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The body's ability to maintain an upright posture
over a relatively small base of support (our feet) is a fascinating and
complicated system of checks, and well, balances. There are three main
sensory systems by which our brain detects our balance status; the
vestibular system, proprioceptive (position detectors), and vision.
Proprioception, the sense of your body's position in
space (without looking) is mediated through nerves in your muscles that
carry information back to the parts of the brain involved in planning and
coordinating movement. Extend your arms in front of you, close your eyes,
and then touch your nose with one of your index fingers. You should have
been able to touch your nose without punching yourself in the face. This
is proprioception. This mechanism sends a message
through your central nervous system for analysis. The information is then
relayed to the rest of the body about how to react and with what amount of
tension.
The vestibular system is a labyrinth of fluid filled
canals in the skull that sense fluid perturbations that the brain
interprets as movement. Spinning in place causes you to be dizzy even
after you stop moving because this fluid continues to move inside the
canals, confusing the signals to your brain. Finally vision, intuitively,
enables you to plan your movement relative to the physical space around
you.
Our sense of balance evolves and changes at different points in our life.
Children learning to sit up and walk primarily rely on their vestibular
and proprioceptive systems to maintain their balance. Of note, children of
this age tend to have perfect posture, posture and gait being linked
intimately with balance. For reasons that are not completely understood,
possibly increased awareness of social interactions, children begin to
rely more heavily on their vision for orientation between the ages of 4-6.
This trend continues into adulthood, where some adults and seniors rely
primarily on their vision. This is adequate in most situations, unless the
person finds themselves with in situations where they are walking through
a dark room, have deteriorating vision, or cannot find their glasses.
What most people fail to realize is that
proprioception can be improved through training. In fact, many athletes,
dancers, and practitioners of yoga regularly "exercise" their ability to
sense their body's perception of balance increasing coordination,
stability, and grace of movement. Rehabilitation and training exercises
focus on developing the ability to sense imbalance without relying on
vision, identifying muscular weakness, and teaching people to use the
three main balance strategies that the body employs to correct imbalances
after they have been detected by our sensory systems. These include the
Ankle, Hip, and Step strategies.
The body can be viewed as an inverted pyramid with
the ankles as the focal point of support. During a mild balance threat,
internal and external somatosensory input recruits the ankles to correct
and maintain balance through a gentle sway. The ankle strategy is a
sub-conscious and an ongoing static response for maintaining and
recovering balance. Close your eyes and stand with your feet close
together and you should feel the sway that is your ankles maintaining your
balance.
When the intensity of imbalance is increased, the
ankles become overwhelmed, and the hips take over to recover balance. The
ankle strategy still plays a role, but now, the body adds activation of
the upper and lower limbs to adjust the body's center of gravity,
contraction of the upper body muscles and core muscles for stabilization,
and movement and bending in the hips to recover balance.
When violent disruption of balance over-powers the
ankle and hip strategies, the step strategy is called upon as a last
resort to prevent falling. The sensory systems send signals to indicate
the need to re-position our base of support (i.e. the feet). We do this by
stepping forward, backward or to the side until an adequate base of
support is achieved.
A balance disorder is a disturbance that causes an individual to feel
unsteady, dizzy, woozy, or have a sensation of movement, spinning, or
floating. An organ in our inner ear, the labyrinth, is an important part of our vestibular (balance) system.
The labyrinth interacts with other systems in the body, such as the visual
(eyes) and skeletal (bones and joints) systems, to maintain the body's
position. These systems, along with the brain and the nervous system, can
be the source of balance problems.
When balance sensory and adjustment systems fail the
sequelae can be dangerous; instability, anxiety, falls, injury, and in
some cases death. Instability in our population has become such a problem
that in 2003 Congress issued the Elder Fall Prevention Act instating
education and research programs aimed at reducing the incidence of falls
in one our most vulnerable populations; the elderly. Balance training also
benefits people of all ages as it has been shown to reduce the incidence
of injuries to the ankle, knee, hips, back and upper body. The role of
balance training in maintaining functional joints stability is also an
excellent form of rehabilitation for injuries to the body.
Balance training begins with an evaluation include
identifying trends in balance maintenance techniques using posturography
and a digital balance board that sense's the user's center of balance and
sway patterns which are then analyzed by a computer program. This
information is then used to prescribe exercises and computer mediated
balance training programs to develop ankle, hip, and step balance
maintenance techniques.
For more information about balance, posturography, or for a
computerized balance evaluation, please contact our one of our offices.
Balance evaluation using digital posturography is relevant for people of
all ages and fitness levels for injury and fall prevention.
Here is a partial list of balance problems that benefit from retraining:
- Stroke
- Parkinson's Disease
- Cerebral hemorrhage with balance symptoms
- Diabetic neuropathy
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Multiple sclerosis
- Muscular weakness
- Back pain and
splinting
- Foot, knee and leg injuries
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