Galvanic Vestibular Stimulation Produces Cross-Modal Improvements in Visual Thresholds

Abstract

BackgroundStochastic resonance (SR) refers to a faint signal being enhanced with the addition of white noise. Previous studies have found that vestibular perceptual thresholds are lowered with noisy galvanic vestibular stimulation (i.e., “in-channel” SR). Auditory white noise has been shown to improve tactile and visual thresholds, suggesting “cross-modal” SR.ObjectiveWe investigated galvanic vestibular white noise (nGVS) (n = 9 subjects) to determine the cross-modal effects on visual and auditory thresholds.MethodsWe measured auditory and visual perceptual thresholds of human subjects across a swath of different nGVS levels in order to determine if some individual-subject determined best nGVS level elicited a reduction in thresholds as compared the no noise condition (sham).ResultsWe found improvement in visual thresholds (by an average of 18%, p = 0.014). Subjects with higher (worse) visual thresholds with no stimulation (sham) improved more than those with lower thresholds (p = 0.04). Auditory thresholds were unchanged by vestibular stimulation.ConclusionThese results are the first demonstration of cross-modal improvement with galvanic vestibular stimulation, indicating galvanic vestibular white noise can produce cross-modal improvements in some sensory channels, but not all.

Effects of additive sensory noise on cognition

“…Thus, for each CTB task, a range of AWN and nGVS levels were assessed for each subject. Four nGVS levels [(0.2, 0.4, 0.6, and 0.8 mA)] and three AWN levels [(40, 55, and 70 dB SPL)] were tested in a randomized order, as has been done in our prior work ( Voros et al, 2021 ). Speed and accuracy were corrected to account for trial-specific differences and learning effects, using corrections from Basner et al (2020) .…”

“…Therefore, it is believed that an “optimal” level of noise is required to achieve throughput enhancement ( Galvan-Garza, 2018 ). Psychophysical experimentation suggests that SR can improve perceptual performance, such as lowering auditory thresholds, both within the same sensory modality [e.g., using auditory white noise (AWN) to improve hearing ( Zeng et al, 2000 )] and across separate sensory modalities [e.g., using noisy galvanic vestibular stimulation (nGVS) to improve visual perception ( Voros et al, 2021 )]. While perception has been shown to be affected by additive noise, there is limited research on whether higher order cognitive processes is subject to SR.…”

Noise and vestibular perception of passive self-motion

“…The vestibular stimulation occurs without head motion. Noisy broadband GVS has been shown to ameliorate vestibular perception ( 131–135 ), as well as other vestibular-mediated responses such as ocular counter-rolling ( 136 ), balance ( 133 , 137–139 ), vestibulo-spinal reflexes ( 135 ), mobility ( 140 ), locomotion ( 134 , 141 ), and cross-modal visual perception ( 142 ). The effects on performance generally follow the nonlinear trend observed by ( 15 ) using mechanical noise, i.e., optimal GVS amplitude coincides with low-to-intermediate noise levels.…”

The Effect of Galvanic Vestibular Stimulation on Visuospatial Cognition in an Incomplete Bilateral Vestibular Deafferentation Mouse Model

“…Furthermore, GVS enhances the neuronal activation demonstrated via an increase in c-Fos positive cells in the hippocampus following the multiplesession administration (29,70). Besides, based on the concept of sensory substitution, strengthening the function of other sensory systems, such as visual (30,71) and somatosensory functions (72) and boosting reciprocal intersensory interactions could be considered a beneficial influence of the GVS to enhance efficiency in the spatial memory and navigation activities (73). All the aforementioned mechanisms just assist us somewhat in imagining the explanation of the GVS effects on strengthening the function of spatial navigation.…”