Interferential Therapy (IFT).Class.pptx

IFT, PRINCIPLES, TYPES OF ELECTRODES, METHODS, INDICATIONS, CONTRAINDICATIONS, THERAPEUTIC EFFECTS

1. PREPARED BY :- NIYATI PATEL INTERFERENTIAL THERAPY 1 P/B :- DR NIYATI PATEL

2. INTRODUCTION Interferential current was developed in the 1950s by Dr Hans Nemec in Vienna, and became increasingly popular in the UK during the 1970s . So it is also known as Nemec’s current. Interferential current is the waveform produced by the interference of two medium frequency currents are used to produce a low frequency effect . 2 P/B :- DR NIYATI PATEL

3. Two medium frequency currents which are slightly out of phase, passed through the tissues simultaneously, where they are set up so that their paths cross and in simple terms they interfere with each other. This interference gives rise to an interference or beat frequency which has the characteristics of a low frequency stimulation. Two medium-frequency currents are used to produce a low frequency currents. 3 P/B :- DR NIYATI PATEL

4. Principle of Interferential Therapy The basic principle of Interferential Therapy (IF) is to utilize the strong physiological effects of low frequency electrical stimulation of muscle and nerve tissues at sufficient depth without the associated painful and somewhat unpleasant side effects of such stimulation. Interference produced by two currents in the tissues is called the beat frequency. 4 P/B :- DR NIYATI PATEL

5. The resistance (impedance) of the skin is inversely proportional to the frequency of the stimulation. In other words, the lower the stimulation frequency, the greater the resistance to the passage of the current i.e. Z = 1/2 fC The skin impedance at 50Hz is approximately 3200 ohms whilst at 4000Hz it is reduced to approximately 40 ohms.   5 P/B :- DR NIYATI PATEL

6. Medium frequency currents of around 4000Hz , while able to stimulate motor and sensory nerves, encounter a much lower skin impedance. These two waveforms are delivered through two sets of electrodes through separate channels in the same stimulator. 6 P/B :- DR NIYATI PATEL

7. PHYSICAL PRINCIPLES These currents are of medium frequency i.e. 4000 or 5000 Hz that rhythmically increases and decreases in amplitude at low frequency. One current is normally of fixed frequency, for example at 4000Hz, and the other current is adjustable, for example between 4000 and 4200Hz. The two currents summate or cancel out each other in a predictable manner, producing the resultant amplitude-modulated ‘INTERFERENTIAL CURRENT’. 7 P/B :- DR NIYATI PATEL

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9. A : 4000Hz (carrier frequency) B : 3900Hz produces a resultant ‘interferential current’ C : Amplitude modulated frequency of 100Hz 4000 4000 3900 3900 1 00 9 P/B :- DR NIYATI PATEL

10. PRINCIPLES OF WAVE INTERFERENCE CONSTRUCTIVE DESTRUCTIVE CONTINUOUS 10 P/B :- DR NIYATI PATEL

11. Principles of wave interference: Combined Effects Constructive interference: when two sinusoidal waves that are exactly in phase or one, two or three wavelengths out of phase, the waves supplement each other in constructive interference 11 P/B :- DR NIYATI PATEL

12. Principles of wave interference: Combined Effects Destructive interference: when the two waves are different by half wavelength (of any multiple) the result is cancellation of both waves 12 P/B :- DR NIYATI PATEL

13. Principles of wave interference: Combined Effects Continuous Interference: Two waves slightly out of phase collide and form a single wave with progressively increasing and decreasing amplitude 13 P/B :- DR NIYATI PATEL

14. TYPES OF ELECTRODES Three types of electrodes : 1. Plate electrode 2. Vacuum electrode 3. Combined electrode 14 P/B :- DR NIYATI PATEL

15. PLATE ELECTRODE Made of conducting rubber which are comfortable and long lasting larger plates electrodes give more comfortable treatment and deeper effect Smaller electrodes are used for a localized effect, but this effect is more superficial Attached to the patient by means of straps to assure a good contact and greater tolerance of treatment 15 P/B :- DR NIYATI PATEL

