Fig. 2.

Overview of height-induced alterations of visual exploration, postural and locomotion control in individuals with visual height intolerance (vHI) and healthy insusceptible subjects (HS) while being exposed to heights on an emergency balcony 20 m above ground. a Behavioral alterations during quiet upright stance. b Behavioral alterations during locomotion. Top panel: group means and interquartile ranges of head orientation and histograms of the direction of corresponding saccadic eye movements. During both standing and walking, individuals with vHI show considerably reduced head movements. Saccadic eye movements during stance in individuals with vHI are preferably directed along the horizontal plane. In contrast, during locomotion, they perform saccades primarily along the vertical plane. Bottom panel: during height exposure, postural control in individuals with vHI is characterized by increased co-contraction of anti-gravity muscles and increased body sway amplitudes. Locomotion is characterized by a slow and cautious mode of walking, with a reduced stride length and a broadened base of support