Browsing by Author "McCreary, Cheryl R."

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    Assessment of T2 Magnetic Resonance Relaxation as an Imaging Biomarker of Normal Brain Aging over the Adult Lifespan
    (2021-01-11) Wang, Xing; Frayne, Richard; Lebel, Catherine A.; McCreary, Cheryl R.
    Quantitative T2 relaxation time (qT2) was proposed for assessing brain tissue changes. In this study, qT2 was evaluated to examine normal brain aging across the adult lifespan. I explored the specific hypotheses that 1) short- (weeks) and long-term (years) qT2 repeatability were equivalent, and 2) qT2 increased with age-related increases in tissue water content and demyelination but decreased with increased iron accumulation. The repeatability assessment found qT2 estimation robust over >4 years. Long-term was similar to, but worse than short-term repeatability. A quadratic regression model was determined to be the best fitting analytical model. Linear mixed effects models were used to evaluate qT2 changes with age in twelve regions and qT2 change rates from six regions compared against a reference region. The results supported the hypothesis that qT2 increases with age; however, could not demonstrate that these T2 changes result from changes in tissue water content, demyelination or iron accumulation.
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    Effects of aging on the association between cerebrovascular responses to visual stimulation, hypercapnia and arterial stiffness
    (Frontiers, 2014-02-19) Fluck, Daniela; Beaudin, Andrew E.; Steinback, Craig D.; Kumparpillai, Gopukumar; Shobha, Nandavar; McCreary, Cheryl R.; Peca, Stefano; Smith, Eric E.; Poulin, Marc J.
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    Neuroimaging Correlates of Gait Control in Cerebral Amyloid Angiopathy
    (2023-01-16) Sharma, Breni; Smith, Eric E.; Harris, Ashley; Ismail, Zahinoor; McCreary, Cheryl R.
    Cerebral amyloid angiopathy (CAA) is the second most common subtype of cerebral small vessel disease (CSVD) and is characterized by the buildup of beta-amyloid protein in the walls of small-medium sized arteries and arterioles of the leptomeninges. Much is known about common clinical manifestations of the disease, such as presence of white matter hyperintensities, lacunar infarcts, cerebral microbleeds, cortical superficial siderosis, and phenotypic presentations, such as the cognitive profile of CAA and its contribution to neurodegeneration and dementia. However, little had been known about the gait profile of CAA or the neural correlates underlying any abnormalities observed, such as grey matter atrophy, white matter damage, or brain iron accumulation. To address these gaps in the literature, I first conducted a systematic review and meta-analysis of the existing literature covering CSVD and its relation to gait and falls. Once evident that gait difficulties were a feature of CSVD as a whole, I examined gait abilities of patients with CAA, when compared to normal controls (NC), patients with Alzheimer’s disease (AD), and mild cognitive impairment (MCI). With this, I also looked at associations with falls history and fear of falling, as well as the relationships between gait ability and cognition, WMH volume, and CMB count. Significant gait impairments were found in CAA, prompting an examination of associations between these impairments and grey and white matter damage and iron content in select brain regions. In CSVD, there was a general consensus across studies of an association between greater CSVD burden and worse gait and greater falls. Looking specifically at CAA, significant impairments were found in gait compared to NC but not to AD. Further investigation of this lead to associations between worse gait and grey matter atrophy in frontal, AD-affected, and subcortical regions and with greater white matter structural damage. Iron content, however, did not differ between CAA and NC. Overall, gait appears to be negatively impacted by CAA pathology. Further examination of neural correlates may help to better understand the disease and incorporation of the current findings may help to inform clinicians on the functional outcomes of CAA patients.