2. What is TENS ?
The electrical impulses required for electrotherapy to treat
the pain are provided by an instrument called TENS
(Transcutaneous Electrical Nerve Stimulator).
•The impulses are produced in a battery powered pulse-
generator to which a pair of electrode-tipped wires can be
attached. Applied to the skin overlying any painful area of the
body, these electrodes provide continuous, mild electrical
stimulation.
•These signals seem to jam the pain signals travelling along the
nerve pathways before they can reach the brain. The result is
analgesia, often for hours after stimulation ends.
3. The pain control is explained by:
(i)The Gate Control Theory which suggests that by electrically
stimulating sensory nerve receptors, a gate mechanism is closed in a
segment of the spinal cord, preventing pain carrying messages from
reaching the brain and blocking the perception of pain.
(ii) The Endorsphin Release Theory which suggests that electrical
impulses stimulate the production of endorphin and enkaphalins in
the body. These natural, morphine-like substances block pain
messages from reaching the brain, in a similar fashion to conventional
drug therapy, but without the danger of dependence or other side-
effects.
4. Waveforms
The Square wave and the spike wave are optimally and
equally effective in relieving pain.
Most stimulators feature adjustable settings to control the
amplitude (intensity) of stimulation by controlling voltage,
current and the width (duration) of each pulse.
Electrodes are placed at specific sites on the body for
treatment of pain. The current travels through the electrodes
and into the skin stimulating specific nerve pathways to
produce a tingling or massaging sensation that reduces the
perception of pain.
5. Typically, the stimulator is based around a 500 ms spike pulse, having
an adjustable amplitude of 0 to 75 mA and an adjustable frequency of
12 to 100 pulses per second.
The instrument powered by three standard flashlight batteries of
1.5V each gives about 100 hours of continuous operation.
Transcutaneous or skin surface application of electrical stimulus is
accomplished by application of the conducting pads to various trigger
zone areas, acupuncture sites or even peripheral nerves.
Skin irritation at the site of electrode application is diminished by the
use of carbonized rubber electrodes applied with a tincture of Benzoin
interface. The skin electrode system must be designed so as to minimize
impedance variations with motion, to conform to the body surface to
provide a uniform impedance across the surface of the electrode and to
have an adequate surface area.
6. The adequate surface area can be determined keeping in view the
peak square-wave current at the threshold of thermal damage as a
function of the electrode surface area. The thermal damage threshold
varies widely with skin impedance, which is a function of skin
preparation.
Transcutaneous Electrical Nerve Stimulation (TENS) electrodes are
commonly moulded from an elastomer such as silicon rubber, loaded
with carbon particles to provide conductance.
A thin electrode may exhibit an impedance which is not negligible as
compared to the impedance of the interface and tissue under it. Thus,
the design of an electrode with the required conformability and
current distributing properties becomes a compromise in electrode
geometry and material properties. The frequency-dependence of the
electrode performance also has to be considered since the impedance
between the electrode and subcutaneous contains capacitance.
7. GAIT Assessment
• Gait - The manner or style of walking. Gait cycle is
a repetitive pattern involving steps and strides.
• What is gait?
The manner or technique of walking, running or
stepping is known as gait. It can also be
described as a sequence of alternating, rhythmical
movements of the limbs and trunk which leads to
progression in the forward direction of the body.
A series of "controlled falls" is another way to
define gait.
9. GAIT Assessment
Gait analysis and therapy is an effective way to deal with
joints and muscular problems related to your legs.
A Physio analyse your walking style or technique and makes
and assessments of the points to work on. Improper gait
can lead to many health issues.
Gait speed :The time it takes to walk a specified distance, usually 6 m or less.
Slower speeds correlate with an increased risk of mortality in geriatric patients.
Normal walking speed primarily involves the lower extremities, with the arms
and trunk providing stability and balance.
Faster speeds - body depends on the upper extremities and trunk for propulsion,
balance and stability with the lower limb joints producing greater ranges of motion
10. GAIT Assessment
The walking technique has a significant role in your well being because it manages
the stress distribution while walking to all the joints below your waist. People often
presume that previous injury or problem is the reason for the pain in their legs.
They fail to recognise the fact that their improper walking gait is responsible for
the strain on the affected areas.
Majority of people wrongly believe that they have been walking all through their
lives, therefore there is no need to learn how to walk again after an injury. What they
need to understand here is the unfortunately, a number of spine injuries and lower
extremities have an adverse effect on walking mechanics.
If neglected and not corrected with proper physical therapy and effective fitness
training, the situation can ultimately result in additional disability. No matter with or
without an injury, walking mechanics or gait, often deteriorates with age. This
happens not due to age, but because of the bones that become weaker.
11. GAIT Assessment
A Physio will observe the patients visually while they are on a
treadmill or moving up and down in a straight path. A treadmill helps a
Physio to control the speed and then have a close observation of the
walking style. If the Physio will find it necessary, then a video can also be
recorded of the whole walking/running session. This video is then
analysed later by repeating, slowing down and reversing to get a
detailed assessment of the gait.
Symmetry of the gait cycle, walking base, cadence, length, step and
stride are few things that are analysed by Physios during evaluation of
gait. Analysing symmetry is considered as an important part of the
whole assessment process. The movement made by one side of the
body should be identical with the other half of the body. Step length,
foot placement, foot impact and arm swing should be in a similar right
vs. Left movement.
12. GAIT Assessment
Usually, weakness and injuries may lead to heavier impact of the
opposite side of the body, but this might not be the case always. On an
average 10-15,000 steps are taken by a human being every day. By
increasing the impact on a foot with a force of around 10 lbs for each
step, this can put up a lot of stress on the leg.
Foot placement is another common gait deviation. If a person is
unable to control where the foot is landing like turned out/in or too
close to the other leg, then there might be an occurrence of hip muscle
weakness or neurological issues.
If you are having trouble with your gait, then it can be treated with the
help of a Physio.
