Aggravated cognitive and brain functional impairment in mild cognitive impairment patients with type 2 diabetes: a resting-state functional MRI study.

Type 2 diabetes mellitus is a metabolic disorder and a risk factor for dementia and mild cognitive impairment (MCI), which could also increase the risk of progression from MCI to dementia. The present study evaluated the spontaneous neuronal activity of 31 patients with MCI using resting-state functional MRI. The patients were divided into two groups (17 MCI patients without diabetes, and 14 patients with type 2 diabetes who were considered as the MCI-DM group) and 17 well-matched healthy controls were also recruited. The amplitude of low-frequency fluctuations (ALFF) of spontaneous blood oxygen level dependent signals was then applied to assess neuroimaging changes. To further investigate the impact of type 2 diabetes on cognition, the correlation of ALFF and the neuropsychological tests for the MCI-DM and MCI group were calculated. MCI-DM patients showed diffused ALFF changes in a variety of brain regions that were significantly related to cognitive performance, including the frontal lobe, the temporal lobe, the hippocampus, the amygdala, and the precuneus during a resting state; whereas, the alterations were much less pronounced in the MCI patients without diabetes. These findings provide new insights into understanding essential of diabetes mellitus and may help to clarify the relationship between diabetes mellitus and dementia.