Browsing by Author "Severeyn, Erika"

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An aide diagnosis system based on k-means for insulin resistance assessment in eldery people from the Ecuadorian highlands
(Institute of Electrical and Electronics Engineers Inc., 2018) Wong de balzan , Sara Null; Astudillo Salinas, Darwin Fabián; Encalada Torres, Lorena Esperanza; Severeyn, Erika
The lack of standardized cut-off values for the surrogate methods to diagnose Insulin resistance (IR) and the fact that the sensitivity of these methods have been studied in specific populations have limited their use in clinical routine. We developed a system that could aide to diagnosis IR in elderly people, analyzing four surrogate methods of IR estimation using a k-means clustering algorithm. Study subjects included 119 nondiabetic participants over 65 year old from Ecuadorian highlands. Blood tests included a two-point oral glucose test tolerance. The k-means clustering algorithm, was applied in one-dimensional experiments for the Homa-IR, Quicki, Avignon and Matsuda. The population was divided into three clusters: C N with normal values, C IR with IR and C a with values in between. The number of individuals classified in each C Ir was very different according to each method. With the cut-off values obtained, for each method, the system for the evaluation of IR in elderly people was developed. Our work is intended to aid physicians in the early detection of IR by using information from diverse methods.
Cardiac autonomic modulation in response to a glucose stimulus
(2019) Perpiñan, Gilberto; Severeyn, Erika; Wong de balzan , Sara Null; Altuve, Miguel
This paper focuses on the effect of a sudden increase of plasma glucose concentration in the cardiac autonomic modulation using time-domain and frequency-domain heart rate variability (HRV) measures. Plasma glucose and insulin levels, measured each 30 min during an oral glucose tolerance test, and RR ¯ $overline { ext {RR}}$ (mean of the RR interval), SDNN (standard deviation of normal-to-normal heartbeats), rMSSD (root-mean-square of successive differences between normal heartbeats), TP (total spectral power), LF and HF (power of the low- and high-frequency bands), LF norm and HF norm (LF and HF in normalized units), and LF/HF ratio of the HRV signal, obtained from 5-min-long ECG recordings during each phase of the test, were analyzed for subjects with the metabolic syndrome, marathon runners, and a control group. Results show that, after the glucose load, subjects with the metabolic syndrome experienced an increased sympathetic and decreased parasympathetic tone, which suggests an imbalance in cardiac autonomic modulation as a consequence of hyperglycemia and hyperinsulinemia. The significance of this study lies in the use of the ECG to assess the effects of a sudden increase in plasma glucose concentration on the cardiac autonomic modulation in subjects with different cardiovascular and metabolic conditions. Graphical Abstract Time-domain and frequency-domain heart rate variability measures are altered in subjects with different cardiovascular and metabolic conditions during an oral glucose tolerance test
Towards the insulin resistance and obesity diagnosis: A dimensional analysis approach
(Institute of Electrical and Electronics Engineers Inc., 2018) Velásquez, Jesús; Severeyn, Erika; Herrera, Hector Antonio; Utrera, Nestor; Encalada Torres, Lorena Esperanza; Wong de balzan , Sara Null; Velásquez, Jesús
Diabetes mellitus and cardiovascular diseases are ailments related to insulin resistance (IR) and obesity. The existing methods for IR and obesity diagnosis are the HOMA-IR and body mass index (BMI), respectively. Those methods have limitations in the diagnosis. The aim of this research is to propose dimensionless indexes that can diagnose subjects with IR and obesity using anthropometrics and biochemical variables (waist circumference, height, weight, systolic blood pressure, diastolic blood pressure and triglycerides). Three dimensionless indexes, designed from the π Vaschy-Buckingham theorem, were assessed using receiver operating characteristic (ROC) curves and a database of 829 subjects. The index π 1 , constructed with the variables: waist circumference, triglycerides height and weight; obtained a better performance as classifier of IR and obesity, presenting an area under the ROC curve of 0.78, sensitivity of 0.82 and specificity of 0.68 for IR diagnosis, and an area under the ROC curve of 0.68, sensitivity of 0.66 and specificity of 0.65 for obesity diagnosis. The π 1 dimensionless index designed in this study is a simple method that allows diagnosing two pathologies from variables that can be collected in a routine medical examination.