Grant: CIHR Fellowship

Upper limb amputation is a debilitating injury with significant impact on quality of life. In healthy limbs the body provides rich sensory information (such as touch) that is vital to the brain's processing. Yet artificial limbs do not provide sensation and the amputee may never truly feel their prosthesis belongs to their body. This impacts the user's ability to control their prosthesis and often leads to abandonment. However, in amputees with a specific nerve surgery, we have demonstrated that prosthetic touch and movement can be experienced as though it were their missing hand. My work will optimize these techniques to allow amputees to feel their prosthesis as part of their body. The way the brain subconsciously processes movement, and the way movement is consciously felt require different information. Fully understanding this relationship in healthy limbs is critical to providing relevant sensation to prosthetic users. We will explore this in able-bodied participants and use techniques to trick them into feeling their limb is moving. We will show them matched or mismatched hand movements in time with movement sensations and use psychological measure to assess how the brain processes these experiences. We will then use techniques to introduce sensations of missing hand touch and movement in amputee participants who have undergone nerve surgery. When these participants use an advanced prosthetic system, we can turn on-and-off what they see the prosthesis doing and what they feel in their missing hand. Using psychological measures we can assess how best to provide information allowing users to feel the prosthesis as a part of their body and believe they are fully in control of the limb. This work tells us how the brain uses sensory information and how best to allow prosthetic users to believe their device is part of their body. It addresses a very real challenge in prosthetic use and may help provide more functional prostheses that increase user satisfaction.