Volume Changes Of Regional Grey Matter And The Effects On Subcognitive Domains In Patients With Amnestic Mild Cognitive Impairment

BackgroundAlzheimer's disease(AD)is an age-dependent,progressive dementia syndrome characterized by cognitive neurodegeneration.Mild cognitive impairment(MCI)is featured by complaint of objective cognitive decline or subjective cognitive deterioration based on neuropsychological testing without social or basic instrumental impairments.MCI can be divided into amnestic and non-amnestic subtypes in clinical.Amnestic mild cognitive impairment(aMCI)presents a stronger tendency to develop into AD-type dementia compared to the non-amnestic subtype.Therefore,early detection and intervention on aMCI could effectively delay and even prevent the onset of dementia.Currently the structural magnetic resonance imaging(MRI)can provide aMCI-related atrophic markers,which assists for the early detection.ObjectiveThe cross-sectional research aims to combine the comprehensive cognitive tests and structural MRI to extract regional brain volumes based on voxel-based morphometry,and explore the contributions of regional atrophy to cognitive function in patients with aMCI,through the comparison of grey matter volumes between normal controls and patients with aMCI,and the association analysis between grey matter volumes and subcognitive domains.MethodsWe collected the neuropsychological data of community-dwellings aged from 65 to 80 through the cross-sectional survey in Yanlou Town,Yanggu County,Liaocheng City,Shandong Province in the phases of August and December,2014.We diagnosed for the cognitive status using the cognitive examinations and select some villagers for MRI scans in random,including 77 patients with aMCI and 116 normal controls.We measured the absolute volumes of grey matter(GM)of brain regions using CAT12.We compared the volumes of bilateral hippocampus,posterior cingulate gyri,thalamus,frontal lobes and total intracranial volumes in two groups using the general linear regression.We analyzed the influence of regional grey matter volumes on testing results of subcognitive domains,including Fuld object-memory Evaluation(FOM),Forward Digit Span and Backward Digit Span(FDS and BDS),Rey Auditory Verbal Learning Test(AVLT).ResultPatients with aMCI showed greater atrophy of bilateral hippocampal GM compared to normal controls.The FOM result improved significantly with the increase of the GM volume of the right hippocampus.The CVF result improved significantly with the increase of the GM volume of the right posterior cingulate gyrus and the right thalamus.The CVF result decreased marginally with the increase of GM volumes of the right hippocampus and the left posterior gyrus(p=0.043,0.048).Similarly,the AVLT-delay result decreased marginally with the increase of GM volumes of the left hippocampus(p=0.042).ConclusionsCompared to the normal control,patients with aMCI showed significant atrophy on bilateral hippocampus.The increased volume of the right hippocampus correlated to the FOM evaluation.The increased volumes of the right posterior cingulate gyrus and the right thalamus presented evident association to the CVF evaluation.