Electrical stimulation

Electric stimulation works by mimicking the natural way by which the body exercises its muscles. The electrodes attached to the skin deliver impulses that make the muscles contract. It is beneficial in increasing the patient's range of motion and improves the circulation of the body.

1. ELECTRICAL STIMULATION By:- Dr. Arjun Patel M.P.T . (Musculoskeletal and sports science 1 ELECTRICAL STIMULATION

2. How movement is produced? ELECTRICAL STIMULATION 2

3. VARIANTS OF DIRECT CURRENT ELECTRICAL STIMULATION 3 Continuous Direct Current Interrupted Direct Current Depolarized Direct Current Intermittent Depolarized Direct Current

4. PARAMETERS OF ALTERNATING CURRENT ELECTRICAL STIMULATION 4

5. PARAMETERS OF ELECTRIC CURRENT Continuous or uninterrupted alternating current: It is bidirectional flow of alternating current without interruption. Pulsed or pulsatile or interrupted alternating current: It is flow of alternating current with periodic ceases for definite period of time.   Monophasic pulsed current : In this type, flow of alternating current is unidirectional. Biphasic pulsed current: In this type, flow of alternating current is bidirectional. ELECTRICAL STIMULATION 5

6. PARAMETERS OF ELECTRIC CURRENT Pulse and Phase: It is an isolated electrical event separated by definite time from next electrical event. Pulse includes flow of electric current on both directions. Phase is a part of pulse which indicates flow of electric current in only one direction. One pulse has either one or two phases. Pulse duration: It is the time between onset of pulse and termination of same pulse to complete one complete cycle of bidirectional flow of alternating current. Phase duration: It is the time between onset of phase and termination of same phase to complete unidirectional flow of alternating current. ELECTRICAL STIMULATION 6

7. PARAMETERS OF ELECTRIC CURRENT Intensity or amplitude or magnitude: It is the amount of maximum current reached in one phase.   Rise time: It is the time taken by phase to rise from zero intensity to maximum intensity.   Decay time: It is the time taken by pulse to decrease from maximum intensity to zero intensity. Interpulse interval: It is time between termination of one pulse and onset of next successive pulse. ELECTRICAL STIMULATION 7

8. PARAMETERS OF ELECTRIC CURRENT Frequency: It is number of complete pulses passes through a fixed point in space in a unit time. Unit: For general purpose: Hertz (Hz) For continuous alternating current: cycles per second (cps) For pulsed alternating current: pulses per second ( pps ) Classification of current according to frequency: Low frequency current: Up to 1,000 Hz Medium frequency current: 1,000 Hz to 10,000 Hz High frequency current: More than 10,000 Hz ELECTRICAL STIMULATION 8

9. PARAMETERS OF ELECTRIC CURRENT Waveform: It is geometric shape of the pulse or phase as they appear on the graph of current or voltage versus time graph. ELECTRICAL STIMULATION 9

10. Surface electrodes: Electrodes are attached to skin Invasive or indwelling electrodes: Electrodes are implanted near the nerves or bones Internal electrodes: Electrodes are inside the body cavities Physiotherapists are using surface electrodes only so our discussion will be for surface electrodes only in detail. CLASSIFICATION OF ELECTRODE ACCORDING TO ITS PLACEMENT SITE IN BODY 10 ELECTRICAL STIMULATION

11. In different clinical settings different types of electrodes are used depending on individual preference. Each type has its merits and demerits. Rubber electrodes Metal electrodes Vacuum electrodes Self-adhesive electrodes TYPES OF SURFACE ELECTRODES 11 ELECTRICAL STIMULATION

12. RUBBER ELECTRODES They are made up of carbon and silicone. These electrodes are used most commonly. Their color is mostly black. They have hole to connect it with lead on one side. By shape they are rectangular, square or circular depending on manufacturer. Advantages: They are user friendly. They can be adjusted according to body contour making firm contact. Disadvantages: They need gel or water to make contact between skin and electrode. Without this conducting medium current will not enter to patient ’ s skin. They become very dirty and less flexible to make firm contact with patients ’ body with more use. They must be disinfected with sterilizing material after every use. They may crack in between after sometime. They need stabilization with strap or adhesive tape on the skin. 12 ELECTRICAL STIMULATION

