title: 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.
authors.affiliation: Graduate Institute of Electrical and Communications Engineering, Feng Chia University, Taichung, Taiwan, ROC.
authors.forename: Ben-Yi
authors.initials: BY
authors.lastname: Liau
authors.forename: Shoou-Jeng
authors.initials: SJ
authors.lastname: Yeh
authors.forename: Chuang-Chien
authors.initials: CC
authors.lastname: Chiu
authors.forename: Yu-Chou
authors.initials: YC
authors.lastname: Tsai
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003929:Diabetic Neuropathies / Q000503:physiopathology*; D005260:Female; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D015233:Models, Statistical; D012815:Signal Processing, Computer-Assisted