The woman’s ability to feel pressure and texture has returned thanks to the bionic hand, and it has also helped her experience less post-amputation phantom agony.
Although prosthetic hands have advanced significantly, many of them are still too cumbersome and impractical for daily usage. Despite lacking the dexterity of a normal hand, most prosthetics are unable to provide the user with neurological input, making tactile or kinesthetic sensation impossible. Yet a new kind of prosthetic is coming, due to a project called DeTOP: A bionic hand that offers unmatched range and sensation because it is connected to the user’s bone and neurological system.
DeTOP stands for “dexterous transradial osseointegrated prosthesis,” and it was developed through a partnership involving research institutions in Sweden, Italy, Switzerland, and the UK. The groups have been collaborating since 2018 in an effort to develop a prosthetic limb that can mimic the dexterity of a normal hand while also sensing pressure and texture. In 2019, DeTOP developed its first working prototype, and soon after that, it started working with a Swedish woman whose lower arm had been amputated in a farming accident twenty years before. She would be the first applicant for a bionic hand at DeTOP.
The prototype’s success over the previous four years is covered in the Science Robotics cover story for October. According to reports, the woman who goes by the name Karin can carry out 80% of what a normal hand can do. It’s a big improvement over her previous situation, which was characterized by limited mobility and almost constant agony from phantom limbs.
In a statement for Scuola Superiore Sant’Anna, an Italian university involved in DeTOP, Karin said, “It felt like I continually had my hand in a meat grinder, which generated a high degree of tension, and I had to take heavy dosages of various painkillers.” Conventional prosthetics, she continued, were neither practical nor pleasant enough to be worthwhile. “This research has meant a lot to me since it has improved my life,” she said.
Karin had to finish a rehabilitation regimen that helped her forearm bones, the radius and ulna, regain strength before she could begin using DeTOP’s bionic hand. (Bones can weaken after partial amputations because they’re less common.) She had to use virtual reality to practice controlling her missing hand. The bionic hand was then electrically wired to Karin’s nervous system and bonded to her bones. Karin is able to control each finger and feel pressure and texture thanks to electrodes that have been placed in her forearm and linked to the bionic hand.
Data from Science Robotics show that Karin’s mobility and general quality of life have improved since getting the bionic hand. Her problems from work and sleep have considerably lessened, as have her phantom pain, limb discomfort, and other symptoms.
Though it’s unclear if DeTOP intends to improve upon its first functional bionic hand, the program’s successes might serve as an inspiration for a new generation of better prosthetics for amputees.