Assessment of Walking Stability of Elderly by Means of Nonlinear Time-Series Analysis and Simple Accelerometry

Ohtaki, Yasuaki; Arif, Muhammad; Suzuki, Akihiro; Fujita, Kazuki; Inooka, Hikaru; Nagatomi, Ryoichi; Tsuji, Ichiro

doi:10.1299/jsmec.48.607

Cited by 15 publications

(21 citation statements)

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“…Rehabilitation can reduce fatigue and enhance walking by improving force, movement patterns (efficiency of the gait-cycle), dynamic balance and self-efficacy [16-18]. Concerning LDS, It has been observed that fall prevention training programs could significantly improve gait stability in elderly people [19]. Although it has been recently shown that MS patients are less locally stable than healthy controls [20], the effect of therapeutic interventions has not been studied.…”

Section: Introductionmentioning

confidence: 99%

Local dynamic stability as a responsive index for the evaluation of rehabilitation effect on fall risk in patients with multiple sclerosis: a longitudinal study

et al. 2013

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BackgroundGait and balance problems are common in patients with multiple sclerosis, leading to high risk for falls. Local Dynamic Stability (LDS), a non-linear gait stability index, has been advocated as an early indicator of risk for falls. With this longitudinal study over three weeks, we aimed to assess the responsiveness of Local Dynamic Stability to a rehabilitation program and to compare it to other measures.MethodsEighteen patients (mean 54 years, median EDSS score: 5) participated. They were admitted to inpatient rehabilitation and received a three weeks individually tailored program. They performed a 3-minute walking test at the beginning and at the end of the stay, as well as pain, wellbeing, fatigue, and balance assessment. The Local Dynamic Stability was computed from the acceleration signals measured with a 3D-accelerometer.ResultsAt the end of the rehabilitation process, patients reported reduced pain (Effect Size: −0.7), fatigue (ES:-0.6), and increased wellbeing (ES: 1.1). A small positive effect on static balance was observed (ES: 0.3). LDS was improved (ES: 0.6), and the effect was higher than walking speed improvement (ES: 0.4).ConclusionsThe Local Dynamic Stability seemed responsive to assess rehabilitation effects in patients with multiple sclerosis. It could constitute a valuable gait quality index, which could evaluate potential effects of rehabilitation on fall risk.Trial registrationCurrent Controlled Trials ISRCTN69803702.

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Section: Introductionmentioning

confidence: 99%

Local dynamic stability as a responsive index for the evaluation of rehabilitation effect on fall risk in patients with multiple sclerosis: a longitudinal study

et al. 2013

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“…Consequently, two episodes of 20 strides and 25 patients have been used in the present study. Other studies successfully used LDS in short walking trials of 30 strides [22,24,37], 16 m walking distance [26], or 8 strides [44]. Although it is likely that long duration trials could provide a higher precision, the results show that LDS was responsive to footwear change despite the low number of analyzed strides.…”

Section: Discussionmentioning

confidence: 96%

“…LDS has already been shown relevant in the evaluation of various conditions such as in patients with peripheral arterial disease [22], in unilateral transtibial amputees [23], in knee osteoarthritis [10], or in Anterior Cruciate Ligament (ACL) rupture [11]. LDS has been also used to study the effect of aging and fall risks in elderly [24-26]. The relative change in LDS induced by orthopaedic shoes lay between 7% and 10%.…”

Section: Discussionmentioning

confidence: 99%

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Do orthopaedic shoes improve local dynamic stability of gait? An observational study in patients with chronic foot and ankle injuries

