Noninvasive brain stimulation promising for managing brachial plexus injury pain

Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct-current stimulation (tDCS) can effectively treat neuropathic pain after brachial plexus injury (NPBPI) without aggravating pain and anxiety state, a recent study has found.

Twenty NPBPI patients were enrolled into the present randomized, placebo-controlled study. Twelve patients (mean age 34 years, 100 percent men) received either 10-Hz rTMS or anodal 2 mA tDCS, which were applied over the motor cortex over five daily consecutive sessions; after a 30-day interval, participants were given the alternative stimulation condition.

Outcomes, including the improvement in pain intensity as per a visual analogue scale, were compared with the remaining eight patients (mean age 31 years, 100 percent men) who received sham rTMS and tDCS in the same format as the active interventions.

Compared with sham controls, both rTMS (p=0.016) and tDCS (p=0.047) stimulation led to significantly lowered normalized pain intensity scores. Pain relief was likewise greater after the fifth consecutive stimulation session and after the 30-day interval for rTMS (p<0.001 and p=0.033, respectively) and tDCS (p<0.001 and p=0.005, respectively), as compared with pre-stimulation.

In particular, rTMS and tDCS were able to induce a significantly stronger analgesic effect relative to the sham intervention after the fifth session and after the 30-day interval. The difference between rTMS and tDCS did not reach statistical significance.

“Our results highlight the potential use of tDCS for chronic pain management in traumatic brachial plexus injuries with little distinction from rTMS, which may promote the use of an easier and more available technique as part of an interdisciplinary approach in rehabilitation services for patients following upper limb deafferentation,” the researchers said.