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Autonomic dysfunction (or dysautonomia)
What
is it?
Autonomic
dysfunction (or dysautonomia) is defined as a disorder of
the autonomic nervous system which is due to abnormalities
of one or both of its sub-systems.
The ANS controls the heart rate and many other vital functions.
A disorder of such a system may be silent and can cause sudden
death if not detected early.
In the case of diabetes, dysautonomia is due to damage of
the nerve fibers of the autonomic system caused by glucose.
How
does the ANSiscope reflect this?
Since
the ANSiscope measures the activities of the parasympathetic
and sympathetic systems with every new heart beat, it further
becomes possible to integrate the way these two systems function
together, how well they interact. Based on the measurement
of these activities, the ANSiscope offers a specific measurement
of autonomic dysfunction.
How
is the measurement made?
The
patient is required to be in a supine position (i.e. to lie
down) and at rest (i.e. without any external stimulation).
The ECG electrodes are connected to the body and readings
for 500 heart beats are taken, representing around 5 to 10
minutes. At the end of it the ANSiscope displays two pieces
of information.
1.
A percentage of autonomic dysfunction
2. A classification of the patient according to the percentage
of dysfunction
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Because
the ANSiscope is able to make this measurement, it is an excellent
tool for the prevention of the complications of diabetes.
Many
endocrinologists have said that it is possible to treat this
condition if it is detected early enough.
The
American Diabetes Association recommended (as far back as
1988) that ANS testing be done on at least a yearly basis
when diabetes was detected. However, no measurement device
was available to allow this to be done simply and elegantly,
no ANS testing existed prior to the measurement capability
of the ANSiscope. Some MDs previously proposed a sequence
of cumbersome maneuvers (such as the Valsalva, the Tilt Test,
or Respiratory Sinus Arrythmia) which require too much time,
full participation of patients and subsequent analysis, for
being able to test this dysfunction. In fact this autonomic
scoring is nor accurate, nor reproducible. No measurement
device was available until now to allow this classification
and detection to be done simply, elegantly and quickly.
How
does it make the measurement?
We
define autonomic dysfunction as a lack of coupling between
the sympathetic and the parasympathetic systems measured by
our two ANSindices . A mathematical evaluation of this lack
of coupling provides the two indicators of autonomic dysfunction,
namely the level of the dysfunction and the degree of autonomic
neuropathy.
Some
preliminary results presented at various conferences (available
on this web site) show that the dysautonomia measurement of
the ANSiscope is able to order the patients in very clear
groups according to their levels of dysfunction. Furthermore,
these groups stay stable under changes in the observation
window and do not overlap, so that it is only necessary to
have a 5-10 minutes measurement under supine conditions.
The
measurement is thus highly accurate and stable, providing
excellent repeatability. Doctors are now able to chart the
course of DAN in their patients and can very quickly determine
whether this particular complication of diabetes is stable,
progressing or regressing.
How
can it make a difference ?
Accurate
measurement is at the core of prevention. Treatments can now
be adapted to the condition and neuropathy stage of the patient,
knowing what to do, when to start and through measure one
can further assess how to dose and when to stop the treatment.
Drugs acting at the sole level of nerve damage could reverse
functional disorders of the ANS, stage which is known only
through the ANSiscope’s instrumental measurement.
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