Effect of Dual Therapy with Botulinum Toxin A Injection and Electromyography-controlled Functional Electrical Stimulation on Active Function in the Spastic Paretic Hand.

Abstract

Many previous studies have demonstrated that botulinum toxin A (BTX-A) injections satisfactorily reduce spasticity. Nevertheless, BTX-A, with or without an adjuvant therapy, effectively improves the direct functional movement in few patients with spastic upper extremity paralysis. Therefore the present study aimed to determine the effectiveness of task-orientated therapy on spasticity and functional movement by using electromyography-triggered functional electrical stimulation (EMG-FES) after BTX-A injections. Open-label, prospective clinical trial Method: The subjects were 15 patients with spastic paresis (12 male, 3 female; age range, 17-74 years; 14 due to stroke, 1 due to spinal cord injury) who received BTX-A injections. Before the study was started, all subjects had undergone task-orientated therapy sessions with EMG-FES for 4 months. Despite all patients showing a various extent of improved upper extremity function, upper extremity function reached a plateau because of upper extremity spasticity. After BTX-A injection, all patients underwent task-orientated therapy sessions with EMG-FES for 4 months. The outcomes were assessed with the modified Ashworth scale, the simple test for evaluating hand function, box and block test, grip and release test, finger individual movement test, and grip strength. Assessments were performed at baseline and 10 days and 4 months after BTX-A injection. The median modified Ashworth scale score decreased from 2 at baseline to 1 at 10 days and 4 months after BTX-A injection. The finger individual movement test score increased slightly at 10 days (p=0.29) and further increased at 4 months (p<0.05). The simple test for evaluating hand function, grip and release test, box and block test, and grip strength decreased after 10 days (p<0.05, p=0.26, p<0.01, and p<0.01, respectively) but increased after 4 months (p<0.01, p<0.05, p<0.01, and p=0.18, respectively). Task-orientated therapy with EMG-FES after BTX-A injection effectively reduced spasticity and improved upper limb motor function. Our results also suggest that spasticity occurs as a compensation for the force of the affected muscles and leads to misuse movements and ostensible dexterity in many patients. In addition, we hypothesize that BTX-A injection initializes the abnormal adapted movement pattern and that more active hand movements with facilitation of the paretic muscles when using EMG-FES induce an efficient muscle reeducation of the inherent physiological movement pattern that ultimately could prove useful in the activities of daily living.