Terrier

Lüthi

Dériaz

2013

BMC Musculoskelet Disord

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BackgroundComplex foot and ankle fractures, such as calcaneum fractures or Lisfranc dislocations, are often associated with a poor outcome, especially in terms of gait capacity. Indeed, degenerative changes often lead to chronic pain and chronic functional limitations. Prescription footwear represents an important therapeutic tool during the rehabilitation process. Local Dynamic Stability (LDS) is the ability of locomotor system to maintain continuous walking by accommodating small perturbations that occur naturally during walking. Because it reflects the degree of control over the gait, LDS has been advocated as a relevant indicator for evaluating different conditions and pathologies. The aim of this study was to analyze changes in LDS induced by orthopaedic shoes in patients with persistent foot and ankle injuries. We hypothesised that footwear adaptation might help patients to improve gait control, which could lead to higher LDS:MethodsTwenty-five middle-aged inpatients (5 females, 20 males) participated in the study. They were treated for chronic post-traumatic disabilities following ankle and/or foot fractures in a Swiss rehabilitation clinic. During their stay, included inpatients received orthopaedic shoes with custom-made orthoses (insoles). They performed two 30s walking trials with standard shoes and two 30s trials with orthopaedic shoes. A triaxial motion sensor recorded 3D accelerations at the lower back level. LDS was assessed by computing divergence exponents in the acceleration signals (maximal Lyapunov exponents). Pain was evaluated with Visual Analogue Scale (VAS). LDS and pain differences between the trials with standard shoes and the trials with orthopaedic shoes were assessed.ResultsOrthopaedic shoes significantly improved LDS in the three axes (medio-lateral: 10% relative change, paired t-test p < 0.001; vertical: 9%, p = 0.03; antero-posterior: 7%, p = 0.04). A significant decrease in pain level (VAS score -29%) was observed.ConclusionsFootwear adaptation led to pain relief and to improved foot & ankle proprioception. It is likely that that enhancement allows patients to better control foot placement. As a result, higher dynamic stability has been observed. LDS seems therefore a valuable index that could be used in early evaluation of footwear outcome in clinical settings.

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“…Ohtaki et al [25] have studied the Lyapunov exponents of young and elderly subjects, and of groups before and after exercise intervention. Experimental results demonstrated that exercise intervention improved the local dynamic stability of walking.…”

Section: Discussionmentioning

confidence: 99%

Analysis of body responses to an accelerating platform by the largest-Lyapunov-exponent method

Acharya

Goh

Iijima

et al. 2008

Proc Inst Mech Eng H

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Various disciplines have benefited from the advent of high-performance computing in achieving practical solutions to their problems, and the area of health care is no exception to this. Non-linear signal-processing tools have been developed to understand the hidden complexity of the time series, and these will help clinicians in diagnosis and treatment. Postural study helps the elderly and people with a balancing problem due to various pathological conditions. In elderly subjects, falls are common and may result in injury. Correct postural balance is basic to well-being and it influences our daily life significantly. These postural signals are non-stationary; they may appear to be random in the time scale and it is difficult to observe the subtle changes for the human observer. Hence, more hidden information can be obtained from the signal using non-linear parameters. In this paper, ten young normal subjects are subjected to the balancing platform whose acceleration is gradually increased from 1 m/s2 to 5 m/s2 to study the postural response. The ankle front-back acceleration and ankle pitch angular velocity sensor data were studied using the largest Lyapunov exponent (LLE). The results show that for higher acceleration of the platform the ankle movement follows a particular rhythm, resulting in a lower Lyapunov exponent. During lower acceleration of the balancing platform, this value is higher because of the random movement of the ankle. In this work, the pattern of the body response was studied using LLE values for different accelerations using ankle data as the base signal for the normal subjects.

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Assessment of Walking Stability of Elderly by Means of Nonlinear Time-Series Analysis and Simple Accelerometry

Cited by 15 publications

References 15 publications

Local dynamic stability as a responsive index for the evaluation of rehabilitation effect on fall risk in patients with multiple sclerosis: a longitudinal study

Local dynamic stability as a responsive index for the evaluation of rehabilitation effect on fall risk in patients with multiple sclerosis: a longitudinal study

Do orthopaedic shoes improve local dynamic stability of gait? An observational study in patients with chronic foot and ankle injuries

Analysis of body responses to an accelerating platform by the largest-Lyapunov-exponent method

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