Sana Suri
University of Oxford, Psychiatry, Graduate Student
Research Interests:
Dementia is one of the major causes of personal, societal and financial dependence in older people and in today's ageing society there is a pressing need for early and accurate markers of cognitive decline. There are several subtypes... more
Dementia is one of the major causes of personal, societal and financial dependence in older people and in today's ageing society there is a pressing need for early and accurate markers of cognitive decline. There are several subtypes of dementia but the four most common are Alzheimer's disease, Lewy body dementia, vascular dementia and frontotemporal dementia. These disorders can only be diagnosed at autopsy, and ante-mortem assessments of "probable dementia (e.g. of Alzheimer type)" are traditionally driven by clinical symptoms of cognitive or behavioural deficits. However, owing to the overlapping nature of symptoms and age of onset, a significant proportion of dementia cases remain incorrectly diagnosed. Misdiagnosis can have an extensive impact, both at the level of the individual, who may not be offered the appropriate treatment, and on a wider scale, by influencing the entry of patients into relevant clinical trials. Magnetic resonance imaging (MRI) may help ...
Research Interests:
Research Interests:
Important risk factors for... more
Important risk factors for Alzheimer's disease (AD) are ageing and the Apolipoprotein E (APOE) ε4 allele, with female APOE ε4 carriers having the greatest risk. In this study we investigated effects of AD risk factors on connectivity of the hippocampus, a structure that shows early AD related pathology. Resting-state functional magnetic resonance imaging and diffusion tensor imaging data from 86 cognitively healthy subjects aged 30 to 78years were analysed. Female APOE ε4 carriers showed overall significantly reduced functional connectivity between the hippocampus and precuneus/posterior cingulate cortex (PCC) and a significant age-related decrease in connectivity of these regions. In females and APOE ε4 carriers we found significantly reduced white matter integrity of the tract connecting the hippocampus and PCC with a significant positive correlation of white matter integrity and resting-state connectivity. Increased vulnerability of the connection between the hippocampus and PCC might be one reason for increased AD risk in female APOE ε4 carriers. Interventions targeting hippocampal connectivity might be especially effective in this at risk population.
Research Interests:
Functional magnetic resonance imaging (MRI) studies have shown that APOE ε2- and ε4-carriers have similar patterns of blood-oxygenation-level-dependent (BOLD) activation suggesting that we need to look beyond the BOLD signal to link... more
Functional magnetic resonance imaging (MRI) studies have shown that APOE ε2- and ε4-carriers have similar patterns of blood-oxygenation-level-dependent (BOLD) activation suggesting that we need to look beyond the BOLD signal to link APOE's effect on the brain to Alzheimer's disease (AD)-risk. We evaluated APOE-related differences in BOLD activation in response to a memory task, cerebrovascular reactivity using a CO2-inhalation challenge (CO2-CVR), and the potential contribution of CO2-CVR to the BOLD signal. APOE ε4-carriers had the highest task-related hippocampal BOLD signal relative to non-carriers. The largest differences in CO2-CVR were between ε2- and ε4-carriers, with the latter having the lowest values. Genotype differences in CO2-CVR accounted for ∼70% of hippocampal BOLD differences between groups. Because CO2-CVR gauges vascular health, the differential effect of APOE in young adults may reflect a vascular contribution to the vulnerability of ε4-carriers to late-l...