Spontaneous oscillations of cerebral oxygenation signal and its correlation with transcranial Doppler hemodynamic parameters

The objective of this study is to assess the correlation between the prefrontal cerebral oxygenation oscillations measured by near-infrared spectroscopy (NIRS) and cerebral artery hemodynamic parameters as measured by transcranial Doppler (TCD). The cerebral oxygenation signal was monitored for 10 minutes from the left prefrontal lobe using NIRS. TCD monitoring was performed to measure the hemodynamic parameters including end diastolic, peak systolic, and mean cerebral blood flow velocities. With spectral analysis based on wavelet transform of NIR signal, five frequency intervals were identified (I, 0.005-0.02 Hz, II, 0.02-0.06 Hz, III, 0.06-0.15 Hz, IV, 0.15-0.50 Hz and V, 0.50-2.0 Hz). Significant negative correlation was found between the cerebral [Hb] and [HbO₂] oscillations in frequency intervals III (0.06-0.15 Hz), IV (0.15-0.5 Hz), V (0.5-2 Hz) and the mean velocity in left middle cerebral artery (MCA) (p<;0.05). The results suggested that the cerebral oscillations measured from the frontal lobe were closely related to the vessel stiffness of MCA.