HAPTIX: Hand Proprioception and Touch Interfaces

With a focus on wounded warriors and facilitating their return to military service, the Hand Proprioception and Touch Interfaces (HAPTIX) program is pursuing key technologies to enable precision control of and sensory feedback from sensor-equipped upper-limb prosthetic devices. 

If successful, the resulting system would provide users near-natural control of prosthetic hands and arms via bi-directional peripheral nerve implants. The program has a strong focus on technology handoff and aims to create and transition clinically relevant technology in support of wounded warriors suffering from single or multiple limb loss.

HAPTIX builds on prior DARPA investments in the Reliable Neural-Interface Technology (RE-NET) program, which created novel neural interface systems that overcame previous sensor reliability issues to now last for the lifetime of the patient. 

A key focus of HAPTIX is on creating new technologies to interface permanently and continuously with the peripheral nerves in humans. HAPTIX technologies are being designed to tap into the motor and sensory signals of the arm to allow users to control and sense the prosthesis via the same neural signaling pathways used for intact limbs. 

Direct access to these natural control signals will, if successful, enable more natural, intuitive control of complex hand movements, and the addition of sensory feedback will further improve hand functionality by enabling users to sense grip force and hand posture. Sensory feedback may also provide important psychological benefits such as improving prosthesis “embodiment” and reducing the phantom limb pain that is suffered by approximately 80 percent of amputees.

In addition to developing the low-power microelectronics needed for the system, HAPTIX performer teams also conduct fundamental neuroscience research to understand how the nervous system encodes motor and sensory information for the hand. This knowledge guides development of algorithms that enable intuitive control of the prosthesis and provide rich sensations of touch and proprioception. 

If successful, the completed HAPTIX system will be integrated with one of the advanced prosthetic limbs developed under DARPA’s Revolutionizing Prosthetics program to create the first dexterous prosthetic limb with full sensory and motor capabilities that is suitable for home use. DARPA anticipates a 12-month, take-home clinical trial of the complete HAPTIX system as the culmination of the program.