2. TENS is a method of electrical
stimulation which primarily aims to
provide a degree of symptomatic pain
relief by exciting sensory nerves and
thereby stimulating either the pain
gate mechanism and/or the opioid
system. The different methods of
applying TENS relate to these
different physiological mechanisms
3. Transcutaneous Electrical Neuromuscular
Stimulation
Pain control treatment
Can cause muscle contractions, but that is not
why it is used
Decreases patient’s pain perception by
decreasing the conductivity & transmission of
noxious impulses from small pain fibers (effects
large diameter fibers)
Moderate caffeine levels (200 mg, approx 2-3 c.
coffee) may decrease effectiveness of TENS
4. What is pain?
“An unpleasant sensory and
emotional experience associated
with actual or potential tissue
damage, or described in terms of
such damage” ISAP (1979)
5. DEFINITION
Pain is a noxious unwanted perception in
which the patient seeks medical
intervention.
“Pain is subjective, individual and modified
by degrees of attention, emotional state
and the conditioning of past experiences.”
(Livingstone 1943). The intensity of the
pain is not directly proportional to the
degree of suffering. Because it is basically
a psychological experience and depends
on how it is interpreted or experienced
6. TYPES
Acute pain – shorter duration up to six months
Acute monophonic pain
Recurrent acute non-malignant pain
Chronic pain – longer duration > six months
Chronic malignant pain - progressive
Intractable-benign
Chronic pain associated with non-malignancy disease –
identifiable pathology
Chronic non-malignant pain syndrome
Recurrent acute – migraine
Chronic and acute pain may have different causes –
behavioral factors may be involved in acute pain
8. How do we experience pain?
Specificity theory – Desecrates
posits that there are specific sensory receptors for different types of
sensations (i.e., pain, touch, pressure)
Pattern theory – Melzack & Wall (1982)
posits that pain results from the type of stimulation received by the
nerve ending and the key determination of pain is the intensity of
the stimulation
Both theories have limitations
pain can be experienced without tissue damage
tissue damage can occur without pain being felt
Phantom limb pain experience not accounted for by the theories –
Fordyce (1988) study of amputees
9. PHYSIOLOGY OF
PAIN
Receptors
A fibers – Localized and
quick type of pain C fibers
– Slow acting type of
pain(Peripheral Nervous
System)
Spinal Cord (Substantia
Gelatinosa)
Spinothalamic Tracts
(Lateral / Anterior)
Thalamus
Cerebral Cortex
(Somatosensory Cortex)
Influenced
by Limbic
system &
Reticular
formation
10. Gate Control Theory
Gate control theory –
Melzack & Wall (1965)
severity of pain sensation determined by balance between
excitatory and inhibitory inputs to T cells in spinal cord
C & A-delta nociceptor afferents give excitatory input to dorsal root
ganglion of spinal cord– A-delta (myelinated) about 40 mph and C
fibers (unmyelinated) about 3 mph, other sensory information
travels at about 180 -240 mph
Substantia gelatinosa, large diameter A-beta non-nociceptor
afferents give inhibitory input
Increased firing of non-nociceptor afferents causes presynaptic
inhibition of T cells and the spinal gate from excitatory cells to the
brain is closed. –
Physical agent modalities and physical activities believed to close
the gate by activating the non-nociceptor afferents
The theory does not explain pain modulation descending from brain
11. Central Control Mechanisms of Pain
Not well understood
Periaqueductral gray seems to be
involved in pain – electrical
stimulation can block the experience
of pain
Spinothalamic tract which carries the
impulses up the spinal cord, through
the brain stem to the thalamus
Cerebral cortex
sensory area of parietal lobe: localization
and interpretation of pain - somatosensory
cortex
limbic system: affective and autonomic
response
temporal lobe: pain memory
12. The same part of the
brain – the anterior
cingulate cortex –
responds to physical
and emotional pain.
Where is pain in the brain?
13. Chemical processes involved in pain
Substance P
Chemical mediator thought
to be involved with transmission of
pain.
