| Background:Delusional misidentification syndromes（DMS）is a psychiatric disorder in which the patient believes that his or her identity has changed.Failure to identify correctly can affect the patient’s normal life and reduce the quality of life.However,its low prevalence and frequent misdiagnosis as schizophrenia make it difficult to conduct scientific studies due to the lack of subjects.Previous studies have suggested that the emergence of delusional symptoms may be due to disruptions in autobiographical memory and self-linkage,but current research has only explored the behavioral domain and has not provided neurophysiological evidence.Methods:In this study,hypnosis was used as an instrument to screen 34 subjects with high hypnotic perception as the experimental group and 30 with low hypnotic perception as the control group.All subjects were required to report 15 negative autobiographical memories and 15 positive autobiographical memories before the experiment and to fill in the relevant scales.All subjects received a direct hypnotic suggestion of identity shift during the formal experiment.The autobiographical memory revisiting task was completed under hypnosis and EEG data were recorded simultaneously.Results:At the behavioral level,there was no significant difference between the two groups in hypnosis degree（t=1.463,p=0.15）and sense of identity transformation（t=1.74,p=0.09）,but there was significant difference between the two groups in belief of identity transformation（t=2.61,p=0.01）.When the identity conversion rate was analyzed,the difference of stimulus type(F（1,63）=0.88,p=0.77)and intergroup×stimulus type(F（1,63）=0.32,p=0.57)was not significant.The inclusion of gender as a covariable in the analysis revealed a significant intergroup effect p=0.03.For the analysis of recall accuracy,there was no significant difference between positive and negative memory accuracy（p=0.883）,but there was significant difference between emotional memory and neutral stimulus（p<0.05）.There were significant differences among the three types of stimulation in the control group（p<0.05）.For P200 analysis,group(F（1,60）=11.40,p<0.001),and brain(F（2,60）=7.94,p<0.001)have the significant main effect,but the main effect of stimulus type was not significant(F（2,60）=0.04,p=0.97).In addition,under the three stimulus conditions,the amplitude of the midline region in the experimental group was greater than the left and right hemispheres（p<0.001）,but there was no significant difference between the left and right hemispheres（p>0.05）.When the subjects in control group watched negative and neutral stimulus materials,the right hemisphere had an advantage compared with the center line and left hemisphere（p<0.05）,while the left hemisphere and the center line had no significant difference（p>0.05）.In the control group,the amplitude of the median line was greater than that of the left and right hemispheres（p>0.05）,but there was no difference between the left and right hemispheres（p=0.20）.By analyzing frontal lobe LPP,both positive and negative memories evoked larger amplitudes than neutral stimuli（p<0.001）,but there was no significant difference between emotional memories p=0.62.Experimentally induced LPP waves were larger（p<0.001）.The amplitude of LPP induced by the right hemisphere was（p<0.05）in the left hemisphere and midline region.However,there was no significant difference between the midline region and the left hemisphere（p=0.52）.In addition,no interaction was found between group×electrode point(F（2,60）=0.06,p=0.94),electrode point×stimulus type(F（4,60）=0.74,p=0.57)and group×electrode×stimulus type(F（4,60）=1.28,p=0.29).The analysis of the parietal LPP showed that the main effect was significant(F（1,60）=12.67,p<0.001),the main effect was significant(F（2,60）=11.25,p<0.001),the main effect was significant(F（2,60）=3.39,p<0.001),the main effect was significant(F（2,60）=3.39,p<0.001),Group×electrode(F（2,60）=2.51,p=0.09),group×electrode×stimulation type(F（4,60）=1.08,p=0.38)interactions were not significant.However,there was significant difference between neutral and negative stimuli（p=0.05）,between neutral and positive stimuli（p=0.12）and between emotional stimuli（p=0.99）.In the control group,there was no significant difference between neutral and positive stimuli（p=0.87）,and significant difference between negative stimuli and the other two types of stimuli（p<0.001）.On O1 electrode,the amplitude induced by positive memory was greater than that of neutral and negative stimuli（p<0.05）,and the amplitude induced by negative memory was greater than that of neutral stimuli（p=0.005）.At Pz and O2electrodes,the amplitude of LPP induced by positive memory was higher than that induced by neutral stimulus（p<0.05）,but there was no significant difference between negative memory and positive memory and neutral stimulus（p>0.05）.Conclusion:A virtual patient with symptoms of delusional misidentification syndrome can be shaped by hypnosis,and when the subject was in a hypnosis-induced delusional state,there was a shift in identity as well as impaired memory extraction.The subject’s connection between the self and autobiographical memory is disrupted and damage to the autobiographical memory system occurs after the change in self-identity.This was followed by an increase in P200 amplitude due to abnormal brain activity.During the late phase of stimulus presentation,subjects need to allocate cognitive resources to the two cognitive processes of memory extraction and false memory content discrimination,and old identity-related memories are suppressed and take up cognitive resources resulting in increased LPP component amplitudes in the frontal and parietal lobes. |
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