Electromyographic biofeedback (EB) detects and amplifies neurological activity and converts it to auditory and/or visual signals. EB serves as an adjunct treatment for muscle re-education, strengthening, or relaxation by measuring electrical activity in muscles and providing feedback to help restore normal neurological pathways. Basic EB units have silver electrodes that measure electrical activity in muscles to provide feedback and help patients re-establish motor control inhibited by conditions like injury or immobilization.

1. Electromyographic Biofeedback Casey Christy, MA, ATC, CSCS

2. Biofeedback Electromyographic Biofeedback (EB) detects and amplifies neurological activity, and then converts it to auditory and/or visual signals.

3. Biofeedback EB serves as an adjunct treatment for muscle re-education, strengthening or even to encourage relaxation of a muscle group.

4. Biofeedback Basic EB units have silver surface electrodes with three sensors grouped together as one adhesive electrode. Two of the sensors are “active electrodes” that measure electrical activity within the muscle. The other sensor is the “reference electrode,” which filters out non-meaningful electrical activity.

5. Biofeedback Image courtesy of Starkey, therapeuticmodalities.com, FA publishers

6. Biofeedback Edema, pain, surgery, immobilization, and decreased output from joint receptors can inhibit voluntary muscle contractions. EB can help the CN re-establish sensory-motor loops “forgotten” by the patient.

7. Biofeedback Biofeedback measures the electrical activity in the muscle, not the strength of contraction.

8. Biofeedback The strength of muscle contraction is improved once normal neurological pathways are restored.

9. Biofeedback To help retain the newly learned neurological pathways, the patient should perform active muscle contractions without the EB immediately after the treatment.

10. Biofeedback Contraindications include conditions in which muscular contractions, joint movement or motion is contraindicated.

11. Biofeedback Electrodes should be placed over the muscle’s motor point or the muscle belly.

12. Biofeedback Myotrac controls Gain x1,x10,x100 Threshold Higher gain= less sensitivity to contraction= more difficulty Higher threshold= less sensitivity to contraction= more difficulty

13. Biofeedback Clinical Application Examples Place over VMO while patient performs terminal knee extensions Place over rhomboids while patient performs scapular retraction Place over mid quadricep while patient performs quad setting exercises

14. Biofeedback Myotrac Threshold setting Patient must hold contraction in target zone for 4 seconds in order for alarm to sound.

15. Biofeedback Some biofeedback units are combined with electrical stimulation to enhance muscle re-education. Electrical simulation starts once the patient achieves a voluntary contraction beyond a set threshold or target.

16. Reference Starkey, Therapeutic Modalities, 3rd Edition.