People with major upper limb amputation lose significant dexterity and function because the prosthetic devices that replace the lost limb contain fewer degrees of freedom than the physiological hand and lack sensory feedback. The development of multi-functional prosthetic hands has accelerated over the past two decades however none of the commercially available devices provide sensory feedback. The goal of this project is to design, develop, and test a prosthetic limb system which provides physiologically appropriate sensory feedback with a multi-functional prosthetic hand. In short, this project plans to recreate the sense of touch for persons with upper-limb amputation. Two hypotheses will be investigated. 1) Persons with limb loss using a prosthetic system including a myoelectric multi-DoF prosthetic hand and physiologically appropriate sensory feedback will significantly improve performance and learn quicker when performing activities of daily living compared to performing the same tasks without sensory feedback. 2) Persons feeling physiologically appropriate feedback when performing activities of daily living with a myoelectric multi-DoF prosthesis will experience an increased sensation of embodiment compared to persons not experiencing the sensory feedback.
Three specific aims will be accomplished in order to answer the hypotheses.
In specific aim 1, an advanced prosthetic limb system will be developed in order to test the hypotheses. This prosthesis will integrate the following technologies into a seamless, real-time prosthetic limb system: 1) surface electromyographic (EMG) sensors, 2) the myoelectric postural control algorithm, 3) the six DoF Bebionic prosthetic hand, 4) Numatac fingertip sensors (Syntouch LLC. Los Angeles, CA), and 5) FINE for stimulation of peripheral nerves and delivery of sensory feedback.
In Specific Aim 2, tests of activities of daily living will be performed in order to quantify the functional improvements of the advanced prosthetic limb system with and without sensory feedback. Finally in Specific Aim 3, the prosthesis incorporation measure (PIC) and control bottleneck index (CBI) outcome measures will be used to quantify the embodiment experienced by the subjects. This project will dramatically improve prosthetic limb technology. Scientific knowledge and clinical practice with respect to persons with upper limb amputation will both be advanced. We believe this system could reduce the rejection rates of prosthetic users by improving their ability to perform functional tasks and thereby reduce comorbities such as cumulative trauma disorders in the sound-side limb. We also expect that this system will improve the quality of life in people with an amputation by reducing phantom limb pain and increasing the embodiment of the prosthesis. The cost in time and money due to phantom limb pain is a massive healthcare concern, and any method to reduce this burden would be a monumental achievement in the ability to provide better healthcare for Veterans and non-Veterans alike. The proposed collaboration is a unique opportunity within the VA health care system that can positively impact the clinical healthcare and rehabilitation of Veterans.
The proposed research is relevant to the health and healthcare of Veterans on many fronts. The delivery of physiologically appropriate sensory feedback to persons with upper limb amputation could reduce secondary health concerns by enabling persons to use the prosthesis in a more intuitive manner. The treatment of phantom pain is a major health concern for Veterans and this method of delivery of sensory feedback may reduce the existence of phantom pain. An increase in embodiment of prosthesis should encourage regular use of the prosthesis and thereby increase the functional ability of persons with upper limb amputation. Finally, the prosthetic limb system developed will be used for many years to come as a tool to study state-of-the-art rehabilitation techniques. All these aspects will advance the health and healthcare of Veterans and non- Veterans alike.