16. VACUUM ELECTRODE Made from a vacuum unit plug into a rubber suction cup connected to a machine capable of producing a vacuum, Suction should not be constant because it can be uncomfortable and causes bruising Wet sponges are placed in the cups and moisten the edges of the cups for better adherence, Excellent for treating flat smooth areas for example back or a plump knee Not indicated for treatment of the hairy areas because can’t get an airtight seal 16 P/B :- DR NIYATI PATEL

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18. COMBINED ELECTRODE all four contacts are embedded in some insulating material and can be applied as one pad there are different sizes (small, medium and large) for different surfaces to be treated limited by the low intensity of current that can be tolerated so general effect is small if possible, use larger separate plate electrodes!! 18 P/B :- DR NIYATI PATEL

19. METHOD OF APPLICATION Two methods, 1. QUADRIPOLAR application 2 . BIPOLAR application 3. QUADRIPOLAR method with AUTOMATIC VACTOR SCAN 19 P/B :- DR NIYATI PATEL

20. QUADRI-POLAR TECHNIQUE. 20 P/B :- DR NIYATI PATEL

21. QUADRI-POLAR TECHNIQUE. The four electrodes are positioned around the target treated area so that each channel runs perpendicular to the other and the current crosses at a midpoint. The interference effect branch off from the center of the treated area in the shape of a four leaf clover. Tissues within this area receive the maximal treatment effect . The electrodes are positioned in a coplanar arrangement to treat a flat surface . 21 P/B :- DR NIYATI PATEL

22. QUADRI-POLAR TECHNIQUE 22 P/B :- DR NIYATI PATEL

23. COPLANAR APPLICATION FOR BACK. 23 P/B :- DR NIYATI PATEL

24. The maximum AMF is obtained in the intersection of the two applied alternating currents. (point of superimposition) Balance control : to allow the output of one channel to be increased while decreasing the other. USE : for selective stimulation of deeper lying tissue. and highly suitable for shoulder, knee, neck and lower back. 24 P/B :- DR NIYATI PATEL

25. QUADRIPOLAR [4EL] 4 electrodes supplied by two channels. 25 P/B :- DR NIYATI PATEL

26. BIPOLAR [2EL] In this mode, the AMF is generated inside the equipment and supplied to the patient through two electrodes. This method makes it very easy to localise the area of stimulation because the AMF is present in the entire region between the two electrodes. USE : suitable for the treatment trigger points, muscle and skin zones. 26 P/B :- DR NIYATI PATEL

27. Disadv . of bipolar mode is more sensory stimulation, since the low freq. current is already produced by the machine, and has to go through the skin and it is unpleasant 27 P/B :- DR NIYATI PATEL

28. BIPOLAR TECHNIQUE 28 P/B :- DR NIYATI PATEL

29. QUADRIPOLAR METHOD USING AUTOMATIC VECTOR SCAN 4EL 45 OR 4EL 90 In this technique, the intensity of the alternating currents is varied. As a results, a point of superimposition rotates within the area of intersection enlarging the area of effective treatment. USE : suitable when the point to be treated can not be exactly localised . 29 P/B :- DR NIYATI PATEL

30. TREATMENT PARAMETERS AMPLITUDE MODULATED FREQUENCY FREQUENCY SWEEP CURRENT INTENSITY TREATMENT DURATION 30 P/B :- DR NIYATI PATEL

31. FREQUENCY Excitable tissues can be stimulated by low frequency alternating currents. Although to some extent, all tissues in this category will be affected by a broad range of stimulations, it is thought that different tissues will have an optimal stimulation band, 31 P/B :- DR NIYATI PATEL

32. These are detailed frequencies below: Sympathetic Nerve 1-5Hz Parasympathetic Nerve 10-150Hz Motor Nerve 10-50Hz Sensory Nerve 90-100Hz Nociceptive fibers 90-150Hz Smooth Muscle 0-10Hz 32 P/B :- DR NIYATI PATEL

