Effects of transcranial magnetic stimulation in modulating cortical excitability in patients with stroke: a systematic review and meta-analysis.
Zhongfei Bai, Jiaqi Zhang, Kenneth N K Fong
PMID 35193624WHAT IT FOUND
Low-frequency stimulation to the unaffected side increased excitability in the damaged side and decreased it in the healthy side.
High-frequency and intermittent theta burst also boosted the damaged side. Continuous theta burst showed no clear effect. These are neurophysiological changes, not proven functional gains.
Key findings
01Multiple sessions of low-frequency rTMS to the unaffected motor cortex significantly decreased the resting motor threshold of the affected side.
02A single session of high-frequency rTMS to the affected motor cortex significantly increased the amplitude of motor evoked potentials by 73.11%.
03Continuous theta burst stimulation to the unaffected side did not effectively modulate cortical excitability in the studies reviewed.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTsWhat it means for SLPs
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What it does not show
The review focused on neurophysiological measures (like MEPs) rather than clinical outcomes, so it does not confirm that these brain changes translate to better movement. Many included studies had small sample sizes, leading to high heterogeneity and potential publication bias in some analyses. The findings may not apply to patients with severe motor impairment, as MEPs are often undetectable in these cases, limiting the studies that could be included. Methodological quality varied, with many studies failing to blind therapists or participants to the stimulation condition.
Declared interests
The study was funded by the General Research Fund of the Research Grants Council, University Grants Committee, Hong Kong, and the Shanghai Sailing Program, Shanghai, China. No specific conflicts of interest were declared by the authors in the provided text.
The easy way to misread this
Do not assume that the observed changes in brain excitability mean the patient will get better function. This paper reports on neurophysiological measures, not clinical motor recovery, and previous large trials have failed to show superior functional outcomes for some of these protocols.