• Dementia and Neurocognitive Disorders
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• v.22 no.4
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• pp.139-147
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• 2023

Background and Purpose: Dual walking task such as crossing over an obstacle may serve as an excellent tool for predicting early cognitive decline. Thus, this study aimed to investigate correlation between walking while crossing over an obstacle and executive functions under different gait phases to validate the use of walking with an obstacle for predicting early cognitive decline. Methods: A cross-sectional study was conducted on 48 elderly individuals from 2 day-care centers and 3 welfare-centers in Seoul and Gyeonggi, Korea. Executive function tests (Trail Making Test, Stroop test) and dual walking tests (gait speed, cadence, stance time, gait cycle time) were performed and compared using partial correlation analysis. Results: There were significant correlations between executive function and most of the gait variables (stance time, cadence, and gait cycle time) (p<0.05) when crossing over an obstacle while walking. Especially, stance time exhibited significant correlations with most executive functions (p<0.05). Conclusions: When evaluating executive function during walking with an obstacle, post-obstacle-crossing phase and stance time need to be observed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.7 s.94
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• pp.1864-1873
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• 1993

A biomechanical approach was carried out to analyze foot-floor reaction forces acting on five male subjects performing a walking task. The task analyzed was walking over an obstacle with the right bare foot. The foot-floor reaction data were measured from a force plate, and then processed using a software developed. The source program was coded in the C language for easier on-line data acquisition and graphic displays. High repeatability was found in the reaction data acquired from three trials by each subject. For obstacle height from 0 to 25 cm, the maximum in reaction force reached up to 1.048 BW in the vertical, 0.174 BW in the anterior-posterior, and 0.054 BW in the medio-lateral components, respectively. A quantity was defined by the difference between two vertical reaction values, and this quantity was found to be proportional to the obstacle height. It was also shown that the whole body motion could be predicted the measured foot-floor reaction data.

• Physical Therapy Korea
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• v.15 no.3
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• pp.35-43
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• 2008

The purpose of this study was to compare spatio-temporal parameters during walking between patients with idiopathic Parkinson's disease and a control group matched for age, height, and weight. Thirty-three subjects were included in this study. Fifteen normal subjects (age, $63.3{\pm}5.8$ yrs; height, $164.1{\pm}8.7$ cm; weight, $60.7{\pm}17.5$ kg) and eighteen patients (age, $64.0{\pm}7.7$ yrs; height, $164.7{\pm}7.3$ cm; weight, $63.6{\pm}7.7$ kg) participated in the study. The Vicon 512 Motion analysis system was used for gait analysis in each group during walking, with and without an obstacle. The measured spatio-temporal parameters were cadence, walking speed, stride time, step time, single limb support time, double limb support time, stride length, and step length. Results in stride length and step length, when walking without an obstacle, showed a significantly greater decrease in the patient group compared to the control group. During walking with an obstacle, the patient group showed a significantly greater decrease in the step length as compared to the control group. For the control group, there were significant decreases in parameters of cadence and walking speed and increases in parameters of stride time, step time, and single limb support time when walking with an obstacle. The patient group had lower cadence and walking speed and higher stride time, step time, and single limb support time during walking with an obstacle than in walking without an obstacle. These results suggest that patients with Parkinson's disease who walk over an obstacle can decrease cadence, stride length, and step length. Further study is needed, performed with more obstacles and combined with other external cues, such as visual or acoustic guides.

• Physical Therapy Korea
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• v.18 no.3
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• pp.16-25
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• 2011

This study aimed to evaluate factors related to the ability of ambulatory patients with cerebral palsy (CP) to walk over vertical and horizontal obstacles. Twenty patients with spastic CP who were able to walk independently for at least 10 m with or without walking devices were recruited for the study. Participants were required to walk over small obstacles (1, 4, and 8 cm in height or width; total of 6 conditions). A 'fail' was recorded when either the lower limbs or the walking device contacted the obstacle. Linear regression analyses were used to determine the effects of age, sex, walking devices, eyeglasses, subtype (hemiplegia or diplegia), ankle foot orthoses, functional level, and score of body mass index on the ability of obstacle crossing. Fifteen participants (75%) failed to adequately clear the foot or walking device over obstacles in at least 1 condition. The chance of failure in crossing vertical obstacle was affected by the use of ankle foot orthoses, eyeglasses, gender, and CP subtype (p<.05). The failure rate crossing horizontal obstacle was affected by CP subtype. These findings suggest that rehabilitation procedures should (1) consider the clinical characteristics of patients in order to prepare them to be more independent while performing daily activities, and (2) incorporate environmental conditions that patients encounter at home and in the community.

