Sensory feedback restoration in leg amputees improves walking speed, metabolic cost and phantom pain

• Published in: Nature Medicine Vol. 25; no. 9; pp. 1356 - 1363
• Main Authors: Petrini, Francesco Maria, Bumbasirevic, Marko, Valle, Giacomo, Ilic, Vladimir, Mijović, Pavle, Čvančara, Paul, Barberi, Federica, Katic, Natalija, Bortolotti, Dario, Andreu, David, Lechler, Knut, Lesic, Aleksandar, Mazic, Sanja, Mijović, Bogdan, Guiraud, David, Stieglitz, Thomas, Alexandersson, Asgeir, Micera, Silvestro, Raspopovic, Stanisa
• Format: Journal Article Magazine Article
• Language: English
• Published: New York Nature Publishing Group US 01.09.2019; Nature Publishing Group
• Subjects: 631/378/1959/2605; 631/378/2620/2621; 631/378/2620/410/2610; 692/308/575; Adult; Amputation; Amputees - rehabilitation; Artificial Limbs; Automatic; Biomechanical Phenomena; Biomedical and Life Sciences; Biomedicine; Cancer Research; Clinical trials; Engineering Sciences; Fatigue; Feedback; Feedback, Sensory; Feet; Human health and pathology; Humans; Infectious Diseases; Knee; Knee - innervation; Knee - physiopathology; Leg; Letter; Life Sciences; Male; Metabolic Diseases; Middle Aged; Molecular Medicine; Neural prostheses; Neurobiology; Neurons and Cognition; Neurosciences; Pain; Phantom Limb - physiopathology; Phantom Limb - prevention & control; Population studies; Prosthetics; Restoration; Sensors; Sensory feedback; Stimulation; Tibial nerve; Tissues and Organs; Trans-femoral amputees; Walking; Walking Speed - physiology; Serbia; Neuroprothèses; Neuroprostheses; Sensation fantôme; Stimulation neurale sélective; Amputation
• ISSN: 1078-8956; 1546-170X; 1744-7933
• DOI: 10.1038/s41591-019-0567-3

Conventional leg prostheses do not convey sensory information about motion or interaction with the ground to above-knee amputees, thereby reducing confidence and walking speed in the users that is associated with high mental and physical fatigue 1 – 4 . The lack of physiological feedback from the remaining extremity to the brain also contributes to the generation of phantom limb pain from the missing leg 5 , 6 . To determine whether neural sensory feedback restoration addresses these issues, we conducted a study with two transfemoral amputees, implanted with four intraneural stimulation electrodes 7 in the remaining tibial nerve (ClinicalTrials.gov identifier NCT03350061). Participants were evaluated while using a neuroprosthetic device consisting of a prosthetic leg equipped with foot and knee sensors. These sensors drive neural stimulation, which elicits sensations of knee motion and the sole of the foot touching the ground. We found that walking speed and self-reported confidence increased while mental and physical fatigue decreased for both participants during neural sensory feedback compared to the no stimulation trials. Furthermore, participants exhibited reduced phantom limb pain with neural sensory feedback. The results from these proof-of-concept cases provide the rationale for larger population studies investigating the clinical utility of neuroprostheses that restore sensory feedback. A new prosthetic leg that can transmit sensory signals via implanted electrodes is shown to restore meaningful sensory feedback that improves walking performance and lowers phantom limb pain during use in two human lower-limb amputees.