Stimulation Parameters Used During Repetitive Transcranial Magnetic Stimulation for Motor Recovery and Corticospinal Excitability Modulation in SCI: A Scoping Review

Abstract

There is a growing interest in non-invasive stimulation interventions as treatment strategies to improve functional outcomes and recovery after spinal cord injury (SCI). Repetitive transcranial magnetic stimulation (rTMS) is a neuromodulatory intervention which has the potential to reinforce the residual spinal and supraspinal pathways and induce plasticity. Recent reviews have highlighted the therapeutic potential and the beneficial effects of rTMS on motor function, spasticity, and corticospinal excitability modulation in SCI individuals. For this scoping review, we focus on the stimulation parameters used in 20 rTMS protocols. We extracted the rTMS parameters from 16 published rTMS studies involving SCI individuals and were able to infer preliminary associations between specific parameters and the effects observed. Future investigations will need to consider timing, intervention duration and dosage (in terms of number of sessions and number of pulses) that may depend on the stage, the level, and the severity of the injury. There is a need for more real vs. sham rTMS studies, reporting similar designs with sufficient information for replication, to achieve a significant level of evidence regarding the use of rTMS in SCI.

The Role of Transcranial Magnetic Stimulation, Peripheral Electrotherapy, and Neurophysiology Tests for Managing Incomplete Spinal Cord Injury

“…The conclusions are similar to ours—there are still many gaps in the rTMS algorithms presentation and, in general, in SCI research. This summary also confirms that TMS is a minimally invasive, safe, and easy-to-use method that may provide various positive clinical and neurophysiological results and should be considered in the rehabilitation of the SCI population [ 37 ].…”

“…A very interesting summary of the literature on the use of TMS as a therapeutic method was used by Brihmat et al [ 37 ]. He and his team provide a very detailed analysis of various stimulation algorithms and their evaluation methods.…”

Activation of MAP2K signaling by genetic engineering or HF-rTMS promotes corticospinal axon sprouting and functional regeneration

“…A wide array of rTMS parameters has been tested in patients with SCI for therapeutic purposes, with variable functional outcomes ( 104 ). The exact downstream mechanisms by which rTMS enables neuroplasticity, axon growth, and certain long-lasting effects in neurological patients remain to be fully elucidated ( 105 ).…”

The effectiveness and safety of repetitive transcranial magnetic stimulation on spasticity after upper motor neuron injury: A systematic review and meta-analysis

“… Todd et al (2010) discovered that the effect of the 6 Hz rTMS was greater in young adults than in old individuals. Brihmat et al (2022) concluded that young patients usually had greater potential for inducing plasticity changes in response to rTMS than elder participants. Hanlon and McCalley (2022) found that gender maybe a critical influencing factor on the effect of rTMS, and they inferred that the reason may be related with gender difference in gray matter density and gyrification, proximity of the brain to the scalp and cortical excitability.…”

“…Studies were excluded if they met one of the following criteria: (1) factorial RCTs ( Montgomery et al, 2003 ), N of 1 RCT ( Ulbrich-Zurni et al, 2018 ) or cluster RCTs ( Ribeiro et al, 2018 ); (2) full text were unavailable through various approaches; (3) duplications; (4) the data cannot be extracted; (5) other patterns of TMS, such as deep TMS, paired associative stimulation; (6) other non-invasive brain stimulation techniques, such as transcranial direct current stimulation (tDCS) and electrical stimulation alone ( Brihmat et al, 2022 ).…”