Researchers are developing prosthetic limb technology, allowing amputees to more effectively interact with the world around them. By integrating biology with mechanics, prosthetic technology allows amputees to engage in simple daily activities that may once have been challenging. Researchers are able to design prosthetics capable of reading brain signals from the patient, and translating the information into subtle arm and hand movements. Research from Swedish and American scientists has begun recreating artificial sensation in amputees, through a more seamless connection between technology and biology.
A paper published in the Science Translational Medicine journal earlier this month documented the success of a long term, first of its kind, prosthesis study. In January 2013 Max Ortiz Catalan and his team at Chalmers University of Technology, Gothenburg, connected a prosthetic arm directly into the bone, nerves and muscles of the arm of an amputee. The process of connecting an artificial implant to the bone is known as osseointegration, rather than conventional methods that connect the prosthetic via the skin. The Swedish team used this technique to create a more stable connection between the artificial limb and biology of the amputee. Neuromuscular electrodes were fused with the nerves and muscles of the arm to send signals to the control system. This way the user may more effectively control the arm with their mind.
Osseointegration was originally developed by Richard Branemark and colleagues at Sahlgranska Univeristy Hospital. Max Ortiz Catalan collaborated with Richard Branemark on this current, long term, research project. Through osseointegration the Swedish amputee may perform once challenging routine tasks with greater precision and care. Driving a truck for his living he may now better operate the machinery and clamp a trailer load. The patient has described his new arm as feeling “like a real arm, it’s working so well.” The durable arm may be easily attached and detached at the titanium connector.
Max Ortiz Catalan’s research is the first osseointegration study to analyse the long term effects of the technique. The results appear to show success in improving an amputee’s quality of life, and similar patients may receive the treatment later this year. The team are keen to expand the integration of biology and technology by developing the sense of touch in prosthetics. Whilst the patient may send signals from their brain, through neuromuscular electrodes and into the arm, researchers also want the signal to work in the other direction. Therefore, the process may be bidirectional.
Research from America at Case Western Reserve University has recently made similar, valuable contributions to this field – helping to solve the challenge of regaining sensation. The research from Daniel W. Tan and his colleagues has allowed two amputees to regain the sense of touch, by attaching their bionic hand to the nervous system. The team mapped certain sensations to different parts of the hand, giving the amputees the ability to sense pressure and texture. The patients described the sense as ‘natural’. Both the Swedish and American teams may one day combine their bionic technological advances. By bringing together bone, muscle and nerve integration with a ‘natural’ sense of touch, prosthetic technology may become more lifelike.
“Going beyond the lab to allow the patient to face real-world challenges is the main contribution of this work.” says Max Ortiz Catalan on prosthetic technology. The technology aims to create natural bionic attachments for amputees, allowing them to perform daily activities with ease. This may be done through an understanding of the nervous system – seamlessly uniting the brain and machine in effective cooperation.
How else may bionic limb technology advance?