Digital Volume Pulse Research Articles

A digital volume pulse device-finger photo pulse plethysmography to trace the vascular integrity amongst the low back pain subjects with lumbar disc degenerative diseases diagnosed by MRI analysis.

Finger photo pulse plethysmography is a simple, inexpensive and non-invasive method for measurement of arterial stiffness. The objective is to assess the correlation of arterial stiffness in low back pain subjects with lumbar disc degeneration. Thirty-four back pain patients of both sexes in age group of 30-65 were included. Anthropometric measures like height, body weight, body mass index (BMI) were included. Stiffness index (SI) and reflection index (RI) were measured from the digital volume pulse waveform. There was a negative correlation between SI/RI and no correlation between SI and RI with BMI in both sexes. A significant correlation found between weight and BMI in both sexes. Arterial stiffness may not have any influence on disc degeneration. BMI showed some influence on disc degeneration and back pain.

Effect of duration of hypertension on arterial stiffness

Background: Hypertension is one of the common and prime causes contributing to 18% of deaths globally. Prevalence of essential hypertension increases with age, and individuals with relatively high blood pressure at younger ages are at increased risk for the subsequent complications of hypertension. The morphological and physiological changes in vasculature have been described in the evolution and maintenance of hypertension. Hypertension can increase the risk of cerebral, cardiac, and renal events. Aims and Objectives: (1) To record the arterial stiffness index (SI) and reflection index (RI) in subjects with hypertension and a control group of age-matched normotensives. (2) To compare the above vascular parameters between control and hypertensive subjects. (3) To classify the hypertensive subjects based on the duration of the disease and compare the vascular parameters among them. Materials and Methods: A cross-sectional study on 160 subjects aged between 30 and 60 years was conducted. Institutional ethical committee approval and informed written consent were obtained. They were divided into four groups. Group 1- control group (Healthy subjects), and study group of hypertensives are classified into three groups based on the duration of illness. Arterial stiffness was evaluated by SI and RI, calculated from recording digital volume pulse (DVP). DVP was measured by an instrument known as finger pulse photo plethysmography. Results: The results were analyzed using analysis of variance test and were considered statistically significant with P < 0.05 with respect to arterial stiffness indices compared with the duration of hypertension. Conclusion: This study concludes a strong positive correlation between two indices of arterial stiffness that is the RI and SI values increases with the duration of hypertension.

A Cloud-Based Assessment of Arterial Stiffness Through Contour Analysis of A Photoplethysmography

<p>Cardiovascular diseases (CVDs) are the leading cause of mortality globally. To effectively prevent CVDs, a variety of techniques have been employed to evaluate the mechanical properties of arteries, among which, aortic stiffness measured by aortic pulse wave velocity (PWV) has been proven to be an independent predictor of CVDs. However, the traditional way to measure PWV is complex and time consuming. Recent studies suggest the digital volume pulse (DVP) waveform to be an effective non-invasive method to obtain PWV. In this study, we present a cloud computing system that analyzes and calculates the relevant indices of arterial stiffness after receiving the measured DVP signals. The result of the analysis can be retrieved online for the user to view or download for further analysis. With this technique, arterial Stiffness Index (SI) for population can be obtained easily and inexpensively. This will help health authorities to do mass screening at population level and, hence, establish references of arterial SI for different cohorts by age, gender, ethnicity, and diseases.</p> <p> </p>

Clustered photoplethysmogram pulse wave shapes and their associations with clinical data.

Photopletysmography (PPG) is a non-invasive and well known technology that enables the recording of the digital volume pulse (DVP). Although PPG is largely employed in research, several aspects remain unknown. One of these is represented by the lack of information about how many waveform classes best express the variability in shape. In the literature, it is common to classify DVPs into four classes based on the dicrotic notch position. However, when working with real data, labelling waveforms with one of these four classes is no longer straightforward and may be challenging. The correct identification of the DVP shape could enhance the precision and the reliability of the extracted bio markers. In this work we proposed unsupervised machine learning and deep learning approaches to overcome the data labelling limitations. Concretely we performed a K-medoids based clustering that takes as input 1) DVP handcrafted features, 2) similarity matrix computed with the Derivative Dynamic Time Warping and 3) DVP features extracted from a CNN AutoEncoder. All the cited methods have been tested first by imposing four medoids representative of the Dawber classes, and after by automatically searching four clusters. We then searched the optimal number of clusters for each method using silhouette score, the prediction strength and inertia. To validate the proposed approaches we analyse the dissimilarities in the clinical data related to obtained clusters.

