Separating independent components in heart period signal / 生物医学工程学杂志

To extract sub-signal of heart period signal (HPS), a new statistical signal processing approach, namely independent component analysis (ICA) was addressed. Electrocardiosignal (ECS) was acquired from ten volunteers. ECS was sampled 8 minutes when the volunteer was in supine position, and then when the same volunteer was in erect position. HPS was extracted from ECS. According to time-delay, HPS was divided into five groups as mixed signals. Five signals were reconstructed into two groups by ICA. The rebuilt signals were transformed by Fourier transformation. One centralized in low frequency (called IC1); the other did in high frequency (called IC2). The power of IC1 was significantly increased (P<0.01) while that of IC2 showed no significant change (P>0.05), and the ratio of IC1 to total power also significantly increased with the change from supine position to erect position. Comparsion between the two postural results reveals that IC1 may express sympathetic activity, and IC2 represents parasympathetic activity. Sympathetic and parasympathetic nervous functions can be evaluated respectively and quantitatively by use of data and graphs from the two decomposed components.

Detection and evaluation of gastric motility for the patients with erosive gastritis / 中国实用内科杂志

Objective In order to investigate the comlex course of electricity and mechanism of erosive gastritis(EG) and its relative factors,and to extract gastric motility feature indexes.Methods 30 volunteers of erosive gastritis were selected.The signal processing device was designed by Chongqing University of Posts and Telecommunications.By the means of spectrum analysis technic,the signals could be classified according to the dominant power and dominant frequency.Some indexes such as frequency of EGG and IGM,signal power spectrum and dynamic spectrum,the rates of rhythm and power for the normal EGG and IGM and so on could also be calculated.Results The power ratio in 2~4 cpm was 59.2?4.4,the frequency ratio was 70.4?25.5,the frequency instability coefficient was 0.182?0.059,and the power instability coefficient was 1.576?0.481.The parameters changed signifcantly between health adult and patient(P0.05).Conclusion The results of the experiments show that the method based on the synchronous measurement of EGG and IGM can provide a non-invasive way to investigate and evaluate erosive gastritis corresponding to gastrointestinal physiology and pathology conditions.