Resting State Amplitude Of Low-frequency Fluctuation Alterations Of Mild Cognitive Impairment In Patients With Multiple System Atrophy

Purpose:Multiple system atrophy(MSA)is a sporadic,adult-onset and progressive neurodegenerative disease,which we have no effective treatment for.Therefore,it is always considered as a malignant Parkinson’s disease.Its clinical symptoms mainly include motor and non-motor dysfunctions.Among them,cognitive impairment is widespread in MSA patients,which seriously affects the quality of life of patients and increases the burden on their families and the society.However,the mechanism of cognitive impairment in MSA patients remains unclear,and there is no effective imaging index for the early detection.Resting state functional magnetic resonance imaging(rs-fMRI)is an important part of multi-mode MRI,which has been widely used in studies of mental and neurological diseases.Among the indexes,the low frequency amplitude(ALFF)can reflect functional activity of brain regions,which also has a good stability and repeatability.In this study,we used ALFF approach to investigate cognitive-related changes of spontaneous brain activity in MSA patients and to explore its possible mechanism.Materials and Methods:62 MSA patients were collected from Parkinson’s Department of Neurology in the first affiliated Hospital of China Medical University from June 2017 to February 2019.They were divided into 29 MSA patients with normal cognitive function(MSA-NC)and 33 MSA patients with mild cognitive impairment(MSA-MCI)according to scores of Montreal Cognitive Assessment scale(MoCA)and Mini-Mental State scale(MMSE).33 healthy controls(HC)matched with sex,age and education were collected as well.The subjects received rs-fMRI,and changes of spontaneous brain activity were compared between subgroups using ALFF approach.Spearmann correlation test was taken between patients’ alff values of changed brain regions and MoCA scores.Results:Compared to HC,MSA-NC showed increased ALFF in left angular gyrus and right middle temporal gyrus(MTG).MSA-MCI showed decreased ALFF in bilateral ventral prefrontal cortex(VLPFC),dorsolateral prefrontal cortex(DLPFC),anterior and middle cingulum cortex(ACC,MCC)compared to HC,while it showed increased ALFF in bilateral inferior temporal gyrus(ITG),angular gyrus,left middle occipital gyrus,right middle temporal gyrus(MTG),precuneus,right cerebellum and vermis in the same comparison.Compared to MSA-NC,MSA-MCI showed decreased ALFF in right frontal lobe and increased ALFF in right cerebellum.In addition,MSA patients’ alff values in right frontal lobe were positively correlated with MoCA scores(r=0.531,P<0.05),while the correlation was negative in the right cerebellum(r=-0.449,P<0.05).Conclusion:Functional damages in frontal lobe and cerebellum are associated with MSA specific mild cognitive impairment,and the cerebellum may play a compensatory role.