Prosthetic Hands

Every morning when we wake up, we can easily unscrew the cap on the toothpaste tube or open the fridge to pour ourselves a glass of milk. Without putting much thought into it, we use our hands to do almost anything and everything. What would happen if suddenly our ability to do one of these basic tasks suddenly declined? What would happen if we could only use of our hands to tie our shoes or get dressed? While this may bring troublesome thoughts in our minds, many people must face this exact situation on a daily basis.

However, with newer, better, and more promising technology, hand amputees may soon be able to obtain prosthetic hands that are powered by their own thoughts. Scientists at the University of Houston have created a method that is not invasive and can allow amputees to do the basics task of holding a bottle and credit cards with an eighty percent success rate. This entire process is done through the thought process and was created by an algorithm. Interestingly enough, the new hand shows similar success rates as the myoelectric hand that comes with the invasive procedure.

This new type of prosthetic arm incorporates the use of measuring the tiny electrical signals that flow out of the scalp which are captured by an electroencephalogram or EEG. The EEG cap covers the amputees head and the neural activity captured is converted into motor signals which allows for the amputee to grasp objects – at this point bottles and cards are tested. The reason this works is because the researchers claim that the brain is supposed to predict plausible movement. The noninvasive process definitely has its perks which include the no risk from surgical processes as well as helping those who may not have the neural activity that remains with the muscles.

However, the myoelectric prosthetic hand briefly mentioned before may actually be better for other cases. As Dr. Akhtar mentioned in his talk about designing a myoelectric hand, there are at least 30 million people with hand amputations in poor countries. The myoelectric prosthetic hand created by his team known as the Dextrus is certainly more affordable and allows for a wider range of grasps in addition to being able to grasp a bottle. These grasps range from being able to have a grip on a drill or a key to a small battery as well as other small household items. Myoelectric prosthetic hands work by electrodes being implanted deep into the muscles and nerve in the arm. This would result in myoelectric control of the arm where the electrical signals from the muscles would cause the prosthetic hand to function and move.

When it comes to comparing the different types of prosthetic hands available, it is important to realize that there is still a long journey ahead. While the Dextrus offers a wider range of motion due to its control being myoelectric, the prosthetic hand controlled by EEG signals is noninvasive. Perhaps, the ideal hand will come in the future which combines both of these methods. Until then remember to appreciate your hands every morning.

Akhtar, A., Bretyl, T., Nguyen, M., Slade, P. (2015). Tact: design and performance of an open-

source, affordable, myoelectric prothetic hand.The International Conference on Robotics
and Automation, 1-6.

University of Houston. (2015, March 31). Non-invasive technique allows amputee to use

bionic hand, powered by his thoughts. ScienceDaily.  http://www.sciencedaily.com/releases/2015/03/150331131336.htm