Resting-state brain default mode network in patients with mild Alzheimer's disease: an functional MRI study / 中华神经医学杂志

ABSTRACT

Objective To explore the activity of brain default mode network (DMN) in patients with mild Alzheimer's disease (AD) by resting state functional magnetic resonance imaging (fMRI) and investigate its possible neural mechanism. Methods Twenty-four patients with mild AD,admitted to our hospital from January 2009 to June 2010,and 25 normal controls (NCs) were chosen in this study.All subjects were examined by Mini Mental State Examination (MMSE), Mattis Dementia Rating Scale (DRS) and fMRI.Resting-state whole brain data were analyzed by amplitude of low frequency fluctuation (ALFF) with two-sample t test and the brain regions in mild AD patients having significantly different ALFF comparing to NCs were observed. Results As compared with that in NCs,the memory function in mild AD patients was seriously impaired (P＜0.05).As compared with NCs,mild AD patients showed significantly decreased ALFF in the posterior cingulate cortex,ventral medial prefrontal cortex and dorsal medial prefrontal cortex, which were closely relevant to the memory (P＜0.05). Conclusion AD patients show significantly decreased active intensity of some DMN nodes that relate to memory in resting state; DMN abnormalities play an important role in early memory impairment of AD patients.