Browsing by Author "Choi, Jae"
Now showing 1 - 1 of 1
Results Per Page
Sort Options
Item Reliability, Asymmetry and Age Influence on Dynamic Cerebral Autoregulation Measured by Spontaneous Fluctuations of Blood Pressure and Cerebral Blood Flow Velocities in Healthy Individuals(Wiley, 2014) Ortega-Gutiérrez, Santiago; Petersen, Nils; Masurkar, Arjun; Reccius, Andrés; Huang, Amy; Li, Min; Choi, Jae; Marshall, RandolphBackground: Cerebral autoregulation (CA) enables the brain to maintain stable cerebral blood flow (CBF). CA can be assessed non-invasively by determining correlations between cerebral blood flow velocity (CBFV) and spontaneous changes in blood pressure. Post-recording signal analysis methods have included both frequency- and time-domain methods. However, the testretest reliability, cross-validation, and determination of normal values have not been adequately established. Methods:In 53 healthy volunteers a transfer function analysis was applied to calculate phase shift (PS) and gain in the low frequency range (0.06-0.12 Hz) where CA is most apparent. Correlation analysis was used to derive mean velocity index (Mx). Intra-class correlation and bivariate correlation coefficients were applied to assess asymmetry, cross-validity, and test-retest. Results:The bihemispheric average PS, gain and Mx means were 45.99+/−14.24 degrees, 0.62+/−0.38 cm/sec/mm Hg and 0.41+/− 0.13 respectively. Gain exhibited a difference by age (p=0.03). PS, gain and Mx values showed excellent inter-hemispheric correlation (r>0.8; p<0.001). PS and gain showed good reliability (R ICC=0.632, L ICC=0.576; p<0.001). PS and Mx showed fair correlation (r=−.37; p<0.001). Conclusions: CA parameters obtained by time- and frequency-domain methods correlate well, and show good inter-hemispheric and test-retest reliability. Group means from healthy controls may provide adequate norms for determining abnormal CA in cerebrovascular patients.