Associated with inflammatory pain
It excites pain transmitting
neurons when released
Its mechanism is not fully
understood
Glutamate – release affects
amount of pain experienced
Prostaglandins, bradykinin –
released when tissue
damaged
14. Chemical processes involved in pain Endorphins
Pain perception modulated by these opiate like
neurotransmitters
The endorphins bind to certain sites on the nervous
system including peripheral nerves
They suppress pain transmission at the spinal cord level
by inhibiting the release of the neurotransmitter gamma
aminobutyric acid (GABA) in the periaqueductal gray
matter (PAGM) and raphe nucleus of the brain
High concentration of opiate receptors in limbic area of
brain explains the stress relief and euphoria associated
with opiates
Limbic system involved with emotional component of pain
20. Stimulation of appropriate nerve root(s)
Stimulate the peripheral nerve (best if
proximal to the pain area)
Stimulate motor point (innervated by the
same root level)
Stimulate trigger point(s) or acupuncture
point(s)
Stimulate the appropriate dermatome,
myotome or sclerotome
26. Case sheet reading
Go through the medical reports
Find out diagnosis/general contra-
indications/previous physiotherapy
treatment
27. Checking general contraindications
Hyper pyrexia
Epilepsy
Severe renal and cardiac problems
Severe hypo/hypertension
Cardiac pacemakers
Infections
Pregnant women
Metal implants
Mentally retarded/upset patients
Malignancy
Anterior aspect of neck/carotid sinus/eyes
28. Tray preparations
Skin resistance
lowering/testing tray
Pillows
Cotton
Soap
Towel
Mackintosh
Petroleum jelly
Test tubes ( hot &cold)
U-pin (sharp &blunt)
Clips
Bowl of water
IR lamp
Hot &cold packs
Treatment tray
Pillows
Towel
Bed sheet
Cotton
Adhesive tapes
Straps/goggles
Salt/Powder
Scissor/ Inch tape
Paper
Graph paper
Pencil/scale/eraser
Machine& accessories
Sand bags/crepe bandages
29. Checking local contraindications
Open wounds
Scars
Local skin infections
Cuts
Abrasions
Eczema
Local hemorrhagic spots
Skin sensitivity (testing)
30. Apparatus preparation
Check the apparatus& accessories like
electrodes, leads, cables, plugs, power
sockets, switches, controls, dials and
others
31. Apparatus checking
Demonstration of the treatment
Check the functioning of machine in
front of the patient
Explanation of treatment
35. Placement of electrodes
Appropriate placement according to the
condition &patient
Use adhesives &straps
Apply gel evenly on electrode
Maintain good contact with the skin
No leads crossing each other
Confirm connections &above all
36. Instructions & warnings
Instructions
Don’t move
Don’t sleep
Don’t touch leads,
apparatus,
therapist and any
other metal near by
you
Warnings
Inform more
heating/uncomforta
ble sensations
Inform burning
sensation
immediately
37. Treatment
Proper execution of treatment
Appropriate intensity should be used
Set duration of treatment acc. to
condition status
Supervise the treatment through out the
session
38. Termination
Put knobs to zero
Remove electrodes
Switch off the machine &mains
Clean the area &inspect for adverse
reactions
Manage if anything &give instruction
regarding next coming
Winding up procedure
39. Recording
Accurate record of all parameters of
treatment including area treated ,
technique, dosage and the outcomes
40. CONTRAINDICATIONS
Patients who do not comprehend the physiotherapist’s instructions or
who are unable to co-operate
• It has been widely cited that application of the electrodes over the
trunk, abdomen or pelvis during pregnancy is contraindicated BUT a
recent review suggests that although not an ideal (first line) treatment
option, application of TENS around the trunk during pregnancy can be
safely applied, and no detrimental effects have been reported in the
literature (see www.electrotherapy,org for publication details)
• TENS during labour for pain relief is both safe and effective
• Patients with a Pacemaker should not be routinely treated with TENS
though under carefully controlled conditions it can be safely applied. It
is suggested that routine application of TENS for a patient with a
pacemaker or any other implanted electronic device should be
considered a contraindication.
• Patients who have an allergic response to the electrodes, gel or tape
• Electrode placement over dermatological lesions e.g. dermatitis,
eczema
• Application over the anterior aspect of the neck or carotid sinus
41. PRECAUTIONS
If there is abnormal skin sensation, the electrodes should
preferably be positioned elsewhere to ensure effective
stimulation
• Electrodes should not be placed over the eyes
• Patients who have epilepsy should be treated at the
discretion of the therapist in consultation with the
appropriate medical practitioner as there have been
anecdotal reports of adverse outcomes, most especially
(but not exclusively) associated with treatments to the
neck and upper thoracic areas
• Avoid active epiphyseal regions in children (though there
is no direct evidence of adverse effect)
• The use of abdominal electrodes during labour may
interfere with foetal monitoring equipment and is therefore
best avoided