Nerve function restoration following targeted muscle reinnervation after varying delayed periods

Targeted muscle reinnervation has been proposed for reconstruction of neuromuscular function in amputees.However,it is unknown whether performing delayed targeted muscle reinnervation after nerve injury will affect restoration of function.In this rat nerve injury study,the median and musculocutaneous nerves of the forelimb were transected.The proximal median nerve stump was sutured to the distal musculocutaneous nerve stump immediately and 2 and 4 weeks after surgery to reinnervate the biceps brachii.After targeted muscle reinnervation,intramuscular myoelectric signals from the biceps brachii were recorded.Signal amplitude gradually increased with time.Biceps brachii myoelectric signals and muscle fiber morphology and grooming behavior did not significantly differ among rats subjected to delayed target muscle innervation for different periods.Targeted muscle reinnervation delayed for 4 weeks can acquire the same nerve function restoration effect as that of immediate reinnervation.

Combined surface electromyography,near-infrared spectroscopy and acceleration recordings of muscle contraction:The effect of motion

Noninvasive techniques,surface electromyography(sEMG)in particular,are being increasingly employed for assessing muscle activity.In these studies,local oxygen consumption and muscle metabolism are of great interest.Measurements can be performed noninvasively using optics-based methods such as near-infrared spectroscopy(NIRS).By combining energy con-sumption data provided by NIRS with muscle level activation data from sEMG,we may gain an insight into the metabolic and functional characteristics of muscle tissue.However,muscle mo-tion may induce artifacts into EMG and NIRS.Thus,the inclusion of simultaneous motion measurements using accelerometers(ACMs)enhances possibilities to perceive the effects of motion on NIRS and EMG signals.This paper reviews the current state of noninvasive EMG and NIRS-based methods used to study muscle function.In addition,we built a combined sEMG/NIRS/ACM sensor to perform simultaneous measurements for static and dynamic exercises of a biceps brachii muscle.Further,we discuss the effect of muscle motion in response of NIRS and EMG when measured noninva-sively.Based on our preliminary studies,both NIRS and EMG supply specific information on muscle activation,but their signal responses also showed similarities with acceleration signals which,in this case,were supposed to be solely sensitive to motions.