Study On Working Memory And Event-related Potentials Of Contralateral Delayed Activity In Patients With First-episode Schizophrenia

Objective:This study is based on the working memory and event related potentials in patients with first-episode schizophrenia,to explore the electrophysiological changes of working memory impairment and decreased working memory capacity,and to analyze the relationship between working memory indexes,electrophysiological indexes and clinical symptoms,which provides an objective and reliable basis for the evaluation of working memory,working memory capacity and clinical symptoms by event-related potentials.Methods:We selected 32 first-episode schizophrenia patients from the Second Affiliated Hospital of Jining Medical University since June 2018 to October 2019 as the research group,and 33 healthy volunteers was enrolled as the control group.The general demographic data of all subjects were collected,including gender,age,years of education and occupation level.The working memory was evaluated by Digital Sequence test and Spatial Span test in the Chinese version of MATRICS Consensus Cognitive Battery?MCCB?.The Positive and Negative Symptom Scales?PANSS?was used to assess the severity of psychiatric symptoms in the study group.All subjects induced contralateral delay activity?CDA?by change detection task,and recorded behavioral and EEG data during the experiment.We choose PO_3/4?PO_5/6?PO_7/8as research electrodes to compare the CDA amplitude.According to the size of K score,the two groups were divided into high and low capacity groups for intra-group and inter-group comparison.SPSS 17.0 software was used to process the data statistically.Independent sample t test was used to compare the general demographic data,working memory,CDA amplitude,reaction time and so on.Chi-square test was used to compare the accuracy rate.Pearson linear correlation analysis was used to analyze the correlation among CDA amplitude,working memory capacity,general demographic data and severity of disease.Results:1.The Results of working memory shows that the scores of the first-episode schizophrenic group in Spatial Span test?t=-7.077,P=0.000?and Digital Span test?t=-6.519,P=0.000?were lower than those of the control group.2.Behavioral results showed the accuracy rates of the first-episode schizophrenia group at low load?x²=54.139,P=0.024?and high load?x²=57.063,P=0.000?were lower than those in the control group.There was no significant difference in reaction time between the two groups in low load?t=0.629,P=0.530?and high load?t=-1.554,P=0.125?.3.The amplitudes of CDA in first-episode schizophrenia group were higher than the normal group at high load?t=0.025,P=0.048?,the amplitude difference at low load between the two groups were not statistically significant?t=0.382,P=0.704?.The difference of amplitude between the high and low capacity groups in the first-episode schizophrenia group at low memory load was statistically significant?t=-2.307,P=0.028?,while there was no statistical difference at high memory load?t=-1.239,P=0.227?.There was no statistical difference between the high and low capacity groups of the control group at low memory load?t=-0.521,P=0.607?,but there was significant difference at high memory load?t=1.735,P=0.037?.After matching the working memory capacity between the first-episode schizophrenic group and the control group,the amplitude differences between the two groups were statistically significant under the conditions of low?t=-2.276,P=0.032?and high memory load?t=-2.154,P=0.045?.4.In the first-episode schizophrenia group,the Digital Span test results was positively correlated with the year of education?r=0.438,P=0.012?,working memory capacity of high memory load?r=0.328,P=0.047?,the accuracy rate?r=0.445,P=0.011?and the working memory capacity?r=0.403,P=0.022?at low memory load,and negatively with the course of the disease?r=0.529,P=0.020?and scores of negative symptoms scale?r=0.392,P=0.027?.The Spatial Span test was positively correlated with the years of education?r=0.376,P=0.034?,and working memory capacity at high memory load?r=0.340,P=0.048?,the accuracy rate?r=0.378,P=0.032?,working memory capacity?r=0.368,P=0.038?at low memory load,and negatively correlated with disease course?r=-0.423,P=0.016?.At low memory load,CDA amplitude was positively correlated with accuracy rate?r=0.494,P=0.004?,working memory capacity?r=0.488,P=0.005?,and the positive scale scores?r=0.146,P=0.030?,while was negatively correlated with the negative scale?r=-0.470,P=0.027?.At high memory load,CDA amplitude was positively correlated with scores of Digital Span test?r=0.584,P=0.000?and Spatial Span test?r=0.382,P=0.031?,working memory capacity?r=0.445,P=0.011?.But it has a negatively correlation with negative scale scores?r=-0.285,P=0.043?.Conclusion:1.Patients with first-episode of schizophrenia have working memory impairment,and the ability of visual working memory decreased significantly.2.The working memory capacity of first-episode schizophrenia patients is decreased,and the ability of information encoding and retention are damaged.3.If patients with first-episode schizophrenia has the higher level of education,the shorter of the disease'courses,then the accuracy rate of the experiment and working memory capacity performed better.The more severe the negative symptom was,the smaller the CDA amplitude and memory capacity would be.