Losing an arm does not mean losing all sense of touch as researchers have developed a new sensorial control module that allows prosthetic users to feel and hold things as delicate as a child's hand.
"We are returning the feeling to someone who lost his hand, the idea is that we no longer want the prosthetic hand to feel like a tool, we want it to feel like an extension of the body," said Aadeel Akhtar of the University of Illinois in Urbana-Champaign in the United States.
"Commercial prosthetics do not have a good sensory response, this is a step towards obtaining reliable sensory information for prosthetic users," said Akhtar, lead author of an article describing the sensory control module.
In the study published in the journal Science Robotics, the researchers described a control algorithm that regulates the current so that the prosthesis user feels a constant sensation, even when the electrodes begin to detach or when the sweat accumulates.
Prosthetic arms that offer nerve stimulation have sensors on the fingertips, so that when the user comes in contact with something, an electrical signal on the skin corresponds to the amount of pressure exerted by the arm.
For example, a light touch would generate a feeling of light, but a hard impulse would have a stronger signal.
However, there have been many problems in providing users with reliable comments, said study lead researcher Timothy Bretl, a professor at the University of Illinois at Urbana-Champaign.
During normal use over time, electrodes connected to the skin may begin to detach, causing an accumulation of electrical current in the area that remains attached, which can give painful discharges to the user.
Alternatively, sweat can impede the connection between the electrode and the skin, so that the user feels less or even no feedback at all.
"A stable and reliable sensory experience could significantly improve the quality of life of a prosthetic user," Bretl said.
The new controller monitors the comments that the patient is experiencing and automatically adjusts the current level so that the user feels a constant response, even when sweating or when the electrodes are detached by 75%, the study said.
In a test in which electrodes were progressively peeled backward, the researchers found that the control module reduced electrical current so that users reported constant feedback without shocks.
The researchers believe that adding the controlled stimulation module would cost much less than the prosthesis itself.
The group is working on the miniaturization of the module that provides the electrical feedback, so that it fits inside a prosthetic arm instead of joining it to the outside.
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(This story has not been edited by the Business Standard staff and is automatically generated from a syndicated feed)