Galvanic Vestibular Stimulation Induces a Spatial Bias in Whole-body Position Estimates.

Peripheral galvanic vestibular stimulation (GVS) has been shown to temporarily ameliorate left spatial neglect [1]. Specifically, anodal (facilitatory) stimulation over the left mastoid bone coupled with cathodal (inhibitory) over the right mastoid reduces visuospatial‐neglect scores in line cancellation [2] and line bisection tasks [3, 4]. This montage increases activity in the left vestibular nerve and suppresses activity in the right [5], which has been shown to focally activate vestibular networks that occupy visuospatial attention mechanisms, primarily in the non‐dominant hemisphere [5]. Thus, it appears that electrical stimulation of the peripheral vestibular system can shift visuospatial attention to the left side of space [4]. However, whether such a shift of spatial attention in normal subjects can influence perception of spatial position during whole body spatial translations is unknown. We hypothesised that shifting attention to the left would result in participants underestimating spatial position estimates during rightward whole‐body translations and overestimating spatial position estimates during leftward whole‐body translations.