Calculation of an Improved Stiffness Index Using Decomposed Radial Pulse and Digital Volume Pulse Signals

The stiffness index (SI) is used to estimate cardiovascular risk in humans. In this study, we developed a refined SI for determining arterial stiffness based on the decomposed radial pulse and digital volume pulse (DVP) waveforms. In total, 40 mature asymptomatic subjects (20 male and 20 female, 42 to 76 years of age) and 40 subjects with type 2 diabetes mellitus (T2DM) (23 male and 17 female, 35 to 78 years of age) were enrolled in this study. We measured subjects' radial pulse at the wrist and their DVP at the fingertip, and then implemented ensemble empirical mode decomposition (EEMD) to derive the orthogonal intrinsic mode functions (IMFs). An improved SI (SInew) was calculated by dividing the body height by the mean transit time between the first IMF5 peak and the IMF6 trough. Another traditional index, pulse wave velocity (PWVfinger), was also included for comparison. For the PWVfinger index, the subjects with T2DM presented significantly higher SInew values measured according to the radial pulse (SInew-RP) and DVP signals (SInew-DVP). Using a one-way analysis of variance, we found no statistically significant difference between SInew-RP and PWVfinger when applied to the same test subjects. Binary logistic regression analysis showed that a high SInew-RP value was the most significant risk factor for developing T2DM (SInew-RP odds ratio 3.17, 95% CI 1.53-6.57; SInew-DVP odds ratio 2.85, 95% CI 1.27-6.40). Our refined stiffness index could provide significant information regarding the decomposed radial pulse and digital volume pulse signals in assessments of arterial stiffness.

Vasodilatation Measurement Using Finger Vascular Images by Near-Infrared Light and Comparison with RH-PAT

Examination of vascular endothelial function can help infer atherosclerosis progression. This study investigated whether vascular visualization by near-infrared (NIR) light can detect vasodilatation after cuff pressure release of the upper arm and what the correlation is between the brightness decrease ratio (R1) corresponding to vasodilation and the reactive hyperemia index (RHI). We obtained finger vascular images of 53 male subjects by photographing NIR light (wavelength 850 nm) transmitted through the middle phalanx of the middle finger with a charge-coupled device camera. The upper arm was compressed for 10 min using a cuff (200 mmHg), and vascular images before and after cuff compression release were obtained. We analyzed the finger vascular images by NIR light and digital pulse volume using endothelial peripheral arterial tonometry (Endo-PAT). We also calculated the average brightness of each vascular image. Using only the data of the ischemic finger, R1 was defined using the average brightness just before cuff release and the minimum average brightness after cuff release. The brightness of vascular images of the ischemic finger decreased after cuff release probably because of vasodilation. We found significant correlation between R1 and the RHI (r = 0.52; P < 0.001). R1 in the lowest RHI quartile was significantly smaller compared to the highest and second-highest RHI quartiles (P < 0.05). Vascular visualization by NIR light can detect vasodilation after cuff release. This is significantly correlated with the RHI on Endo-PAT.

Preclinical atherosclerosis in cystic fibrosis: Two distinct presentations are related to pancreatic status

