Prosthetic hand works by Brain-computer interfaces (BCIs), which read signals from small groups of neuronal cells.
For the BCIs to work, electrodes should be implanted into the brain to read signals and to distinguish narrowly defined activities. The implantation limits the capabilities of BCIs and constraints it to small experiments.
Researchers at the University of Houston used a traditional electroencephalography (EEG) to deal with this limitation and identified brain signals, which worked when volunteers reached to grasp objects.
The advanced interpretation of these signals is captured non-invasively and was then used to create a template to be able to identify hand grasps in an amputee. The amputee was able to control a prosthetic hand using nothing but the power of thought. Researchers believe that one day they will develop thought-controlled prosthetic devices that don't require a hole in the skull.