Abstract
Purpose :
1. Quantify severity of fear of falling (FOF) by comparing temporal characteristics of postural control during the task of Gait Initiation (GI) in healthy adults under the conditions of normal vision, low vision sight simulator (SS), and virtual reality (VR) environment.
2. Assess association of low vision (LV) with changes in postural control during GI.
Methods :
8 adults with LV (mean age 63.3 ± 11.2 y), and 8 age-gender matched healthy adults (mean age 68.1 ± 9.72 yrs) were recruited. All participants performed the task of GI barefoot under normal conditions with 5 trials on a Tekscan™ High Resolution Floor Mat System. Healthy participants performed trials under 2 more conditions: GI with SS, and GI with VR headset (HTC VIVE Cosmos Elite 3D VR system and the Richie’s Plank VR experience were used to induce FOF). Absolute temporal events of foot position were obtained from the vertical ground reaction forces corresponding to the swing and stance limbs during GI. To normalize temporal parameters of GI, time from onset of movement to stance limb toe-off was defined as 100% of the GI cycle. The temporal events measured were: 1) time from onset of movement to swing limb toe-off (Anticipatory Postural Adjustment: APA) and 2) time from swing limb heel strike to stance limb toe-off (Double Support Time: DST).
Results :
Table 1 and Graph 1 (image) show absolute and normalized temporal data means. Normalized APA during GI with VR headset (47.36% ± 6.50) was similar to GI with SS (46.08% ± 3.11) and normal GI conditions (44.52% ± 4.74) in healthy patients. Normalized APA during GI in LV patients (55.04% ± 5.69) exceeded that for all 3 conditions in healthy patients. Normalized DST during GI with VR headset (32.39% ± 11.74) had much longer duration than GI with SS (23.35% ± 8.93) and normal GI conditions (20.60% ± 2.96) in healthy patients. Normalized DST during GI for LV patients (17.95% ± 3.78) was shorter than that for all 3 conditions in healthy patients.
Conclusions :
Both APA and DST for securing the weight shift necessary to execute the first step from a static standing position can be used as objective biomarkers to quantify the severity of FOF. APA values demonstrate that low vision has a similar impact on postural control as VR use in healthy adults, and prolonged DST is observed in healthy adults with induced new-onset FOF during GI.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.