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Lee K.B.,Catholic University of Korea | Kim J.S.,Catholic University of Korea | Hong B.Y.,Catholic University of Korea | Kim Y.D.,Human Movement Research Center | And 2 more authors.
Behavioural Neurology | Year: 2015

Although studies have demonstrated that several specific brain lesions are related to the severity of functional outcomes, the effects of specific brain lesions are not yet clear. This study investigated the effects of hemorrhagic stroke lesions on motor recovery. Eleven subjects with hemorrhagic stroke were assessed. Using the Fugl-Meyer Assessment and functional ambulation category, clinical motor and sensory impairments were tested four times in total: initially within 2 weeks and 1, 3, and 6 months after the onset of stroke. Brain lesions and size were evaluated using MRIcron, SPM8, and Talairach Daemon software. Trunk control, motor function in the lower limbs, and sensory function improved significantly within 3 months, after which the change was no longer significant. Upper limb function and gait were unchanged within 1 month but improved significantly 3 months after onset and continued to improve for 6 months. Involvement of the anterior putamen, internal capsule, thalamus, periventricular white matter, and premotor cortex was related to poor upper limb recovery in patients with hemorrhagic stroke. These results should be useful for planning rehabilitation strategies and understanding the prognosis of hemorrhagic stroke. © 2015 Kyung Bo Lee et al.

Gu Y.,Liverpool John Moores University | Li J.,Human Movement Research Center | Ren X.,Liverpool John Moores University | Lake M.J.,Liverpool John Moores University | Zeng Y.,Beijing University of Technology
Skin Research and Technology | Year: 2010

Background: The human heel pad is a complex biological structure consisting of the fat pad and the skin. The mechanical properties of the skin layer are of significant importance to the load-bearing function of the heel pad and human locomotion. The condition of the heel skin is also directly associated with some medical conditions such as heel ulcers that may become a site for the skin breakdown, which is the most common precursor to lower extremity amputation among persons with diabetes. It is essential to develop a detailed understanding of the properties of the heel skin layer and its effect on hind foot biomechanics during heel strike. Objectives: This work aims to gain a better insight into the biomechanical behaviour of the heel skin layer through a combined experimental and numerical study. The main objective is to characterise the biomechanical responses of the hind foot system during heel strike with potential variation of the skin stiffness based on a subject-specific finite element (FE) model and biomechanical testing. Methods: A three-dimensional (3D) FE model of the human hind foot incorporating a separate heel skin layer was developed based on subject-specific medical images. An inverse FE analysis of the in vivo indentation test was carried out to study the nonlinear material property of the heel skin. The FE model was then used to study the deformation of the hind foot during heel strike in comparison with the plantar pressure measurement results and to establish the effects of stiffness of the heel skin on the stress and pressure distributions. Results: The FE foot model with subject-specific heel skin properties was successfully used to predict the deformation of the hind foot during heel strike, and the results showed good agreements with biomechanical pressure measurements. The results showed that the high pressure and stress in the heel skin appeared in the centre region during a heel strike. Heel skin stiffness sensitivity studies showed that an increase in the skin stiffness had a limited effect on the stress and contact pressure of the hind foot bones, but caused a slight increase in the skin stresses, while skin softening caused a decrease in the peak plantar pressure and its distribution pattern changed. In addition, the results also suggest that skin softening may cause a higher stress level in the bones and ligaments. Conclusion: The nonlinear parameter of the heel skin has been successfully predicted from in vivo indentation tests based on a subject-specific FE model. Skin properties' sensitivity tests clearly showed that the stiffness of the heel skin could have a direct effect on the biomechanics of the hind foot. The results suggest that individuals with a pathologically stiffened heel skin could exert an increase in the heel pressure, which may potentially lead to skin breakdown or ulcer. © 2010 John Wiley & Sons A/S.

Lee K.B.,St. Vincent Hospital | Lim S.H.,St. Vincent Hospital | Kim K.H.,Sahmyook University | Kim K.J.,St. Vincent Hospital | And 5 more authors.
International Journal of Rehabilitation Research | Year: 2015

The aim of this study is to compare the time-course changes in neurologic impairments (trunk control, motor function, sensory, and cognition) and recovery in functional impairments (activity of daily livings and gait) simultaneously from initiating rehabilitation to 6 months after stroke. Consecutive stroke patients were recruited from the department of nervous surgery, and transferred into the department of rehabilitation medicine and continued on treatment during the acute stage. Outcome measures were examined at the initial rehabilitation baseline, 1, 2, and 4 weeks after rehabilitation treatment, and 3, 4, 5, and 6 months after stroke. Patients were assessed using the Trunk Impairment Scale, the Fugl-Meyer Motor and Sensory Assessments for the upper and lower limbs, Mini-Mental State Examination, Functional Ambulation Category, and Modified Barthel Index. Twenty consecutive patients were analyzed in the study with complete assessments. The recovery was relatively rapid during the 4 weeks after treatment (P value ranges from < 0.001 to <0.007) and then to a lesser extent decelerated between 3 and 6 months after stroke (P value between < 0.001 and 0.080). Statistical comparison by repeated measures analysis showed a significant interaction between time points and measures of all recovery variables (P <0.001). Significant differences in level of impairments and functional recovery were found at the different time points. In comparison with the lower leg and trunk control, the upper arm showed less recovery, with a significant difference. All variables except for leg motor function improved continuously over 6 months after stroke. Nevertheless, this study confirms the importance of the period within 3 months for recovery after stroke, during which most of the recovery occurred, ranging from 48 to 91%. Therefore, intensive treatment targeting motor and sensory functions early after stroke may be beneficial for recovery of impairments and functional performance. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Shen W.W.,Ningbo University | Ma J.B.,Ningbo University | Li J.S.,Human Movement Research Center | Gu Y.D.,Ningbo University
IFMBE Proceedings | Year: 2013

The purpose of this study is to establish models of the first to the fifth ray of the skeletal plantar arch and to analyze the model in kinematics. Foot models are built through CT scan and editing software and calculated the metatarsal angles and horizontal metatarsal angles using motion analysis system. The first to the fifth metatarsal angle and horizontal metatarsal angle are both different. The lateral and medial metatarsal angles are different too. These results can be used for analysis of foot mechanics during walking or other activities. © 2013 Springer-Verlag.

Gu Y.D.,Human Movement Research Center | Gu Y.D.,Liverpool John Moores University | Ren X.J.,Liverpool John Moores University | Ruan G.Q.,ANTA Sports Products Ltd | And 2 more authors.
International Journal for Numerical Methods in Biomedical Engineering | Year: 2011

The present study reports the development of a detailed three-dimensional (3D) finite element (FE) foot model for investigating the effect of the material properties and thicknesses of the landing mat on stress distribution and concentration point within the metatarsals during landing at an inversion position. Foam material mat insert between the foot and ground with different thicknesses had been systematic studied. The predicted plantar pressure distribution showed a good agreement with the experimental data of controlled biomechanical tests. Results showed that mat insert with optimal properties and thickness could reduce the peak plantar pressure by about 36% comparing to the barefoot-solid ground condition. The fifth metatarsal was the most vulnerable part during the inversion landing, and the peak stress point was located near the proximal part. Material sensitivity study showed that the metatarsals' stress level was affected by the material property of the mat and its thickness. Meanwhile, the influence of thickness for soft material was more effective than that for the hard material. © 2010 John Wiley & Sons, Ltd.

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