A Resting-state FMRI Study On Constant Exotropia

BackgroundThe pathological mechanisms of constant exotropia(XT)is still not fullyunderstood.The purpose of this study is to investigate whether XT-positive patients express brain's neuronal activities changes prior to the critical period of visual development,and furtherly explore how these likely alterations relate with behavioral performance.MethodsFourteen patients with XT and sixteen healthy controls(HCs)underwent resting-state functional magnetic resonance imaging(f MRI)scans.The Regional Homogeneity(Re Ho)method was used to evaluate spontaneous brain activities.The Pearson's correlation analysis assessed the association between the resulting mean Re Ho values of altered regions and behavioral performance.ResultsCompared with HCs,the right secondary visual cortex(V2)of the XT-positive individuals exhibited increased Re Ho values whereas the left Brodmann Area 47(BA47)demonstrated decreased spontaneous Re Ho measures.In the participating XT-patients,the mean Re Ho values of the left BA47 and the duration of strabismus were significantly positively correlated.ConclusionsThese findings indicate that XT-positive patients severely suffer from neural dysfunction in the right V2 and the left BA47,and the progression of severity in the left BA47 is likely influenced by duration of ongoing strabismus within the patients.These results,therefore,may provide clinically important information towards understanding the underlying pathological mechanisms of the XT,and thus can be fundamental in pursuing more XT researches.