BackgroundPatients with cystic fibrosis (CF) are exposed to overlapping cardiovascular risk factors. We hypothesized that CF is characterized by increased arterial stiffness and greater intima-media thickness (IMT). MethodsThis cross-sectional study assessed the digital volume pulse arterial stiffness index (SIDVP) using photopletysmography, measured intima-media complex thickness (IMT) at the common carotid artery, and obtained an extended set of clinical and atherosclerosis-related laboratory parameters. ResultsFifty-five patients with moderate-to-severe CF (mean age 26.3±8.6 years, BMI 20.3±3.1 kg/m2, FEV1 62±26%) and 51 healthy controls (25.1±4.4 years, BMI 21.7±3.0 kg/m2) entered the study. SIDVP was greater in pancreatic insufficient (PI), but not pancreatic sufficient (PS) CF patients compared with control (7.3±1.8 m/s vs 6.0±1.2 m/s; p=7.1 × 10−5). IMT was increased in PS (but not PI) participants relative to control (552±69 µm vs 456±95 µm, p=0.0011). SIDVP was also greater in PI than in PS patients (7.3±1.8 m/s vs 6.3±1.7 m/s, p=0.0232) and IMT was higher in PS compared with PI (552±69 µm vs 453±82 µm, p=0.0002). SIDVP independently associated with age, PI, the lack of liver cirrhosis, and with Pseudomonas aeruginosa colonization. PS was the only independent correlate of IMT in CF. ConclusionsPI patients are at risk of developing general arterial stiffness. PS may relate to carotid IMT thickening, which underscores the need for further study that could lead to reconsideration of dietary guidance in PS CF.

Endothelial impairment evaluation by peripheral arterial tonometry in pediatric endocrinopathies: A narrative review.

Endothelial dysfunction (ED) is characterized by an imbalance between vasodilator and vasoconstriction agents. Several pathological conditions clinically diagnosed in childhood and adolescence are characterized by ED and increased risk for early development of microangiopathic and macroangiopathic impairment, in particular type 1 diabetes mellitus (T1DM), T2DM, obesity, metabolic syndromeand pituitary dysfunction associated to various endocrinopathies. More recently insulin resistance following chemotherapy or radiotherapy for tumors, bone marrow transplantation for hematological malignancies (i.e., cancer survivors), or immunosuppressive treatment for solid organ transplantation has been observed. Assessment of ED by means of non-invasive techniques is the gold standard for early ED detection before clinical manifestation. It is aimed to recognize patients at risk and to avoid the development and progression of more serious illnesses. Reactive hyperemia-peripheral artery tonometry is a noninvasive technique to assess peripheral endothelial function by measuring modifications in digital pulse volume during reactive hyperemia, and represents a non-invasive, reproducible and operator-independent tool able to detect precocious ED. This narrative review aimed to provide an overview of the most important papers regarding ED detection by EndoPat 2000 in children and adolescents with different endocrine diseases. A comprehensive search of English language articles was performed in the MEDLINE database without using other search filters except the publication interval between 2005 and 2020.

Derivation and validation of gray-box models to estimate noninvasive in-vivo percentage glycated hemoglobin using digital volume pulse waveform

Glycated hemoglobin and blood oxygenation are the two most important factors for monitoring a patient’s average blood glucose and blood oxygen levels. Digital volume pulse acquisition is a convenient method, even for a person with no previous training or experience, can be utilized to estimate the two abovementioned physiological parameters. The physiological basis assumptions are utilized to develop two-finger models for estimating the percent glycated hemoglobin and blood oxygenation levels. The first model consists of a blood-vessel-only hypothesis, whereas the second model is based on a whole-finger model system. The two gray-box systems were validated on diabetic and nondiabetic patients. The mean absolute errors for the percent glycated hemoglobin (%HbA1c) and percent oxygen saturation (%SpO2) were 0.375 and 1.676 for the blood-vessel model and 0.271 and 1.395 for the whole-finger model, respectively. The repeatability analysis indicated that these models resulted in a mean percent coefficient of variation (%CV) of 2.08% and 1.74% for %HbA1c and 0.54% and 0.49% for %SpO2 in the respective models. Herein, both models exhibited similar performances (HbA1c estimation Pearson’s R values were 0.92 and 0.96, respectively), despite the model assumptions differing greatly. The bias values in the Bland–Altman analysis for both models were – 0.03 ± 0.458 and – 0.063 ± 0.326 for HbA1c estimation, and 0.178 ± 2.002 and – 0.246 ± 1.69 for SpO2 estimation, respectively. Both models have a very high potential for use in real-world scenarios. The whole-finger model with a lower standard deviation in bias and higher Pearson’s R value performs better in terms of higher precision and accuracy than the blood-vessel model.

