IAP Conference Article

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Effect of EMG Triggered Stimulation (ETS) and Constraint Induced Movement Therapy (CIMT) for stroke Rehabilitation.

Dr. J Dhanajeyan
Director
Spectrum Physio Center
Bangalore

Today's medical management protocol is incomplete without rehabilitation program. In the case of neurological insults such as stroke and traumatic brain injury with movement impairments this is even truer. Every day this field of movement rehabilitation is experiencing immense growth backed with latest evidences born because of marriage between science and art of handling the patients with neurological impairments.

It is a known fact that hand forms the most challenging aspect of this programme, often refusing to budge to any attempt at moulding it functional. In recent times this jinxed part of rehabilitation has undergone a revolution with the advent of constraint induced movement therapy introduced CIMT was developed by Dr. Edward Taub of the University of Alabama at Birmingham. He argued that, after a stroke, the patient stops using the affected limb because they are discouraged by the difficulty. As a result, a process that Taub calls "learned non-use" sets in, furthering the deterioration. It is this process that CIMT seeks to reverse.This novel approach when combined with EMG monitored stimulation is responsible for even quicker positive outcomes.

This process can be explained in the following manner. EMG triggered stimulation device having audio visual feedback effect along with stimulation for muscle contraction occurs to the maximum threshold. A pre programmed threshold with a wider or narrow range is designed and the EMG electrodes are placed on the muscle or muscle group to be rehabilitated. This along with CIMT augments the motor learning and aids in developing good motor control. Using this active and co ordinate function of the hand muscle is achieved at the earlier phase of rehabilitation in the persons with stroke.

This concept was put to test in our center using a male patient aged 72. His MRI was suggestive of right middle cerebral hemorrhage lesion along with clinical findings of contra lateral side paralysis. He was able to walk with mild circumductory gait and reasonably good balance; his upper limb had a MRC grading of muscle strength 0/5 in the hand muscles and 1/5 in the wrist, 2/5 in elbow, and 2/5 in shoulder. Initially the conventional intervention using CIMT was planned for his hand function for duration of 1 hour daily for a period of 1 month. The patient was encouraged to use the affected left hand for hand function kits which had multiple size and shape like rectangle, square, circle, conical, thread into holes etc. The normal hand was tied for near total restriction of movements. The affected hand was encouraged for normal pattern of ADL movements like combing, bathing, tying, etc. Post reading was taken using MRC and MRI findings to check for the outcomes. Later EMG triggered stimulation was added to the protocol.

The pad type electrodes were placed in the motor point of the stimulated muscles of the wrist extensor and wrist flexor respectively and a feedback electrode was kept on the lateral epicondyle. A command of 'Work' and 'Rest' was initiated, as the person start to initiate contraction. Stimulation is generated to create full range of contraction followed by rest period. E M G triggered stimulation was also applied for thenar and hypothenar muscles including pollicis, and lumbricals also. For the shoulder the electrodes were placed on the anterior & lateral deltoid, supra spinatus, in elbow at biceps and triceps respectively. 40 contractions for each individual muscles with increase in the threshold and stimulation to prevent accommodation was performed to extract maximal contraction along with visual effect and audio command. The total duration for stimulation was about 30 minutes daily. This was followed by constraint induced movement therapy session as planned for the conventional therapy.

Followed by this therapy a MRI was done. It showed new activation in the contra lateral motor/premotor cortices along with increased activation of the ipsilateral motor cortex and SMA compared with the was observed in the other patient. The findings were suggestive of plastic changes of the motor network occurred as a result of neural basis of the improvement subsequent to the CIM therapy augmented by EMG triggered stimulation. Further controlled and ramdomized clinical trials are necessary to validate the finding which has immense application in stroke rehabilitation.

Bhatt E, Nagpal A, Greer KH, Grunewald TK, Steele JL, Wiemiller JW, Lewis SM, Carey JR. (2007) Effect of finger tracking combined with electrical stimulation on brain reorganization and hand function in subjects with stroke.

Exp Brain Res. Oct; 182(4):435-47. Epub 2007 Jun 12. Blickenstorfer A, Kleiser R, Keller T, Keisker B, Meyer M, Riener R, Kollias S. (2008) Cortical and subcortical correlates of functional electrical stimulation of wrist extensor and flexor muscles revealed by FMRI. Human Brain Mapp.