A wireless sensor-brain interface to restore finger sensation

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

PI: Lucas, Timothy H. Proposal Number: 1404041 Institution: University of Pennsylvania Title: A wireless sensor-brain interface to restore finger sensation The objective of this project is to develop a device, called a sensor-brain interface (SBI), which can restore the sense of touch and the sense of movement in a paralyzed hand. Considerable evidence suggests that these sensations will greatly improve a person?s ability to regain function of their hand. When combined with a therapy for restoring movement, the SBI has the potential to improve the quality of life of millions of people with hand paralysis due to spinal cord injury or other neurological conditions. The SBI has three components: sensors worn on the fingers, electronics that convert the sensor signals into appropriate electrical stimulation patterns, and stimulating electrodes to convey the signals directly to the brain. Novel designs are used for each of these components to achieve a system that is unobtrusive to wear and intuitive to use. The first two components have broader significance in the rapidly expanding field of wearable technology. The third component will inform the multitude of clinical therapies using electrical stimulation to modulate brain function. Collectively, the three components will yield a substantial vertical step towards reconnecting body and brain after paralysis. Somatosensory signals are critical to normal motor function but their transmission, as with movement commands, is interrupted in paralysis. Neuroprosthetic devices are typically designed to restore movement but not sensation in the paralyzed limb. The resulting modest performance has not justified the use of these devices in a wide clinical population. To improve performance, the investigators will develop a sensor-brain interface (SBI) with the goal of restoring sensation to a paralyzed hand. The SBI has three components corresponding to the three aims of the project. The first aim is to make wearable tactile and motion sensors that are small and completely wireless and therefore unobtrusive to the user. The investigators will pursue two types of novel battery-free sensors of mechanical stimuli: (1) a battery-free active sensor of fingertip vibration powered by harvesting energy from emitted radio waves and (2) a fully-passive, circuit-free sensor using flexible radiofrequency identification tags to sense fingertip pressure and finger joint angle. The second aim is to design a body-area network (BAN) to wirelessly acquire and process the sensor output, configurably map the sensed signals to neural stimulation parameters, and wirelessly convey the parameters to a neural stimulator. The BAN will be accomplished with two, battery-powered, low-power circuits: (1) a sensor controller worn at the wrist and (2) a stimulation controller worn near the head. The third aim is to perform in-vivo tests to validate function of the SBI and evaluate the hypothesis that the cuneate nucleus (CN) of the brainstem is an advantageous site for encoding somatosensory information. The CN maximizes the amount of downstream neural circuitry available to process the artificial stimuli and to make the resulting percepts more intuitive to the user. The encoding performance will be compared to a more conventional, cortical encoding site. Finally, two different encoding paradigms will be compared to assess their relative merit. The scope of this project is to develop a functional SBI prototype and test the device in non-human primates. Following completion of the project, the investigators envision that the SBI could be combined with brain-controlled muscle stimulation for a complete, bidirectional, sensorimotor neuroprosthesis for reanimating a paralyzed hand.