Algorithm allows amputee to use thought-powered bionic hand

Researchers, including one of Indian-origin, have developed an algorithm that enabled a man whose right hand had been amputated to grasp objects using a bionic hand controlled by his thoughts.
The technique uses non-invasive brain monitoring, capturing brain activity to determine what parts of the brain are involved in grasping an object.
With that information, researchers created a computer programme, or brain-machine interface (BMI), that harnessed the subject's intentions and allowed him to successfully grasp objects, including a water bottle and a credit card.
The 56-year-old subject grasped the selected objects 80 per cent of the time using a high-tech bionic hand fitted to the amputee's stump.

Previous studies involving either surgically implanted electrodes or myoelectric control, which relies upon electrical signals from muscles in the arm, have shown similar success rates, according to the researchers.
Jose Luis Contreras-Vidal, a neuroscientist and engineer at University of Houston (UH), said the non-invasive method offers several advantages: It avoids the risks of surgically implanting electrodes by measuring brain activity via scalp electroencephalogram, or EEG.

And myoelectric systems aren't an option for all people, because they require that neural activity from muscles relevant to hand grasping remain intact.
The work, involving graduate student Harshavardhan Ashok Agashe, demonstrates for the first time EEG-based BMI control of a multi-fingered prosthetic hand for grasping by an amputee.

It also could lead to the development of better prosthetics, Contreras-Vidal said.
Beyond demonstrating that prosthetic control is possible using non-invasive EEG, researchers said the study offers a new understanding of the neuroscience of grasping and will be applicable to rehabilitation for other types of injuries, including stroke and spinal cord injury.
The study subjects - five able-bodied, right-handed men and women, all in their 20s, as well as the amputee - were tested using a 64-channel active EEG, with electrodes attached to the scalp to capture brain activity.
Contreras-Vidal said brain activity was recorded in multiple areas, including the motor cortex and areas known to be used in action observation and decision-making, and occurred between 50 milliseconds and 90 milliseconds before the hand began to grasp.

That provided evidence that the brain predicted the movement, rather than reflecting it, he said.
The study was published in the journal Frontiers in Neuroscience.