| ObjectiveTo investigate the alterations of spontaneous brain activity in diabetic retinopathy by the method of amplitude of low-frequency fluctuations(ALFF)on subbands and to explore its correlation with cognitive function and clinical indications.Materials and Methods(1)In this study,14 T2 DM patients with retinopathy(DR group,8 males,6females),16 non-diabetic retinopathy(NDR group,8 males,8 females),and 17 healthy controls(HC group,8 males,9 females)were recruited in Fuzhou General Hospital from December 2016 to December 2017.All the subjects' clinical data,and results of cognitive neuropsychological tests,including Mini-Mental State Examination,Montreal cognitive assessment,Trail-Making Test Part A and Wechsler Memory Scale were obtained.(2)Brain imaging was performed on a 3.0T commercial scanner(Siemens Magnetom Skyra).Three-dimensional T1-weighted images and the Resting state BOLD-fMRI data were obtained.Then ALFF values on slow-5(0.01-0.027Hz)and slow-4(0.027-0.073Hz)were calculated using DPARSF.The main effects of group and frequency band in ALFF and interaction between groups and frequency band were analyzed with Spm12 and dpabi.Spm12 software was then used to perform post-hoc multiple comparisons of brain regions with significant main effects,and post-event simple effects analysis with significant brain regions for interaction effects.The results were presented with REST software.Results(1)Clinical data comparison.No significant differences were observed in gender,age,education level,BMI,diastolic blood pressure,cholesterol,triglyceride,lowdensity lipoprotein,high density lipoprotein,fasting insulin and C peptide concentration among the three groups(P > 0.05).There was no significant difference in disease duration between DR group and NDR group(P > 0.05).Significant difference were observed in systolic blood pressure,fasting blood glucose,glycosylated hemoglobin,the scores of MoCA,MMSE,visual recognition,image memory,visual reproduction,tactile memory and TMT-A among the three groups(P <0.05).(2)Main effect of the frequency band factor.Compared with the slow-5 band,the slow-4 band exhibited significantly lower ALFF in the left orbitofrontal superior frontal gyrus.(3)Main effect of the group factor.Compared with the NDR patients,the DR patients showed significantly lower ALFF in the bilateral superior temporal gyrus,left cerebellum 4-5.While higher ALFF was shown in the bilateral rectus,bilateral superior orbitofrontal gyrus and right middle frontal gyrus in the DR group.There was no significant difference between the DR patients and the healthy controls.Compared with the healthy controls,the NDR patients showed significantly lower ALFF in the right middle temporal gyrus,bilateral rectus,bilateral superior orbitofrontal gyrus,and bilateral middle orbitofrontal gyrus,with higher ALFF in the left cerebellum crust 1,left caudate,right inferior parietal cortex.(4)Interaction effects between the group and frequency band.We observed significant group and frequency interaction effects on ALFF in the left middle temporal gyrus,left inferior temporal gyrus,bilateral cerebellum crus 1,left fusiform gyrus,left inferior orbitofrontal gyrus,bilateral anterior cingulate gyrus,left cuneus and left medial prefrontal gyrus.Furthermore,a post-hoc t test revealed that ALFF significantly increased in the left fusiform,left inferior temporal gyrus and anterior cingulate in the slow-4 band in the DR patients but did not significantly change in the slow-5 band when compared with the NDR patients.ALFF significantly decreased in the left middle temporal gyrus,left inferior orbitofrontal gyrus in the slow-4 band but significantly decreased in the bilateral cerebellum crus 1 and left ceneus in the slow-5in the DR patients when compared with the healthy controls.ALFF significantly decreased in the left fusiform,left inferior temporal gyrus and anterior cingulate in the slow-4 band in the NDR patients but did not significantly change in the slow-5 band when compared with the healthy controls.Conclusion(1)The present study observed changes of spontaneous brain activity mainly in the visual network,the default network,working memory networks in patients with diabetic retinopathy by the amplitude of low-frequency fluctuations on subbands.(2)It also found that the different abnormal activity brain regions with different degrees of diabetes showed different spatial distribution characteristics in different subbands.Different neuronal activities were regulated by frequency.(3)These results indicated that the spontaneous activity of the brain in patients with different degrees of diabetes showed frequency dependency.It can provide a new perspective to further explore the physiological mechanism of cognitive impairment in patients with DR.It suggests that it is significant for the prevention and delay of the decline of the cognitive level and the development of retinopathy by controlling blood sugar and blood fat. |
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