Data from: Insular and anterior cingulate cortex deep stimulation for central neuropathic pain: disassembling the percept of pain

Objective: To compare the analgesic effects of stimulation of the anterior
cingulate cortex (ACC) or the posterior superior insula (PSI) against sham
deep (d) repetitive (r) transcranial magnetic stimulation (TMS) in
patients with central neuropathic pain (CNP) after stroke or spinal cord
injury in a randomized, double-blinded, sham-controlled, 3-arm parallel
study. Methods: Participants were randomly allocated into the active
PSI-rTMS, ACC-rTMS, sham-PSI-rTMS, or sham-ACC-rTMS arms. Stimulations
were performed for 12 weeks, and a comprehensive clinical and pain
assessment, psychophysics, and cortical excitability measurements were
performed at baseline and during treatment. The main outcome of the study
was pain intensity (numeric rating scale [NRS]) after the last stimulation
session. Results: Ninety-eight patients (age 55.02 ± 12.13 years)
completed the study. NRS score was not significantly different between
groups at the end of the study. Active rTMS treatments had no significant
effects on pain interference with daily activities, pain dimensions,
neuropathic pain symptoms, mood, medication use, cortical excitability
measurements, or quality of life. Heat pain threshold was significantly
increased after treatment in the PSI-dTMS group from baseline (1.58, 95%
confidence interval [CI] 0.09–3.06]) compared to sham-dTMS (−1.02, 95% CI
−2.10 to 0.04, p = 0.014), and ACC-dTMS caused a significant decrease in
anxiety scores (−2.96, 95% CI −4.1 to −1.7]) compared to sham-dTMS (−0.78,
95% CI −1.9 to 0.3; p = 0.018). Conclusions: ACC- and PSI-dTMS were not
different from sham-dTMS for pain relief in CNP despite a significant
antinociceptive effect after insular stimulation and anxiolytic effects of
ACC-dTMS. These results showed that the different dimensions of pain can
be modulated in humans noninvasively by directly stimulating deeper SNC
cortical structures without necessarily affecting clinical pain per se.