Paired associative stimulation improves motor function in the upper extremity in chronic incomplete spinal cord injury: a corroborative study.
Carl Wahlgren, Richard Levi, Magnus Thordstein
PMID 39539071WHAT IT FOUND
Five people with chronic cervical spinal cord injury completed a 16-session paired associative stimulation programme.
Motor scores in the treated hand rose modestly but missed statistical significance, while the untreated hand showed a small significant gain. Individual responses varied widely.
Key findings
01The primary outcome of muscle strength in the targeted hand improved slightly but did not reach statistical significance.
02Muscle strength in the non-targeted hand showed a statistically significant group-level improvement.
03Individual responses were highly variable, with only two of five participants showing clear improvement in the targeted hand.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
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What it does not show
The study included only five participants, severely limiting statistical power and generalisability. The primary outcome (targeted hand MMT) was not statistically significant, despite the title implying improvement. Participants had chronic injuries (mean 10 years) and were older (mean 64 years) than previous studies, which may have reduced plasticity and response to stimulation. Most participants continued medication for spasticity or neuropathic pain, which can interfere with the mechanism of action of PAS. There was no control group or sham stimulation, so natural history or placebo effects cannot be excluded.
Declared interests
The authors declared no conflicts of interest. The study was funded by the Swedish Research Council, Region Östergötland, and Linköping University.
The easy way to misread this
Do not interpret the title's claim of improved motor function as a statistically significant finding for the treated hand. The primary outcome missed significance (p = 0.078), and the significant results occurred in the untreated hand, suggesting the effect may not be specific to the targeted intervention.