A new method of screening for diabetic neuropathy using laser Doppler and photoplethysmography

Abstract

The purpose of this study is to suggest a simple, new method of screening for diabetic neuropathy. We measured blood volume changes by photoplethysmography (PPG) and blood perfusion by laser Doppler (LD) in the index fingers and big toes in 40 control subjects and in 50 (19 mild, 17 moderate, and 14 severe based on the nerve conduction velocity (NCV) test) and 35 diabetic patients with and without neuropathy, respectively. According to the results of PPG and LD measurements, the toe to finger ratios obtained from the neuropathic group were significantly higher than those from the control (p < 0.001) and the non-neuropathic groups (p < 0.001). Based on the NCV, the sensitivity of the LD method (92.0%) was higher than that of the PPG method (84.0%) for both left and right sides. Although specificity of the LD (92.8%) was also higher than the PPG (84.3%) bilaterally, the PPG showed better reproducibility (5.5 versus 9.5%) and a significant ratio increase with severity, while the LD did not. Our suggested PPG method using the toe to finger ratio is reliable, simple, economical, and accurate, and could become an effective new screening tool for the early detection of diabetic neuropathy.

Prediction of ATLS Hypovolemic Shock Class in Rats Using the Perfusion Index and Lactate Concentration

“…The variability of the perfusion index could be greatly reduced in humans because it is not difficult to attach the probe to a human finger for stable contact. In this rat study, the mean reproducibility (standard deviation/mean  100) of the perfusion index in the resting period was 69.0% (n = 78); however, that of the perfusion index using the laser Doppler system in humans was only 9.5% (n = 125) in our previous study (30).…”

Investigation of photoplethysmographic signals and blood oxygen saturation values on healthy volunteers during cuff-induced hypoperfusion using a multimode PPG/SpO2 sensor

“…Apart from PPG signals being used in estimation of the SpO 2 values, these volumetric changes in the finger PPG signal appear as an information source for several indirect measurement methods [4,7,12]. In a previous study [6], a moderate correlation (r = 0.54) was found between fingertip PPG waveform variability (PPGV) and systemic vascular resistance (SVR).…”

Peripheral photoplethysmography variability analysis of sepsis patients

“…More recently, there has been increasing interest in the photoplethysmography (PPG) or pulse oximetry waveform. This ubiquitous technique uses red and infrared light to analyse the oxygen content of blood [14] but also produces a waveform that represents instantaneous change in blood volume within a body area, and therefore may carry important information about control, performance and compensatory changes occurring within the cardiovascular system [3,11,16,32,35].…”