Search

Background: This research aims to compare lower limb inter-segmental coordination, a higher order property of the human movement system, during walking between healthy controls and people with multiple sclerosis (PwMS) with and without fall history., Methods: Fifty PwMS (25 patients with fall history and 25 patients without fall history) and 25 healthy controls participated in the present study. Three-dimensional coordinate data of the lower limbs were collected during treadmill walking at a preferred walking speed. The phasing relationship and its variability between lower limb segments were evaluated using the mean absolute relative phase (MARP) and deviation phase (DP) during the stance and swing phases of gait., Results: Compared to healthy controls, both groups of PwMS demonstrated significantly greater shank-thigh MARP values during the stance phase (p < 0.001). In addition, MARP values of foot-shank coordination were significantly smaller in both groups of PwMS than the healthy controls during both the stance and swing phases (p < 0.001). For the DP of shank-thigh coordination, our analysis revealed greater values in both MS fallers and non-fallers compared to healthy controls during the stance (p < 0.001) and swing phases (p < 0.001, p = 0.004, respectively). Moreover, MS fallers demonstrated greater DP values than non-fallers in swing phase (p = 0.02). For the DP of foot-shank coordination, MS fallers showed greater values compared to non-fallers and healthy controls during the stance (p = 0.009, p = 0.001, respectively) and swing phases (p = 0.01, p = 0.006, respectively)., Conclusion: Our results suggest that in addition to traditional gait parameters, examining and also facilitating lower limb inter-segmental coordination should be considered in future studies aimed at improving gait performance and reducing risk of falling in PwMS., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: The purpose of the current study was to compare the effects of cognitive or motor tasks on gait performance between healthy controls and multiple sclerosis (MS) patients with and without fall history., Methods: The investigation included MS patients with fall history (n = 25) and without fall history (n = 25) and matched healthy controls (n = 25). Participants walked at their preferred speed on a motorized treadmill under three walking conditions in a randomized order: walking only, walking while performing a concurrent cognitive task (counting backward aloud by 3s), and walking while performing a concurrent motor task (carrying a tray with glasses)., Results: The findings showed that in patients with MS, regardless of fall history, spatiotemporal gait parameters were different compared to healthy controls. In contrast to average gait parameters, variability in stride length and stride time could discriminate between MS fallers and non-fallers. Simultaneous performance of cognitive task and walking resulted in higher dual-task costs (DTC) in gait performance compared to the motor dual-task. However, the pattern of change was not different among the three groups. All participants responded to the cognitive task challenges by increasing stride length and decreasing cadence and stride length variability while maintaining cognitive task performance., Conclusions: The findings may reflect successful adaptation of locomotor system to preserve cognitive task performance under cognitive dual-task condition. Future studies should examine more complex concurrent cognitive and motor tasks to better understand the dual-task-related gait changes and their contribution to falls in patients with MS., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Purpose: The present experiment was conducted to examine the hypothesis that challenging control through narrow-base walking and/or dual tasking affects ACL-injured adults more than healthy control adults., Methods: Twenty male ACL-injured adults and twenty healthy male adults walked on a treadmill at a comfortable speed under two base-of-support conditions, normal-base versus narrow-base, with and without a cognitive task. Gait patterns were assessed using mean and variability of step length and mean and variability of step velocity. Cognitive performance was assessed using the number of correct counts in a backward counting task., Results: Narrow-base walking resulted in a larger decrease in step length and a more pronounced increase in variability of step length and of step velocity in ACL-injured adults than in healthy adults. For most of the gait parameters and for backward counting performance, the dual-tasking effect was similar between the two groups., Conclusions: ACL-injured adults adopt a more conservative and more unstable gait pattern during narrow-base walking. This can be largely explained by deficits of postural control in ACL-injured adults, which impairs gait under more balance-demanding conditions. The observation that the dual-tasking effect did not differ between the groups may be explained by the fact that walking is an automatic process that involves minimal use of attentional resources, even after ACL injury. Clinicians should consider the need to include aspects of terrain complexity, such as walking on a narrow walkway, in gait assessment and training of patients with ACL injury., Level of Evidence: III.

Knowledge about intra-limb coordination (ILC) during challenging walking conditions provides insight into the adaptability of central nervous system (CNS) for controlling human gait. We assessed the effects of cognitive load and speed on the pattern and variability of the ILC in young people during walking. Thirty healthy young people (19 female and 11 male) participated in this study. They were asked to perform 9 walking trials on a treadmill, including walking at three paces (preferred, slower and faster) either without a cognitive task (single-task walking) or while subtracting 1׳s or 3׳s from a random three-digit number (simple and complex dual-task walking, respectively). Deviation phase (DP) and mean absolute relative phase (MARP) values-indicators of variability and phase dynamic of ILC, respectively-were calculated using the data collected by a motion capture system. We used a two-way repeated measure analysis of variance for statistical analysis. The results showed that cognitive load had a significant main effect on DP of right shank-foot and thigh-shank, left shank-foot and pelvis-thigh (p<0.05), and MARP of both thigh-shank segments (p<0.01). In addition, the main effect of walking speed was significant on DP of all segments in each side and MARP of both thigh-shank and pelvis-thigh segments (p<0.001). The interaction of cognitive load and walking speed was only significant for MARP values of left shank-foot and right pelvis-thigh (p<0.05 and p<0.001, respectively). We suggest that cognitive load and speed could significantly affect the ILC and variability and phase dynamic during walking., (Copyright © 2014 Elsevier Ltd. All rights reserved.)