Low-Frequency Vibration Facilitates Post-Exercise Cardiovascular Autonomic Recovery

It is important to use short breaks to accelerate post-exercise recovery in sports. Previous studies have revealed that vibration can reduce post-exercise muscle soreness. However, there is still high heterogeneity in the effects of vibration on cardiovascular autonomic activities, and most studies to date have focused on high-frequency vibration. This study aimed to investigate the effect of low-frequency lower-body vibration (LBV) on post-exercise changes in heart rate variability and peripheral arterial tone. Ten men and 9 women aged 20 to 25 were recruited for this study. Each subject visited the testing room three times with at least 2 days in between. Each time, the subject received one of the three different vibration frequencies (0, 5, and 15 Hz) in a random order in the sitting position for 10 minutes. LBV was performed immediately after a static standing (control) test and 3-min-step test. Heart rate variability and digital volume pulse wave were recorded during the vibration phase (V1: vibration 0-5 minutes; V2: 6-10 minutes) and the recovery phase (Rc1: recovery phase 11-15 minutes; Rc2: 16-20 minutes). The result of digital pulse wave analysis showed that the reflection index (RI) under 15 Hz decreased during V1. Heart rate of the 15-Hz group also decreased during Rc1 and Rc2. According to the analysis of heart rate variability, low-frequency power/high-frequency power (LF/HF) decreased and normalized high-frequency power (nHF) increased during V2, Rc1 and Rc2 under 15 Hz and, during Rc2 under 5 Hz vibration. This study confirmed that the application of low-frequency LBV after exercise can reduce peripheral vascular tone, accelerate heart rate recovery, decrease cardiac sympathetic nerve activity, and promote parasympathetic nerve activity. The effect was more pronounced at 15 Hz than at 5 Hz. The findings provide a method to accelerate cardiovascular autonomic recovery after exercise.

EVOLUTION OF TRANSIT TIME BETWEEN THE SYSTOLIC AND DIASTOLIC PRESSURE PEAKS OF THE RADIAL PULSE WAVEFORM AFTER KIDNEY TRANSPLANTATION

Objective: The transit time between peak systolic and peak diastolic digital volume pulse had been proposed as a measure of arterial stiffness. Indeed, the height of an individual divided by such transit time can be used to estimate a pulse wave velocity. In a cohort of patients with end-stage kidney disease, we aim to examine whether the reduction of aortic stiffness that occurs after kidney transplantation (KTx), translates into improvement of radial artery systolic-diastolic pulse transit time. Design and method: Before and three months after KTx, we recorded radial pressure waveforms using applanation tonometry in 62 patients. We used a two gaussian method to break down the radial pressure waveforms to extract transit time. Radial waveforms were recorded over a 10 seconds period and ensemble-averaged (using in house-MATLAB program) to obtain a single waveform and then modelled using two Gaussian functions. Transit time (dT) was determined as the difference between the first systolic peak (T1) and the early diastolic peak (T2). Generalized transfer function was used to estimate central blood pressures. Carotid-radial and carotid-femoral pulse wave velocities (cr-PWV, cf-PWV) were also measured. Results: 62 patients (66% male, mean age: 48 ± 14 years, mean eGFR: 66 ± 17 ml/min/1.73m2) were assessed. After KTx, there was a significant reduction in cr-PWV (9.49 ± 1.50 to 8.94 ± 1.34, p = 0.001) and cf-PWV (11.56 ± 2.65 to 10.19 ± 1.72, p < 0.001), as well as in central and peripheral blood pressure (p < 0.001). While T1 significantly declined (0.184 [0.172–0.199] to 0.179 [0.164–0.194]s, p = 0.008), there were no significant changes in transit time (0.139 [0.119–0.165] to 0.134 [0.118–0.178]s, p = 0.390) nor in T2 (0.325 [0.293–0.361] to 0.319 [0.283–0.357]s, p = 0.119). Conclusions: Contrary to our expectation, three months after KTx, we did not observe a significant change in transit time. Our results suggest that transit time between the systolic and diastolic pressure peaks of the radial pulse waveform may not be used as a marker of arterial stiffness. We propose that the radial artery pressure wave integrates information from both upstream and downstream vascular beds and so the transit time cannot be used as a reliable surrogate for arterial stiffness.

