Human translingual neurostimulation alters resting brain activity in high-density EEG.
Zack Frehlick, Bimal Lakhani, Shaun D Fickling and 4 others
PMID 31133021WHAT IT FOUND
In healthy adults, one 20-minute tongue stimulation session increased resting alpha EEG activity, with no difference between high- and low-frequency settings.
Main microstate comparison showed no change, and order testing found alpha and theta increases only when high-frequency stimulation came first.
Key findings
01A 20-minute PoNS session increased resting alpha EEG activity, and the increase did not differ between high-frequency and low-frequency stimulation.
02The main microstate analysis found no significant session or stimulation effects, but paired tests found a longer attention-related microstate D after high-frequency stimulation.
03In post-hoc order testing, participants who received high-frequency stimulation first showed increased alpha and theta power after both sessions, while those who received low-frequency first did not.
STILL TO COME
How it was doneWhat they found
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What it does not show
The study was done in healthy adults, so it does not show what happens in patients with stroke, mild traumatic brain injury, or multiple sclerosis. Only one 20-minute session was tested, and it was not paired with task-specific therapy, so repeated use during clinical treatment was not evaluated. The main microstate analysis was null, and the microstate and order findings came from paired tests or post-hoc sub-analysis. Stimulation levels were self-selected and varied between participants, and high-frequency levels differed between order groups. A true sham condition is difficult because tongue stimulation is perceivable, so a perceivable level may have a non-neutral effect on the brain. Two participants were excluded for poor EEG signal, and one more was omitted from microstate analysis.
Declared interests
Helius Medical Technologies funded the study and is named as the maker of the PoNS device, which is described as investigational.
The easy way to misread this
Do not read these EEG changes as proof that PoNS improves patient function or that high-frequency stimulation is clinically better. The study was in healthy adults, used one 20-minute session without therapy, and the main microstate analysis was null; the order effect was a post-hoc sub-analysis.