BOLD-fMRI Study Of Executive Dysfunction In Patients With Diarrhea Predominant Irritable Bowel Syndrome

Objective: To explore the impairment of executive function in patients with diarrhea irritable bowel syndrome(IBS-D)and its influencing factors,and to reveal the neural mechanism of impaired executive function in patients with irritable bowel syndrome(IBS-D),the study used a block-designed Bold-f MRI technique with task states of the Wisconsin Card Sorting Test(WCST),as well as neuropsychological and IBS symptom related scales.Methods: In this study,20 IBS-D patients(IBS group)and 20 healthy volunteers with normal intestinal function(HC group)matched with their gender,age and education years were included.Some scale was completed,include Montreal Cognitive Assessment Scale(MOCA),Hospital Anxiety and Depression Scale(HADS),Self-Rating Anxiety Scale(SAS)and Symptom Severity Scale of Irritable Bowel Syndrome(IBS-SSS),as well as block-designed WCST task.BOLD-f MRI images were processed by ANFI software to compare the differences in the activation of executive function brain regions between the two groups.The intensity of ROI activation was correlated with WCST error types,neuropsychological scale scores,and symptom severity.Results: There was no significant difference in gender,age and years of education between IBS group and HC group(P > 0.05).HAD-A and SAS scale indicated anxiety in IBS group and normal in HC group,and the difference was statistically significant(P < 0.05).The total error rate,detection error rate,persistent error rate and random error rate of IBS group in WCST were higher than those of HC group,and the difference was statistically significant(P < 0.05).The persistent error rate in the IBS group was positively correlated with HAD-D and IBS-SSS scores,and the random error rate was positively correlated with IBS-SSS scores.The results of Bold-f MRI showed that the executive function network in both groups included extensive bilateral frontal lobes,bilateral parietal lobes,temporal lobes,occipital lobes,insula lobes,basal ganglia region,thalamus and cerebellum.In the IBS group,the relative activation decreased mainly in bilateral the anterior prefrontal cortex(APFC),including the right premotor cortex,part of the inferior parietal lobule and the left superior temporal gyrus,while the relative activation increased in the IBS group including the the right superior frontal gyrus(DLPFC/VLPFC),parhippocampal gyrus and part of the left precuneus.The reduced activation of bilateral APFC was negatively correlated with HAD-A and IBS-SSS scores and persistent errors,and the difference was statistically significant(P < 0.05).Conclusion: IBS-D patients have impaired executive function,especially impaired cognitive flexibility,distraction and increased susceptibility to interference,which may be related to abnormal changes in functional activities of bilateral frontal lobes,right inferior parietal lobes,parhippocampal gyrus and left superior temporal gyrus,and precuneus.In IBS-D patients,functional activity in bilateral PFC brain regions was mainly reduced,especially in the APFC brain region,which was affected by the severity of IBS gastrointestinal symptoms.Functional abnormalities in the corresponding brain regions may be an important neural mechanism of impaired cognitive flexibility and anxiety symptoms in IBS-D patients.