Restricted gaze behavior under static visual stimuli in patients with persistent postural-perceptual dizziness

Background: Patients with persistent postural-perceptual dizziness (PPPD) suffer from symptoms of chronic dizziness that exacerbate in a moving environment. However, not much is known regarding gaze behavior in a static condition. The present study investigated gaze stability under static visual stimuli in patients with PPPD. Methods: Three groups of participants were recruited; 22 PPPD, 9 Ménière’s disease (MD) and 19 healthy participants (HC). Participants were asked to undergo a free viewing test of emotionally neutral images through a virtual reality headset with a gaze-recording system. Bivariate Contour Ellipse Area (BCEA), a measure for gaze stability, and saliency values at points of gaze fixations were measured. Results: PPPD showed smaller BCEA compared to MD and HC, with high anxiety state being a possible confounding factor. There was no difference in saliency values between all three groups. Conclusions: PPPD, MD, and HC all tended to fixate on salient parts of the images, but in PPPD, gaze was restricted to a smaller area compared to MD and HC. Considering that previously reported studies on PPPD patients showed gaze instability under dynamic stimuli, the gaze behavior from the present study, involving static stimuli, may reflect the opposite pole to that of dynamic stimuli.