| Objective To explore the relationship between changes in brain function and the cognitive level in essential hypertensive patients without significant cognitive impairment,the taskrelated BOLD-f MRI combined with N-back block design and independent component analysis were used to analyze the digital working memory activated brain regions and working memory network in patients with hypertension.Materials and methods24 right-handed with essential hypertension were selected,including 12 males and 12 females.In addition,23 healthy volunteers matched for gender,age and education level were recruited as the control group.The SIEMENS 3.0T Trio Tim magnetic resonance scanner was used to perform T2 WI,T2-FLAIR,sagittal T1WI-3D imaging and task-state BOLD-f MRI scans.Before magnetic resonance imaging,all subjects were collected for general data,blood pressure,blood biochemical tests,and neuropsychological tests.The collection of general data included: age,gender,education level,duration of hypertension,weight and height.The blood pressure was measured for three times,and the final results were obtained by using the mean value of three times.Biochemical tests included: Fasting plasma glucose,high density lipoprotein,low density lipoprotein,triglyceride,and total cholesterol.Neuropsychological cognitive tests included: Mini Mental Scale(MMSE),Trail Making Test A(TMTA),Digit Span Test(DST)and N-back block test.The magnetic resonance imaging data were pretreated with MATLAB 2012 software.SPM12 and GICA kits were used to analyze the working memory brain regions and working memory network,and the activation intensity values and functional connectivity values of different brain regions were extracted.Two independent samples T test was used to compare the clinical data of the patients,the neuropsychological cognitive test,the activation intensity values and functional connectivity values of different brain regions in the two groups.The Pearson's correlation analysis was used to analyze the correlation between the blood pressure level,the duration of disease and the results of neuropsychological test,and the correlation between the activation intensity values,functional connectivity values of different brain regions and the results of neuropsychological test,blood pressure level,the duration of disease.Results1.The results of general clinical data and neuropsychological test:(1)There was no significant difference between the two groups in age,sex,education,BMI,fasting plasma glucose,triglyceride,cholesterol,high density lipoprotein and low density lipoprotein.However,the systolic blood pressure,diastolic blood pressure,mean arterial pressure,pulse pressure difference and course of disease were statically different;(2)There was a significant difference in Mo CA score and 2-back reaction time between the two groups.The performance of hypertension group was slightly worse than that of normal control group.There were no significant differences in other neuropsychological outcomes.2.The results of digital working memory activated brain regions and working memory network:(1)The distribution of activated brain regions in the two groups was similar.Compared with the normal control group,the activation range was wider in the hypertension group.The activation intensity of left superior frontal gyrus and middle frontal gyrus were stronger,and there was no obvious reduced activation of the brain area.(2)The distribution of working memory network was similar in the two groups.Compared with the normal control group,the functional connectivity values of the left middle frontal gyrus and the precentral gyrus were decreased in hypertension group.3.The results of correlation analysis:(1)There was no significant difference between the correlation between the blood pressure,duration of disease and the Mo CA score,2-back reaction time in the two groups.(2)The activation intensity of left middle frontal gyrus was positively correlated with systolic blood pressure(r=0.56)and mean arterial pressure(r=0.50)in hypertension group,and was negatively correlated with 2-back reaction time(r=-0.59).The correlation was statistically significant.While the correlation between the activation intensity of left superior frontal gyrus in the two groups,the activation intensity value of left middle frontal gyrus in normal control group and the blood pressure,duration of disease,Mo CA score,2-back reaction time was not statistically significant.(3)There was no significant difference in the correlation between the functional connectivity values of the left middle frontal gyrus,the precentral gyrus and the blood pressure,course of disease,Mo CA score and 2-back reaction time in the two groups.Conclusions1.The BOLD-f MRI imaging in the task related can be used to detect the brain function in patients with hypertension before cognitive impairment.2.The emergence of compensation mechanism in essential hypertensive patients,working memory area and working memory network may alleviate the occurrence of cognitive impairment3.In patients with hypertension,an properly increase in systolic blood pressure and mean arterial pressure may be an important factor leading to the emergence of brain compensatory mechanisms. |
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