1) IFT and TENS are electrotherapy modalities used to reduce pain. IFT uses two medium frequencies modulated at a low frequency to penetrate deeper tissue more comfortably than low-frequency TENS. 2) Studies have found IFT effective at increasing pain thresholds and cutaneous blood flow. However, results are mixed on whether any frequency is most effective. Studies also found TENS and IFT similarly effective at reducing heat pain. 3) Overall, the studies found IFT and TENS can increase pain thresholds, but effects depend on stimulation parameters and no modality consistently outperformed others for all outcomes. Both techniques remain useful options for pain management.

1. IFT AND TENS
Presented by- Pushpendra Yaduvanshi
Asst. prof., Physiotherapy
Career Point University, Kota

2. INTERFERENTIAL CURRENT
Intro. by Dr. Nemec in Vienna in the early
1950’s.
The transcutaneous application of
alternating medium-frequency electrical
currents, amplitude modulated at low
frequency for therapeutic purposes.
medium frequency A + medium frequency
B = low (therapeutic) frequency C

4. why use 2 medium frequency currents???

5. Medium frequency currents associated with
a lower skin resistance (impedance),thus
more comfortable than low frequency
current using a medium frequency, a more
tolerable penetration of current through the
skin is possible

6. Physiological Effects of IFC:-
Relief of Pain
Reduction of Swelling
Edema Reduction
Inflammation
Post-surgical pain
Post-traumatic acute pain

7. CONTRAINDICATIONS:-
Arterial disease
Deep Vein Thrombosis
Infective conditions
Pregnant Uterus
Danger of haemorrhage
Malignant tumors
Artificial pacemakers

8. TENS
It is a form of electrical stimulation with
surface electrodes to modulate pain
perception.

9. How does TENS reduce pain perception?

10. There are 4 theories about the physiological
effects of TENS:
1. Gate control theory
2. Opiate-mediated control theory
3. Local vasodilatation of blood vessels in
ischemic tissues
4. Stimulation of acupuncture points causes a
sensory analgesia effect

11. TENS used for
Acute pain after surgery, injury, or trauma
Chronic pain like low back pain
neck pain
muscle pain
pelvic pain
nerve pain and headache

12. TENS is a complementary treatment commonly
used in medicine. It is used to decrease pain without
the use of drugs, needles, or surgery.
Pain is experienced after unpleasant signals travel
through the nervous system. The TENS unit is
designed to block or prevent pain by providing an
opposing stimulation to compete with pain signals.
The TENS sensations interrupt pain signals as those
signals try to travel through the pain pathway to the
brain.

13. IFT Vs TENS
1. Interferential Stimulation differs from
TENS because it allows a deeper
penetration of the tissue with more comfort
(compliance) and increased circulation.
2. Interferential stimulation is concentrated at
the point of intersection between the
electrodes.TENS deliver most of the
stimulation directly under the electrodes

14. 3. TENS and muscle stimulators use discrete
electrical pulses delivered at low frequencies
of 2-160 Hz per second. However,
Interferential stimulators use a fixed carrier
frequency of 4,000 Hz per second.
When the fixed and adjustable frequencies
combine (heterodyne), they produce the
desired signal frequency (Interference
frequency).

15. ARTICLE-1
 An Investigation Into the Analgesic
Effects of Different Frequencies of the
Amplitude-Modulated Wave of
Interferential Current Therapy on Cold-
Induced Pain in Normal Subjects
Mark I. Johnson
Arch Phys Med Rehabil 2003

16. Objective: To investigate the analgesic
effects of different amplitude-modulated
frequencies of interferential current therapy
(IFT) on cold-induced pain in healthy
subjects.

17. Participants: Sixty unpaid, pain-free volunteers
without a known pathology that could cause
pain.
Interventions: IFT delivered on the
nondominant arm at a strong but comfortable
intensity without visible muscle twitches,using
a quadripolar application technique at 1 of 6
possible amplitude modulated beat frequencies
(20, 60, 100, 140, 180, 220Hz).

18. Outcome Measures: The percentage change
in pain threshold, pain intensity, and pain
unpleasantness from the pretreatment
baseline.

