Correlation between cognitive function and the association fibers in patients with Alzheimer's disease using diffusion tensor imaging.
White matter (WM) changes, along with well-characterized cortical abnormalities, occur in patients with Alzheimer's disease (AD). We investigated the integrity of WM tracts within association fibers by the use of fractional anisotropy (FA), and the relationship between FA values and cognitive function in patients with AD. Neuropsychological examination and conventional MRI, as well as diffusion tensor imaging, (DTI) were conducted on 12 patients with mild to moderate AD and 18 cognitively healthy volunteers. DTI was performed to measure FA in the bilateral inferior fronto-occipital fasciculus (IFOF) and the superior longitudinal fasciculus (SLF). Mini-Mental State Examination (MMSE) scores and Montreal Cognitive Assessment (MoCA) values were used to evaluate cognitive function and the Clinical Dementia Rating (CDR) scale was used as a staging tool for dementia severity. FA measures were analyzed and correlated with neuropsychological data. No patient showed any WM tract abnormality on either T1-weighted or T2-weighted MRI. However, the FA values in the bilateral IFOF and SLF and the MoCA scores in patients with AD were significantly decreased (p<0.05) compared to the controls. Furthermore, the decreased FA values in the SLF were positively correlated with cognitive function (MMSE scores - right: r=0.672, p=0.033, left: r=0.919, p<0.01; MoCA values - right: r=0.747, p=0.013, left: r=0.679, p=0.031). Our findings confirmed that the loss of integrity of microstructural WM connectivity has a role in the cognitive decline of patients with AD. The data also suggest that the FA values of the SLF may be used as a clinical marker of cognitive function.
Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing, Jiangsu Province 210029, China.
Jing-Zhi
JZ
Meng
Li-Wei
LW
Guo
Hong
H
Cheng
Yun-Jie
YJ
Chen
Lin
L
Fang
Ming
M
Qi
Zhen-Yu
ZY
Jia
Wasif
W
Mohammed
Xun-Ning
XN
Hong
D000544:Alzheimer Disease / Q000150:complications / Q000473:pathology*; D016880:Anisotropy; D001921:Brain / Q000473:pathology*; D003071:Cognition; D003072:Cognition Disorders / Q000209:etiology / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D009412:Nerve Fibers / Q000473:pathology*; D009434:Neural Pathways / Q000473:pathology*; D009483:Neuropsychological Tests