Editorial: symposium on algorithms for continuous glucose monitoring and control.

1 S YSTEMS AND CONTROL THEORY is the basis for algorithms embedded in many of the products (both high and low " tech ") that we use in our daily lives. While consumers appreciate the relative compactness of CD and DVD players and microdrives, for example, and value the manufacturing technology involved in minia-turization, they probably do not think much about the mathematical algorithms that enable these systems to operate. There are a number of devices/products in the market, or under development, for continuous glucose monitoring and control. A primary goal of this symposium is to give clini-cians a better understanding of how a systems engineering approach can be applied to diabetes technology. A secondary audience consists of systems engineers seeking to understand some of the challenges related to blood glucose monitoring and control in diabetes. The first two papers study continuous glucose monitoring. Challenges to the use of continuous subcutaneous glucose sensors are that the signals can have substantial measurement noise, they must be calibrated based on a blood glucose measurement, and there is a dynamic lag between the blood and subcutaneous glucose concentrations. The article in this symposium by Palerm et al. 1 focuses on filtering the noisy subcutaneous sensor signal and predicting the future subcutaneous glucose concentration as a function of time to provide a warning of impending hypoglycemia. This study details the effects of sample time, prediction horizon, and hypoglycemic threshold on the sensitivity and 1 Ϫ specificity (rate of false alarms). The analysis is applied to an ide-alized signal (sinusoid) to understand the inherent limitations of hypoglycemia warning indicators. One of the major uses of continuous glucose monitoring, initially, is for a nocturnal hypoglycemic warning device for juveniles. The approach developed by Palerm et al. 1 should lead to a better understanding of how the parameters affect the rate of false-positives, and thus improve the design of a hypoglycemic alarm. The article by Knobbe and Buckingham 2 applies optimal estimation techniques to estimate the blood glucose from continuous sub-cutaneous sensor signals. Their approach accounts for the time lag between blood glucose and the subcutaneous sensor. This approach is applied to patients in the Diabetes Research in Children Network (DirectNet) program using the Medtronic MiniMed (Northridge, CA) continuous glucose monitoring system (CGMS ®). One of the long-term goals of continuous glucose monitoring is to provide a sensor signal that can be used in a closed-loop artificial …