| 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
Click Image for Larger View
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.