedics, University of Twente