The Assessment Of Elbow Spasticity For Post-stroke Patients Based On Multi-sources Signal

The post-stroke spasticity has decreased worldwide in the past two decades.Providing a valid and reliable assessment for post-stroke spasticity,not only can help them to monitor and management the stage of the pathologic processes,but also can significantly affect the course of interventions.Currently,some quantitative methods still have not been used in clinical application.The possible reasons are: the signal source and movement mode are too less to provide enough signals for assessment of spasticity;and the assessment performance is usually susceptible to several interferences such as electrode size,electrode shift and the individual differences,which would greatly decay the validity and stability.Therefore,this paper aims to work on the assessment of elbow spasticity for post-stroke patients based on multi-sources signal.Firstly,this paper developed a quantitative evaluation strategy based on surface Electromyography(sEMG)and Mechanomyography(MMG)signals for the low validity and stability of passively physiological electric signals assessment.Additionally,the time domain feature was optimized by normalized method based on muscles cocontraction indexes.By using the proposed method,the correlation between Modified Ashworth Scale(MAS)and neurophysiologic signals was improved.The optimal sEMG and MMG normalized method can improve the validity of assessment spasticity,which would provide important guidelines for the clinical application.Secondly,this paper proposed a quantitative evaluation strategy based on biomechanical signals in order to assess elbow spasticity for the single signal source can not provide enough information of muscle spasticity.According to different movement mode,we analyzed for three points:To begin with,this paper investigated the quantifying biomechanical measures of the maximum isometric voluntary contraction(MIVC)with active movement for the problem of complex spasm pathology which could not be fully manifested in the traditional isokinetic contraction.The three indexes(peak torque,tp;rise time,tr;keep time,tk)of measurements required by the MIVC affected side and unaffected side of post-stroke to obtain a valid and reliable estimate of upper-extremity spasticity.Results showed that by using the MIVC with active movement,more than 0.8 of the intra-class correlation coefficient would be obtain by affected side,greatly improving the stability of the assessment for elbow spasticity.Then,this paper developed two methods: body weight normalization method and MIVC method based on isokinetic contraction with passive movement for the effect of interferences on the environment and the inter-subject differences.Results showed that both of the two methods can effectively increase the correlations between MAS and biomechanical signals and the MIVC method better than body weigh method on reduce the inter-subject force variations which could improve the validity of the elbow spasticity.Lastly,this paper investigated the difference isokinetic contraction between passive movement and active movement while the unaffected side isokinetic contraction on active movement was compared for the subjects who had finished the active movement.Results showed that the muscle strength in paretic limb was significantly weaker than that in contralateral limb and the response curve of the active movement was strikingly higher than passive movement.