Medical Research: Sensory feedback improves leg prosthetic use

A new prosthetic leg that can restore sensory feedback signals is shown to improve walking performance and reduce phantom limb pain during use in a case study of two patients, published this week in Nature Medicine.

Neural prosthetics that allow direct interaction between the nervous system and external devices - also known as brain - machine interfaces - can improve the quality of life for patients living with brain or spinal cord injuries, degenerative disease, or the loss of limbs. Although considerable progress has been made in this area, a major hurdle preventing the real-world application of brain - machine interfaces is a lack of ‘sensory’ feedback from the prosthetics. Sensory feedback is needed to help fine-tune motor commands and restore interactions with the external world.

Stansia Raspopovic and colleagues describe an improved prosthetic leg device outfitted with a number of external sensors, representing foot touch and pressure and knee joint angle. These sensors transmit sensory signals back to the nervous system through a set of stimulation electrodes implanted into the tibial nerve. The authors found that, for two patients with lower-limb amputations, the use of this prosthetic improved walking performance and boosted endurance in both a laboratory setting and a real-world environment. In addition, using the prosthetic reduced the patients’ phantom limb pain.

The authors conclude that the proof-of-principle results from this case study demonstrate a promising application of sensory feedback prosthetics in real-world setting. However, future research in larger groups followed for longer periods of time will be required.