VN clinical status related to V1 response to congruent visuo-vestibular stimuli
Reduced V1 BOLD signal during congruent stimulation correlates with subjective dizziness scores
No association between V1 BOLD signal and incongruent visuo-vestibular stimulation
Changes in V1 activity may reflect cortical adaptive mechanisms following VN
VestibularÂ neuritisÂ (VN) is characterised by acuteÂ vertigoÂ due to a sudden loss of unilateralÂ vestibular function. A considerable proportion of VN patients proceed to develop chronicÂ symptomsÂ of dizziness, including visually induced dizziness, specifically during head turns. Here we investigated whether theÂ developmentÂ of such poor clinical outcomes following VN, is associated with abnormal visuo-vestibular cortical processing. Accordingly, we appliedÂ functional magnetic resonance imagingÂ to assessÂ brainÂ responses of chronic VN patients and compared these to controls during both congruent (co-directional) and incongruent (opposite directions) visuo-vestibularÂ stimulationÂ (i.e. emulating situations that provoke symptoms in patients). We observed a focal significant difference in BOLD signal in the primaryÂ visual cortexÂ V1 between patients and controls in the congruent condition (small volume corrected level ofÂ pâ€¯<â€¯.05 FWE). Importantly, this reduced BOLD signal in V1 was negatively correlated withÂ functional statusÂ measured with validated clinical questionnaires. Our findings suggest that central compensation and in turn clinical outcomes in VN are partly mediated by adaptive mechanisms associated with the early visual cortex.