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PurposeTo investigate spontaneous brain activity in patients with dry eye (DE) and healthy control (HC) using the fractional amplitude of low frequency fluctuation (fALFF) technique with the aim of elucidating the relationship between the clinical symptoms of DE and changes in brain function.Material and MethodsA total of 28 patients with DE and 28 matched healthy volunteers (10 males and 18 females in each group) were enrolled. Resting-state functional magnetic resonance imaging scans were performed in both groups. Then all subjects were required to complete a comprehensive Hospital Anxiety and Depression Scale (HADS). Receiver operating characteristic (ROC) curve analysis was used to evaluate the differences in fALFF values between the two groups and their diagnostic value. Linear correlations between HADS and fALFF values in different brain regions of DE patients were analyzed using the Pearson correlation coefficient.ResultsPatients with DE had significantly higher fALFF values in the left calcarine sulcus (CS) than the HC group, while fALFF values in the bilateral middle frontal gyrus (MFG) and right MFG/right inferior frontal gyrus (IFG) were significantly lower in DE patients than in HC group. fALFF values had a high diagnostic value for differentiating patients with DE from the HC group (P < 0.001). Right MFG and right MFG/IFG were significantly correlated with HADS values.ConclusionOur study found that DE mainly involved functional disorders in the brain areas of the left CS, bilateral MFG and right MFG/right IFG, which helped us to find possible clinical features of DE disease and reflected the potential pathological mechanism of DE.

Optic neuritis (ON) is a general term for inflammation of any part of the optic nerve resulting from demyelination or infection. The number of patients with MOG-lgG antibody-related optic neuritis is increasing recently. Our study uses the fractional amplitude of lowfrequency fluctuation (fALFF) method to compare the activity of specific brain regions in MOG-lgG ON patients and healthy controls (HCs). We selected a total of 21 MOG-lgG ON patients and 21 HCs were included in the study. All subjects underwent resting-state functional magnetic resonance imaging (rs-fMRI). The independent-samples t-test was used to compare demographic data and average fALFF values between groups. The specificity and sensitivity of fALFF values for distinguishing between MOG-lgG ON patients and HCs were evaluated by receiver operating characteristic (ROC) curve analysis. Pearson's correlation analysis was used to analyze the relationship between fALFF values and clinical characteristics in MOG-lgG ON patients. Our results showed that fALFF values of the right cerebellum and left middle cingulum were lower whereas those of bilateral inferior temporal lobes, right gyrus rectus, and the left superior and right middle frontal lobes of MOG-lgG ON patients were higher than those of HCs (P < 0.05). The average fALFF value of the left superior frontal lobe in MOG-lgG ON patients was positively correlated with Hospital Anxiety and Depression Scale score (HADS) (r = 0.6004; P < 0.05) and duration of MOG-lgG ON (r = 6487; P < 0.05). Thus, patients with MOG-lgG ON have abnormal activity in the brain regions related to vision. Changes in fALFF value can reflect functional sequelae of MOG-lgG ON, including abnormal anxiety or depressive emotional changes. [ABSTRACT FROM AUTHOR]