33. SWEEP FREQUENCY Nerves will accommodate to a constant signal & a sweep (or gradually changing frequency) is often used to overcome this problem. The sweep (range) should be appropriate to the desired physiological effects, The mode of delivery of the selected sweep varies with machines. The most common application is the 6 second rise and fall between the pre-set frequencies. 33 P/B :- DR NIYATI PATEL

34. SWEEP FREQUENCY For example, if a 10-25 Hz range has been selected, the machine will deliver a changing frequency, starting at 10 Hz, rising to 25Hz over a 6 second period. Once this upper limit has been achieved, the frequency will once again fall, over a 6 second period to its starting point at 10Hz. This pattern is repeated throughout the treatment session. 34 P/B :- DR NIYATI PATEL

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36. Other patterns of sweep can be produced on many machines 36 P/B :- DR NIYATI PATEL

37. CURRENT INTENSITY The intensity of the current is dependent on the desired physiological effect and the tissue to be stimulated. In general the current could be administered at sensory level, motor level, or noxious level. Use an intensity of current which produces a strong but comfortable prickling without a muscular contraction. Steps to follow: 1) Increase current until the patient feels a definite prickling, and leave for one minute for it to decrease 2) Increase current again until the patient reports a slight muscular contraction, then decrease until contraction stops. may teach the patient to increase intensity periodically in order to obtain longer lasting pain relief 37 P/B :- DR NIYATI PATEL

38. DURATION OF TREATMENT IFC usually applied for 10-15 minutes treatment at a normal intensity should not be given to one area for longer than 20 minutes if more than one area is to be treated è total time should not exceed 30 min. Vary widely according to the usual clinical parameters of acute/chronic conditions & the type of physiological effect desired. Acute conditions 5-10 minutes Chronic conditions 20-30 minutes **too long a Rx makes pt. unacceptably tired later in the day!** 38 P/B :- DR NIYATI PATEL

39. FREQUENCY OF TREATMENT in most cases, treatment every other day (i.e. 3x/wk.) is ideal treatment less than twice/week is usually a waste of time a course of 12 treatments is given 39 P/B :- DR NIYATI PATEL

40. WAVEFORMS TRIANGULAR –acute condition RECTEANGULAR- sub acute condition TRAPEZOIDAL-chronic condition 40 P/B :- DR NIYATI PATEL

41. Uses of Interferential Therapy The are 5 main clinical uses for which IF appears to be beneficial: 1- Relief and management of acute and chronic pain. 2- Muscle stimulation 3- Increased blood flow 4- Reduction of edema 5- Stimulating of soft tissues healing and repair. 41 P/B :- DR NIYATI PATEL

42. 1. Relief of Pain important because pain produces spasm, unnatural movement, and production of more strain. IF current is used management of acute and chronic pain of different origin specially Post traumatic pain Sympathetically maintained pain as in shoulder hand syndrome, reflex sympathetic dystrophy and Reynolds disease *IFC is not effective in post-traumatic pain in the acute stages!! It is effective in cases of chronic pain with or without swelling. set F at 80-100Hz which gives analgesic effect with a vasodilatory effect on the tissues. 42 P/B :- DR NIYATI PATEL

43. Mechanisms of Pain control by interferential therapy Stimulation with the higher frequencies about 100Hz at sensory level stimulation stimulate the pain gate mechanisms & thereby mask the pain symptoms. Stimulation with lower frequencies up to 10Hz at motor level intensities can be used to activate the opoid mechanisms, again providing a degree of relief. Decrease activity of the sympathetic ganglion and sympathetic nerves in cases of sympathetically maintained pain. 43 P/B :- DR NIYATI PATEL

44. 2. Muscle contraction Stimulation Stimulation of the motor nerves to induce contraction of muscle can be achieved with a wide range of frequencies (10-50Hz). Clearly, stimulation at low frequency (e.g. 1-10Hz) will result in a series of twitches, with stimulation at 50Hz will result in a tetanic contraction. The choice of treatment parameters will depend on the desired effect. 44 P/B :- DR NIYATI PATEL

