Restoring somatosensory feedback to people with limb amputations is crucial for improving prosthesis acceptance and function. Epidural spinal cord stimulation is a commonly used clinical procedure that targets sensory neural pathways in the dorsal spinal cord to treat pain conditions. A similar approach could be developed as a clinically translatable means to restore somatosensation in amputees. We show that epidural stimulation of the dorsal spinal cord evoked sensory percepts, perceived as emanating from the amputated arm and hand, in four people with upper-limb amputation. After an initial caudal movement immediately following the implantation, the leads stabilized, exhibiting a median migration of <5 mm (each electrode contact is 3 mm long) over the remainder of the study in all the subjects. This was reflected in the consistent locations of evoked percepts in the hand across four subjects throughout the period of implantation, which lasted up to 29 days. The median change in the centroid location was 1.2 to 35.3 mm and the median change in percept area was 0 to 40%. While most of the evoked percepts were paresthetic in nature, a subset was described as naturalistic (e.g. touch or pressure) in three subjects. Modulating the stimulus amplitude affected the perceived intensity of the sensation in all subjects. A variety of sensory percepts were evoked in all subjects irrespective of the level of amputation or the time since amputation, suggesting the approach is amenable to a diverse population of amputees.
Correction: Sensory restoration by epidural stimulation of the lateral spinal cord in upper-limb amputees
