An emerging area of future technology is motor augmentation – using motorised wearable devices such as exoskeletons or extra robotic body parts to advance our motor capabilities beyond current biological limitations.

While such devices could improve the quality of life for healthy individuals who want to enhance their productivity, the same technologies can also provide people with disabilities new ways to interact with their environment.

Professor Tamar Makin from the Medical Research Council Cognition and Brain Sciences Unit (MRC CBU) at the University of Cambridge said: “Technology is changing our very definition of what it means to be human, with machines increasingly becoming a part of our everyday lives, and even our minds and bodies. These technologies open up exciting new opportunities that can benefit society, but it’s vital that we consider how they can help all people equally, especially marginalised communities who are often excluded from innovation research and development. To ensure everyone will have the opportunity to participate and benefit from these exciting advances, we need to explicitly integrate and measure inclusivity during the earliest possible stages of the research and development process.”

Dani Clode, a collaborator within Professor Makin’s lab, has developed the Third Thumb, an extra robotic thumb aimed at increasing the wearer’s range of movement, enhancing their grasping capability and expanding the carrying capacity of the hand. This allows the user to perform tasks that might be otherwise challenging or impossible to complete with one hand or to perform complex multi-handed tasks without having to coordinate with other people.

The Third Thumb is worn on the opposite side of the palm to the biological thumb and controlled by a pressure sensor placed under each big toe or foot. Pressure from the right toe pulls the Thumb across the hand, while the pressure exerted with the left toe pulls the Thumb up toward the fingers. The extent of the Thumb’s movement is proportional to the pressure applied, and releasing pressure moves it back to its original position.

Over the course of five days, the team tested 596 participants, ranging in age from three to 96 years old and from a wide range of demographic backgrounds. Of these, only four were unable to use the Third Thumb, either because it did not fit their hand securely, or because they were unable to control it with their feet (the pressure sensors developed specifically for the exhibition were not suitable for very lightweight children).

Participants were given up to a minute to familiarise themselves with the device, during which time the team explained how to perform one of two tasks.

The results are published today in Science Robotics: https://www.science.org/doi/10.1126/scirobotics.adk5183 

The full University of Cambridge press release can be read here: https://www.cam.ac.uk/stories/third-thumb