Optimize the Effects of Repetitive Transcranial Magnetic Stimulation on Neuropathic Pain

Optimize the Effects of Repetitive Transcranial Magnetic Stimulation on Neuropathic Pain

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.

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.

Inclusion Criteria:

• （1）woman or man over 18 years and under 85 years; （2）Clinical diagnosis of neuropathic pain (3) pain for at least 3 months, at least moderate intensity (≥ 4/10 assessed by VAS) ; (4) stable pharmacological treatment for pain at least 2 weeks before inclusion; (5) able to cooperate in completing questionnaire.

Exclusion Criteria:

• (1)Any clinically significant or unstable ongoing medical or psychiatric disorder including major depression; (2) History of substance abuse (alcohol, drugs); (3) Past treatment with repetitive transcranial magnetic stimulation (rTMS); (4) Contraindications to rTMS (previous severe head trauma or neurosurgical intervention, past or current epilepsy, active brain tumor, intracranial hypertension, implanted ferromagnetic devices, e.g., cardiac pacemaker, neurostimulator, or cochlear implants); (5) other type of pain more severe than neuropathic pain; (6) Any difficulty to fill out questionnaires (due to language or cognitive problems); (7) impossibility to be followed during the time course of the study;