Dynamic cerebral autoregulation assessment using chaotic analysis in diabetic autonomic neuropathy

Abstract

Cerebral autoregulation (CA) was assessed by chaotic analysis based on mean arterial blood pressure (MABP) and mean cerebral blood flow velocity (MCBFV) in 19 diabetics with autonomic neuropathy (AN) and 11 age-matched normal subjects. MABP in diabetics dropped significantly in response to tilting (91.6 +/- 14.9 vs. 74.1 +/- 13.4 mmHg, P < 0.05). Valsalva ratio of heart rate was reduced in diabetics compared to normal (1.1 +/- 0.1 vs. 1.5 +/- 0.2, P < 0.05). It indicated AN affects the vasomotor tone of peripheral vessels and baroreflex. Nonlinear results showed higher correlation dimension values of MABP and MCBFV in diabetics compared to normal, especially MABP (3.7 +/- 2.3 vs. 2.0 +/- 0.8, P < 0.05). It indicated CA is more complicated in diabetics. The lower Lyapunov exponent and the higher Kolmogorov entropy values in diabetics indicated less predictable behavior and higher chaotic degree. This study suggests impaired autoregulation would be more chaotic and less predictable.

Unraveling the Nature of Hyperactivity in Children With Attention-Deficit/Hyperactivity Disorder

“…46 One previous study calculating MLE on heart rate variability used 20 000 points, 70 while another study calculating MLE, correlation dimension, and Kolmogorov entropy of cerebral blood flow velocity used 5 to 10 minutes of data with a sampling rate of 60 Hz. 71 An article calculating MLE for postural displacement used 100 seconds of data sampled at 100 Hz. 39 Our time series with 45 000 data points collected over 15 minutes is larger than most previously published series but collected at a slightly slower sampling rate (50 Hz).…”

Dynamic cerebral autoregulation: different signal processing methods without influence on results and reproducibility

“…In a study on traumatic brain injury patients, better reproducibility was shown with MMPF phase compared to ARI [10]. Also non-linear approaches have been tried to evaluate dCA [11, 15], but clear benefits have not been shown yet.…”

Cerebral Autoregulation

“…Higher correlation dimension values between ABP and CBFV, lower values of Lyapunov exponent and higher values of Kolmogorov entropy were all found in diabetic subjects with autonomic neuropathy in comparison with normal subjects, Liau et al (2008). Higher correlation dimension values between ABP and CBFV, lower values of Lyapunov exponent and higher values of Kolmogorov entropy were all found in diabetic subjects with autonomic neuropathy in comparison with normal subjects, Liau et al (2008).…”