Exploratory Development Of Elbow Spasticity Assessement In Hemiplegic Patients Using SEMG

BACKGROUNDSpasticity is most commonly defined as a motor disorder characterized by a velocity-dependent increase in the muscle tone with exaggerated tendon jerks, resulting from hyperexcitability of the stretch reflex (SR), as one component of theupper motor neuron syndrome.It is a major source of disability caused by central nerve injuries such as cerebrovascular accidents (CVA),spinal cord lesion (SCL), cerebral palsy, multiple sclerosis etc. Spasticity is the manifestation of a lesion of the supraspinal motor pathways and is caused by adaptive changes in transmission in the spinal networks distal to a lesion of the descending motor pathways,which produced many problems,such as movement disorders,difficult for activities of daily living,nursing and so on. Spasticity assessment could find out wheather spasm exsit or not and its degree,and also compare the treatments,so as to determine the treatment goals and guide improving plans. The circumstances under which the individuals have been tested, such as the time of the day, hours and type of activity before the test, ambient temperature,emotional status, general health (such as urinary tract infection, constipation, pain, fatigue), use of drugs,clothing and especially the testing position, that is,all not controlled factors may contribute to variability in the scores.The measurement of the spasticity is a difficult and unresolved problem, partly due to its complex and multi-factional nature. The previous methods of quantifying or qualifying the spasticity are based on clinical scales or the biomechanical and neurophysiological analysis of the limb resistance to passive or voluntary movements.A quantitative assessment of spasticity and spasms is important for evaluation of potential effects of treatment interventions The Ashworth scale was proposed by Ashworth in1964,which was divided into five grades,0～4grade, according to the resistance that raters felt during the whole range of passive movement, and made spasticity transformed from qualitative to quantitative.In1987, Bohannon and Smith found that many of their patients demonstrated levels of spasticity towards the lower end of the scale and included an extra category (1+) to render the scale more discrete. At the same time, they modified the definitions slightly. AS and MAS are the most frequently used clinical methods for estimation of spasticity.Their assessment lack correcting and made the feel of passive resistense as basic assessment,so the raters’ability to judge, were limited.As the literatures repoted, AS and MAS neglect tendon reflex and clonus,and they have more reliability for upper limb.sEMG’signals are the dynamic electromyography and bioelectrical activity of the neuromuscular system,which are the one-dimensional time series signals gained by guiding,enlargeing,displaying,recording from the skin.The amplitude and frequency of signals depend on physiological factors,such as muscle’s functional status, the level of muscle activity, the raise of muscle fibers,the place of electrodes.the thickness of subcutaneous fat and so on.sEMG have many advantages,for examples, non-invasive,real-time,multi-target measuring.It has been widely used in rehabilitation.Analysis of sEMG’signals mainly concentrated in the time domain analysis and frequency domain analysis.IEMG and root mean square are index of time domain analysis.Both of them reflected the variation of amplitude on time dimension,and the later reflex the square of the average square root of transient EMG amplitude during period of time.It depended on the muscle load factors and the link between muscle physiological and biochemical processes,which was related to electric power directly and made more drect physical sense. RMS was used to assess the contractile properties of muscle during the unit time. Frequency domain analysis were the frequcency spectrum and power spectrum of signals,which gaind from the Fast Fourier Transform. Frequency domain index was important for analying muscle fatigue,and could reflex that the signals of sEMG changed in the different frequency components,so it was able to better reflect the sEMG’change in frequency dimension.OBJECTIVEThe purpose of this study is to explore the correlation of characteristics from biceps brachii(BB) and triceps brachii(TB) with the Modified Ashworth Scale (MAS) during a passive movement of the spastic elbow in patients with hemiplegy after a brain lesion using surface electromyography(sEMG),having an assessment and analyzation for elbow spasticity.MATERIAL S AND METHODS1.Subjects:37inpatients with traumatic brain injury or cerebral vascular accident.they came from Rehabilitation Department of Nanfang Hospital Affiliated to Southern medcal universityInclusive criteria:1)There was brain tissue injury in one side by the proving of CT and MRI,and they presented hemiplegia;b) The elbow of lateral hemiplegia could be moved passively full joint range120°;3)They could sit alone by themselves(sitting balance Ⅱ～Ⅲgrade);4)MMSE:>20scores,They should be able to do the raters commands;5)They are willing to participate in the experiment.Rejective criteria:1)The patients with unconsciousness or heavy cognitive dysfunction;2) The patients with the peripheral nerve injury of upper limb;3)The patients with limitation of activity in shoulder or elbow caused by injury,fracture,tissue injury,contracture etc;4)The patients could not sit alone;5)The patients with complete apfasia or sensory aphasia.2.Methods2.1Circumstance:All subjects’measurement were completed in specialized room by the experienced therapist with the temperature22～26℃,and sat down by themselves with the shoulder flexion60°on the occupationl treatment table,elbow extensed passively,completly relaxed. 2.2Laboratory equipmentsa):sEMG recorded by the ME6000-T8,which was provided by the company Mega in Finland.b):Electrodes used one-time silver/chloride ECG electeodes.2.3Recording methodsa):Pre-recording:Skin preparation:The skin was polished,wiped with alcohol before placing electrodes.Electrodes placed:The testing electrodes were affixed at the location of the measured muscle(biceps brachii and triceps brachii).The reference electrodes were affixed at the radial side of the testing electrodes.Preparation action:The measured limb was slowly passively moved to prevent subjects from tension.Spasticity assessment and sEMG recording:37hemiplegic patients’elbow spasticity were assessed by a same therapist, sEMG recording the electric signals of the BB and TB synchronously.2.4Analysis parameters and data analysis:Recorded the raw sEMG signals of BB and TB,analized by the soft of Megawin2.4,got three times complete raw signals to convert to RMS by0.1s as one cycle,and then got the average of three times.There were four forms to analysis the correlation of characteristics from biceps brachii(BB) and triceps brachii(TB) with the Modified Ashworth Scale (MAS) during a passive movement,as follows:agonist, antagonist, agonist+antagonist antagonist-agonist.STATISTICAL METHODSSPSS13.0statistic analysis software was used for statistic analysis.Described RMS of agonist, antagonist, agonist+antagonist antagonist-agonist according to MAS in form of x±s,and Spearman correlation analysis between MAS and RMS was done.RESULTS1.During the assessment of MAS for patients with hemiplegy, the singles of BB and TB increased as the MAS grades rising; 2.The Spearman’s rho of root mean square (RMS) from BB, TB, TB+BB,TB-BB with MAS respectively were:0.651,0.912,0.905,0.903(P<0.01).3.The Spearman’s rho of RMS from BB,TB,BB+TB,BB-TB with MAS respectively were:0.848,0.518,0.850,0.711(P<0.01).CONCLUSIONS1. During the assessment of MAS for patients with hemiplegy, the singles,which is a passive movement, the RMS of agonist and antagonist increased as the MAS grades rising.2.Co-contraction of agonist and antagonist may influence the resistance of passive movements to assess spasticity by sEMG assessment.3.sEMG could be used to analyze the electrical activities of agonist and antagonist by detecting the changes of the muscle electrical signals during passive movements of both elbow flexion and extension. It would be an quantitive reference for spasticity assessment and clinical treatment.