Ppt of ITF

1. Interferential Current
Therapy
Dr N.K. Choudhary
Assistant Professor

2. SET INDUCTION

3. SPECIFIC LEARNING OBJECTIVES
 Introduction
 Principle
 Sweep
 Parameters
 Techniques and applications/electrodes
 Physiological effects
 Indications & Contraindications
 Precautions
 Summary
 References

4. CONTENTS
 Definition Main clinical applications
 History Indications & contraindications
 Amplitude modulated frequency Precautions
 Static interference
 Dynamic interference
 Triangular
 Rectangular
 Trapezoidal
 Frequency
 Dosage
 Bipolar
 Quadripolar
 Vector

5. DEFINITION
 Developed by Dr. Hans Nemec of Vienna, Austria in
the early 1950’s.
 It may be described as the transcutaneous
application of two alternating medium frequency
electrical currents, which are slightly out of phase
causing amplitude modulation at low frequency for
therapeutic purposes

6. PRINCIPLE
 The main principle of IFT is that when two medium
frequency alternating currents of slightly different
frequency are passed through the tissues where the
current intersect to produce a low frequency current.
 The interference produced by the two currents in the
tissue varies in amplitude is called BEAT
FREQUENCY or AMPLITUDE MODULATED
FREQUENCY
 The current is delivered through two sets of electrode
via two separate channel in the same stimulator

9. Amplitude Modulated Frequency
(AMF)
 The AMF or beat frequency is the effective
component of IFT, it mimics the low freq current and
creates differential stimulation of nerve.
 Low AMF, elicits a beating or taping sensation, while
higher AMF elicits a tingling sensation.

11. STATIC INTERFERENCE :
 If the two medium frequencies remain constant, the
beat frequency will also be constant
 When a constant beat frequency is selected for eg 10
Hz, 50Hz or 100Hz…or any frequency between 1 to
250Hz is called as constant mode or static mode or
static interference system.
 It may lead to gradually diminishing response due to
habituation of this particular current

13. DYNAMIC INTERFERENCE
 An arrangement that allows the beat frequency to
change automatically and regularly in the given
time period is called frequency modulation or
sweep or swing or dynamic Interference system.
 Here there is moving of the area of interference
current in a to and fro manner through 45 °.

14.  Thus the machine could be set to sweep
 Eg: between 20 to 80Hz over a period of 6secs and
back over next 6 secs.
 This pattern and timing of the modulation is
adjustable and sometimes called as spectrum.
 This dynamic system helps to prevent nerve
accomadation.

16. Types of sweep pattern
 Triangular sweep pattern
 Rectangular Sweep Pattern
 Trapezoidal Sweep Pattern

18. PARAMETERS
 FREQUENCY
 DOSAGE

19. FREQUENCY
 High AMF: 1) Frequency ranges from 100Hz-150Hz
2)Useful for relief of acute and chronic
pain
 Low AMF : 1)Frequency below 50Hz
2)Useful for sub acute pain

20. DOSAGE
 Intensity of Current:
It should be gradually increased till patient feels
comfortable tingling sensation

21. Treatment Duration
 10 – 15 mins of treatment not exceeding 20 mins to
one area.

22. SWEEP
 The principle of using the sweep is that the machine
is set to automatically vary the effective stimulation
frequency using either pre-set or user set sweep
ranges. Such sweep prevents accommodation of
nerves

23. METHOD OF APPLICATION
 Bipolar Application
 Quadripolar Application
 Vector or scanning mode

25. Quadripolar Application
 Interferential current is produced by applying two
medium frequency currents via 4 electrodes.
 Electrodes are used in two pairs.(color coded)
 Each pair should be placed diagonally
 It produces modulated current in a clover leaf
pattern.

27. Vector or scanning mode
 Specific area of the tissue at any depth can be
treated in patients with diffuse area of pathology
and when the arrangement of the lesion within the
static interference field is doubtful,
 The vector principal which produces a scanning
movement of the field, so that all the field are
subjected to have maximal interferential effect

34. Suction Vs Plate electrode
 IFT is often applied via electrodes that are held in
place using the intermittent suction unit. Alternately
flat carbon electrodes may be used.
 Suction has claimed to stimulate cutaneous nerves
and vasodilatation.

35. PHYSIOLOGICAL
EFFECTS

36. This depends upon:
 Magnitude of current
 Type of mode used i.e. Rhythmic or constant
 The frequency range used
 Accuracy of electrode positioning

37. Main clinical applications are :
 Pain relief
 Muscle stimulation
 Increased local blood flow
 Reduction of edema

38. Pain Relief
 Pain relief is achieved by stimulation of AB fibers by
using short duration pulses of frequency 100 Hz.
(pain gate theory)
 While 15Hz is applied to stimulate the small
diameter c and Ad fibres via descending pain
supression pathway.

39. MUSCLE STIMULATION
 For patients who can not generate useful voluntary
contraction, IFT may be beneficial. Most effective
motor nerve stimulation range is between 10-25Hz
When employing IFT it is possible to continue to
stimulate the muscle beyond its point of fatigue.
 It helps in reducing oedema

40. Increase circulation
 Deep tissue penetration stimulates parasympathetic
nerve fibers for increased blood flow
 It improves circulation of blood and helps wash away
the chemicals that stimulate the nociceptive nerve
endings and thus help to reduce pain too.

41. OEDEMA
 Local muscle contraction combined with its local
vascular changes encourages the reabsorbtion of
tissue fluid.

42. Indications
 Pain and muscle spasm
 Oedema relief
 Stress Incontinence

52. Interferential Precautions
• If there is abnormal skin sensation, electrodes
should be positioned in a site other than this area
to ensure effective stimulation
• Patients who have (marked) abnormal circulation
• For patients who have febrile conditions, the
outcome of the first treatment should be
monitored

53. • Patients who have epilepsy, advanced cardiovascular
conditions or cardiac arrhythmias should be treated at
the discretion of the physiotherapist in consultation
with the appropriate medical practitioner
• Treatment which involves placement of electrodes
over the anterior chest wall

54. Summary
 History of IFT
 Amplitude or beat frequency
 Interferences( static and dynamic)
 Types of sweep
 Parameters
 Techniques
 Effects
 Precautions

55. References
1.Textbook of electrotherapy Jagmohan Singh
2. Electrotherapy evidence-based practice by Sheila kitchen
3.https://www.slideshare.net/.../interferential-current-or-therapy-for-
physiotherapy-stude

56. THANK YOU