19. Results: Two-way repeated-measures analyses
of variance found no effects for groups for
pain threshold (P=.11) or pain ratings (P<.05).
There were no effects for cycle for any of the
outcome measures. Effects for group by cycle
interaction were noted for pain intensity and
unpleasantness ratings (P.05), although post
hoc analysis failed to determine the nature of
this interaction.

20. Conclusions: Experimentally induced cold
pain was not influenced by IFT frequencies.

21. ARTICLE-2
The effect of three electrotherapeutic
modalities upon peripheral nerve
conduction and mechanical pain
threshold
J. Alves- Guerreiro
Clinical Physiology 2001

22. Objective: The current study was designed
to examine the neurophysiological and
hypoalgesic effects of three types of
electrical stimulation.

23. Participants:Healthy volunteers (n = 40; 20
males and 20 females; age 20-40 years.

24. Subjects were randomly allocated in equal
numbers to the following groups:
control,TENS; 150 Hz, 125 ms,IFT; 150
Hz, 125 ms,or action potential stimulation
therapy (APS; 153 Hz, 6.4 ms).

25. All treatments were applied under double-blind
conditions for 15 min over the course of the
median nerve in the subject's right forearm.
Antidromic median nerve compound action
potentials (CAPs) were recorded pretreatment,
immediately post-treatment (i.e. at 15 min) and
then at 25, 35 and 45 min.

26. Immediately following CAP recording,
mechanical pain threshold (MPT) was
recorded from two sites on the palmar
surface of the right hand.

27. Result: Statistical analysis showed significant
differences between groups for peak to peak
amplitude (PPA) at 25, 35 and 45 min
(Kruskal± Wallis: P . 0á01, 0á01 and 0á02).
A significant increase in PPA in the IFT
group compared with all other groups at 25
and 35 min and compared with the TENS
and APS groups at 45 min.

28. Conclusion : No significant differences
were found for the MPT data. This study
has therefore demonstrated that none of the
a forementioned modalities produced a
significant hypoalgesic effect; however, IFT
produced a significant change in PPA
compared with TENS and APS.

29. ARTICLE-3
ANALGESIC EFFECTS OF
TRANSCUTANEOUS ELECTRICAL
NERVE STIMULATION AND
INTERFERENTIAL CURRENTS ON
HEAT PAIN IN HEALTHY SUBJECTS.
Gladys L. Y. Cheing and Christina W. Y.
Hui-Chan
J Rehabil Med 2003

30. Objectives:-This study examined whether
transcutaneous electrical nerve stimulation
or interferential current was more effective
in reducing experimentally induced heat
pain.

31. METHODS:-Forty-eight young healthy
subjects were randomly divided into the
following groups: (i) TENS (ii) IFT and (iii)
no stimulation.

32. A multi-function electrical stimulator was
used to generate the TENSstimulation or
IFT.
A thermal sensory analyser was used to
record the heat pain threshold.
The stimulation lasted for 30 minutes and
the heat pain thresholds were measured
before, during and after the stimulation.

33. RESULTS:-TENS (p = 0.003) and IFT (p =
0.004) significantly elevated the heat pain
threshold, but ‘‘no stimulation’’ did not.
The thresholds of the TENS and IFT groups
were significantly higher than that of the
control group 30 minutes into the
stimulation (p = 0.017).

34. CONCLUSION:- Both TENSand IFT
increased the heat pain threshold to a
similar extent during stimulation.
However, the poststimulation effect of IFT
lasted longer than that of TENS.

35. ARTICLE-4
A comparison of the analgesic efficacy of
medium-frequency alternating current and
TENS.
Alex R. Ward , Stacey Lucas-Toumbourou,
Brigid McCarthy
Physiotherapy (2009)

36. Objective :-To compare the analgesic
efficacy of burst-modulated medium-
frequency alternating current (BMAC) and
transcutaneous electrical nerve stimulation
(TENS) using an experimental cold pain
model.

37. Participants= Twenty healthy subjects.
Interventions= BMAC (4-kHzAC applied in
4-millisecond bursts at 50 Hz) and TENS
(125-microsecond phase duration applied at
a frequency of 50 Hz) administered to each
participant on separate occasions.

