Distinct behavioral response of primary motor cortex stimulation in itch and pain after burn injury

Model System:

Burn

Reference Type:

Journal article

Accession No.:

J89134

Journal:

Neuroscience Letters

Year, Volume, Issue, Page(s):

2019 , 690, , 89-94

Publication Website:

Abstract:

Study assessed the effects of transcranial direct current stimulation (tDCS) on post-burn neuropathic pain and itch. A randomized controlled clinical trial was conducted comprised of two phases of active or sham primary motor cortex (M1) tDCS. Sixteen patients were assigned to the active group and 15 to the sham group. Phase I consisted of 10 stimulation sessions followed by a follow-up period of 8 weeks; Phase II included an additional 5 sessions followed by a follow-up period of 8 weeks, and a final visit 12 months from baseline). Pain levels were assessed with the Brief Pain Inventory and levels of itch severity were assessed with the Visual Analogue Scale. Measurements were collected at baseline, after the stimulation periods, at 2, 4 and 8-week follow up both for Phase I and II, and at the final visit. Ten sessions of active tDCS did not reduce the level of pain or itch. Itch levels were reduced at 2-week follow-up after the sham tDCS session, while no placebo effect was found for the active group. No difference between active and sham groups was observed for pain. Results did not show any treatment effects during Phase II. Based on these findings, it seems that an important placebo effect occurred during sham tDCS for itch, while active M1 tDCS seems to disrupt sensory compensatory mechanisms. The authors conclude that pain and itch are complementary but distinct mechanisms of adaptation after peripheral sensory injury following a burn injury and need to be treated differently.

Author(s):