Visual dependence affects the motor behavior of older adults during the Timed Up and Go (TUG) test

Background: Older adults show greater postural instabilities under misleading visual cues relative to younger adults. We investigated the effects of age-related visual dependence on motor performance under increased attention demands by adding a motor task and visual stimulus to the Timed Up and Go (TUG) test sub-components. Method: We designed a cross-sectional quantitative study. Twenty-eight younger (n = 12) and older (n = 16) adults completed the TUG test while wearing a head-mounted display (HMD) that presented a visual stimulus and/or carrying a cup of water. Outcome measures were turning cadence; gait speed; pitch, yaw, and roll peak trunk velocities (PTVs); and acceleration ranges of sit-to-stand and stand-to-sit. Results: Wearing the HMD caused significant performance differences in the TUG test tasks due to age and visual dependence, although performance was lower across all groups with the HMD (p < 0.01). Older adults showed lower roll PTV in turning compared to younger adults (p = 0.03). Visually dependent older adults showed smaller mediolateral and vertical acceleration ranges (p < 0.04) in sit-to-stand compared to visually independent older adults. Conclusion: The demand for orienting posture to a vertical position during sit-to-stand may differentiate older adults who are more visually dependent-and thus at greater fall risk-from those who are more visually independent. Age-related differences in turning behavior suggest a relationship with fall risk that warrants further investigation.