Optimize the Effects of Repetitive Transcranial Magnetic Stimulation on Neuropathic Pain
Condition: Neuropathic Pain; Repetitive Transcranial Magnetic Stimulation
MeSH terms: Neuralgia
Study type: Interventional

Summary: 
      Neuropathic pain (NP) is one type of refractory chronic pain condition,medical treatments for
      NP is limited because of its poorly response.Repetitive transcranial magnetic stimulation
      (rTMS) can induce neuroplastic changes which has been used to manage chronic pain conditions.
      Indeed, high-frequency (≥ 5 Hz) rTMS over the primary motor cortex (M1) is suggested to be
      able to reduce neuropathic pain in randomized controlled studies. Overall, the clinical
      application of rTMS in chronic pain is still limited by the response rate, whereby it is
      close to moderate and far from being excellent at its best. Therefore this project designed a
      series of clinical trials to optimize the analgesic efficacy of rTMS. According to the
      research results of investigators previous project, patients with neuropathic pain were
      divided into responders and non-responders after 5 consecutive days of 10HZ rTMS or pcTBS
      intervention (see project ID:2021-0751)according to the change of pain intensity, and then
      different trials will be applied to responders and non-responders to optimize the analgesic
      effect of rTMS.
    

Detailed description: 
      For non-responders (whose visuo-analogic scale (VAS) decreased less than 20 mm or
      T1-T0/T0×100%<30%), a feasible method is to switch stimulation targets. So the investigator
      will change the stimulation target from M1 to dorsolateral prefrontal cortex (DLPFC), and
      then delivered another 5 days consecutive interventions to assess the efficacy.

      For responders (whose VAS decreased an average of 20 mm or more or T1-T0/T0×100%≥30%), the
      investigator further investigate the long-lasting effect of rTMS. the patients will
      participate a continuous trials (2 sessions weekly for 2 weeks) and 4 weeks follow up.
    

Intervention name(s): Repetitive transcranial magnetic stimulation; Repetitive transcranial magnetic stimulation
Intervention type(s): Device; Device
Intervention description(s): Magnetic stimulation was performed using a figure-eight coil connected to a Magstim Rapid2 system, All patients seat in a comfortable reclining chair and delivered pcTBS protocol using repetitive transcranial magnetic stimulation . The stimulation intensity was set to 80% of the resting motor threshold, which is measured as the minimal intensity of stimulation evoking an electromyographic response ≥50µV on the first dorsal interosseus muscle of the hand contralateral to the stimulated hemisphere in at least 5 out of 10 trials. For this measurement, a figure-of-eight coil is positioned over the hand motor hotspot and oriented perpendicular to the central sulcus (parallel to the hemispheric midline).; Magnetic stimulation was performed using a figure-eight coil connected to a Magstim Rapid2 system, All patients seat in a comfortable reclining chair and delivered 10HZ protocol using repetitive transcranial magnetic stimulation . The stimulation intensity was set to 80% of the resting motor threshold, which is measured as the minimal intensity of stimulation evoking an electromyographic response ≥50µV on the first dorsal interosseus muscle of the hand contralateral to the stimulated hemisphere in at least 5 out of 10 trials. For this measurement, a figure-of-eight coil is positioned over the hand motor hotspot and oriented perpendicular to the central sulcus (45° away from the hemispheric midline).
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Intervention model description: After 5 consecutive days of 10HZ rTMS or pcTBS intervention of previous study, patients were divided into responders and non-responders according to the change of pain intensity measured with VAS and both of them will receive different trial of interventions.
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Prevention