First human experiments with a novel non-invasive, non-optical continuous glucose monitoring system

This paper describes a non-invasive continuous glucose monitoring system based on impedance spectroscopy. Changes in the glucose concentrations can be monitored by varying the frequency in the radio band over a range, optimised to measure the impact of glucose on the impedance pattern. A number of clinical-experimental studies (hyperglycaemic excursions) were performed with healthy subjects in order to prove the applicability of this approach. The sensor used in these experiments is the size of a wristwatch and holds an open resonant circuit coupled to the skin and a circuit, performing an impedance measurement. In most cases, the experiments showed a good correlation between changes in blood glucose and the sensor recordings. A detailed description of the trials is presented. The results of this first series of experiments can be considered as a proof of concept for this novel non-invasive monitoring approach. Nevertheless, partly due to the indirect measurement, a considerable number of questions remain to be clarified. (C) 2003 Elsevier B.V. All rights reserved.