Transcutaneous Electrical Acustimulation Ameliorates Motion Sickness Induced by Rotary Chair in Healthy Subjects: A Prospective Randomized Crossover Study

Motion sickness (MS) is a common physiological response to real or virtual motion. The purpose of this study was to investigate the effects of transcutaneous electrical acustimulation (TEA) on MS and the underlying mechanisms in healthy subjects. A total of 50 healthy participants were recruited and randomly assigned into two groups to complete two separate sessions in a crossover study. A Coriolis rotary chair was used as a model to provoke severe MS. The total tolerable rotation time and Graybiel scoring scale were recorded. Gastric slow waves were detected by electrogastrogram. The autonomic nervous function, including the vagal activity, was evaluated by the analysis of heart rate variability derived from the electrocardiogram recording. The serum levels of arginine vasopressin (AVP) and norepinephrine (NE) were examined. Of note, 22 participants in TEA and only 11 participants in the sham-TEA session completed the entire five-rotation MS stimuli (p = 0.019). TEA significantly prolonged the total tolerable rotation time of MS stimuli (220.4 ± 11.59 vs 173.6 ± 12.3 seconds, p < 0.001) and lowered MS symptom scores (12.56 ± 2.03 vs 22.06 ± 3.0, p < 0.001). TEA improved the percentage of normal gastric slow waves, compared with sham-TEA (56.0 ± 2.1% vs 51.6 ± 2.0%, p = 0.033). TEA also significantly enhanced vagal activity compared with sham-TEA (0.41 ± 0.02 vs 0.31 ± 0.02, p < 0.001). In addition, the increased serum levels of AVP and NE on MS stimulation were markedly suppressed by TEA treatment, compared with sham-TEA (AVP, 56.791 ± 4.057 vs 79.312 ± 10.036 ng/mL, p = 0.033; NE, 0.388 ± 0.037 vs 0.501 ± 0.055 ng/mL, p = 0.021). Needleless TEA is a potent therapeutic approach for severe MS, as it increases participants' tolerance and ameliorates MS symptoms, which may be attributed to the integrative effects of TEA on autonomic functions and neuroendocrine balance.