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P4‐186: Structural Neural Correlates of Impaired Mobility and Subsequent Decline in Executive Functions: A 12‐Month Prospective Study
Author(s) -
Hsu Chun Liang,
Best John R.,
Chiu Bryan K.,
Voss Michelle W.,
Handy Todd C.,
Bolandzadeh Niousha,
Liu-Ambrose Teresa
Publication year - 2016
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2016.06.2278
Subject(s) - subclinical infection , cognitive decline , cognition , prospective cohort study , white matter , medicine , longitudinal study , gerontology , magnetic resonance imaging , psychology , physical medicine and rehabilitation , effects of sleep deprivation on cognitive performance , dementia , psychiatry , disease , pathology , radiology
burden to Alzheimer’s disease (AD) in addition to sharing common risk factors (hypertension, diabetes mellitus etc.) is evidence of the pathophysiological ground for the heart-brain association in ageing. One mechanism of cognitive impairment in dementia is through the disruption of white matter (WM) connections between brain regions working in tandem to perform cognitive functions. However, literature investigating the additive effects of AD on white matter structural integrities of those already at high risk for CVD is lacking. Methods: 30 subjects diagnosed with mild AD (mean age1⁄469.76. SD1⁄48.49) and 24 healthy controls (mean age1⁄464.96. SD1⁄47.48) confirmed to be at high risk of CVD burden, were subjected to detailed neuropsychological assessments and diffusion tensor imaging. On the basis of high CVD burden, we evaluated the compromise of WM integrity due to the coupling effect of AD pathology by performing tract-based spatial statistic in fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity, and radial diffusivity (RD).We further investigated the relations between the four WM measures and cognitive functions in the subjects. Results:Early AD subjects displayed significantly lower FA in the corpus callosum, left corticospinal tract, right tapetum and inferior fronto-occipital fasciculus (Fig 1A, Table 1). Correspondingly, this group showed greater diffusivities in the corpus callosum, tapetum and posterior corona radiata (Fig 1B, Table 1). Furthermore, the disturbance of WM integrity at these locations was significantly correlated with diminishing capabilities of selected cognitive domains (p <0.05, corrected for multiple comparisons; Table 2), such that episodic memory showed significant correlations with all the aformentioned WM tracts, while language and visuospatial performance were significantly correlated with corpus callosum. Conclusions: Our cross-sectional study demonstrated that the subsistence of early AD has an additive effect on individuals with high CVD burden specifically compromising the integrity of WM affected in dementia as corroborated by other studies. Moreover, these WM integrity changes are exemplified in specific cognitive functions. Longitudinal studies are warranted to characterize the association between AD pathology and CVD and their impact on aging brain and cognition.