A new approach of inducing proprioceptive illusion by transcutaneous electrical stimulation.
Rohit Rangwani, Hangue Park
PMID 33941209WHAT IT FOUND
In eight healthy people, electrical stimulation over two elbow flexor muscles made them feel their elbow extending.
All reported a tingling sensation with the illusion. No lasting arm-matching shift was measured. This is a lab proof of concept, not a treatment.
Key findings
01Electrical stimulation over the biceps brachii and brachioradialis produced an illusion of elbow extension in all eight subjects.
02During arm matching, stimulation shifted the replicated elbow angle by 7.89° at a 135° reference and by 5.73° at a 90° reference.
03After stimulation stopped, arm matching returned to baseline, and the paper reports no aftereffect in that test.
STILL TO COME
How it was doneWhat they found
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What it does not show
Only eight healthy, right-handed people were tested, and the authors state that people with disability or sensorimotor deficits need follow-up studies. The study was a laboratory proof of concept, not a clinical treatment trial. The electrode location used for most subjects was chosen from the first three subjects only. Thresholds and stimulation amplitudes were not measured with standard psychophysics methods. Tingling and other cutaneous sensations were present, and the paper says the contribution of skin-based electrotactile feedback to the illusion cannot be excluded. The authors note possible expectation effects and visual feedback effects, even though subjects were blindfolded during the main tests. The number of sessions was small, so variability between people and between sessions needs further testing.
Declared interests
Funded by The Institute for Rehabilitation and Research Foundation (TIRR Foundation).
The easy way to misread this
Do not read this as evidence that transcutaneous electrical stimulation can improve proprioception or motor function in patients. The study tested only eight healthy people in a laboratory illusion task, and the authors state that people with disability or sensorimotor deficits need follow-up studies.