Assessment of diabetics with various degrees of autonomic neuropathy based on cross-approximate entropy

Abstract

Noninvasive assessment of the severity of autonomic neuropathy in diabetic patients is an important theme for discussion. In this study, we investigate the feasibility of using the nonlinear cross-approximate entropy (Co-ApEn) of mean arterial blood pressure (MABP) and mean CBF velocity (MCBFV) as a signature to assess diabetics with various degrees of autonomic neuropathy. To this aim, 69 subjects were recruited. Among them, 11 were healthy adults (normal subjects), 15 were diabetics with no autonomic neuropathy symptoms, 25 were diabetics with mild autonomic neuropathy symptoms, and 18 were diabetics with severe autonomic neuropathy symptoms. For each subject, continuous CBFV was measured using a TCD (Transcranial Doppler ultrasound, EME TC2020), and continuous ABP recorded using a Finapres (Ohmeda 2300) device in supine position.The Co-ApEn calculation of MABP and MCBFV with length of 200 data points is normalized. The normalization method is achieved by subtracting the mean and divided by the standard deviation. The ANOVA and Scheffe between the four groups are applied for the statistical analysis. Four groups have statistically significant differences among each other. Especially, there exists statistical significance between normal subjects and diabetics with autonomic neuropathy. These results indicate that the Co-ApEn analysis of similarity between the MABP and MCBFV can be helpful to be a noninvasive preliminary screening test for diabetics with or without neuropathy. © 2011 Springer-Verlag.