Researchers try to recreate a feeling of touch in prosthetic legs

The University of Pittsburgh has a team working to create prosthetic limbs that look like the ones in Star Wars movies.

13 June 2022 Monday 09:54
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Researchers try to recreate a feeling of touch in prosthetic legs

The University of Pittsburgh has a team working to create prosthetic limbs that look like the ones in Star Wars movies.

Lee Fisher, a biomedical engineering engineer, says that Luke Skywalker has lost a hand during a lightsaber battle.

Luke can even say "ouch" to a medical droid when it prods his prosthetic fingers.

Fisher states, "That's our long term goal," "to restore sensory feedback to the missing limb."

To perform basic tasks like holding a cup or coffee, the human brain needs constant tactile feedback. Even the most advanced motorized legs aEUR", including those that are controlled only by thoughts, don't give this kind of feedback. Even the most advanced prosthetics can frustrate users.

Fisher is among more than 80 researchers, staff, and trainees in the university's Rehab Neural Engineering Labs. They are working to bring the feeling of touch to prosthetics. The aim is to create artificial hands and feet that can be linked to the person's nervous system using sensors.

Fisher's laboratory, for instance, links prosthetic legs and prosthetic arms to a device that is implanted in the spine of a person.

He says that it looks almost like a spaghetti noodles. They can be inserted using a needle so it's very minimally invasive to insert them.

This device was originally created to relieve chronic pain by sending electrical pulses to the spine. Fisher's lab uses it to relay information to a prosthetic foot or hand from sensors.

Fisher says the trick is to stimulate nerve fibers that were once connected with the person's limb. This requires some trial and error.

"The first thing that we do is to try and understand what stimulation felt like." He says. "Can we create a sensation that feels as if it's coming out of their missing hand or their missing foot?" It can be changed how intense it feels.

Four people have found that the answer is yes, according to a study. Pat Bayne describes the sensation of stimulation in a video that was made by the university. She says, "I know there is no hand there but I can feel it." They can make my palm feel like my hand. It's quite exciting.

Participants also reported that stimulation reduced the pain perception from missing limbs aEUR," a common problem following an amputation.

Fisher's team is also using the spinal implants to provide feedback from artificial feet and legs.

Fisher believes that the addition of prosthetic limbs could make them more useful because they rely on continuous feedback from their feet to keep them upright. He says that we are essentially a pendulum upside-down, which you need to move around in order to maintain balance.

Preliminary data suggests that at least one person with a prosthetic foot was helped or assisted by the feedback.

Fisher stated that Fisher saw improvements in Fisher's balance and stability when standing. She also noted an improvement in her confidence.

Paralysed people could benefit from artificial limbs that have a sense touch, Jennifer Collinger, associate professor at the university's department for physical medicine and rehabilitation, said.

The Pittsburgh group has worked with paralyzed volunteers for many years to teach them how to control a robot arm using their thoughts.

Collinger states that the goal is to make technology more accessible to enable them to live independently. Collinger says, "What we are moving towards is being able feed ourselves, being capable of making a meal, and being able get dressed."

However, it will be hard to perform tasks such as this if one relies on only their eyes to see what the robot arm is doing. The Pittsburgh scientists have added the same touch sensors to their prosthetic arms. In this instance, however, the sensory information is delivered directly to the brain and not through the spine.

Robert Gaunt (biomedical engineer) said that one study showed that touch can make a huge difference in the lives of people.

He says that it cuts down on the time it takes to move objects around and pick them up. In some cases, the task was completed almost as quickly as an able-bodied individual.

Scientists have so far been unable to provide a basic sense of touch for prosthetic limb users.

Gaunt states that the feedback is sufficient to tell when a foot has been weighed or if a hand has touched an object. Users describe the sensation as a buzzing, tingling, vibration or pressure.

Fisher states that the information Fisher is able to provide "is definitely not a complete replacement for what they lost."

Gaunt states that the information will get better as more sensors are made and scientists discover better ways to connect them with the nervous system. It won't be able to match the sensitiveness of Luke Skywalkers prosthetic hand anytime soon.

Gaunt states that "our ability to discriminate between different types of objects and textures, surfaces, that is a difficult problem" Gaunt hopes that this is possible.



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