A team at Case Western University has created a prosthetic arm with a greater sense of human touch.
It can vary the pressure, depending on the task.
Pressure sensors in the hand send electrical signals to bundles of nerves in a patient's arm.
Those signals go to the brain, telling the user whether the grip is right, or needs adjusting.
Keith Vanderheuvel says he can now hold his granddaughters without gripping too hard.
"Without sensation, you can't tell. With sensation on, I grabbed her with both hands and picked her up and was holding her and not squeezing too tight. And she gave me a big hug. That one just, that one gets to me," he said.
Keith can also now butter toast and break eggs for breakfast without crushing them.
On a trip to Washington to show the technology to the VA, he shook defense secretary Ash Carter's hand with his right hand, not his left.
And he no longer thinks of his prosthetic arm as a "tool," but a part of himself.
Researchers create prosthetic arm with sense of human touch