Altered visual conscious awareness in patients with vestibular dysfunctions; a cross-sectional observation study

Mishaal Sharif; Yougan Saman; Rose Burling; Oliver Rea; Rakesh Patel; Douglas J K Barrett; Peter Rea; Amir Kheradmand; Qadeer Arshad

doi:10.1016/j.jns.2023.120617

Altered visual conscious awareness in patients with vestibular dysfunctions; a cross-sectional observation study

J Neurol Sci. 2023 May 15:448:120617. doi: 10.1016/j.jns.2023.120617. Epub 2023 Mar 22.

Authors

Mishaal Sharif¹, Yougan Saman², Rose Burling¹, Oliver Rea¹, Rakesh Patel³, Douglas J K Barrett¹, Peter Rea⁴, Amir Kheradmand⁵, Qadeer Arshad⁶

Affiliations

¹ inAmind Laboratory, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester LE1 7RH, UK.
² inAmind Laboratory, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester LE1 7RH, UK; Balance Clinic, E.N.T Department, Leicester Royal Infirmary, Leicester LE1 5WW, UK.
³ Faculty of Health and Life Sciences, De Montfort University, The Gateway, Leicester LE1 9BH, UK.
⁴ Balance Clinic, E.N.T Department, Leicester Royal Infirmary, Leicester LE1 5WW, UK.
⁵ Department of Neurology, The Johns Hopkins University, Baltimore, MD, USA; Department of Neuroscience, The Johns Hopkins University, Baltimore, MD, USA. Electronic address: akherad@jhu.edu.
⁶ inAmind Laboratory, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester LE1 7RH, UK; Neuro-Otology Unit, Division of Brain Sciences, Charing Cross Hospital Campus, Imperial College London, Fulham Palace Road, London W6 8RF, UK. Electronic address: qa15@leicester.ac.uk.

Abstract

Background: Patients with vestibular dysfunctions often experience visual-induced symptoms. Here we asked whether such visual dependence can be related to alterations in visual conscious awareness in these patients.

Methods: To measure visual conscious awareness, we used the effect of motion-induced blindness (MIB,) in which the perceptual awareness of the visual stimulus alternates despite its unchanged physical characteristics. In this phenomenon, a salient visual target spontaneously disappears and subsequently reappears from visual perception when presented against a moving visual background. The number of perceptual switches during the experience of the MIB stimulus was measured for 120 s in 15 healthy controls, 15 patients with vestibular migraine, 15 patients with benign positional paroxysmal vertigo (BPPV) and 15 with migraine without vestibular symptoms.

Results: Patients with vestibular dysfunctions (i.e., both vestibular migraine and BPPV) exhibited increased perceptual fluctuations during MIB compared to healthy controls and migraine patients without vertigo. In VM patients, those with more severe symptoms exhibited higher fluctuations of visual awareness (i.e., positive correlation), whereas, in BPPV patients, those with more severe symptoms had lower fluctuations of visual awareness (i.e., negative correlation).

Implications: Taken together, these findings show that fluctuations of visual awareness are linked to the severity of visual-induced symptoms in patients with vestibular dysfunctions, and distinct pathophysiological mechanisms may mediate visual vertigo in peripheral versus central vestibular dysfunctions.

Keywords: BPPV; Vestibular migraine; Visual conscious awareness; Visual vertigo.

Publication types

Research Support, N.I.H., Extramural

MeSH terms

Benign Paroxysmal Positional Vertigo* / diagnosis
Cross-Sectional Studies
Dizziness
Humans
Migraine Disorders* / diagnosis
Visual Perception / physiology

Grants and funding

R01 DC018815/DC/NIDCD NIH HHS/United States