Experimental neurology
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Experimental neurology · May 2007
Randomized Controlled TrialReaction to topical capsaicin in spinal cord injury patients with and without central pain.
Central neuropathic pain is a debilitating and frequent complication to spinal cord injury (SCI). Excitatory input from hyperexcitable cells around the injured grey matter zone is suggested to play a role for central neuropathic pain felt below the level of a spinal cord injury. Direct evidence for this hypothesis is difficult to obtain. ⋯ Touch, punctuate stimuli, cold stimuli and topical capsaicin was applied above, at, and below injury level in 10 SCI patients with central pain below a thoracic injury, in 10 SCI patients with a thoracic injury but without neuropathic pain, and in corresponding areas in 10 healthy control subjects. The study found increased responses to touch at injury level compared to controls (p=0.033) and repetitive punctuate stimuli above and at injury level compared to controls and pain-free SCI patients (p<0.04) but not an increased response to capsaicin in patients with central pain. These results suggest that SCI patients with below-level pain have increased responses to some but not all sensory input at the level of injury.