13. Advantage: They are also easy to use. They are not breakable. They do not need conducting gel but lint pad should be dipped in water. METAL ELECTRODE They are made up of metals as the name suggests. They are used less frequently. Disadvantages: They need wet lint pad made up of cloth that surrounds electrode on each side as direct contact of electrode with skin leads to skin chemical burn. They are not flexible to body contour. They also need stabilization with strap of adhesive tape. 13 ELECTRICAL STIMULATION

14. VACUUM ELECTRODES Advantages: They do not need stabilization by strap of tap. It can be placed over the body ’ s irregular body part. They also do not need conducting gel. They are cup like structure made up of plastic. Inside this cup like structure, there will be electrode. Vacuum will be created by machine between cup and body so electrode will be held over the body part. Disadvantages: Cost of machine will be higher because of extra vacuum component. 14 ELECTRICAL STIMULATION

15. SELF-ADHESIVE ELECTRODES They are adhered to patients ’ body by sticky material on it. These are most recent advance used now-a-days. Advantages: They are very easy to use. They do not need any type of stabilization material. Disadvantages: They tend to wear after repeated use. 15 ELECTRICAL STIMULATION

16. TYPES OF STIMULATORS Constant current or Regulated current type Intensity is in Current. Unit:- Ampere Accurate Mostly used for diagnosis purpose Constant voltage or Regulated voltage type Intensity is in Voltage Unit:- Volt Comfortable Mostly used for treatment purpose ELECTRICAL STIMULATION 16

17. CONTRA-INDICATIONS Over thoracic region Cardiac pacemakers Phrenic nerve Urinary bladder Carotid sinus Hypertensive patients Uncooperative patients Inflammation Tuberculosis Superficial metal implant Peripheral vascular disorders Neoplasm Infection Pregnant females Proximity to diathermy Obese patients Thrombosis Active infection Sensation alteration N.M.E.S. 17

18. ACCOMODATION When current is applied at constant intensity nerve declines to response. Sudden rise or fall in current is LESS effective than gradual rise or fall in current. 18 ELECTRICAL STIMULATION

19. EFFECT OF FREQUENCY OF STIMULATION 0 to 20 Hz – No Tetany (Complete contraction followed by complete relaxation of muscle) 20 to 60 Hz – Partial Tetany (Complete contraction followed by incomplete relaxation of muscle) More than 60 Hz – Tetany (Complete contraction without relaxation of muscle) 19 ELECTRICAL STIMULATION

20. STRENGTH OF CONTRACTION It depends on… No. of motor units activated (which depends on intensity) Rate of change of current i.e. waveform e.g. with gradually increasing intensity type of waveform, intensity needed is more and with sudden increasing intensity type of waveform, intensity needed is less. 20 ELECTRICAL STIMULATION

21. EFFECTS OF ELECTRICAL STIMULATION Chemical effects Physical effects Thermal effects ELECTRICAL STIMULATION 21

22. TYPES OF PULSE DURATION ELECTRICAL STIMULATION 22

23. FARADIC CURRENT It is short duration interrupted current with a pulse duration of 0.1-1 ms and a frequency of 50-100 Hz. It was produced by faradic coil, type of induction coil. Now faradic coils are replaced by modern electronic stimulators. They both have same physiological effects though they differ considerably. 23 ELECTRICAL STIMULATION

24. DIFFERENCE BETWEEN ORIGINAL FARADIC AND MODERN ELECTRIC STIMULATOR Original Faradic Current Modern Electric Stimulator 24 ELECTRICAL STIMULATION

25. MODIFIED FARADIC CURRENTS Faradic type currents are surged for treatment pulse. In original faradic coil, current was surged by hand but now it happens automatically. It is desirable that duration of surges and interval between them should be decided by separate knobs. ELECTRICAL STIMULATION 25

26. EFFECT OF NERVE STIMULATION Bell- Magendie’s law Effect on sensory nerves Prickling sensation and erythema formation Effect on motor nerves Muscle contraction Effect on motor nerve trunk 26 ELECTRICAL STIMULATION

