Effect of Gaze Diversion during Obstacle Crossing for Younger and Older Adults

<p><strong>Overview of Study: </strong>We conducted a laboratory-based experiment on human locomotion (or gait) and determine how gaze diversion affected gait when stepping over an obstacle. We examined both younger and older adults to identify age-related changes, since older adults are more likely to be injured from falls. Obstacles were examined as tripping on an obstacle is a major cause of falls.    </p>

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<p><strong>General Protocol</strong>: Participants walked down an 8 m walkway, and stepped over an obstacle in the middle of the walkway. In some conditions, their gaze was diverted by a reaction time (RT) task. Gaze could be diverted to the obstacle (low sensory interference), or away from the obstacle (high sensory interference). Gait was recorded with three-dimensional motion tracking (Vicon). Reflective markers were placed on the body, and the marker position was tracked as the participant completed the task.    </p>

<p>The RT task was to depress a button on a hand-held remote when a light cue appeared. The RT task appeared once as the person walked toward the obstacle. Therefore, relative to other tasks in published studies, the RT task was lower in difficulty in terms of cognitive demand and temporal demand.  </p>

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<p><strong>Specific Details  </strong></p>

<p>Purpose: To determine if sensory interference alters performance under low levels of cognitive, temporal, and gait demand, and if the change in performance is different for younger versus older adults        </p>

<p>Participants: 17 younger adults and 14 older adults                                                       </p>

<p>Sensory interference was manipulated by the location of RT task cue</p>

<p>Independent Variables: Participants completed five conditions:</p>

<p>1) standing with RT task on the obstacle (no sensory interference),</p>

<p>2) standing with RT task at eye level away from the obstacle (no sensory interference),</p>

<p>3) obstacle crossing baseline without RT task (no sensory interference),</p>

<p>4) obstacle crossing with RT task on the obstacle (low sensory interference)</p>

<p>5) obstacle crossing with RT task at eye level away from the obstacle (high sensory interference)</p>

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<p>The trials were collected in two blocks. In both blocks, 10 trials of each of the five conditions were observed, and conditions were presented in a random order. Thus, 20 trials of each of the five conditions were collected.</p>

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<p>Dependent Variables: The mean for each participant in each condition is provided in the excel workbook “RT Gaze Diversion YA vs OA.xlsx”, which contains two worksheets “Gait Variables” and “RT Variables”</p>

<p>See Read_Me.docx for more details regarding dependent variables.</p>