POS-758 IMPACT OF REDUCTION OF ARTERIAL STIFFNESS AFTER KIDNEY TRANSPLANT ON RADIAL ARTERY SYSTOLIC-DIASTOLIC PEAK-TO-PEAK TRANSIT TIME

Chronic kidney disease leads to cumulative vascular damage that increases aortic stiffness, which is an independent predictor of cardiovascular events. Analysis of Digital Volume Pulse recordings has been proposed to assess arterial stiffness. It is proposed that the systolic peak timing (T1) represents the forward-travelling pressure from the ventricle, and the peak diastolic component (T2) arises mainly from the reflected wave pressures from the lower parts of the body. Hence, using height of a subject and the transit time, one could calculate a pulse wave velocity and estimate arterial stiffness.

Recommendation for Measuring Digital Volume Pulse in Mobile Application: For Healthy Normal Subject

The aim of this study was to identify changes in photoplethysmogram waveform with decreasing sampling frequency and quantization bit depth and suggest appropriate criteria for measurements. We performed down-sampling and re-quantization of phoplethysmogram measured at high resolution. Changes of waveform were quantitatively observed. Photoplethysmograms recorded at a 1-kHz sampling frequency and 16-bit quantization bit depth were converted to signals with sampling frequencies of 500-, 250-, 100-, 50-, 25-, and 10-Hz by means of down-sampling. We then performed re-quantization to convert the quantization bit depth into 16, 14, 12, 10, 8, and 6 bits for each down-sampled signal. Degradation of signal was quantified in terms of morphological change and feature-point deviation. Morphological analysis revealed that the correlation coefficient was decreased while normalized root mean square error was increased with decreasing sampling frequency and quantization bit depth. Feature-point analysis revealed that the mean absolute time error and amplitude error of feature points tended to increase with decreasing sampling frequency and quantization bit depth. Although there were differences according to pulse onset and systolic peak, sampling frequency ≥ 250-Hz and 16-bit quantization bits were required in order to have ≤ 1 ms of timing error and a normalized amplitude error ≤1%. In addition, sampling frequency ≥ 100-Hz and 12-bit quantization bits are recommended to have feature-point time errors and amplitude errors < 10 ms and a normalized amplitude error < 10%.

Preclinical, Multi-Aspect Assessment of the Reliability of a Photoplethysmography-Based Telemonitoring System to Track Cardiovascular Status

Telemonitoring systems equipped with photoplethysmography-based contour analysis of the digital arterial volume pulse (DVP) can be optimal tools for remote monitoring of cardiovascular patients; however, the method is known to be sensitive to errors. We aimed to show that DVP analysis is a reliable method to track cardiovascular status. We used our proprietary SCN4ALL telemedicine system and analyzed nine parameters derived from the DVP and its second derivative (SDDVP). First, we assessed the repeatability of system measurements by detecting artificial signals. Then test–retest reliability of human measurements was evaluated in healthy individuals under standardized conditions. The SCN4ALL system analyzed each parameter with high accuracy (coefficients of variation (CVs) &lt; 1%). Test–retest reliability of most parameters (stiffness index, reflection index, left ventricular ejection time index, b/a, heart rate) was satisfactory (CVs &lt; 10%) in healthy individuals. However, aging index and d/a ratio derived from the SDDVP were more variable. Photoplethysmography-based pulse contour analysis is a reliable method to monitor cardiovascular status if measurements are performed with a system of high accuracy. Our results highlighted that SDDVP parameters can be interpreted with limitations due to (patho)physiological variations of the DVP. We recommend the evaluation of these parameters only in measurements where all inflections of SDDVP are detected reliably.

Prognosis of Diabetic Peripheral Neuropathy via Decomposed Digital Volume Pulse from the Fingertip.

