Variation in blood pressure is associated with white matter microstructure but not cognition in African Americans.

摘要: Elevated blood pressure (BP) is a significant risk factor for cerebrovascular disease (CVD), and it becoming more prevalent as the population grows proportionally older sedentary. Complications arising from high BP are widespread in African American communities relative to other racial groups (Howard et al., 2006; Taylor 2008), there evidence suggest that group, Americans susceptible serious consequences of CVD, such stroke vascular-related cognitive decline (Singh, Cohen, Krupp, & Abedi, 1998; Whitfield 2008). It possible this increased susceptibility vascular events may also result heightened subtle brain changes neuropsychological impairment. Several studies have now provided substantial long-standing hypertension can cause alterations structure (den Heijer 2003; Firbank 2007; Guo 2009; Taki 2004; Wiseman 2004). Damage white matter, particular, well documented, with many reports associated greater percentage matter lesions (WML; WM hyperintensities measured on T2 or fluid-attenuated inversion-recovery (FLAIR) imaging) (Murray 2005; Verdelho 2007). While these commonly found periventricular areas (Henskens 2009), they been observed frontal lobe subcortical regions (Hoptman Raz, Rodrigue, Kennedy, Acker, van Es In addition causing lesions, and/or general indices CVD damage fiber tracts. For example, recent study “stroke risk” (a classification includes part its formula) was reduced tissue integrity genu corpus callosum, major pathway providing interhemispheric connectivity (Delano-Wood The vulnerability pathways, compromise has documented severe disorders dementia (Schmahmann, Smith, Eichler, Filley, 2008; Zarei 2009). Schmahmann colleagues (Schmahmann 2008) suggested arise thickening arterial walls, followed by consistently restricted flow, particularly microvascular regions. White thought be vulnerable because fact pathways fed smaller vessels, making them ischemic injury Reduced flow results lower oxygenation, which could ultimately contribute degeneration neuronal death (Havlik 2002; Knopman, Mosley, Catellier, Sharrett, Skoog, 2005). Regionally-specific hypertension-related reported, including prefrontal (Raz, Kennedy 2007), connections nuclei (Jokinen posterior Haacke, However, despite seemingly regional impact structure, predominant finding at least an initial direct selective anterior regions, absence overt impairment. This connecting (Debette Gouw Jouvent 2008); (Gold 2004) callosum fibers (Chen Delano-Wood supported patients advanced diseases, Hallam report dementia, factor, (genu) bilateral frontal-subcortical majority examined group opposed association values. Given structural not unexpected decrements cognition, primarily executive functions, domain aging linked cortex structures (Brady, Spiro, Gaziano, Sorond, Schnyer, Serrador, Milberg, Lipsitz, Notably, individuals one elevated pressure, perform poorly measures attention, concentration, higher-order thinking (Brady Raz Supporting structure-function connection, impairments reported conjunction changes. al. (2007) higher markers were functioning A decreased untreated hypertensives correlated indicators (mean diffusivity assessed through DTI) (Hannesdottir Thus, summary, preponderance points primary targets pressure. While indicating risk, few associations across range indexed quantitatively, grouping dichotomously presence (i.e., hypertensive nonhypertensive; low versus risk), none studies, our knowledge, exclusively cohort. current study, we relationships among continuous quantitative integrity, pressure. We used DTI acquisition analysis procedures investigate three aims: (1) Determine how measure gauge (white matter). Specific interest (ROIs) included (anterior genu), (posterior splenium), whole diffusion tensor imaging (DTI) measure. predicted levels would fractional anisotropy (FA), index level, but splenium location. (2) whether variation impacts specifically memory function, respectively. executive, functioning. (3) each ROIs relates cognition. FA whole-brain FA, scores (and thus better performance) composite score. These collective predictions based prior literature documenting function deficits relatively those without any early case sample. Ultimately, expect findings significantly knowledge regarding specific population, larger relationship