DocumentCode :
3135849
Title :
Evaluation of Spasticity in the Ankle of a Hemiplegic Subject Using a Step-like Response
Author :
Murayama, Daisuke ; Uchiyama, Takanori ; Uchida, Ryusei
Author_Institution :
Sch. of Fundamental Sci. & Technol., Keio Univ., Yokohama
fYear :
2006
fDate :
Aug. 30 2006-Sept. 3 2006
Firstpage :
6084
Lastpage :
6087
Abstract :
The objective of this study is to propose a new indices to evaluate spasticity in the ankle joint of hemiplegic patients. Each subject sat on a bed with one foot supported with a jig, which was used to measure the response of the ankle joint angle. The subject was instructed to relax and not to generate voluntary force. A step-like load was applied to dorsiflex the ankle joint. The ankle joint angle and electromyograms of the soleus and tibialis anterior muscle were recorded. First, the step-like response was approximated with a mathematical model, which is based on musculoskeletal and physiological characteristics using the least squares method in order to estimate net inertia and the elastic and viscous coefficients of the foot. The torque generated by the elastic component was then estimated. The normalized elastic torque was approximated with a dumped sinusoid using the least squares method. The time constant and frequency of the normalized elastic torque were calculated. We propose two indices estimated from the relationships between the time constant and the frequency. One of the indices reflected the step-like load dependency. The other reflected the difference from healthy subjects. Both indices increased as the Ashworth scale increased
Keywords :
biomedical measurement; bone; electromyography; least squares approximations; orthopaedics; Ashworth scale; ankle joint angle; elastic coefficient; elastic torque; electromyograms; hemiplegic subject; least squares method; mathematical model; musculoskeletal characteristics; physiological characteristics; soleus anterior muscle; spasticity; step-like load; tibialis anterior muscle; time constant; torque estimation; viscous coefficient; Cities and towns; Electromyography; Foot; Frequency estimation; Least squares approximation; Least squares methods; Mathematical model; Muscles; Pulleys; Torque; ankle; elasticity; spasticity; viscosity;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Engineering in Medicine and Biology Society, 2006. EMBS '06. 28th Annual International Conference of the IEEE
Conference_Location :
New York, NY
ISSN :
1557-170X
Print_ISBN :
1-4244-0032-5
Electronic_ISBN :
1557-170X
Type :
conf
DOI :
10.1109/IEMBS.2006.260012
Filename :
4463196
Link To Document :
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