ABSTRACT
AIMS: Impaired vision is an additional risk factor in elderly for falls. We investigated the hypothesis that treadmill (TM) walking affects visual function in both healthy elderly and those with early-moderate visual dysfunction due to glaucoma. METHODS: Thirty healthy controls (HC) aged 64-83 years and 18 glaucoma patients (GLA) aged 62-82 years participated in this cross-sectional study. The impact of TM-walking on visual function was assessed binocularly for (i) best-corrected visual acuity (BCVA) with and without crowding effect, (ii) contrast sensitivity (CS), and (iii) and visual field (mean deviation, VF-MD). Visual function was tested while participants were standing or during TM-walking for 2 speed conditions: (i) fast walking at their preferred speed and (ii) walking at a fixed speed of 3.5 km/h. RESULTS: GLA, most with early-moderate VF loss, performed equally well as HC. Independent of GROUP, an impact of SPEED on visual functions was statistically evident with large statistical effect size for (i) both types of BCVA with a mean loss of 0.02-0.05 logMAR (η2 = 0.41) and (ii) VF-MD with mean loss of 1 dB (η2 = 0.70), but not for CS. CONCLUSIONS: Here, we introduce a paradigm for the assessment of visual function during walking. We provide proof-of-concept that our approach allows for the identification of walking induced visual function loss, i.e., a deterioration of BCVA and VF-sensitivity during TM-walking in both groups. It is therefore of promise for the investigation of the relation of vision impairment and mobility, ultimately the increased frequency of falls in advanced glaucoma.
ABSTRACT
Purpose: To investigate gait kinematics during single- and dual-task walking in glaucoma patients compared with healthy controls. Methods: Nineteen glaucoma patients (10 females, 9 males) and 30 healthy controls (17 females, 13 males) participated in this cross-sectional study. Spatiotemporal gait parameters (e.g., stride length, velocity, minimum toe clearance [MTC]) were assessed using inertial measurement units (sampling frequency 100 Hz) during single-task walking and dual-task walking at a comfortable velocity. During dual-task walking, participants walked and concurrently performed different cognitive tasks in a random order: (i) reaction time task, (ii) N-Back-task, and (iii) letter fluency task with two difficulty levels, respectively. Repeated measures analyses of covariance (Group × Condition) were conducted to analyze the data. Results: A significant effect of group was found for the coefficient of variation (CoV) of the MTC, F(1,39) = 4.504, P = 0.040, \({\rm{\eta }}_{\rm{p}}^2\) = 0.104, with higher values in glaucoma patients. Based on the effect sizes, a main effect of group was also found for the MTC, F(1,39) = 2.668, P = 0.110, \({\rm{\eta }}_{\rm{p}}^2\) = 0.064, and the MTCCoV dual-task costs, F(1,38) = 3.225, P = 0.08, \({\rm{\eta }}_{\rm{p}}^2\) = 0.078, which was lower and higher, respectively, in glaucoma patients. Conclusions: The present study revealed a significantly higher MTC variability as well as medium effect sizes for a lower MTC and higher MTC dual-task costs in glaucoma patients compared with healthy controls, which might be related to a higher risk of falling owing to tripping. Translational Relevance: The minimum toe clearance might mirror disease-related changes in walking performance and might have prognostic value for assessing fall risk in glaucoma patients.
