Brain responses to energy intake and its association with cognition in Alzheimer’s Disease

Background To evaluate the brain response to energy intake using cerebral blood flow(CBF) in Alzheimer’s disease (AD), mild cognitive impairment (MCI) and healthy controls (HC) and its relationship with cognition. Method A self‐comparison design was used to test the effects of energy intake on brain activity in participants with AD (n = 30), MCI participants (n = 32), and HC (n = 30) and its relationship with cognitive function. Brain perfusion was measured using arterial spin labeling (ASL) functional brain imaging. Participants arrived at the site in the morning and underwent the ASL‐MRI with at least 10 hours fasting overnight. Then the second ASL‐MRI at 30 minutes after eating a standard breakfast was performed. Energy response ΔCBF was computed by subtracting the fasting CBF from the postprandial CBF obtained from ASL‐MRI. Whole brain grey matter voxel‐wise paired T test and linear regression analyses were used for statistical analysis. Result AD and MCI group had different energy response ΔCBF pattern with HC group. In AD group, energy intake induced a significantly decreased CBF in temporal lobe including lateral inferior and superior temporal gyrus, right superior temporal gyrus, parietal lobe including bilateral superior and inferior parietal lobe, postcentral gyrus and precuneus, most of occipital lobe and frontal lobe including right rolandic operculum, right precentral gyrus and left middle frontal gyrus. (q < 0.05, false discovery rate corrected). MCI had similar energy intake response pattern with AD. HC group had no significantly changed CBF response to energy intake. Energy response ΔCBF in the vicinity of the superior temporal gyrus showed significant negative correlation with Minimum Mental State Examination (MMSE) in all AD, MCI and HC groups. Conclusion The different energy response ΔCBF pattern may help to characterize the energy disorder in AD and may indicate the different brain energy rescue effect in the three groups. Energy response ΔCBF in the superior temporal gyrus is an indicator of cognitive function in AD.