Referred Sensation Areas in Bilateral Upper Limb Amputee

Phantom limb pain (PLP) following amputation considerably reduces the quality of life, given a difficult to treat pain of highly variate profile. The loss of sensory input induces a complex pattern of neuroplastic changes of the sensory neural pathways and their central projections. Referred sensation areas (RSAs) may occur on the stump as a consequence of amputation, providing a direct path towards the altered central sensory projections. Modulated electrical stimulation of RSAs was investigated in a long-term experiment in the case of a 62 years-old participant with bilateral upper limb amputation due to traumatic injury. RSAs were investigated using mechanical (vibration and pressure) and electrical stimuli over five sessions within a five weeks period. Further test of sensations induced by steady state and modulated electrical stimuli was performed during additional 4 sessions. Location and features of RSAs were highly dependent on the type of stimulus and time of delivery between sessions.Clinical Relevance— The case study presents a variety of types and locations of the sensation induced by electrical and mechanical stimuli that may eventually be used as artificially generated sensory input as individualized alternative form of therapy for PLP alleviation. Furthermore, possible multichannel stimulus delivery on RSAs on both arms and the cross-over effect of the bilateral amputation in perception of the induced sensation in the opposite phantom hand may be considered in dedicated design of an experimental setup that may possibly help investigation of mechanisms for PLP.