Energetic hemodynamic parameters in the carotid artery as a strong predictor of cognitive impairment.

The difference in aortic and carotid impedance between younger and older people. In younger people, aortic compliance is greater than carotid impedance; hence, impedance mismatch occurs. As a result, not all pulsatile energy from the heart is transmitted to the carotid artery. In older people, aortic stiffness enhances transmission of pulsatile energy from the heart to the brain.