Correlation Between Cognitive Impairment And Brain Structure In MRI In The Patients With Alzheimer’s Disease

Objective: To study the correlation between the cognitive scale score of Alzheimer’s disease patients and the structural diameter parameters of brain MRI,and to explore the correlation between the injury of different cognitive domains and the changes of different brain regions,so as to provide a more convenient and reliable basis and evaluation method for clinical diagnosis and disease assessment.Methods: Collected clinically diagnosed patients with Alzheimer’s disease with amnestic as the main manifestation(AD group)and patients with mild cognitive impairment with amnestic as the main manifestation(MCI group)as the experimental group,and recorded their clinical data comprehensively,including their ages,genders,education degrees,etc.Completed the assessment of neuropsychological cognitive function scales,including MMSE,Digit Span Test(Forward/Backward),Trail Making Test A/B,Immediate Memory Test,Recall Test,Cued Recall Test and Long-Delayed Recall Test,and complete the brain and hippocampal MRI examination.The normal control group(NC group)also performed the above-mentioned neuropsychological cognitive function scale assessments and imaging examination.Measured the structural MRI of the brain of the study subjects: bilateral transverse and height diameter of hippocampus,width of third ventricle,maximum diameter of forehead horn,the width of the brain where the maximum forehead horn diameter lies,maximum diameter of caudate nucleus,the width of the brain where the maximum caudate nucleus diameter lies and the maximum cerebral width,and then,calculated forehead horn diameter ratio,caudate nucleus diameter ratio,Huckman value and EVANS index.Analysis of Variance was performed on the cognitive function scores and related parameters of linear measurement of brain MRI of the three groups of study subjects,and compared whether there were statistical differences in the cognitive function scores and structural diameter parameters of brain MRI between the three groups.Spearman Correlation Analysis was used to determine whether there was a correlation between the scores of cognitive function scales and structural diameter parameters of brain MRI.All of the above statistical analyses were performed by SPSS Statistics22.0.Results: There was no significant difference in the general situation(age,gender composition,education level)among the three groups(P>0.05).In the comparison of the scores of neuropsychological cognitive function scales,there was significant difference between the three groups in the scores of MMSE,Digit Span Test(Backward),Trail Making Test B,Immediate Memory Test,Recall Test,Cued Recall Test and Long-Delayed Recall Test(P<0.05).Compared with MCI group,MMSE,Immediate Memory Test,Recall Test,in AD group were significantly lower than those in MCI group(P < 0.05).Compared with NC group,the scores of other cognitive function scales in AD group and MCI group were lower than those in NC group except for Digit Span Test(Forward),Trail Making Test A(P < 0.05).In the comparison of structural diameter parameters of brain MRI,there was significant difference among the three groups in bilateral transverse and height diameter of hippocampus,width of third ventricle,forehead horn diameter ratio,nucleus diameter ratio,Huckman value and EVANS index(P<0.05).In the comparison between AD group and NC group,bilateral transverse and height diameter of hippocampus of AD group were lower than that of NC group,in which the decrease of transverse was more obvious than that of height,and the width of third ventricle,forehead horn diameter ratio,nucleus diameter ratio,Huckman value and EVANS index were significantly higher than those of NC group(P<0.05).Compared with the MCI group,there was significant difference only in the width of third ventricle(AD group was slightly higher than MCI group)and bilateral transverse diameter of hippocampus(AD group was lower than MCI group)(P<0.05),while in the comparison between MCI group and NC group,bilateral transverse diameter of hippocampus of MCI group was lower than that of NC group,and the width of third ventricle,forehead horn diameter ratio,nucleus diameter ratio,Huckman value and EVANS index of the MCI group were higher than those of the normal group.The difference was statistically significant(P < 0.05).Compared with the width of the brain where the maximum forehead horn diameter lies and the maximum cerebral width,there was significant difference in the width of the brain where the maximum caudate nucleus diameter lies among the three groups.AD group and MCI group were significantly lower than NC group(P<0.05),but there was no significant difference between AD group and MCI group(P<0.05).The score of memory-related scale(immediate memory,delayed recall,cued recall and long-delayed recall)was positively correlated with bilateral transverse and height diameter of hippocampus,and negatively correlated with ventricular-related measurement parameters(width of third ventricle,forehead horn diameter ratio,nucleus diameter ratio,Huckman value and EVANS index)(P<0.05).The score of Digit Span Test(Backward)and the accuracy of Trail Making Test B was positively correlated with bilateral transverse diameter of hippocampus(P<0.05),but there was no significant correlation with bilateral height diameter of hippocampus.The score of Digit Span Test(Backward)and the accuracy of Trail Making Test B was negatively correlated with the width of third ventricle,and nucleus diameter ratio(P<0.05).The accuracy of Trail Making Test B was negatively correlated with EVANS index.However,there was no correlation between the structural diameter parameters of brain MRI and the score of Digit Span Test(Forward)with the accuracy of Trail Making Test A.Conclusion:1.Episodic memory is impaired earlier than other types of memory in AD.The Cued Recall Test or Long-Delayed Recall Test are helpful to identify patients in the early process of AD.Digit Span Test(Backward)and the accuracy of Trail Making Test B are more helpful to identify attention and executive function impairment in patients in the early process of AD.2.In the process of AD,the functional impairment lagged behind the structural change.3.The executive ability and attention impairment during the progression of AD may be related to atrophy of thalamus and caudate nucleus.4.Where the maximum caudate nucleus diameter lies can reflect the overall atrophy of the surface of the cerebral cortex or brain tissue...