The manuscript, titled “No evidence for stochastic resonance effects on standing balance when applying noisy galvanic vestibular stimulation in young healthy adults”, was published in the Journal Scientific Reports. (Link to the article)
Low-intensity noisy galvanic vestibular stimulation (nGVS) is an increasingly used non-invasive brain stimulation technique to improve vestibular-perceptual and -motor function in health and disease. The mechanism underlying these improvements is presumed to be stimulation-induced stochastic resonance (SR) in the peripheral vestibular system. Accordingly, nGVS has been shown to sensitize vestibular perception and to reduce vestibulospinal reflex thresholds in a stimulus-dependent manner consistent with the exhibition of SR (Galvan-Garca et al. Brain Stimul 2018, Wuehr et al. Brain Stimul 2017).
In the present study, we examined whether previously reported nGVS-induced improvements in postural control (e.g., Inukai et al. Brain Stimul 2017, Fujimoto et al. Sci Rep 2019) can be explained by the exhibition of SR. To this end, we systematically analyzed modulations of body sway in dependence of varying intensities of nGVS in young healthy individuals during different stance conditions. By means of established quantitative and qualitative criteria, we demonstrate that stimulus-dependent modulations of body sway in young healthy adults are actually not consistent with the exhibition of SR. Based on this observation, we discuss alternative explanations for previously reported beneficial effects of nGVS on standing balance in healthy individuals.