Soft Wearable Device for Thumb Rehabilitation

This case study describes the design of a wearable device for thumb rehabilitation, and is based on work carried out by Maeder-York et al. (2014)

Clinical Need

As discussed in the PneuNets glove case study, loss of grasping ability is a significant problem which negatively impacts quality of life in patients. It is possible to recover some lost function through intensive physical therapy, which typically involves the use of repetitive task practice (RTP). However, RTP requires a therapist to assist the patient and guide the hand through the correct motions. As RTP also needs to be performed continuously for several hours, this results in high therapy costs and limits the number of patients a therapist can see. 

The aim of the project described here was to develop a wearable device that replicates and restores correct thumb motor function for opposition grasp for patients with neurologically caused hand disabilities.


The design consists of a multi-segment fiber-reinforced actuator, mounted to a a conformable neoprene-padded aluminum attachment with Velcro straps, and tethered to a portable control system.

In order to determine the types of motion required from the actuator, electromagnetic (EM) trackers (3D Guidance TrakSTAR from Ascension Technology Corp.) were used to study the motion of the thumb during opposition grasp. This study yielded values for the amount of bending, twisting, and extension required of the actuator. Following the guidelines described on this page, the project team was able to design an actuator which, when inflated, would mimic the motion of the thumb.

In any wearable device design, methods of attaching to the patient are a non-trivial issue. In this project, one end of the actuator was mounted to a conformable aluminum plate which could wrap around the patient's hand. Velcro straps along the length of the actuator attached it to the patient's thumb. The full assembly was sewn into a glove.

The portable control box for the device was a modified version of the Soft Robotics Toolkit control board, as described on this page.
This video gives a demonstration of the final device in operation.