Translingual Neurostimulation for the Treatment of Chronic Symptoms Due to Mild-to-Moderate Traumatic Brain Injury.

The study compared two stimulation dosages, not stimulation against no stimulation or a sham device, so it cannot separate the effect of tongue stimulation from physical therapy or routine care. The design changed after approval from using the low-frequency arm as a control to a dosage comparison, which weakens inference about whether stimulation itself produced the improvements. The sample was small and single-site: 57 candidates were screened, 44 were randomized, 43 were analyzed, 39 completed stage 2, and 37 completed stage 3. Missing data were not imputed, so participants who dropped out may have affected the results. The study was powered only for the Sensory Organization Test primary outcome; secondary and exploratory findings are less certain, and exploratory endpoints were not assessed with inferential statistics. Baseline 6-minute walk distance was significantly higher in the low-frequency group than in the high-frequency group (P = .031), which may have affected comparisons. More women than men were enrolled (28 women and 16 men), and sex differences in response to brain injury or physical activity could have influenced results. Oculomotor deficits were not controlled, and 5 of 44 participants had significant oculomotor abnormalities that could affect balance, gait, visual attention, reading, or headache. The treatment schedule required 2-3 hours of daily training 6 days weekly for 14 weeks, which was the primary factor in attrition and may limit real-world feasibility. Participants had chronic mild-to-moderate traumatic brain injury and had plateaued after prior physical therapy, so results may not apply to acute injury or patients who were still improving.

No funding or conflict-of-interest statement is provided in the supplied text. The article lists device and software suppliers: PoNS from Simplex Scientific, NeuroCom Sensory Organization Test from Natus Medical, R from R Foundation for Statistical Computing, VassarStats from VassarStats, and SAS from SAS Institute.

Do not read the within-group improvements as proof that tongue stimulation works. Every participant received physical therapy, and the study compared two stimulation dosages instead of comparing stimulation with no stimulation, so the contribution of stimulation cannot be separated.