A Study Of FMRI On The Neural Mechanism Of Cognitive Function In First-episode Patients With Schizophrenia Using Fractional Amplitude Of Low-frequency Fluctuation

BACKGROUND: Cognitive dysfunction is an important primary pathological manifestation of schizophrenia,but the pathophysiological mechanism of cognitive dysfunction in schizophrenia remains unclear.This research performed the fractional amplitude of low-frequency fluctuation(fALFF)analysis method in resting-state functional magnetic resonance imaging(fMRI)to study the local abnormal spontaneous brain activity in resting state of patients with schizophrenia and the correlation between the fALFF value of abnormal brain regions and the scores of various cognitive functions,to explore the underlying neurobiological mechanisms of cognitive dysfunction in schizophrenia.METHODS: 57 first-episode patients with schizophrenia(FES)and 50 healthy controls matched by gender and age were enrolled.Resting-state f MRI data and cognitive test data were collected from all subjects.The FES group was given a Positive And Negative Syndrome Scale score to assess the severity of their psychopathological symptoms.In addition,the correlation between the f ALFF value of abnormal brain regions in the FES group and the scores of various cognitive functions of Measurement and Treatment Research to Improve Cognition in Schizophrenia(MATRICS)consensus cognitive battery was analyzed.Finally,the f ALFF value of abnormal brain regions was used as parameters to distinguish patients with schizophrenia from healthy controls using support vector machines.RESULTS: Compared with the healthy control group,the FES group had lower scores on various cognitive tests,including the Trail Making Test-A,Brief Assessment of Cognition in Schizophrenia: Symbol Coding,Category Fluency:Animal Naming,Continuous Performance Test-Identical Pair,Maze Test,Brief Visuospatial Memory Test-Revised and Hopkins Verbal Learning Test-Revised,with statistically significant differences.In the fMRI study,it was found that the f ALFF value decreased in several brain regions in the FES group,including bilateral precuneus,left precentral gyrus/postcentral gyrus,right central posterior gyrus,left postcentral gyrus/superior parietal lobule,bilateral paracentral lobule and bilateral supplementary motor area.Partial correlation analysis showed that the fALFF value of bilateral precuneus was positively correlated with Animal Naming test score(r=0.298,P=0.032)in the FES group,whereas the fALFF value of the other brain regions was not significantly correlated with various cognitive functions.The best classification results were obtained by support vector machine classification with the combination of fALFF values of bilateral paracardial lobules and right central posterior gyrus as parameters,with an accuracy of 98.13%,sensitivity of 98.25% and specificity of 98.00%.CONCLUSIONS: Compared with the healthy control group,FES had extensive cognitive dysfunction and abnormal spontaneous activity in local brain regions,and the abnormal spontaneous activity in bilateral precuneus was related to the performance of information processing speed.The study of support vector machine classification with fALFF as the input characteristic provided a scientific basis for exploring the pathophysiological mechanism of cognitive dysfunction in schizophrenia and clinical auxiliary diagnosis.