2.2. Procedures
depression, Depression
Eligible participants were asked to complete initial, four-week, and eight-week follow-up evaluations in the laboratory. During these visits, participants completed clinical, balance, and gait activities under the supervision of a trained investigator (SRO). During the initial visit, participants were asked to complete questionnaires in regards to their fall history, smartphone usage, and medications. During all visits, assessments of depression and perception of balance ability were performed using the Geriatric Depression Scale (GDS) [Participants were then asked to stand quietly in a computerized dynamic posturography system, with immersive virtual environments and a sway referenced force plate (Bertec Inc., Columbus, OH, USA) for 6 postural conditions to complete the sensory organization test (SOT). Each condition consisted of up to three 20 s trials. For condition 1, participants were asked to stand quietly on the force plate with their eyes open. For condition 2, participants were asked to stand quietly with their eyes closed. For condition 3, participants were asked to stand quietly with their eyes open, with the visual surround changing based on their postural sway. For conditions 4–6, participants stood while the force plate swayed at a 1:1 ratio in reference to their body sway. For condition 4, eyes were open; for condition 5 eyes were closed; for condition 6, eyes were open, but the visual surrounding also changed based on their postural sway. During all standing trials in the posturography system, a fall-arrest harness was placed on participants, with a trained investigator present to ensure safety. The equilibrium scores (ES) across each of the six conditions were automatically computed, with scores closer to 0 indicating increased anteroposterior sway and loss of balance [Subsequently, thirty-nine reflective markers were placed on bony landmarks of the body, following the Vicon full-body plug-in gait model. Three-dimensional marker trajectories were captured using a 10-camera motion-analysis system (Vicon Motion Systems, Centennial, CO, USA) at 100Hz. Participants were asked to ambulate at a self-selected comfortable speed across a 10 m walkway under single- and dual-task conditions. Since an impaired ability to maintain balance while simultaneously performing cognitive tasks is associated with an increased risk of falling [Spatiotemporal and balance measures during gait were determined across all walking conditions. The whole-body center of mass (CoM) was computed based on the weighted sum of a 13-segment model and anthropometric measures [