27. PHYSIOLOGICAL EFFECTS Body tissue is conductor for electric current as it contains fluid with ions Epidermis has high resistance i.e. 1000 Ω or more… Good conductor has more blood supply (e.g. Muscle) Poor conductor has less blood supply (e.g. Fat) 27 ELECTRICAL STIMULATION

28. PHYSIOLOGICAL EFFECTS Stimulation of sensory nerve Stimulation of motor nerve Effects of muscle contraction Stimulation of denervated muscle Chemical effects 28 ELECTRICAL STIMULATION

29. INDICATIONS Facilitation of muscle contraction Re-education of muscle Training a new muscle action Neurapraxia of motor nerve Severed motor nerve Improved venous and lymphatic drainage Prevention and loosening of adhesions 29 ELECTRICAL STIMULATION

30. TECHNIQUE STEP 1: Check for contra-indications STEP 2: Check the apparatus STEP 3: Application STEP 4: Wind-up 30 ELECTRICAL STIMULATION

31. SMART-BRISTOW COIL Pulses of electric current as used in faradic treatment in physiotherapy departments are usually generated by electronic apparatus with facilities for pulsating the bursts of electric pulses. In older machines a faraday coil is used which generates the pulses by the interruption of current to an inductor (similar to a car ignition coil). The Smart Bristow faradic coil used in physiotherapy apparatus has a retractable iron core which is moved in and out of the coil to change the strength of the pulses. 31 ELECTRICAL STIMULATION

32. MODE OF TREATMENT Motor point stimulation For individual muscle Group muscle stimulation For quadriceps, pelvic floor muscles etc. Faradic foot-bath For interrossei , lumbricals and abductor hallucis Faradism under pressure For upper limb and lower limb 32 ELECTRICAL STIMULATION

33. MOTOR POINTS Definition: Anatomically: It is point where nerve enters into the muscle. Physiologically: It is point where one can get maximum contraction with minimum intensity of current. Location: It is situated at junction of proximal 1/3 and distal 2/3 ELECTRICAL STIMULATION 33

34. INTERMITTENT GALVANIC CURRENT It is by most usual modification of direct current, the flow of current commencing and ceasing at regular intervals. Selective impulses – Used for stimulation of denervated muscles Duration may be increased up to 300 to 600 ms. More the duration, more the effective contraction. If pulse duration increases, frequency must be decreased. ELECTRICAL STIMULATION 34

35. INTERMITTENT GALVANIC CURRENT Mostly depolarized impulses are used so there are less chances of chemical burns. Depending on different knobs adjustment, definite parameters of electric current may be availed for treatment purpose. Current is always applied to the patient via potentiometer as this allows the intensity of current to be turned up from zero. ELECTRICAL STIMULATION 35

36. PHYSIOLOGICAL EFFECTS Stimulation of denervated muscle (If pulse duration and intensity are sufficient.) Stimulation of sensory nerves Stimulation of motor nerves Contraction with slowly rising current is more effective than suddenly rising current for denervated muscle as there is no accommodation in denervated muscle. ELECTRICAL STIMULATION 36

37. INDICATIONS MAIN INDICATION IS… Stimulation of denervated muscle It may slow down process of loss in muscle properties like irritability, contractibility, extensibility and elasticity. In early stage of regeneration of muscle.. Note:- Stimulation must be strong enough to produce muscle contraction. ELECTRICAL STIMULATION 37

38. FOR THERAPEUTIC PURPOSE Intermittent Galvanic Current/ Modified Direct Current Pulse duration more than 10 ms (Long duration pulse) Frequency 30/min It is used for stimulation of denervated muscle. It is variant of direct current For electrical stimulation, cathode or anode can be active. It gives stabbing sensation Surge Faradic Current Pulse duration less than 10 ms (Short duration pulse) Frequency 50-100 Hz It is used for stimulation of denervated or innervated muscle. It is variant of alternating current. For electrical stimulation, cathode is active. It gives prickling sensation. ELECTRICAL STIMULATION 38

39. REFERRENCES ELECTRICAL STIMULATION 39

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41. QUE STI ONS ? If you ask the question you will be considered fool for one minute. If you do not ask the question you will remain fool forever. 41 ELECTRICAL STIMULATION

42. T H A N K Y U O 42 ELECTRICAL STIMULATION