Regaining the Sense of Touch

Prosthetic hands have progressed significantly in the past few years in terms of functionality and general mechanics, but there is still one aspect of prosthesis’ that hasn't vastly improved, touch. The sense of touch has proved to be the most difficult aspect to manipulate amongst prosthetic hands, due to the varying factors of pressure, vibration, and temperature. The majority of prosthetic hands are controlled by visual cues and physical movements by the user, not on the natural sense of touch. This makes handling fragile objects nearly impossible and a major impedance of using a prosthetic device. The developers from SynTouch LLC sought to fix this problem through the development of BioTac. BioTac is a liquid-filled, biomimetic tactile sensor that is placed on the finger of a prosthetic for sensing surfaces. It mimics the natural fingertip through pressure sensing and measuring directional forces due to the displacement of the fluid in the elastic skin. This information can then be relayed back to the prosthetic device to which it is attached in order to stop constriction and maintain control of the object. The sensors used to comprise BioTac are complex due to the three-dimensional nature of sensing, which complicates matters for the signaling process. Beyond rudimentary signaling devices, such as tactors, effective communication from the BioTac hasn’t been achieved. Tactors, such as an air pressure cuff, can give the person using the BioTac an idea of how much pressure is being applied to the object through a set response. The goal for the signaling process is to for the individual to be able to control the prosthetic through his/her thoughts. Targeted Muscle Reinnervation has proven to be successful for some prosthetic patients to be able to “feel” the presence of a limb. Through the use of this surgery, BioTac, and coordination with the brain, the restoration of touch is not all too unfeasible.  

                The advancement of biomedical devices, such as BioTac, are fascinating to me in that they can significantly improve the life of an individual. For people to have lost a sense, and then to be able to regain that sense through a device is amazing in my opinion. Positively changing people’s lives through biomedical implantation should be the ultimate goal of this portion of biomedical engineering.

               

http://www.the-scientist.com/?articles.view/articleNo/32513/title/Missing-Touch/