Vestibular evoked potentials (VsEPs) of cortical origin produced by impulsive acceleration applied at the nasion.

Neil P M Todd,Aisha Mclean,Karolina Kluk,James G Colebatch,Aurore Paillard

doi:10.1007/s00221-014-4067-x

Abstract

We report the results of a study to record vestibular evoked potentials (VsEPs) of cortical origin produced by impulsive acceleration (IA). In a sample of 12 healthy participants, evoked potentials recorded by 70 channel electroencephalography were obtained by IA stimulation at the nasion and compared with evoked potentials from the same stimulus applied to the forefingers. The nasion stimulation gave rise to a series of positive and negative deflections in the latency range of 26–72 ms, which were dependent on the polarity of the applied IA. In contrast, evoked potentials from the fingers were characterised by a single N50/P50 deflection at about 50 ms and were polarity invariant. Source analysis confirmed that the finger evoked potentials were somatosensory in origin, i.e. were somatosensory evoked potentials, and suggested that the nasion evoked potentials plausibly included vestibular midline and frontal sources, as well as contributions from the eyes, and thus were likely VsEPs. These results show considerable promise as a new method for assessment of the central vestibular system by means of VsEPs produced by IA applied to the head.

Highlights

The vestibular apparatus plays a central role in balance and proprioception and mediates key reflexes for the stabilisation of posture and gaze
Extensive analyses were conducted starting from the simplest models, we report here only the final outcomes which employed a symmetrical pair of regional sources (RSs) for the ocular components along with three or four dipoles
Consistent with previous literature on somatosensory evoked potentials (SEPs) in response to tactile pulses applied to the index fingers, the main peak recorded in this study following finger acceleration resembles the contralateral N50/P50 component described by Hämäläinen et al (1990), which was believed to be generated in the primary somatosensory cortex

Summary

Introduction

The vestibular apparatus plays a central role in balance and proprioception and mediates key reflexes for the stabilisation of posture and gaze. Exp Brain Res (2014) 232:3771–3784 et al 2009) When using this stimulus, well-defined responses can be measured in both ascending and descending projections to vestibulo-ocular (Todd et al 2008a; Govender et al 2011), vestibulo-collic (Rosengren et al 2009) and vestibular-spinal systems (Laube et al 2012). Well-defined responses can be measured in both ascending and descending projections to vestibulo-ocular (Todd et al 2008a; Govender et al 2011), vestibulo-collic (Rosengren et al 2009) and vestibular-spinal systems (Laube et al 2012) Such responses have been shown to be dependent on the direction of acceleration. The aim of the present study was to evaluate evoked potentials produced by IA of both positive and negative polarity at the nasion, compared with the same applied to the right and left index fingers

Methods

Results

Discussion