The aim of this study was to analyze and compare the deterministic nonlinear structure of cutaneous laser Doppler flowmetry signals obtained from the forearm and foot of normal subjects and @entity6 @entity1 without @entity16 (D), with @entity1897 (DPN) and with combined autonomic and @entity1897 ( @entity6880 ). @entity450 were evaluated under baseline conditions, after local warming of the skin to 44   C and after warming plus iontophoresis of @entity2647 . The presence of nonlinearity was investigated by three complementary approaches: (i) attractor reconstruction, (ii) calculation of largest Lyapunov exponents (LLEs), and (iii) correlation dimension analysis. Conclusions were validated against surrogate stochastic time series generated by randomizing the Fourier phase of the raw data. In the control and D groups, the combination of @entity2647 and warming unmasked flowmotion with a prominent component at 0.1 Hz. Attractor reconstruction revealed toroidal structure and estimated LLEs were positive. LLEs decreased to zero and dimension estimates increased for surrogate data, consistent with loss of determinism. In @entity6 subjects with @entity16 estimates of LLE were not significantly different from zero and dimensions were unaffected by phase randomization. Evidence for nonlinear structure was also obtained under baseline conditions in normal and D subjects, but was lost on warming alone. We conclude that deterministic control mechanisms contribute to cutaneous flowmotion, particularly when pseudo-quasiperiodic behavior is enhanced by @entity2647 . Nonlinear analysis of laser Doppler signals may provide previously unrecognized insights into the effects of @entity3949 on perfusion because it can identify loss of complexity independently of the amplitude of the signals recorded.

Deterministic nonlinear features of cutaneous perfusion are lost in XXXX subjects with @entity16 .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity6 :: ('MESH:D003920', 'Disease') :: ['diabetic'] @entity6880 :: ('4681', 'Gene') :: ['DAN'] @entity16 :: ('MESH:D009422', 'Disease') :: ['neuropathy'] @entity3949 :: ('MESH:D003929', 'Disease') :: ['diabetic neuropathy'] @entity450 :: ('MESH:D006940', 'Disease') :: ['Flow oscillations'] @entity1897 :: ('MESH:D010523', 'Disease') :: ['peripheral neuropathy'] @entity2647 :: ('MESH:D010656', 'Chemical') :: ['phenylephrine']
@entity6 :: (MESH:D003920,Disease) :: ['diabetic']
