Sunday, April 22, 2018
Health

Experiment with artificial hand adds sense of touch

WASHINGTON — To feel what you touch — that's the holy grail for artificial limbs. In a step toward that goal, European researchers created a robotic hand that let an amputee feel differences between a bottle, a baseball and a mandarin orange.

The patient only got to experiment with the bulky prototype for a week, and it's far from the bionics of science fiction movies. But the research released Wednesday is part of a major effort to create more lifelike, and usable, prosthetics.

"It was just amazing," said Dennis Aabo Sorensen of Aalborg, Denmark, who lost his left hand in a fireworks accident a decade ago and volunteered to pilot-test the new prosthetic. "It was the closest I have had to feeling like a normal hand."

This isn't the first time scientists have tried to give some sense of touch to artificial hands; a few other pilot projects have been reported in the United States and Europe. But this newest experiment, published in the journal Science Translational Medicine, shows Sorensen not only could tell differences in the shape and hardness of objects, he also could quickly react and adjust his grasp.

"It was interesting to see how fast he was able to master this," said neuroengineer Silvestro Micera of Switzerland's Ecole Polytechnique Federale de Lausanne, who led the Swiss and Italian research team. "He was able to use this information immediately in a quite sophisticated way."

Scientists have made great strides in recent years in improving the dexterity of prosthetics. But the sense of touch has been a much more difficult challenge, and is one reason that many patients don't use their prosthetic hands as much as they'd like.

Consider: Grab something and your own hand naturally grasps with just enough force to hang on. Users of prosthetic hands have to carefully watch every motion, judging by eye instead of touch how tightly to squeeze. The results can be clumsy, with dropped dishes or crushed objects.

"You always have to look and see what's going on, so that's what is so much different from this new hand that I tried," Sorensen, 36, said in a telephone interview.

First, doctors at Rome's Gemelli Hospital implanted tiny electrodes inside two nerves — the ulnar and median nerves — in the stump of Sorensen's arm.

Those nerves normally would allow for certain sensations in a hand. When researchers zapped them with a weak electrical signal, Sorensen said it felt like his missing fingers were moving, showing the nerves still could relay information.

Meanwhile, Micera's team put sensors on two fingers of a robotic hand, to detect information about what the artificial fingers touched.

For one week, cords snaked from a bandage on Sorensen's arm to the artificial hand, and the electrodes zapped the nerves in proportion to what the sensors detected.

They essentially created a loop that let the robotic hand rapidly communicate with Sorensen's brain.

"It is really putting the brain back in control of the system," said biomedical engineer Dustin Tyler of Case Western Reserve University, who wasn't involved with the European work but leads a team in Ohio that recently created and tested a similar touch-enabled hand. "That's an important step."

Added neurobiologist Andrew Schwartz of the University of Pittsburgh: "It shows with a few sensors and some pretty elementary technology, that they can recover a fair amount of functionality."

To be sure Sorensen used touch, and didn't cheat by looking or hearing telltale sounds, he wore a blindfold and headphones as Micera's team handed him different objects.

"Suddenly I could tell if it was a hard object," Sorensen recalled, describing sensations that changed along with his grip. "The response, the feedback from the arm to my nerves and to my brain, they came very strong."

Micera cautioned that it will take several years of additional research to create a first-generation artificial hand that can feel, and looks more like a traditional prosthetic. First, they have to prove these nerve implants can last; for safety reasons, Sorensen's were surgically removed after the experiment.

But a lot of work is under way.

In Ohio, Tyler's team recently issued video showing a blindfolded man gently pulling stems from cherries without crushing them, thanks to similar implanted nerve stimulators and a sensor-equipped prosthetic hand. The main difference, said Switzerland's Micera, is in how the nerve electrodes are implanted. The European approach puts them inside the nerve rather than around it for better control, but that's more invasive and some researchers worry it could damage the nerve over time.

In Pittsburgh, Schwartz's team is about to test another approach — a brain-controlled robotic hand for the paralyzed that would "feel" through electrodes implanted in a brain region known as the sensory cortex.

