Taking Back Control

The Feinstein Institutes for Medical Research are giving new hope to the millions of people living with paralysis. There, the Bouton lab is exploring novel techniques that allow paralyzed persons to regain control of their own arms and hands, under control of their own thoughts.

In recent years, researchers in this lab have been deciphering the neural signals generated by the motor cortex of the brain during normal arm movement. In parallel, they have been working to understand how to apply electrical signals to the forearm in order to control the muscles of the arm and hand. With the insights gained from these experiments, they were able to build a sort of artificial nervous system that is capable of bypassing a damaged spinal cord. This artificial system works by capturing neural signals via a brain implant; those deciphered signals are then used to control forearm-mounted electrodes that trigger muscle movements. This device was demonstrated by a man, who is paralyzed from the chest down, playing the video game Guitar Hero.

Building on these advancements, the team is now focusing their attention on a new, noninvasive device that does not require the user to undergo brain surgery. This new device, called GlidePath, makes use of a mix of inertial and biometric sensors mounted on the arm, with an Adafruit Feather Huzzah32 microcontroller development board for processing. Data from these sensors is fed into a machine learning algorithm that has been trained to understand the intentions of the wearer. This is combined with flexible electrodes on the forearm that stimulate the muscles in a particular sequence to carry out those intentions. While GlidePath does not offer the same precision of movement that is achievable with a brain implant, the lower regulatory hurdles could allow it to be adopted by the paralyzed community much more quickly.

The researchers are currently refining GlidePath in ways that will speed up calibration of the device, and make it more lightweight and inconspicuous. With further research, they hope one day to be able to allow for better control of complex finger movements, which is currently problematic.

On the neural implant front, they are exploring ideas that might allow them to build a two-way neural bypass, which would allow for sensory feedback to flow from hand to brain and restore normal sensory feedback.