• Journal of the Korean Society of Physical Medicine
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• v.17 no.3
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• pp.51-58
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• 2022

PURPOSE: This study aimed to evaluate the correlation between executive function and gait evaluations for the elderly, and validate the obstacle gait evaluation as a cognitive impairment test tool. METHODS: This study was a cross-sectional design. 79 people aged 65 years or older were selected as subjects. The Korean version of the Mini-Mental State Examination (MMSE-KC) to evaluate overall cognitive function and the Trail Making Test (TMT) A, B to measure executive function were performed. The 4-meter walking speed test and the walking speed test while crossing over an obstacle were carried out to evaluate gait. The Spearman's correlation was used to measure the correlation between cognition and gait speed. RESULTS: There was no significant correlation between the 4 m gait speed and executive function( TMT-A (p = .056), TMT-B (p = .115)). However, there was a significant correlation between the 4 m gait speed and MMSE-KC (r = .277, p < .05). There was also a significant correlation between walking speed while crossing over an obstacle and all tests (MMSE-KC (r = .382, p < .01). TMT-A (r = -.327, p < .01), TMT-B (r = -.283, p < .05)). CONCLUSION: It was found that the gait speed while crossing over an obstacle was correlated with all cognitive function tests. Therefore, we suggest the use of the gait speed test while crossing over an obstacle rather than the simple gait test to diagnose cognitive decline.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.2
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• pp.169-176
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• 2013

To generate the walking path of a humanoid robot in an unknown environment, the shapes of obstacles around the robot should be detected accurately. However, doing so incurs a very large computational cost. Therefore this study proposes a method to classify the obstacle shape into three types: a shape small enough for the robot to go over, a shape planar enough for the robot foot to make contact with, and an uncertain shape that must be avoided by the robot. To classify the obstacle shape, first, the range and the number of the obstacles is detected. If an obstacle can make contact with the robot foot, the shape of an obstacle is accurately derived. If an obstacle has uncertain shape or small size, the shape of an obstacle is not detected to minimize the computational load. Experimental results show that the proposed algorithm efficiently classifies the shapes of obstacles around the robot in real time with low computational load.

• Physical Therapy Korea
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• v.22 no.4
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• pp.71-78
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• 2015

Previous studies have investigated stepping over obstacles in treadmill walking training (TWT-OS) and treadmill walking training (TWT) alone for walking capacity not considering real physical activity. As such, we investigated the effects of TWT-OS on physical activity and changes in different levels of physical activity based on community ambulation in stroke patients. Thirty subjects were randomly assigned to either the experimental group or the control group, with 15 and 15 subjects, respectively. However, one subject from the control group was excluded because of inadequate treatment sessions. All subjects underwent routine physical therapy in the form of treadmill walking. The subjects in the experimental group underwent simultaneous training in obstacle-stepping while walking on the treadmill for 30 min/day, five times/week, for four weeks. Subjects were given a three-axis accelerometer to wear at the hip on a belt for one-week pre- and post-training physical activity. Step counts for seven days, average daily step counts, and the average of minutes spent in sedentary, light, and above moderate activity were chosen as outcome measures of physical activity. No significant differences between the groups were found in terms of step counts for seven days, average daily activity, or daily activity spent at sedentary levels after four-week interventions. However, the average daily activity spent at light levels (-42.60 min vs. -6.71 min) was significantly lower in the experimental group than in the controls. Conversely, average daily activity spent at above moderate levels was higher (19.86 min vs. 11.07 min) (p<.05) after adjusting for each baseline value. Significant pre- and post-training differences were found in all variables of the experimental group (p<.05). Thus, TWT-OS could improve physical levels above moderate activity as a community-oriented task more than simple repetitive waking on a treadmill, and it could provide an opportunity for patients ambulatory after stroke to participate in the community again.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.489-492
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• 2016

In this paper, 본 논문에서는 경사/장애물/특수표면을 이동할 수 있는 얀센 매커니즘 기반의 보행기구 설계에 대해 다루고 있다. 얀센 매커니즘 자체의 조건과 전체 보행기구의 조건을 알아보며, 기구의 완전한 회전운동 조건과 장애물이 있는 거친 표면을 이동할 수 있는 조건을 알아보고자 한다.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.645-650
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• 2003

Legged robots can avoid an obstacle by crawling-over or striding, according to the obstacle’s nature and the current state of the robot. Thus, it can be observed that the mobility efficiency to reach a destination is improved by such action. Moreover, if robots have many legs like 4-legged or 6-legged types, then the robot movement range is affected by the order of swing leg. In this paper, the avoidance action of a quadruped robot is generated by a neural network (NN) whose inputs are information on the position of the destination, the obstacle configuration and the robot's self-state. To realize a free gait in static walking, the order of swing leg is determined using an another NN whose inputs are the amount of movements and the robot’s self-state. The design parameter of the latter NN is adjusted by using genetic algorithm (GA).

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.565-568
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• 1998

In this paper, we implemented the electornic moving aid system for safe walking of the blind. An obstacle detecting of each sector used ultrasound and a distance measurement used time of flight. The alarm is designed to have a sound and a tactile function that can be selected on an user's convenience. This system can detect and obstacle of upward, forward, downward and optimally warn to the blind with vibration, beep sound by appling warning algorithm on object detection. Experimental testing and performance evaluation have been successfully carried out with a prototype cane, and the experiment shows the capability of the function to detect unknown objects within an assigned distance, under knees, over head height, and crushed puddles.