| Background and Objective:The arcuate fasciculus(AF)plays an important role in language function.cerebral infarction usually injury the AF,which usually results in language dysfunction.Therefore,to study the role of the AF in the process of language is helpful for the patients to recover the language function from aphasia.In our study,diffusion tensor imaging(DTI)and probabilistic tractography were used to observe the changes of AF at different stages after subcortical infarction,and to explore the mechanism of language structure recovery.Methods: We recruited patients with lesion load in the subcortical white matter from first-episode acute cerebral infarction,then divided them into aphasia group and non-aphasia group according to the results of Western Aphasia Battery(WAB)test.Two groups underwent assessment of language functional behavior and examine of diffusion tensor imaging(DTI)on 5±2 days(T1 session),30±7 days(T2 session)and 90±7 days(T3 session)after onset.We recruited healthy volunteers,matched with age and education background,and tested with diffusion tensor imaging and language function once.Language functional behavioral evaluation include the Chinese version of Western Aphasia Battery(WAB),spontaneous language frequency test(FT)and picture naming test(PNT).Language functional behavioral evaluation scores were analyzed by SPSS23.0 software,with ANOVA analysis of single factor repeated measurement within group comparison and two independent sample t-test between groups comparison.Diffusion tensor imaging data were preprocessed by FSL V5.0 software,using probabilistic tractography method to tracking the AF in healthy control group,aphasia group and non-aphasia group respectively,and calculated the fractional anisotropy(FA)of AF.SPSS23.0 software was used to analyze the FA values.In group analysis,ANOVA analysis of single factor repeated measurement was used,and two independent samples t-test was used between group analysis,and correlation analysis was done with language test results.P<0.05 indicates that the difference was statistically significant.Result: 1.There were 24 patients with left subcortical cerebral infarction(16 aphasia and 8 non-aphasia)were recruited,and 16 healthy subjects were recruited in healthy control group.There was no significant difference(p>0.05)between the the three groups in demographics,vascular risk factors and scores at T1 session.2.Non-aphasia group had significant difference in Aphasia Quotient(AQ),FT scores and PNT scores in T1 session,T2 session and T3 session with aphasia group(p<0.05).The delta values in AQ,FT scores and PNT scores from T1 session to T3 session were improved.There was no significant difference in the comparison of the score of AQ,SLFT scores and PNT scores between the healthy control group and the non-aphasia group(P>0.05).3.At T1,T2 and T3 session,probabilistic tractography results of aphasia group showed that the left AF was not integrity,whereas the right one was complete.The integrity of the left AF increased from T1 session to T3 session.In the non-aphasic group,the results of probabilistic tractography showed that the left AF was all intact,and so the right one.In the control group,probabilistic tractography showed that both the left and the right AF was complete.4.In the non-aphasia group and the aphasia group,the FA value of the left AF at T1 session is lower when compared with the healthy control group(P<0.0005),in which the aphasia group decreased more.And the FA value of the right AF of the non-aphasia group increased at T1 session(P=0.003),but no significant change of that in the aphasia group(P=0.145).The FA value of the left AF in the T2 and T3 session of the non-aphasic group was higher than that at T1 session(P=0.007),and there was no significant difference when compared with that of the healthy control group((P=0.066?P=0.06).The FA value of the right AF at T2 and T3 session was higher than that of its T1 session(P<0.0005),and there was a significant difference compared with that of the healthy control group(P<0.0005).In the aphasia group,the FA value of the left AF at T2 and T3 session was higher than that at T1 stage,but less than that in the healthy control group and the non-aphasia group(P<0.0005);the FA value of the right AF at T2 and T3 session was higher than that at T1 session(P<0.0005),and was significantly different from that in the healthy control group(P<0.0005).The FA value of the right AF in the aphasia group was lower in the same stage of the non-aphasia group(P<0.0005).5.In the aphasic group,there was correlation between delta values of AQ,FT scores,PNT scores and the change of the FA value of the left AF,and there was correlation between delta values of AQ,FT scores,PNT scores and the change of the FA value of the right AF.Conclusion: 1.The incomplete structure of AF is related to language dysfunction after left subcortical infarction.The right AF may participate in language functional compensatory.2.After subcortical cerebral infarction,the recovery of language function in the subacute phase of aphasia related to the repair of the left damaged AF and the right one compensation,suggesting that the right cerebral hemisphere plays an important role in the recovery of language function.3.Functional lateralization exists in normal human white matter network.In the subacute and chronic phases of the left subcortical infarction,the AF of the right hemisphere was dominant. |
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