Whatever the approach, touch is a complex sense and these are all basic first steps involving how someone grasps, not more sophisticated sensations such as texture or temperature.

"There is definitely tremendous value to having a sense of touch, a sense of feeling from the hand," said Case Western's Tyler. "What that feeling is, how we use it — that's yet to come."

 
Comments
Do not eat any romaine lettuce, the CDC warns

Do not eat any romaine lettuce, the CDC warns

Public health officials are now telling consumers to avoid all types of romaine lettuce because of an E. coli outbreak linked to the vegetable that has spread to at least 16 states and sickened at least 60 people, including eight inmates at an Alask...
Published: 04/20/18
Florida hits a milestone: More than 100,000 people are registered to use medical marijuana here

Florida hits a milestone: More than 100,000 people are registered to use medical marijuana here

Florida has hit a milestone of sorts as it slowly moves toward wider availability of medical marijuana.The number of patients in the state who are registered to use the substance has surpassed 100,000 for the first time, according to Florida Departme...
Published: 04/20/18
Florida Hospital Carrollwood spending $17.5 million to expand emergency department

Florida Hospital Carrollwood spending $17.5 million to expand emergency department

Florida Hospital Carrollwood is expanding its emergency department. The hospital, 7171 North Dale Mabry Highway in Tampa, is spending $17.5 million to add 15 new private treatment rooms, new pediatric rooms and waiting areas, and new technology, acco...
Published: 04/18/18
Barbara Bush’s end-of-life decision stirs debate over ‘comfort care’

Barbara Bush’s end-of-life decision stirs debate over ‘comfort care’

As she nears death at age 92, former first lady Barbara Bush’s announcement that she is seeking "comfort care" is shining a light — and stirring debate — on what it means to stop trying to fight terminal illness.Bush, the wife of former President Geo...
Published: 04/17/18
Preparing for the worst, staffers at Johns Hopkins All Children’s learn through simulation

Preparing for the worst, staffers at Johns Hopkins All Children’s learn through simulation

When the patient got violent, Dr. Michelle Hidalgo didn’t have time to think. She had to react. The woman was moving strangely and seemed erratic. Hidalgo had to make a tough call — it was time to physically restrain her for everyone’s safety.Then th...
Published: 04/16/18
Updated: 04/17/18

Lung cancer patients live longer with immune therapy

The odds of survival can greatly improve for people with the most common type of lung cancer if, along with the usual chemotherapy, they are also given a drug that activates the immune system, a major new study has shown.The findings should change me...
Published: 04/16/18
Thousands of pounds of prepackaged salad mixes may have been tainted with E. coli, officials say

Thousands of pounds of prepackaged salad mixes may have been tainted with E. coli, officials say

A Pennsylvania food manufacturer is recalling 8, 757 pounds of ready-to-eat salad products following an E. coli outbreak that has spread to several states and sickened dozens of people.Fresh food Manufacturing Co., based in Freedom, Pennsylvania, is ...
Published: 04/15/18
St. Anthony’s Cancer Center installs bell dedicated to survivors

St. Anthony’s Cancer Center installs bell dedicated to survivors

ST. PETERSBURGSister Mary McNally, vice president of mission at St. Anthony’s Hospital, stood in front of a room of cancer survivors to unveil a silver bell surrounded by butterfly stickers mounted to the wall of the Cancer Center lobby. "So often pe...
Published: 04/13/18
Hand dryers could leave your hands dirtier than you think

Hand dryers could leave your hands dirtier than you think

Washing your hands after you use the bathroom is a good idea. But using a public dryer could undo all that hard work, according to a new study.A study, published in the journal Applied and Environmental Microbiology, examined 36 men’s and women’s bat...
Published: 04/13/18
Meek and Mighty Triathlon draws the young (siblings who are 7, 9 and 11) and not so young

Meek and Mighty Triathlon draws the young (siblings who are 7, 9 and 11) and not so young

The annual St. Anthony’s Triathlon has for years attracted elite athletes from around the world, making the St. Petersburg race one of the premier triathlon events in the country. There’s a big incentive to run fast, swim hard and be the best on a bi...
Published: 04/13/18