| Posttraumatic stress disorder(PTSD)is a delayed and prolonged mental disorder caused by abnormal or catastrophic psychological trauma.Re-experience symptom is one of the four kinds of core symptoms of PTSD.As a typical re-experience symptom,flashback(also called intrusive imagery)is regarded as a landmark symptom of PTSD.In the prevention and treatment of PTSD,reducing flashbacks is one of the main targets.The cognitive-behavioral approaches have made a good explanation and prediction of PTSD.Among them,the dual representation theory of PTSD(DRT)is quite influential.Based on the perspective of multiple memory systems,DRT underlines the functions of ventral and dorsal streams of visual processing on the formation,consolidation and retrieval of the intrusive imagery.The "dual channel" intervention,based on DRT,emphasizes that the visual-spatial tasks can interfere with the formation and consolidation of the intrusive imagery by taxing the cognitive resources of the dorsal stream of visual processing;while the verbal tasks facilitate the intrusive imagery by taxing the cognitive resources of the ventral stream.In contrast,the"single channel" intervention is based on the working memory model(WMM),and it argues that either of the verbal and visual-spatial tasks can interfere with the formation and consolidation of the intrusive imagery by taxing the cognitive resources as a whole.The DRT and WMM have currently received some empirical support from the research of analogue trauma interventions in nonclinical samples.However,there is too little research examined the intervention effects of the task type and cognitive load simultaneously to accurately compare the DRT and WMM and analyze the relationship between them.Therefore,this study was designed to figure out these questions.This study was carried out among healthy subjects from different universities.Three traffic accident film clips were used to simulate trauma.Through the dual-task paradigm in cognitive psychology studies,the degrees of the cognitive load(i.e.how the cognitive tasks tax the whole cognitive resources of the working memory)of the verbal tasks(continuously counting down)and the visual-spatial tasks(continuously inputting the irregular spatial positions through a special 4×4 keyboard out of sight)were manipulated in the first place.Then,these tasks were performed as cognitive intervention tasks during the analogue trauma and 1 hour after the analogue trauma.This study also aimed to explore the mechanism of intervention effects of the cognitive tasks performed during the analogue trauma.Study one(N= 162)was designed to revise the thoughts and feelings questionnaire(TFQ),provide a qualified measurement for the following exploration of the mechanism of intervention effects of the cognitive tasks performed during the analogue trauma,and examine the effect of the cognitive processing during the analogue trauma on the intrusive imagery.The results showed that:(1)The thoughts and feelings questionnaire-Chines Revised(TFQ-CR)could be appropriately applied in the measurement of the cognitive processing during the analogue trauma.The TFQ-CR included two factors which were the conceptual process and the data-driven process,and the fitting of the 2-factor model is acceptable.(2)The data-driven process during analogue trauma positively predicted the intrusive imagery and the traumatic reactions.The trait anxiety played a moderate role when the data-driven process impacts the traumatic reactions.(3)The conceptual process during the analogue trauma was one of the main factors influencing the subjects’ cued recalls of the contents of the experimental film.In study two,through the dual-task paradigm in cognitive psychology studies,a within subject design was carried out in 30 subjects.The degrees of the cognitive load of two simple tasks(continuously counting down by 2 and continuously inputting 5 irregular spatial positions)and two difficult tasks(continuously counting down by 7 and continuously inputting 12 irregular spatial positions)were matched respectively on the correct rate and the correct reaction time of the visual discrimination reaction time task.Then,a 2 X 2 between subject design was carried out to examine the intervention effects of the task type and cognitive load on the intrusive imagery.Four groups of subjects(N=96)performed different tasks when watching the experimental film.A no-task control group(N=24)was set to compare the intervention effects of these cognitive tasks.The results from MANOVA analysis and independent t-test showed that:(1)The visual-spatial tasks could interfere with the formation of the intrusive imagery by taxing the cognitive resources of the dorsal stream of visual processing,and then reduce the intrusive imageries in the following week.The DRT was supported.(2)The high cognitive load visual-spatial task could increase the subjective suffering of intrusive imageries which reported in the early period after the analogue trauma.The DRT was not supported,but it might also suggest that the immediate intervention effect of visual-spatial tasks was not applicable under the high cognitive load condition.(3)The degree of actual completion of the cognitive tasks during the analogue trauma had a distracting effect on the cued recalls of the contents of the experimental film.The more quickly and correctly,the subjects completed the tasks,the poorer cued recalls they had,which supported the WMM.(4)The visual-spatial tasks during the analogue trauma had no effect on the data-driven process.Therefore,this study indicated no evidence on the intervention mechanism of the visual-spatial tasks on the intrusive imagery.Study three(N=120)focused on the cognitive intervention conducted 1 hour after the analogue trauma,which also used a 2×2 between subject design and set a no-task control group as in Study two.One hour after watching the experimental film,all subjects saw pictures captured from the film to recover their memory and trigger the intrusive imagery.Immediately after that,four groups of subjects performed different tasks for 10 minutes,but the subjects of the no-task group only had a 10-minute rest.The results from MANOVA analysis and independent t-test showed that:(1)All cognitive tasks could reduce the intrusive imagery appearing during the 10 minutes by taxing the cognitive resources of the working memory as a whole,which supported the WMM.(2)The degree of actual completion of the cognitive tasks had effect on the intrusive imagery.The subjects completed the tasks quickly and correctly reported less intrusive imageries in the following week,but the subjects who did not complete the cognitive tasks well reported more intrusive imageries trigged 1 week after.This might be because of the interference with the consolidation of the intrusive imagery by the well-completed cognitive tasks,which basicly supported the WMM.(3)The high cognitive load visual-spatial task during the 10 minutes might interfere with the normal emotional processing after the analogue trauma,and then increase the degree of vividness of the intrusive imagery in the following week.Finally,there was no significant difference in the traumatic reactions and the triggered intrusive imagery between Study two(the cognitive intervention was conducted during the analogue trauma)and Study three(the cognitive intervention was conducted 1 hour after the analogue trauma).Therefore,from the time point when a traumatic event began to 6 hours after the trauma(i.e.within the memory consolidation time window),there might be no so-called "optimal time point" to conduct the cognitive intervention.However,no matter when,the simple visual-spatial tasks were preferred for the cognitive intervention. |
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