Diabetic peripheral neuropathy (DPN) is a very common neurological disorder in diabetic patients. This study presents a new percussion-based index for predicting DPN by decomposing digital volume pulse (DVP) signals from the fingertip. In this study, 130 subjects (50 individuals 44 to 89 years of age without diabetes and 80 patients 37 to 86 years of age with type 2 diabetes) were enrolled. After baseline measurement and blood tests, 25 diabetic patients developed DPN within the following five years. After removing high-frequency noise in the original DVP signals, the decomposed DVP signals were used for percussion entropy index (PEIDVP) computation. Effects of risk factors on the incidence of DPN in diabetic patients within five years of follow-up were tested using binary logistic regression analysis, controlling for age, waist circumference, low-density lipoprotein cholesterol, and the new index. Multivariate analysis showed that patients who did not develop DPN in the five-year period had higher PEIDVP values than those with DPN, as determined by logistic regression model (PEIDVP: odds ratio 0.913, 95% CI 0.850 to 0.980). This study shows that PEIDVP can be a major protective factor in relation to the studied binary outcome (i.e., DPN or not in diabetic patients five years after baseline measurement).

Montmorency Tart Cherries Influence The Urinary Metabolome But Not Vascular Function In Healthy Individuals

There is accumulating evidence that Montmorency tart cherry (MC) polyphenols possess vasomodulatory properties and their intake has been shown to reduce a number of cardiovascular risk factors. Despite this our understanding of the overall mechanisms of action and compounds that exert these benefits has yet to be fully elucidated. PURPOSE: The aim of this study was to characterise the effects of 4-week MC supplementation on vascular function in healthy adults and provide potential mechanistic evidence from urinary metabolite profiling. METHODS: Twenty three healthy non-smoking individuals took part in a study in which they consumed either 30 mL of MC concentrate or an isocaloric placebo (PLA) bi-daily for 4 weeks. The study employed a randomised, double-blind, placebo-controlled, parallel design; mean ± SD age was 25 ± 4 years in the MC group (n = 12) and 22 ± 2 years in the PLA group (n = 11). Blood pressure, arterial stiffness (pulse wave velocity and digital volume pulse) were measured pre- and post- supplementation. Spot urine samples were also collected at the corresponding time points to determine the effect of the intervention on the urinary metabolite profiles. RESULTS: There were no differences in blood pressure or arterial stiffness following the 4-week supplementation with MC compared to PLA. However, metabolite profiling highlighted changes to the urinary metabolome following MC consumption (P < 0.001 within and between groups). Several discriminatory metabolites of interest were putatively identified as metabolites of the tryptophan and histidine pathways. CONCLUSIONS: These findings suggest that bi-daily MC supplementation for 4-weeks has no influence on blood pressure or arterial stiffness in healthy individuals, but does exert distinct metabolic changes. Specifically, MC concentrate appears to influence amino acid metabolism which warrants further investigations.

Clinical significance of endothelial vasodilatory function evaluated by EndoPAT in patients with systemic sclerosis.

Endothelial dysfunction is a hallmark of vasculopathy associated with systemic sclerosis (SSc). Reactive hyperemia peripheral arterial tonometry is a rapid and non-invasive technique to assess peripheral microvascular endothelial function by measuring changes in digital pulse volume during reactive hyperemia. Low scores of the reactive hyperemia index (RHI) imply an impaired vasodilatory response and, accordingly, impaired endothelial and vascular health. To investigate the clinical significance of the RHI in SSc patients, RHI values were measured in 43 SSc patients and 10 healthy controls. In diffuse cutaneous SSc (dcSSc) patients, RHI values were significantly decreased compared with healthy controls, and inversely correlated with disease duration. In total SSc patients, there was a significant inverse correlation between RHI values and skin score, and interstitial lung disease was associated with the decrease in RHI values. Among vascular symptoms, the current and past history of digital ulcers was seen more frequently in patients with decreased RHI values than in those with normal RHI values. Although no SSc patients had pulmonary arterial hypertension, an inverse correlation was evident between RHI values and mean pulmonary arterial pressure measured by right heart catheterization. These results indicate that the decrease in RHI values is associated with skin fibrosis, interstitial lung disease, digital ulcers and pulmonary vascular involvement leading to pulmonary arterial hypertension, supporting the canonical idea that endothelial dysfunction is a critical event underlying the development of tissue fibrosis and vascular complications in SSc.

