Background: Increasing evidence supports an analgesic effect of repetitive transcranial magnetic
stimulation (rTMS) for neuropathic pain (NP). However, the optimal parameters of rTMS (stimulation
frequency and treatment sessions) for achieving long-term analgesic effects remain unknown. This
study analyzed the current findings in the literature.
Objective: The aim of this study was to assess the optimal parameters of rTMS for NP, including
the rTMS sessions needed for inducing acute as well as long-term analgesic effects.
Study Design: A meta-analysis of the analgesic effect of high frequency rTMS (HF- rTMS) for
neuropathic patients.
Setting: This meta-analysis examined all studies involving the analgesic efficacy of HF-rTMS for
NP.
Methods: PubMed, Embase, and the Cochrane library were searched for clinical studies of rTMS
treatment on NP published before December 31, 2014. Crude standardized mean differences
(SMD) with 95% confidence interval (CI) were calculated for pain intensity after different treatment
sessions (from 1 to 10) and follow-up of one or 2 months after rTMS treatment using random
effect models.
Results: Twenty-five studies (including 32 trials and 589 patients) were selected for the metaanalysis according to the inclusion and exclusion criteria. All 3 HF-rTMS treatments (5, 10, and 20
Hz) produced pain reduction, while there were no differences between them, with the maximal
pain reduction found after one and 5 sessions of rTMS treatment. Further, this significant analgesic
effect remained forone month after 5 sessions of rTMS treatment.
Limitations: There are limitations of this meta-analysis. For example, the long-term analgesic
effects of different HF-rTMS and low frequency (LF) rTMS sessions, including the single session of
rTMS on different NP of varying origins have yet not been evaluated; the full degree of pain relief
is still unclear for many rTMS studies.
Conclusions: HF-rTMS stimulation on primary motor cortex is effective in relieving pain in NP
patients. Although 5 sessions of rTMS treatment produced a maximal analgesic effect and may
be maintained for at least one month, further large-scale and well-controlled trials are needed
to determine if this enhanced effect is specific to certain types of NP such as post-stroke related
central NP.
Key words: High frequency, repetitive transcranial magnetic stimulation, neuropathic pain,
single stimulation, multiple stimulation, meta-analysis
Analgesic Effect of Recombinant GABAergic Cells in a Model of Peripheral Neuropathic Pain