Galvanic vestibular stimulation speeds visual memory recall

Abstract

The experiments of Alessandro Volta were amongst the first to indicate that visuo-spatial function can be altered by stimulating the vestibular nerves with galvanic current. Until recently, the beneficial effects of the procedure were masked by the high levels of electrical current applied, which induced nystagmus-related gaze deviation and spatial disorientation. However, several neuropsychological studies have shown that much weaker, imperceptible currents that do not elicit unpleasant side-effects can help overcome visual loss after stroke. Here, we show that visual processing in neurologically healthy individuals can also benefit from galvanic vestibular stimulation. Participants first learnt the names of eight unfamiliar faces and then after a short delay, answered questions from memory about how pairs of these faces differed. Mean correct reaction times were significantly shorter when sub-sensory, noise-enhanced anodal stimulation was administered to the left mastoid, compared to when no stimulation was administered at all. This advantage occurred with no loss in response accuracy, and raises the possibility that the procedure may constitute a more general form of cognitive enhancement.

Galvanic vestibular stimulation modulates the electrophysiological response during face processing

“…GVS has been shown to improve the speed and accuracy of visual judgments in both brain injured and neurologically healthy individuals (Wilkinson et al, 2005(Wilkinson et al, , 2008; however, the underlying electrophysiological response has yet to be investigated. Here, we examined the effect of GVS on the N170, an aspect of the eventrelated component that is associated with early levels of visual coding.…”

“…In blocks 2 and 3, subsensory and supersensory stimulation was administered (the order of which was counterbalanced). Subsensory intensities provided a simple means of blinding participants to the presence/absence of stimulation and are those most commonly used to facilitate behavioral performance (Wilkinson et al, 2005(Wilkinson et al, , 2008(Wilkinson et al, , 2010. By administering separate blocks of supersensory stimulation, it was possible to determine whether higher, albeit still tolerable, levels of current invoked stronger electrophysiological responses.…”

The effect of repeated sessions of galvanic vestibular stimulation on target cancellation in visuo-spatial neglect: Preliminary evidence from two cases

“…for a period of 20 minutes on each of the 5 consecutive days. (Sensory threshold was determined prior to the baseline session using the staircase procedure described by Wilkinson et al [27]). Participants were subsequently encouraged to report any unusual sensation such as itching/tingling behind the ears, but neither did.…”

The Moving History of Vestibular Stimulation as a Therapeutic Intervention

“…Falconer and Mast, 2012) functions. Especially, memory -visual memory recall (Wilkinson et al, 2008), and depending on stimulation side, verbal or spatial recall (Bachtold et al, 2001) -was found to be improved (for a review see Smith et al, 2010). Similarly, a recent EEG study suggested improved memory as well as altered frontal beta power after GVS (Lee et al, 2014).…”