Arterial flow curves in the three groups of patients and in healthy volunteers. The mean arterial flow curve is plotted for each of the four populations over two successive cardiac cycles. In order to simplify the figure, the standard deviations have been intentionally omitted. The flow scale increases from top to bottom. Note the sharper, higher systolic arterial peak in MCI and (to a lesser extent) in AD patients, when compared with healthy elderly volunteers (HEVs) and NPH patients. There were significant differences between these curves (please refer to the values reported in Tables 1 and 2).