State-of-the-art upper limb prostheses are severely limited in their ability to provide sensory feedback to a user. The lack of sensory feedback forces prosthesis users to rely on visual feedback alone in manipulating objects, and often leads to abandonment of the prosthesis in favor of the user's unimpaired arm. Consequently, there is a critical need to develop mechanisms that enable people with upper limb amputations to be able to receive sensory feedback from the environment. Through the use of techniques like targeted reinnervation, there has been significant progress in providing patients with intuitive neural control of their prostheses as well as sensory feedback. Studies have shown that patients receiving sensory stimulation over reinnervated sites while operating a prosthesis more strongly incorporate the artificial limb into their body schema. However, there is limited cutaneous space available over the reinnervated sites for both EMG sensors and stimulators to be placed. As a result, the overall objective of the proposed research is to clinically evaluate a flexible, stretchable epidermal electronic device that conforms to the skin and can simultaneously record EMG and provide electrotactile sensory stimulation at high density over reinnervated sites. We hypothesize that long-term, closed-loop sensorimotor control in prostheses enabled by epidermal electronics will improve fine motor control and promote incorporation of the prosthesis into the body schema, ultimately reducing prosthesis abandonment. We will address this hypothesis through the following Specific Aims, in which I will 1) Optimize and validate a single flexible epidermal device that can both acquire EMG and provide electrical stimulation simultaneously at high density, 2) develop methods for automatic calibration and modulation of electrotactile sensation intensity to enable long-term wear, and 3) improve fine force control, object recognition, and embodiment through the use of sensory feedback. In turn, we expect that daily usage of prosthetic devices will increase due to the incorporation of high resolution sensory feedback. With the training environment provided by Dr. Levi Hargrove at the Rehabilitation Institute of Chicago, and Dr. Timothy Bretl and Dr. John Rogers the University of Illinois at Urbana-Champaign, we will be able to effectively enable long-term, closed-loop upper limb sensorimotor prosthetic control through the use of epidermal electronic devices.

Public Health Relevance

The overall objective of this project is to develop a clinically viable method for simultaneously controlling a prosthetic device with EMG and providing sensory feedback for people with upper limb amputations. Through the use of epidermal electronic systems, signal processing, and mathematical models to control sensation intensity over time, we can improve the quality of life for upper arm amputees by allowing them to easily control and feel their prosthetic device for long-term periods. This is relevant to the part of NICHD's mission to foster the development of scientific knowledge needed to enhance the health, productivity, independence, and quality of life of people with physical disabilities.

National Institute of Health (NIH)
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Individual Predoctoral NRSA for M.D./Ph.D. Fellowships (ADAMHA) (F30)
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Special Emphasis Panel (ZRG1-F03B-D (20))
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Cruz, Theresa
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University of Illinois Urbana-Champaign
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United States
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Cornman, Jesse; Akhtar, Aadeel; Bretl, Timothy (2017) A Portable, Arbitrary Waveform, Multichannel Constant Current Electrotactile Stimulator. Int IEEE EMBS Conf Neural Eng 2017:300-303
Choi, Kyung Yun; Akhtar, Aadeel; Bretl, Timothy (2017) A Compliant Four-bar Linkage Mechanism that Makes the Fingers of a Prosthetic Hand More Impact Resistant. IEEE Int Conf Robot Autom 2017:6694-6699
Akhtar, Aadeel; Aghasadeghi, Navid; Hargrove, Levi et al. (2017) Estimation of distal arm joint angles from EMG and shoulder orientation for transhumeral prostheses. J Electromyogr Kinesiol 35:86-94
DeGol, Joseph; Akhtar, Aadeel; Manja, Bhargava et al. (2016) Automatic Grasp Selection using a Camera in a Hand Prosthesis. Conf Proc IEEE Eng Med Biol Soc 2016:431-434
Xu, Baoxing; Akhtar, Aadeel; Liu, Yuhao et al. (2016) An Epidermal Stimulation and Sensing Platform for Sensorimotor Prosthetic Control, Management of Lower Back Exertion, and Electrical Muscle Activation. Adv Mater 28:4462-71
Akhtar, Aadeel; Choi, Kyung Yun; Fatina, Michael et al. (2016) A Low-Cost, Open-Source, Compliant Hand for Enabling Sensorimotor Control for People with Transradial Amputations. Conf Proc IEEE Eng Med Biol Soc 2016:4642-4645