The Study On Functional Connectivity Of Brain After Post-stroke Aphasia Based On Resting-state Functional Magnetic Resonance Imaging

Objective: Post-stroke aphasia(PSA)is language disturbance caused by cerebrovascular disease.Currently,the functional changes in brain during PSA recovery are still being explored.Previous studies have mostly focused on exploring the functional changes in brain during the subacute or chronic phase of PSA,with little research on the functional changes in brain during the acute phase.The changes of functional connectivity in the brain regions in the acute phase of post-stroke aphasia(PSA)are not well characterized.In this study,we applied dynamic functional connectivity density(d FCD)to investigate the abnormal temporal variability of the functional connectivity in brain in acute PSA,and further explore its potential correlation with clinical severity.Methods: We collected resting-state functional magnetic resonance imaging data from 32 patients with PSA and 32 age-,gender-,and education-matched healthy controls(HCs).The d FCD was assessed by the sliding window method,and the k-means clustering method was applied to identify d FCD states.The two-sample t test was used for between-group comparisons of state metrics and the differences of d FCD value under the same state.What’s more,we also applied the non-parametric Mann Whitney U test to compare the differences in state attributes between the two groups.Spearman’s correlation analysis was used to assess the relationship between d FCD value and the severity of aphasia.Results:(1)In PSA,there were reduced d FCD value in multiple languages and cognitive-related brain regions,whereas increased d FCD value was observed in the right cerebellum;(2)Patients with PSA had abnormal functional connectivity than HCs in the default mode network,left fronto-temporo-paritetal language network and cerebellar network;(3)Two d FCD states were identified by k-means clustering method,and patients with PSA spent more time on state 1.The number of transitions between the two d FCD states was higher in the PSA group;(4)The d FCD value in the left superior temporal gyrus showed positive correlation with the Auditory Comprehension Score(rs=0.387,P=0.029).Conclusions: The results of this study provide valuable insights into brain dysfunction that occurs during the acute phase of PSA.In this study,we found reduced d FCD values in multiple brain networks during the acute phase of post stroke aphasia,and it owing to the disruption of the integration of the brain network.What’s more,we also found increased d FCD values in cerebellar network.Combining previous researches,we believe that this phenomenon may be related to the spontaneous functional recovery of language and the cerebellum plays an important role in language.