Repetitive transcranial magnetic stimulation on the modulation of cortical and spinal cord excitability in individuals with spinal cord injury

Thyciane Mendonça; Rodrigo Brito; Plínio Luna; Mayara Campêlo; Lívia Shirahige; Luís Fontes; Rebeca Dias; Daniele Piscitelli; Kátia Monte-Silva

doi:10.3233/RNN-211167

Repetitive transcranial magnetic stimulation on the modulation of cortical and spinal cord excitability in individuals with spinal cord injury

Restor Neurol Neurosci. 2021;39(4):291-301. doi: 10.3233/RNN-211167.

Authors

Thyciane Mendonça¹, Rodrigo Brito^{1

2}, Plínio Luna¹, Mayara Campêlo¹, Lívia Shirahige^{1

2}, Luís Fontes¹, Rebeca Dias¹, Daniele Piscitelli^{3

4}, Kátia Monte-Silva^{1

2}

Affiliations

¹ Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, UFPE, Recife, PE, Brazil.
² NAPeN Network (Núcleo de Assistência e Pesquisa em Neuromodulação), Brazil.
³ School of Medicine and Surgery, University of Milano-Bicocca, Milano, Italy.
⁴ School of Physical and Occupational Therapy, McGill University, Montreal, Canada.

PMID: 34334434
DOI: 10.3233/RNN-211167

Abstract

Background: Repetitive transcranial magnetic stimulation (rTMS) has been applied for modulating cortical excitability and treating spasticity in neurological lesions. However, it is unclear which rTMS frequency is most effective in modulating cortical and spinal excitability in incomplete spinal cord injury (SCI).

Objective: To evaluate electrophysiological and clinical repercussions of rTMS compared to sham stimulation when applied to the primary motor cortex (M1) in individuals with incomplete SCI.

Methods: A total of 11 subjects (35±12 years) underwent three experimental sessions of rTMS (10 Hz, 1 Hz and sham stimulation) in a randomized order at 90%intensity of the resting motor threshold and interspersed by a seven-day interval between sessions. The following outcome measures were evaluated: M1 and spinal cord excitability and spasticity in the moments before (baseline), immediately after (T0), 30 (T30) and 60 (T60) minutes after rTMS. M1 excitability was obtained through the motor evoked potential (MEP); spinal cord excitability by the Hoffman reflex (H-reflex) and homosynaptic depression (HD); and spasticity by the modified Ashworth scale (MAS).

Results: A significant increase in cortical excitability was observed in subjects submitted to 10 Hz rTMS at the T0 moment when compared to sham stimulation (p = 0.008); this increase was also significant at T0 (p = 0.009), T30 (p = 0.005) and T60 (p = 0.005) moments when compared to the baseline condition. No significant differences were observed after the 10 Hz rTMS on spinal excitability or on spasticity. No inter-group differences were detected, or in the time after application of 1 Hz rTMS, or after sham stimulation for any of the assessed outcomes.

Conclusions: High-frequency rTMS applied to M1 was able to promote increased cortical excitability in individuals with incomplete SCI for at least 60 minutes; however, it did not modify spinal excitability or spasticity.

Keywords: Spinal cord injury; excitability; physiotherapy; spasticity; transcranial magnetic stimulation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Double-Blind Method
Evoked Potentials, Motor / physiology
Humans
Middle Aged
Spinal Cord Injuries* / therapy
Transcranial Magnetic Stimulation*