Brain-controlled interface aided control of a lower limb prosthesis

A brain-controlled interface, which used surface scalp electrodes, aided the control of a lower limb prosthesis in a transfemoral amputee, according to a press release.

Douglas P. Murphy, MD, of Hunter Holmes McGuire VA Medical Center, and associate professor of physical medicine and rehabilitation at Virginia Commonwealth University, led a study to establish the viability of the brain-computer interface (BCI) and presented the research at the Association of Academic Physiatrists Annual Meeting in Las Vegas.

“In our first attempt at using BCI with a lower extremity prosthesis, we wanted to test a simple system before moving on to more complicated ones,” Murphy said in the release. “We chose control of the simplest prosthetic knee, which is the manual-locking knee. When locked, the knee is rigid and straight, and when unlocked [it] swings freely. Someone with an above knee amputation would have to physically [or] manually unlock the knee to sit and could lock or unlock in standing or walking, depending on his [or] her needs. We were interested to see if our participant could ‘think’ [their] way to unlocking the [prosthesis].”

According to the release, the participant was trained to activate a knee-unlocking switch by imagining the movement of their lower extremity. Surface scalp electrodes transmitted brain wave data to a software program that activated the switch. The participant then walked up and down parallel bars and unlocked the knee for swing phase and for sitting down. The success of unlocking the knee mechanism ranged from 50% to 100%, the release noted.

Researchers noted the BCI-controlled prosthesis could provide a hands-free system of control, respond to a variety of needs and require less energy expenditure in complex environments.

“The goal of this research is to provide the individual with a prosthesis that more easily and successfully meets his or her needs for movement and walking,” Murphy said. “The system should be comfortable, easy to use and serve useful purposes. Our subject gave a good example of how this system could help. Sometimes [the subject carries their] daughter down a hill. With BCI control, [the subject] could adjust the prosthesis for descending the hill very easily. This is the type of daily life activity we believe can be improved with BCI.”

The BCI system is in early stages of development; however, the release noted that research may provide rapid growth in the creation of applications for individuals with prostheses.


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