Phantom hand activation during physical touch and targeted transcutaneous electrical nerve stimulation
Restoring the sense of touch is a critical component for a closed-loop prosthetic limb. In an upper limb amputee, we explored regions on the residual limb that elicited sensory activation of the phantom hand through either physical touch or targeted transcutaneous electrical nerve stimulation (tTENS). We found that sensory sites on the residual limb responded to either physical touch or tTENS, but typically not both. Further, some regions of the phantom hand were only activated with one of the stimulation modalities, such as the thumb or wrist. Interestingly, some locations on the phantom hand could be activated with either physical touch or tTENS but at different locations on the residual limb. Our work helps highlight potential differences in perceived location of sensory feedback depending on the stimulation modality.