Abstract:

The objective of this study was to assess the correlation between spontaneous oscillations in Nearinfrared cerebral oxygenation (CO) and arterial blood pressure (ABP) and to propose a method of indicating brain stroke. Continuous recordings of NIRS and ABP signals were obtained from simultaneous measurements in nineteen young subjects (age=24±2 years), thirty two old subjects (age=70.8±5.2 years) at rest. The correlations between CO signals and ABP signals were analyzed using method based on Cross-wavelet Coherence. High common power can be observed in timefrequency domain between the two signals. What′s more, the coherency shows that there are significant relationships as well in interval I and interval II. Significant difference can be observed (P=0.002, F=11.215) after statistical analyzing the coherence between CO signals and ABP signals of the three groups in interval I. The results indicated that comparing with the young the coherence of the frequency reflecting cardiac activity between CO signals and ABP signals became higher, which may signify high stiffness of cerebral vascular.

Key words: cross wavelet coherence, cerebral oxygen, near-infrared