Frontal and temporal lobe structural and functional complications in adults with type 2 diabetes mellitus
Item
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Title
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Frontal and temporal lobe structural and functional complications in adults with type 2 diabetes mellitus
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Identifier
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d_2009_2013:3cfa2061bf2d:10841
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identifier
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11056
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Creator
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Yau, Po Lai,
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Contributor
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Alan Kluger
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Date
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2011
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Language
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English
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Publisher
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City University of New York.
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Subject
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Neurosciences | Endocrinology | Psychology | Cognition | DTI | Hippocampus | Neuroimaging | Obesity | T2DM
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Abstract
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Type 2 diabetes mellitus (T2DM) has been associated with cognitive impairment, with verbal memory reported as being the most frequently affected, but the underlying cerebral mechanisms remain unclear. There is increasing evidence suggesting that the frontal and temporal lobes may be preferentially affected in T2DM. To comprehensively characterize cognitive functioning and the extent of frontal and temporal lobe involvement in T2DM, the current study compared 46 late middle-aged and elderly patients with T2DM to 50 age- and education-matched controls with no evidence of insulin resistance or T2DM utilizing a comprehensive battery of neuropsychological tests and magnetic resonance (MR) based brain volumetric and diffusion tensor imaging assessment methods.;As expected, individuals with T2DM exhibited clear declarative memory impairment, with verbal memory being more prominently affected than visual memory, along with evidence of compromised verbal learning. Supporting these results, brain assessment revealed volume reductions restricted to the hippocampus bilaterally and extensive microstructural abnormalities in the temporal lobe. The observed verbal memory impairments were associated with compromised microstructural integrity of the left parahippocampal gyrus but not atrophy of the hippocampus. Importantly, this study demonstrated for the first time that systolic blood pressure may partially explain the association between body mass index and hippocampal volume reduction among individuals with T2DM who had normal blood pressure or untreated hypertension. In contrary, the frontal lobe was less extensively affected, with only attention being impaired and evidence of non-specific microstructural abnormalities without obvious tissue loss.;As hypothesized, among individuals with T2DM, glycosylated hemoglobin (HbA1C) was inversely correlated with memory performance but was not the most significant metabolic factor after accounting for age and gender. Having hypertension also did not account for the observed attention deficits. A larger sample is necessary to better understand the independent contributions of metabolic factors and their possible interactions. To clarify the mechanisms underlying the observed impairments, future studies should better characterize the nature and extent of brain involvement, utilizing MR spectroscopy to understand neuronal metabolism and resting-state functional MRI to understand network connectivity. In addition, possible involvement of other potential factors, such as inflammation and impairment in vascular reactivity, should be explored.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Psychology
