Date of Award
Master of Science in Biomedical Engineering - (M.S.)
Biomedical Engineering Committee
Stanley S. Reisman
David S. Kristol
Time domain analysis for calculating the Baroreceptor Sensitivity Index (BRSI) did not always provide an accurate result. It also had another limitation in that it could not show the influence of the autonomic nervous system for different subjects. The correlation coefficient is a mechanism that was used to either accept or reject the BRSI values in the time domain but the correlation coefficient values changed drastically depending on how many sample points were selected for the calculation.
On the other hand, frequency domain analysis for the BRSI calculation was relatively easier and provided more accurate information compared to the time domain analysis. The modulus was the frequency domain equivalent of the Baroreceptor Sensitivity Index in the time domain. In the low frequency band (0.07Hz-0.14Hz), the baroreceptor response is influenced by the blood pressure control mechanism. Therefore, different modulus values for different subjects showed the influence of the autonomic nervous system in the calculation of modulus. As correlation coefficient was a measure to either accept to reject the BRSI calculation in the time domain, coherence was a measure to either accept or reject the modulus calculation in the frequency domain.
During the analysis the coherence value did not change as drastically as the correlation coefficient differences of several sample points. Frequency domain calculation therefore, proved to be relatively more accurate, stable, and provided more information compared to the time domain analysis.
Raquib, Tanvir, "Measurement of the baroreceptor sensitivity index (BRSI) in the frequency domains" (1998). Theses. 955.