The Comparison Of PerAF,ALFF And FALFF In Resting-state FMRI Of First-episode Schizophrenia

ObjectiveOur aim was to explore the differences of three resting-state f MRI metric,including percent amplitude of fluctuation(Per AF),amplitude of low frequency fluctuations(ALFF)and fractional amplitude of low frequency fluctuations(f ALFF)in revealing schizophrenia-associated brain dysfunction and the differences in clinical significance of the application of these metric.MethodsA total of 28 patients with first-episode schizophrenia and 33 healthy controls underwent resting-state f MRI.Per AF,ALFF and f ALFF metric were applied to explore the brain dysfunction of patients.The positive and negative syndrome scale(PANSS)was used to evaluate the clinical symptoms of patients with first-episode schizophrenia.The repeatable battery for the assessment of neuropsychological status(RBANS)was used to evaluate the neurocognitive performances and the visual search tasks including happy and fearful facial emotions were used to evaluate the facial emotion recognition ability(also refer to as social cognitive function)of all participants.Per AF,ALFF and f ALFF value of aberrant brain regions were extracted for further correlation analysis with the impaired neurocognitive performances,impaired facial emotion recognition ability and clinical symptoms.At last,the differences between three resting-state f MRI metric in reflecting brain dysfunction and showing clinical value of aberrant brain regions were compared.Results(1)All Per AF,ALFF and f ALFF metric showed widespread brain dysfunction in patients with first-episode schizophrenia,which mainly distributed among the frontal,parietal and occipital lobes.Compared with healthy control,schizophrenia showed increased signal value of three resting-state f MRI metric in right middle frontal gyrus,while decreased signal value in bilateral postcentral gyrus,bilateral precentral gyrus,bilateral calcarine,left paracentral lobule,left lingual gyrus and right supplementary motor area(p < 0.05,Alpha Sim correction).However,1)the differences between aberrant brain regions between schizophrenia and healthy control were more significant in f ALFF metric than Per AF and ALFF metric;in addition,2)except frontal,parietal and occipital lobes,f ALFF metric also showed aberrant brain regions in temporal lobes,included superior temporal gyrus and middle temporal gyrus,but Per AF and ALFF metric showed aberrant brain regions in marginal lobes which included posterior cingulate gyrus.(2)All Per AF,ALFF and f ALFF metric showed the clinical value of neuropathological changes in aberrant brain regions of patients with first-episode schizophrenia.In other words,the neuropathological changes(i.e.,Per AF,ALFF and f ALFF value)in aberrant brain region were correlated with the impaired neurocognitive performances,impaired facial emotion recognition ability and clinical symptoms.The correlation between right middle frontal gyrus and delayed memory scores as well as the correlation between right precentral gyrus and the accuracy of happy emotion recognition were simultaneously showed in Per AF,ALFF and f ALFF metric(|r| > 0.4,p < 0.05).However,1)in the correlation analysis with impaired neurocognitive performances,f ALFF value in aberrant brain regions was correlated with four neurocognitive performances included immediate memory,speech function,attention and delayed memory scores,Per AF value was correlated with two neurocognitive performances included delayed memory and speech function scores,while ALFF value was only correlated with delayed memory scores(|r| > 0.4,p <0.05);2)in the correlation analysis with impaired facial emotion recognition ability,Per AF,ALFF and f ALFF metric showed different brain regions were correlated with the accuracy of happy emotion recognition(|r| > 0.4,p < 0.05);3)in the correlation analysis with clinical symptoms,only f ALFF metric showed the correlation between right medial superior frontal gyrus and negative symptoms,while Per AF and ALFF metric was not correlated with clinical symptoms(|r| > 0.4,p < 0.05).(3)Compared with healthy control,the neurocognitive performances(including immediate memory,visual span,speech function,attention and delayed memory)of patients with first-episode schizophrenia were totally impaired(p < 0.05).In addition,the accuracy,but not reaction time,of facial emotion recognition(including happy and fearful emotion)in schizophrenia was impaired compared with healthy controls(p< 0.05).In the comparison of happy and fearful emotion,the accuracy of fearful emotion recognition was damaged more severely(p < 0.05).Conclusions(1)All the three resting-state analyses are effective in detecting schizophrenia-associated brain dysfunction.However,the group differences in f ALFF analyses of the aberrant regions are more significant than Per AF and ALFF analyses.The f ALFF metric may be more sensitive to detect neuronal activity,which may provide important guidance for optimization of resting-state f MRI metric in neuroimaging markers research of schizophrenia.(2)All the three resting-state analyses showed multiple association with cognitive deficits and clinical symptoms in patients with schizophrenia.However,intrinsic BOLD fluctuations of brain regions in f ALFF metric was simultaneously correlated with multiple neurocognitive impairments and clinical negative symptoms,which indicates f ALFF metric may be better than Per AF and ALFF metric in showing neuromechanism of cognitive deficits and clinical symptoms in schizophrenia.