Multiparameter techniques for non-invasive measurement of blood glucose

Although painless glycemic control could improve life quality of patients, enabling a better regulation of hyper- and hypoglycaemia episodes, none of the available commercial devices offer enough precision to replace lancet approaches. The aim of this work is to describe the technologies of absorption spectroscopy and bioimpedance applied simultaneously to transcutaneous glycemic measurement. Basic electrical and optic theories were studied systematically and in following experiments glucose characteristics were measured in blood. Light spectroscopy studies were done in MIR ranges (5-40 mu m), while complex bioimpedance measurements were scanned from 100 Hz to 30 MHz. Parallel to above parameters, information of epidermis temperature (conductance and IR radiation) was also collected, improving prediction quality. Cutaneous assays showed correlation of 0.43 for impedance and 0.46 for optic spectroscopy alone. The multiparameter analysis allowed the improvement of correlation to 0.57, after data treatment with Partial Least Square and neural networks method in Matlab. (C) 2009 Elsevier B.V. All rights reserved.