38. Results:-The mean time to cold pain threshold with the
BMAC intervention was no different than with TENS.
Statistical analysis showed that both interventions
elevated the cold pain threshold significantly [BMAC:
increase = 15.2 seconds, 97.5% confidence interval (CI)
3.1 to 27.2, P = 0.01; TENS: increase = 15.4 seconds,
97.5% CI 2.5 to 28.4, P = 0.02], and the difference
between interventions was not simply insignificant but
the intervention effects were ‘significantly the same’
(mean difference = 0.3 seconds, 95%CI −15.3 to 15.9, P
= 0.97).

39. Conclusions :-BMAC is as effective as
TENS in increasing cold pain thresholds in
healthy subjects.

40. ARTICLE-5
Pain reducing effect of three types of
transcutaneous electrical nerve stimulation
in patients with chronic pain: a randomized
crossover trial.
Albe`re J.A., Jan S.A.G. Schouten
PAIN,2004

41. Objective:-To compare the effectiveness of
three types of TENS we conducted a
randomized, single blinded crossover trial.
Patients received two times a 2-week period
of daily TENS treatment, separated by a
washout period of 2 weeks.

42. Methods:-Total, 180 chronic pain patients
were randomized into three groups. In group 1,
high frequency, low intensity TENS (HFT)
was compared with high frequency, high
intensity TENS (HIT).
In groups 2 and 3, HFT and HIT were
compared with a control TENS (COT). The
order of applying the different modalities of
TENS in each group was also randomized.

43. Outcome:- patient’s overall assessment of
effectiveness and pain reduction (VAS).

44. Results:-No differences were found in
patient’s assessment or pain reducing effect
between the three groups, indicating no
superiority of one type of TENS. In total,
56% continued TENS after the 2-week
treatment period. At 6 months, 42% of all
patients still used TENS.

45. Conclusion:-They concluded that there were
no differences in effectiveness for the three
types of TENS used in this study

46. ARTICLE-6
Transcutaneous Electric Nerve Stimulation:
The Effect of Intensity on Local and Distal
Cutaneous Blood Flow and Skin
Temperature in Healthy Subjects.
Fiona L. Cramp, DPhil, Gillian R.
McCullough,
Arch Phys Med Rehabil ,2002

47. Objective: To determine what effect TENS
intensity has on local and distal cutaneous
blood flow and skin temperature.

48. Methods:-Forty subjects (20 men, 20
women) randomly assigned to 1 of 4 groups
(10 per group): control, above-
motorthreshold TENS, below-motor-
threshold TENS, or perceptionthreshold
TENS.
Intervention: TENS (4Hz, 200s) was
applied over the median nerve of the right
forearm for 15 minutes.

49. Results: Significant differences occurred
between groups for forearm (P .0001;
repeated-measures analysis of variance) but
not fingertip cutaneous blood flow.
A significant increase in forearm blood flow
during TENS application in the above-motor-
threshold TENS group compared with the
other 3 groups.
No significant differences between groups for
skin temperature data were observed.

50. Conclusions: The effect of TENS on
cutaneous blood flow depends on whether
muscle activity is induced. Low-frequency
TENS applied above the motor threshold
significantly increases local cutaneous
blood flow.
There were no significant differences
between groups for skin temperature.

51. ARTICLE-7
The Effects of Transcutaneous Electrical Nerve
Stimulation on Skin Temperature in Asymptomatic
Subjects.
Rhonda J Scudds,Antoine Helewa ,Roger A Scudds
Physical Therapy,1995

52. Objectives:-This study examined the effects
of two modes of TENS, compared with a
control condition, on skin temperature

53. Subjects. Twenty-four asymptomatic
subjects (23 female,1 male) with no
preuious experience with TENS
participated.
The subjects ranged in age from 19 to 28
years. All subjects participated in a 4-Hz
TENS session, a 100-Hz TENS session, and
a control (no TENS) session.

54. Results. Mean hand temperature after low-
frequency TENS was 1.69OC warmer than
the mean hand temperature following the
high-frequency TENS and 1.60°C warmer
than after the control condition.
No differences in the finger temperature
were found among the three conditions.

55. Conclusion:- High-intensity,low-frequency
TENS prevented cooling of the hand. High-
and low-frequency TENS had no effect on
finger temperature.