Analysis of somatosensory evoked potentials after noninvasive electrocutaneous stimulation of foot and thigh

Following major amputations and the
consequent truncation of nerves, up to 45-85% of
patients are left with a neuropathic pain condition
known as phantom limb pain (PLP). Recent research
has shown that the addition of somatosensory feedback to daily use prostheses has the potential to
alleviate the phenomenon of PLP, as long as a natural sensation, “as if” it was coming from the missing
limb, is restored. One approach to evaluating how
natural a sensation is perceived, is by studying the
neural correlates of somatosensory stimulation,
known as somatosensory evoked potentials (SEPs).
Source localization techniques such as dipole modeling may be used to reconstruct the neural sources of
SEPs, thus mapping the origin of each sensation
within the somatosensory homunculus. Source localization of SEPs has already been demonstrated to
discriminate stimulations in the upper-limb/mouth
corners and between left/right side of the body, however, no evidence so far is present for the lower limb
and same body side. In this work, the discriminability
of SEPs relative to foot vs. thigh stimulations on the
same body side is being studied. The spatiotemporal
evolution of SEPs is analyzed, and preliminary
source localization results are presented.