A new approach for multi-channel surface EMG signal simulation

Simulation models are necessary for testing the performance of newly developed approaches before they can be applied to interpreting experimental data, especially when biomedical signals such as surface electromyogram (SEMG) signals are involved. A new and easily implementable surface EMG simulation model was developed in this study to simulate multi-channel SEMG signals. A single fiber action potential (SFAP) is represented by the sum of three Gaussian functions. SFAP waveforms can be modified by adjusting the amplitude and bandwidth of the Gaussian functions. SEMG signals were successfully simulated at different detected locations. Effects of the fiber depth, electrode position and conduction velocity of SFAP on motor unit action potential (MUAP) were illustrated. Results demonstrate that the easily implementable SEMG simulation approach developed in this study can be used to effectively simulate SEMG signals.

Electromyographic analysis of upper limbs and trunk during elbow extension activities in C_5 and C_6 SCI patients / 中华物理医学与康复杂志

Objective To explore how the spared muscles in upper limbs and trunk compensated for elbow extension movements in patients with SCI at the level of C_5 and C_6.Methods Fifteen patients with SCI at the level of C_5 and C_6 and fifteen healthy subjects were divided into an SCI group and a control group respectively.The surface EMG recorded from the anterior dehoid,middle deltoid,posterior deltoid,triceps braehii muscle,biceps braehii muscle,upper peetoralis,serratus anterior and latissimus dorsi during four elbow extension activities including grasp- ing cup,reaching for light-switch,wheelchair ambulation and upper limb weight-bearing.The relative EMG intensi- ties of muscles were expressed as a percentage of maximal voluntary contraction.Results Several muscles partici- pated in the activity simultaneously when both groups of subjects performed every motor task.But the primary muscles involved in the movements were different between the two groups.Furthermore,the SCI group tended to employ more muscles than the controls to perform a activity.The compensatory strategies used in various motor tasks by the spared muscles were different.Conclusion The motorueuron recruitment patterns used by the C_(5～6)SCI patients in per- forming elbow extension activities could be different from those by the healthy subjects.The patients accomplished performing different motor tasks by changing their compensatory strategies.