Connectivity within the Default Mode Network Is Related Toworking Memory Performance in Young but Not Elderly Healthyadults

(MCI). Methods: Twenty-eight MCI patients (14 males, age1⁄46767yrs, clinical dementia rating score1⁄40.5) and 30 ageand education-matched cognitively normal adults (14 males, age1⁄46767yrs) participated. The carotid arterial (b) stiffness index and the intima-media thickness (IMT) were measured using high resolution 2D Doppler ultrasonography and applanation tonometry in the left and right common carotid arteries (CCA). Peripheral and central pulse-wave-velocity (PWV) were measured between the right common carotid artery and the right radial and left femoral artery, respectively. WMH was assessed in 22 patients with MCI (12 males, age1⁄46767yrs) and 19 controls (5 males, age1⁄46767yrs) using MRI Fluid-Attenuated-Inversion-Recovery (FLAIR) images on a 3T Philips Achieva MR system. Periventricular and deep-brain WMH volumes were quantified and differentiated using semi-automatic programs (MRICro and MatLab). Results: MCI patients showed higher b-stiffness index (7.361.8 vs. 6.361.5, p<0.05) and decreased distensibility (0.3160.07 vs. 0.3760.09%mmHg, P 1⁄4 0.01) in the CCA when compared to the cognitively normal subjects. No significant differences were found in the carotid artery IMT (0.7060.11 vs. 0.6660.10cm/s), peripheral (8.361.2 vs. 8.361.4cm/s) and central PWV (9.762.1 vs. 9.962.2cm/s) between the groups. Deep-brain WMH volume, normalized to the whole intracranium volume, was twice as high in the MCI group relative to the controls (dWMHx, 0.1860.10 vs. 0.0960.07%, P<0.01) although global WMH volume did not differ between the two groups. Conclusions: Deep-brain WMH volume was increased in patients with MCI and was associated with increases in carotid arterial stiffness. The relationship between arterial stiffness and deep-brain WMH volume in MCI merits further investigation.