Oculomotor and Perceptual Measures of Visual Motion Sensitivity in Patients With Chronic Dizziness Symptoms.

OBJECTIVE: The purpose of this study was to provide empirical data describing the relationship between behavioral responses to dynamic visual motion in adults with chronic dizziness symptoms with and without clinically identifiable peripheral vestibular impairment. DESIGN: Prospective, quasi-experimental study including individuals with chronic dizziness symptoms with identified unilateral peripheral vestibular impairment (n=27), and individuals with chronic dizziness symptoms without identified vestibular impairment (n=26). We measured (a) visual perception of verticality in a dynamic background, (b) postural displacement in a dynamic background, (c) eye movement behaviors in various visual contexts, and (d) self-rating degree of anxiety. RESULTS: Status of peripheral vestibular function was not a significant predictor of behavioral responses to visual motion. The data show that the ability to fixate on a visual target was predictive of postural control in a dynamic visual background. Trial-to-trial variability in verticality responses and degree of self-rated anxiety were also associated with postural control. CONCLUSIONS: Apart from vestibular function, oculomotor control is important for maintaining control of whole-body motor responses during exposure to a dynamic visual stimulus. Vertical perception precision-not accuracy-may be more important for understanding real-world consequences of visual motion sensitivity. Traditional diagnostic evaluations focusing exclusively on characterizing the peripheral vestibular system may not provide insight into the behaviors associated with visual motion sensitivity.