Age-related transcranial Doppler findings in the evaluation of cerebral circulation during postprandial and postural tests.

We used transcranial Doppler (TCD) to investigate whether there are cerebral circulation differences between young and elderly subjects in response to postprandial postural changes. Preprandial and postprandial systolic and diastolic blood pressure, heart rate, mean middle cerebral artery (MCA) velocity (Vmean MCA), systolic/diastolic MCA velocity ratio (Vs/Vd MCA) and pulsatility index (PI) were determined in 15 healthy elderly subjects (mean age 74.3 +/- 6.5 years) and in 10 younger subjects (mean age 31.6 +/- 7. 2 years) in the supine position and after a postural change. As compared with young subjects, elderly ones showed a greater postprandial systolic pressure decline (p < 0.05) associated with a significant decrease of Vmean MCA (p < 0.05), and a greater increase of Vs/Vd and PI (p < 0.05 both). We conclude that, as compared with young subjects, elderly ones have reduced cerebrovascular adaptive response to pressure modifications induced by postprandial postural changes.