Altered functional brain connectivity in patients with visually induced dizziness

Abstract

BackgroundVestibular patients occasionally report aggravation or triggering of their symptoms by visual stimuli, which is called visually induced dizziness (VID). These patients therefore experience dizziness, discomfort, disorientation and postural unsteadiness. The underlying pathophysiology of VID is still poorly understood.ObjectiveThe aim of the current explorative study was to gain a first insight in the underlying neural aspects of VID.MethodsWe included 10 VID patients and 10 healthy matched controls, all of which underwent a resting state fMRI scan session. Changes in functional connectivity were explored by means of the intrinsic connectivity contrast (ICC). Seed-based analysis was subsequently performed in visual and vestibular seeds.ResultsWe found a decreased functional connectivity in the right central operculum (superior temporal gyrus), as well as increased functional connectivity in the occipital pole in VID patients as compared to controls in a hypothesis-free analysis. A weaker functional connectivity between the thalamus and most of the right putamen was measured in VID patients in comparison to controls in a seed-based analysis. Furthermore, also by means of a seed-based analysis, a decreased functional connectivity between the visual associative area and the left parahippocampal gyrus was found in VID patients. Additionally, we found increased functional connectivity between thalamus and occipital and cerebellar areas in the VID patients, as well as between the associative visual cortex and both middle frontal gyrus and precuneus.ConclusionsWe found alterations in the visual and vestibular cortical network in VID patients that could underlie the typical VID symptoms such as a worsening of their vestibular symptoms when being exposed to challenging visual stimuli. These preliminary findings provide the first insights into the underlying functional brain connectivity in VID patients. Future studies should extend these findings by employing larger sample sizes, by investigating specific task-based paradigms in these patients and by exploring the implications for treatment.

Cortical alterations in phobic postural vertigo – a multimodal imaging approach

“…From posturographic studies and gait analyses it is known that PPV patients exceedingly rely on visual input during standing and walking . Patients with visually induced dizziness, also known as visual vertigo, also show an increased connectivity between thalamus, occipital cortex, and cerebellar areas . Furthermore, during a self‐motion simulation in PPPD patients higher dizziness handicap values correlated positively with occipital activity .…”

Persistent postural-perceptual dizziness (PPPD): a common, characteristic and treatable cause of chronic dizziness

“…The first neuroimaging studies of visual vertigo,41 chronic subjective dizziness2 and PPPD42 suggest that there may be an additional pathophysiological mechanism underlying PPPD, namely a deficiency in cortical processes that subserve locomotion and spatial orientation at the highest levels. Although the research paradigms differed from one another and the use of imaging techniques for studying PPPD is just getting started, a pattern of results is beginning to take shape.…”

Altered brain function in persistent postural perceptual dizziness: A study on resting state functional connectivity

“…Another study (Van Ombergen et al, 2017) reported increased connectivity in visual cortical areas and decreased connectivity in vestibular cortical areas using a resting state fMRI in patients with visuallyinduced dizziness, but did not account for the psychiatric state of their subjects. Taken together, our results and the findings of these two previous studies indicate that alterations in brain functioning attributable to PPPD itself are decreases in connectivity among the vestibular and visual cortices, the frontal regulatory regions and the hippocampus.…”