EFFECT OF ACUPUNCTURE IN HEART AURICULAR POINT IN TWO INDEXES OF DIGITAL VOLUME PULSE IN HEALTHY SUBJECTS

Objective: The aim of the study was to determine the changes in two indices derived from the digital volume pulse (DVP) elicited by acupuncture in auricular heart acupoint in healthy subjects.&#x0D; Methods: Eighteen healthy subjects aged 26.22±2.98 years (mean±standard deviation) were assigned to receive auricular acupuncture in auricular heart acupoint in the right ear. The DVP was recorded by photoplethysmography. RIDVP was determined by the relative amplitudes of systolic and diastolic components of the DVP and SIDVP, by the relative timing of these components. Auricular acupoint heart was stimulated by manual acupuncture. The RIDVP and SIDVP indices were calculated for basal and post-acupuncture conditions.&#x0D; Results: Both RIDVP (p=0.0375) and SIDVP (p=0.0063) were significantly decreased by acupuncture of the right auricular acupoint heart when comparing the pre- and post-acupuncture values.&#x0D; Conclusions: These results indicate that manual acupuncture of auricular acupoint heart produces acute effects on vascular physiology. RIDVP and SIDVP indices can be used to assess and demonstrate a vasodilatory activity of auricular acupoint heart.

Digital Volume Pulse Analysis to Differentiate Diabetic From Non-Diabetic Subjects

This paper aims to examine the validity of digital volume pulse waveform index namely the diastolic pulse peak (Dpp) in the evaluation of type II diabetics. In total, 153 participants (115 healthy participants and 48 diabetics type II patients) are recruited during the study. A customized algorithm for DVP waveform analysis is developed in MATLAB to analyze and calculate Dpp and b/a indices. The b/a index is found to be negatively correlated with both age and HbA1C test (\(r=-83.8\) and \(r=-66.7\), respectively), while Dpp index is found to be positively correlated with age and HbA1C test (\(r=65.7\) and \(r= 63.3\), respectively). The DVP's Dpp index showed strong association with age and HbA1C test since it remains statistically significant based on the analysis of multi-linear regression. The model revealed that b/a, age, and Dpp contribute by 71.9\% of the variance in HbA1C test. The findings showed that age, b/a, and Dpp indices are promising factors in diabetes type II assessment. These findings expand the potential utility of DVP signal in clinical settings.

Digital Volume Pulse Measured at the Fingertip as an Indicator of Diabetic Peripheral Neuropathy in the Aged and Diabetic

This study investigated the application of a modified percussion entropy index (PEIPPI) in assessing the complexity of baroreflex sensitivity (BRS) for diabetic peripheral neuropathy prognosis. The index was acquired by comparing the obedience of the fluctuation tendency in the change between the amplitudes of continuous digital volume pulse (DVP) and variations in the peak-to-peak interval (PPI) from a decomposed intrinsic mode function (i.e., IMF6) through ensemble empirical mode decomposition (EEMD). In total, 100 middle-aged subjects were split into 3 groups: healthy subjects (group 1, 48–89 years, n = 34), subjects with type 2 diabetes without peripheral neuropathy within 5 years (group 2, 42–86 years, n = 42, HbA1c ≥ 6.5%), and type 2 diabetic patients with peripheral neuropathy within 5 years (group 3, 37–75 years, n = 24). The results were also found to be very successful at discriminating between PEIPPI values among the three groups (p < 0.017), and indicated significant associations with the anthropometric (i.e., body weight and waist circumference) and serum biochemical (i.e., triglycerides, glycated hemoglobin, and fasting blood glucose) parameters in all subjects (p < 0.05). The present study, which utilized the DVP signals of aged, overweight subjects and diabetic patients, successfully determined the PPI intervals from IMF6 through EEMD. The PEIPPI can provide a prognosis of peripheral neuropathy from diabetic patients within 5 years after photoplethysmography (PPG) measurement.