Three men in Austria have received the world’s first prosthetic hands that respond to thought, just as a natural hand does. The appendage is capable of reading signals from the brain and translating them into nerve and muscle function using a procedure doctors refer to as “bionic reconstruction.”

In their study, now published in the online journal The Lancet, the team of researchers from the Medical University of Vienna in Austria have outlined how they were able to successfully complete, not one, but three bionic reconstructions. Previous bionic hands were controlled by the owners using manual settings, The Associated Press reported. This new bionic hand is able to directly get the brain's messages to the new body part, eliminating the need for a third party.

The procedure is split into three steps: The first step involves preparing patients for both the physical and mental changes brought on by the bionic hands. According to the study, this involves an electromyography test, a type of procedure used to check the health of both the muscles and the nerves which control them.

During this test, the researchers may insert a thin needle electrode through the skin into the muscles below and use it to pick up the electrical activity given off by the muscles, The National Library of Health explains. Patients are asked to do activities such as bend their fingers in order to help the sensor measure the muscles’ response to nerve stimulation.

The second step of the procedure involves the physical amputation of the limb. All three men in the study still had their hands but were severely limited in their dexterity due to serious accidents.

“The decision to let go of his own hand is definitely not an easy one. Why? Because the patient still has a hand. But you must not forget that these patients have lived without hand function for about 10, 15 years, and they know what it means to live without hands,” explained lead researcher Professor Oskar Aszmann, EuroNews reported.

The final step is the actual fitting of the bionic hand. This step occurs around six months following the amputation. Once the Austrian patients had their bionic hands fitted, they followed a tailored rehabilitation program designed to enhance the electromyographic signals and their cognitive function.