Characteristic surface myoelectric signals of maximum isometric voluntary contraction of the wrist flexors and extensors in children with hemiplegic cerebral palsy / 中华物理医学与康复杂志

ABSTRACT

Objective To study the characteristic surface myoelectric signals generated by children with hemiplegic cerebral palsy (HCP) during maximum isometric voluntary contraction (MIVC) of the wrist flexors and extensors.Methods Sixty-eight children with HCP 2 to 14 years of age were assessed with surface electromyography (sEMG).The electrodes were applied on the skin over the wrist flexors and extensors.The integrated EMG signals (iEMGs),root mean square amplitudes (RMSs) and co-contraction ratios during MIVC were recorded and analyzed.Results In a MIVC,the RMS,iEMG and co-contraction ratio were all significantly different between the involved and uninvolved hands,though the iEMGs of the wrists of the two hands were strongly correlated.The RMSs of the wrists of the involved and uninvolved hands were also strongly positively correlated when grasping maximally using the involved hand.Conclusions The involved hand of children with HCP has excessive co-activation of the wrist flexors,poor muscle recruitment and little isolated selective control of movement.It may be very important to facilitate wrist extensor contraction,inhibit wrist flexor co-activation and induce involved hand use to improve the hand function of children with HCP.