Abstract
Several organ systems can be monitored by reliable longitudinal testing. These include: 1. Cardiovascular system: a. R-R variation b. Valsalva maneuver c. Postural blood pressure testing. 2. Sudomotor: a. Postganglionic function with QSART. 3. Eye: a. Dark-adapted pupil size after total parasympathetic blockade. Specific research projects may include other tests but these tests do not lend themselves easily for large, multicenter type of studies. The test listed above are noninvasive, quantitative, and are sufficiently standardized to allow longitudinal assessment in diabetic patients. Furthermore, these tests allow evaluation of at least three different organ systems. HAAF, an example of functional autonomic failure in diabetes, is best assessed by evaluation of the glycemic thresholds for epinephrine and pancreatic polypeptide secretion and hypoglycemic symptoms using a stepped hypoglycemic clamp protocol. The status of physiological defense against hyperinsulinemic hypoglycemia can be assessed with the insulin infusion test.