45. 2. Muscle contraction Stimulation If IF is used as neuromuscular stimulation, it can be used for: Relaxation of muscle spasm. Prevention and retardation of disuse atrophy. Muscle re-education. Maintenance of range of motion. 45 P/B :- DR NIYATI PATEL

46. 3. Increase blood flow Increased vasodilatation is noticed following interferential current due to Its effect on parasympathetic nerve fibers for increased blood flow. IC is used in treatment of circulatory disorders, Depressing the activity of certain cervical and lumbo -sacral sympathetic ganglia in patients with increased arterial constrictor tone so increased circulation a in Raynaud’s disease. 46 P/B :- DR NIYATI PATEL

47. 4. REDUCTION OF SWELLING & EDEMA important because organization of the exudate leads to the formation of adhesions and impairment of function set F at 1-30Hz which causes a. electroporation (increased permeability of the cell membrane, which helps ion movement to and from cells) b. increase in venous and lymphatic flow, and increase tone of tissues and vessels which aid in the relief of edema 47 P/B :- DR NIYATI PATEL

48. Chronic post-traumatic edema can be reduced by the use of IF. This effect is attributed to milking of the venous and lymphatic return through electrically evoked contraction. progress Rx by setting beat F at 1-15Hz or a sweep of 10-25 Hz which causes vasodilation , and has a vigorous pumping effect which will increase the physiologic mechanisms for the absorption of the exudate . 48 P/B :- DR NIYATI PATEL

49. 5. Stimulating soft tissues healing and repair IF improve accelerate ossification and is used to enhance fracture healing. IF current also is used to accelerate wound healing by improving cellular function and increasing cell proliferation . - 49 P/B :- DR NIYATI PATEL

50. Contraindications 1)Arterial disease -the stimulatory effect of the current could produce emboli 2) Deep Vein Thrombosis -in the acute phase, it is possible to dislodge the thrombi or increase the inflammation of the phlebitis 3) Infective conditions -could spread the infection or exacerbate due to the stimulatory effects of the current 50 P/B :- DR NIYATI PATEL

51. ` 4) Pregnant Uterus -not safe for fetus -may however use for S.I. joint strain during pregnancy if IFC placed superficially over S.I. ligaments 5) Danger of haemorrhage -stimulating effect can cause an Ý in bleeding 6) Malignant tumors -direct stimulation of tumor is CI, but reffered pain from cancer or metastasis can be treated 7) Artificial pacemakers -a demand unit must sense the electrical activity of the heart, thus avoid an electric device that may interfere with it 51 P/B :- DR NIYATI PATEL

52. 8) Large open wounds -these will cause concentration of the current and distortion of the IF field 9) Dermatological conditions -IFC may exacerbate any dermatological condition in the area being treated 52 P/B :- DR NIYATI PATEL

53. Set-up and Application The usual steps for preparation of patient and the apparatus during electrical stimulation are followed. Apply the electrodes to the treated. Turn on the apparatus by activating the power switch. Select the appropriate beat frequency based on the goal of treatment. Use the appropriate sweep frequency for this treatment protocol. Set the duration of the treatment by adjusting the timer. Start the treatment by pressing the start button. Slowly increase the intensity until the appropriate current level is obtained and guided by the patient’s feeling. 53 P/B :- DR NIYATI PATEL

54. Precautions care should be taken to maintain the suction at a level below that which causes damage or discomfort to the patient. For patients who have febrile conditions, the outcome of the first treatment should be monitors. Patients who have epilepsy, advanced cardiovascular conditions or cardiac arrhythmias should be treated in consultation with the appropriate medical practitioner. 54 P/B :- DR NIYATI PATEL

55. REFERENCES 1. Electrotherapy - evidence-based practice, by Sheila kitchen, 11 th edition, pg no. 287-300 2. Physical agents in rehabilitation – from research to practice 3. Clayton’s Electrotherapy – theory and practice, ninth edition, pg no. 107-111. 4. Physical principles explained by low n reed, pg no. – 128. 5. Therapeutic modalities in rehabilitation, by William E. Prentice, 3 th edition 55 P/B :- DR NIYATI PATEL