The association between pulse wave velocity and cognitive function: the Sydney Memory and Ageing Study

OBJECTIVES Pulse wave velocity (PWV) is a measure of arterial stiffness and its increase with ageing has been associated with damage to cerebral microvessels and cognitive impairment. This study examined the relationship between carotid-femoral PWV and specific domains of cognitive function in a non-demented elderly sample. METHOD Data were drawn from the Sydney Memory and Ageing Study, a cohort study of non-demented community-dwelling individuals aged 70–90 years, assessed in successive waves two years apart. In Wave 2, PWV and cognitive function were measured in 319 participants. Linear regression was used to analyse the cross-sectional relationship between arterial stiffness and cognitive function in the whole sample, and separately for men and women. Analysis of covariance was used to assess potential differences in cognition between subjects with PWV measurements in the top and bottom tertiles of the cohort. Covariates were age, education, body mass index, pulse rate, systolic blood pressure, cholesterol, depression, alcohol, smoking, hormone replacement therapy, apolipoprotein E ε4 genotype, use of anti-hypertensive medications, history of stroke, transient ischemic attack, myocardial infarction, angina, diabetes, and also sex for the whole sample analyses. RESULTS There was no association between PWV and cognition after Bonferroni correction for multiple testing. When examining this association for males and females separately, an association was found in males, with higher PWV being associated with lower global cognition and memory, however, a significant difference between PWV and cognition between males and females was not found. CONCLUSION A higher level of PWV was not associated with lower cognitive function in the whole sample.Joel Singer, Julian N. Trollor, John Crawford, Michael F. O’Rourke, Bernhard T. Baune, Henry Brodaty, Katherine Samaras, Nicole A. Kochan, Lesley Campbell, Perminder S. Sachdev, Evelyn Smit

A study of persistent post-concussion symptoms in mild head trauma using positron emission tomography

Background: Complaints of persistent cognitive deficits following mild head trauma are often uncorroborated by structural brain imaging and neuropsychological examination. Objective: To investigate, using positron emission tomography (PET), the in vivo changes in regional cerebral uptake of 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG) and regional cerebral blood flow (rCBF) in patients with persistent symptoms following mild head trauma. Methods: Five patients with mild head trauma and five age and education matched healthy controls were imaged using FDG-PET to measure differences in resting regional cerebral glucose metabolism. Oxygen-15 labelled water (H(2)(15)O)-PET was also used to measure group differences in rCBF changes during a spatial working memory task. In addition, neuropsychological testing and self report of dysexecutive function and post-concussion symptoms were acquired to characterise the sample. Results: There was no difference between patients and controls in normalised regional cerebral FDG uptake in the resting state in frontal and temporal regions selected a priori. However, during the spatial working memory task, patients had a smaller increase in rCBF than controls in the right prefrontal cortex. Conclusions: Persistent post-concussive symptoms may not be associated with resting state hypometabolism. A cognitive challenge may be necessary to detect cerebral changes associated with mild head trauma