The efficacy and safety of repetitive transcranial magnetic stimulation for comorbid chronic low back pain and insomnia: A randomized, double-blind, sham-controlled pilot trial

Repetitive transcranial magnetic stimulation (rTMS) has shown efficacy in treating chronic pain or insomnia independently. Given the high prevalence of insomnia in individuals with chronic low back pain (CLBP), this pilot randomized controlled trial assessed the feasibility, acceptability, and preliminary efficacy of rTMS targeting either the left primary motor cortex (M1) or right dorsolateral prefrontal cortex (DLPFC) in individuals with comorbid CLBP and insomnia. Thirty-six participants were randomized to receive sham-rTMS, active M1-rTMS (10 Hz, 1500 pulses), or active DLPFC-rTMS (1 Hz, 1500 pulses) over 10 sessions for two weeks (five sessions per week), with a one-month follow-up. Primary outcomes were feasibility and acceptability. Secondary outcomes included pain intensity, insomnia severity, disability, psychological measures, subjective and objective sleep parameters, pain threshold, temporal summation of pain, and conditioned pain modulation. rTMS was highly feasible and acceptable, as evidenced by excellent session attendance and no participant attrition. No serious adverse events were reported. Both active M1- and DLPFC-rTMS significantly reduced pain intensity and enhanced the descending pain inhibitory pathways compared with sham stimulation. Importantly, DLPFC-rTMS was superior to sham in reducing insomnia severity, objective wake after sleep onset, and temporal summation of pain. These findings suggest that rTMS is a feasible, well-tolerated, and promising intervention for individuals with comorbid CLBP and insomnia. While both stimulation protocols yielded analgesic benefits, DLPFC-rTMS may confer additional advantages for addressing sleep disturbance. Further full-scale randomized clinical trials are warranted to validate these preliminary findings and optimize rTMS protocols for this complex clinical population. Perspective: rTMS was feasible for comorbid chronic low back pain and insomnia, with DLPFC stimulation yielding superior effects on sleep disturbance and pain processing. Further large-scale RCTs using neuroimaging are warranted to validate and expand upon these preliminary results and elucidate the neurophysiological basis of treatment efficacy.