Current knowledge of vestibular cortical processing in humans is mostly based on PET or fMRI studies during non-natural stimulation with either caloric testing, galvanic stimulation, or vestibular evoked myogenic potentials (VEMP). However, the use of non-natural stimulation is questionable. This study aims to visualize cortical activity during natural stimulation of the human vestibular organ in healthy participants and in patients with Menière's disease.
Method:Eight patients with right-sided Menière's disease and fourteen healthy controls underwent three FDG-PET-scans. Participants were seated in a self-propelled chair, injected with FDG followed by 35 min of chair motion stimulation. Subsequently, a brain PET was obtained. Two types of stimuli were applied, predominantly towards the right horizontal semicircular canal (rotation) and right utriculus (linear acceleration). For baseline scans, participants were injected with FDG, while seated without movement.
Results:In healthy participants significantly increased FDG-uptake was measured bilaterally in the medial part of Heschl's gyrus, with some overlap into the posterior insula during both stimulation paradigms. Comparison of Menière's patients with healthy controls predominately revealed decreased 18F-FDG-uptake in the medial part of Heschl's gyrus and the posterior insula in patients with Menière's disease Conclusion: This is the first neuroimaging study to visualize cortical processing of natural vestibular stimuli. FDG-uptake was demonstrated in the medial-most part of Heschl's gyrus in healthy participants . Patients with Menière's disease showed lower cortical activity in this area at baseline and during natural vestibular stimulation compared to healthy controls.
