New method of sudomotor function measurement to detect microvascular disease and sweat gland nerve or unmyelinated C fiber dysfunction in adults with retinopathy
Microvascular complications of diabetes such as retinopathy and neuropathy often result in organ and tissue damage. Altered microcirculation of the skin often precedes the detection of other complications of advanced diabetes. The ANS-1 system contains a redesigned sympathetic skin response device (ANS-1 SSR), which measures the function of a sudomotour a photthysthysmographie sensor and a blood pressure device to assess overall cardiac autonomic neuropathy and endothelial dysfunction. The purpose of this study was to determine the relationship between the amplitude of ANS-1 SSR measured: (a) negative electrode (NO) Pico Sweat) with microvascular disease and associated vascular marker and (b) a positive electrode (ISweat Peak) with the function of the fiber C.
All participants (n = 50 healthy controls and patients with retinopathy n = 50) completed the system ANS-1 assessment and a baseline questionnaire on socio-demographic and medical history, including a quality of life measure (SF-36 ). A small blood sample was determined to determine levels of homocysteine, blood urea nitrogen (BUN), C-reactive protein (CRP), and fibrinogen. Symptoms of peripheral foot neuropathy were assessed using a scale from 1 (none) to 10 (worst). Spearman rank correlation, t-tests for independent samples and ROC curves were used to determine the specificity and sensitivity of the sugar-free peak as a marker of potential retinopathy.
Cardiometabolic risk score of the ANS-1 system and all indicators of quality of life in SF-36, other than the role of emotional function, were significantly worse in patients with retinopathy. The sudomotour NO response marker Sweat spike had a sensitivity of 88% and a specificity of 68% (area under the curve = 0.81, p <0.0001) for the detection of retinopathy. NO Sweat peak response marker is inversely correlated with BUN (ρ = 0.41, p <0.0001), homocysteine (ρ = -0.44, p <0.0001), fibrinogen (ρ = – 0 , P <0.0001), cardiac autonomic neuropathy score (Ρ = -0.68, p <0.0001) and the variability of heart rate power (ρ = -0.57, p <0, 0001), and s’ correlates positively with the photoplethysmography index (PTGi; ρ = 0.53 p <0.0001). The ANS-1 sudomotor response marker, iSweat Peak, correlates inversely with the severity of symptoms on the peripheral neuropathy scale (ρ = -0.56, p <0.0001).
The results of the study show that this new method of measuring sympathetic skin response should be useful in detecting early signs of microvascular disease and symptoms of dysfunction C. fiber
Retinopathy ANS-1 sudomotoras Test NO soot iSweat peak-to-peak microvascular disease C dysfunction Complications of Diabetes fiber