Inhibition of flexor tone

Abstract

Purpose: The purpose of this study is to demonstrate a progressive use of neuromuscular electrical stimulation (NMES) by using a systematic approach to the reduction of spasticity. Spasticity can limit function in patients after a cerebral vascular accident (CVA). Flexor synergistic patterns present with variable tone and frequently respond well to electrotherapy. Previous treatment protocols use the approach of stimulating spastic musculature to fatigue or antagonistic musculature to strengthen and facilitate (Currier, 1983). This protocol utilizes an electromesh glove after 30 minutes of antagonistic muscle facilitation to stimulate intrinsic muscle contraction, allowing facilitation of digital extension and abduction, therefore reducing tone and allowing static progressive splinting to minimize tone. Method: Three patients presented after left-sided flexor synergistic tone at approximately 60 degrees of wrist flexion with digital composite flexion, elbow at 40 degrees of flexion without volitional control. NMES was used to stimulate the antagonistic muscle groups consisting of extensor carpi radialis longus and brevis (ECRL/B), extensor digitorum communis (EDC), and triceps. Channel 1 was applied to the triceps to facilitate elbow extension for increased reach envelope for improved functional use of the hand and ease for splinting. Channel 2 was applied to the wrist extensors to facilitate wrist position and digital extension for appropriate pre-contact grasp formation. This configuration was applied for 30 minutes using an alternating ramped burst program with an asymmetrical waveform for same musculature. Channel 2 started after channel 1 had completed the cycle. Channel 1 gradually increased intensity for 0.5 seconds, and then held a set intensity for 5.0 seconds and then decreased intensity over 0.5 seconds. Channel one is then off for 6.0 seconds. As channel intensity is decreasing, channel 2 started increasing intensity, via the same pattern. The negative electrode was placed over motor point with cycle rates used to produce tetany at 25–50 pps (the minimum rate that produced a good tetanized contraction dependent on tone) (Kahn 1987). An electromesh glove was fitted with repositioning of proximal electrodes utilizing channel 2, after stimulation of the antagonistic musculature permitted positioning of the wrist in neutral. The electromesh glove was worn for an additional 30 minutes. A static progressive splint with a wrist hinge hand portion was fabricated over the electromesh glove. The splint is to be worn after application of the above NMES protocol permits wrist at neutral or into extension. Observation: The patients presented with the wrists at neutral after a progression of NMES to triceps and ECRL/B and EDC. Reduction of hand intrinsic musculature tightness was achieved after use of the electromesh glove along with reduction of extrinsic flexor synergistic tone. Reduction of tone allowed ease of static progressive splinting with a hinged wrist splint. Conclusion: Flexor spasticity can be a hindrance to personal hygiene and impedes functional activity. This method of using NMES and electromesh glove to initiate elbow extension, wrist extension, and digital extension with abduction promotes interference to the flexor synergistic pattern of the upper extremity, eliciting motor contraction of previously inactive extensor musculature.