A. Stefanovska et al., Wavelet analysis of oscillations in the peripheral blood circulation measured by laser Doppler technique, IEEE BIOMED, 46(10), 1999, pp. 1230-1239
The wavelet transform technique, a time-frequency method with logarithmic f
requency resolution, was used to analyze oscillations in human peripheral b
lood flow measured by laser Doppler flowmetry. The oscillations extended ov
er a nide frequency scale and their periods varied in time. Within the freq
uency range studied, 0.0095-1.6 Hz five characteristic oscillations were re
vealed, arising from both local and central regulatory mechanisms. After th
e insertion of endothelium-dependent and endothelium-independent vasodilato
rs the spectra of blood flow markedly differed in the frequency interval 0.
0095-0.02 Hz. In this way it was demonstrated that endothelial activity is
a rhythmic process that contributes to oscillations in blood flow with a ch
aracteristic frequency of around 0.01 Hz. The study illustrates the potenti
al of laser Doppler flowmetry combined with dynamical systems analysis for
studies of both the micro- and macroscopic mechanisms of blood flow regulat
ion in vivo.