Memory amplification for trauma: Investigating the role of analogue PTSD symptoms in the laboratory

The nested hierarchical model of self and its non-relational vs relational posttraumatic manifestation: an fMRI meta-analysis of emotional processing

Different kinds of traumatic experiences like natural catastrophes vs. relational traumatic experiences (e.g., sex/physical abuse, interpersonal partner violence) are involved in the development of the self and PTSD psychopathological manifestations. Looking at a neuroscience approach, it has been proposed a nested hierarchical model of self, which identifies three neural-mental networks: (i) interoceptive; (ii) exteroceptive; (iii) mental. However, it is still unclear how the self and its related brain networks might be affected by non-relational vs relational traumatic experiences. Departing from this background, the current study aims at conducting a meta-analytic review of task-dependent fMRI studies (i.e., emotional processing task) among patients with PTSD due to non-relational (PTSD-NR) and relational (PTSD-R) traumatic experiences using two approaches: (i) a Bayesian network meta-analysis for a region-of-interest-based approach; (ii) a coordinated-based meta-analysis. Our findings suggested that the PTSD-NR mainly recruited areas ascribed to the mental self to process emotional stimuli. Whereas, the PTSD-R mainly activated regions associated with the intero-exteroceptive self. Accordingly, the PTSD-R compared to the PTSD-NR might not reach a higher symbolic capacity to process stimuli with an emotional valence. These results are also clinically relevant in support of the development of differential treatment approaches for non-relational vs. relational PTSD.

Challenging memories reduces intrusive memories and the memory amplification effect

This study scrutinizes the influence of attenuating beliefs about the veracity of traumatic experiences on the manifestation of intrusive recollections and the memory amplification effect. Participants were exposed to distress-inducing visual stimuli, subsequently rating their emotional status pre and post exposure. They engaged in a recognition task, identifying scenarios within the stimuli. Participants' recall was contested, casting doubt about the occurrence of certain scenes. Subsequently, they maintained a daily log of intrusive memories over a week. A second session reiterated the same process. This method effectively diminished the certainty in the participants' traumatic memories. Scenes whose occurrence was contested demonstrated a significant decline in both intrusive memories and memory amplification when juxtaposed with uncontested ones. Interestingly, no significant correlation emerged between the diminished belief in traumatic incidents and reductions in intrusive memory or memory amplification. Thus, this study advocates that interrogating the veracity of traumatic recollections can mitigate the prevalence of intrusive memories and the memory amplification effect, suggesting a novel potential therapeutic approach for trauma-related disorders.

I forgot that I forgot: PTSD symptom severity in a general population correlates with everyday diary-recorded prospective memory failures

Extant research suggests a complex relationship between prospective memory (PM) and post-traumatic stress disorder (PTSD) symptom severity. In a general population, this relationship exists for self-report assessment but not objective, in-lab PM performance (e.g., pressing a certain key at a particular time, or when particular words appear). However, both these measurement methods have limitations. Objective, in-lab PM tasks might not represent typical everyday performance, while self-report measurement might be biased by metacognitive beliefs. Thus, we used a naturalistic diary paradigm to answer the overarching question: are PTSD symptoms associated with PM failures in everyday life? We found a small positive correlation between diary-recorded PM errors and PTSD symptom severity (r = .21). Time-based tasks (i.e., intentions completed at a particular time, or after a specified time has elapsed; r = .29), but not event-based tasks (i.e., intentions completed in response to an environmental cue; r = .08), correlated with PTSD symptoms. Moreover, although diary-recorded and self-report PM correlated, we did not replicate the finding that metacognitive beliefs underpin the PM-PTSD relationship. These results suggest that metacognitive beliefs might be particularly important for self-report PM only.

The role of belief in memory amplification for trauma events

BACKGROUND AND OBJECTIVES

Trauma survivors often report trauma events inconsistently over time. Many studies, for example, have found that people report having experienced trauma events that they initially failed to report or remember, a phenomenon called "memory amplification." Other studies have found the opposite: people report experiencing fewer events over time. Nahleen, Nixon, and Takarangi (2019) asked participants at two time-points, with a six-month delay, whether they had experienced 19 sexual assault events on a yes/no scale. Participants reported fewer events over time, that is, memory for sexual assault did not amplify overall. In the current study, we assessed whether inconsistency in reports of trauma exposure over time may be attributed to changes in participants' belief that certain events were experienced.

METHODS

We replicated Nahleen et al. (2019), but rather than respond to a yes/no trauma exposure scale, participants were required to rate the likelihood that each trauma event occurred on an 8-point scale (1 = definitely did not happen; 8 = definitely did happen).

RESULTS

We found that participants believed that they were less likely to have experienced the sexual assault events at follow-up compared to initial assessment.

LIMITATIONS

We could not corroborate trauma experiences or determine causality with our design. Further, not all of our findings were consistent with Nahleen et al. (2019).

CONCLUSIONS

Sexual assault memories did not amplify over time, perhaps because, compared to other types of trauma, the idea of experiencing additional sexual assault events that were not actually experienced is less believable.

Right Hemisphere Memory Bias Does Not Extend to Involuntary Memories for Negative Scenes

Attention is unequally distributed across the visual field. Due to greater right than left hemisphere activation for visuospatial attention, people attend slightly more to the left than the right side. As a result, people voluntarily remember visual stimuli better when it first appears in the left than the right visual field. But does this effect-termed a right hemisphere memory bias-also enhance involuntary memory? We manipulated the presentation location of 100 highly negative images (chosen to increase the likelihood that participants would experience any involuntary memories) in three conditions: predominantly leftward (right hemisphere bias), predominantly rightward (left hemisphere bias), or equally in both visual fields (bilateral). We measured subsequent involuntary memories immediately and for 3 days after encoding. Contrary to predictions, biased hemispheric processing did not affect short- or long-term involuntary memory frequency or duration. Future research should measure hemispheric differences at retrieval, rather than just encoding.

Modeling Patterns of Polyvictimiztion and Their Associations with Posttraumatic Stress Disorder and Complex Posttraumatic Stress Disorder in the Israeli Population

Although evidence is accumulating for the conceptual validity of the ICD-11 proposal for posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD), our understanding of the specificity of trauma-related predictors is still evolving. Specifically, studies utilizing advanced statistical methods to model the association between trauma exposure and ICD-11 proposals of traumatic stress and differences in profiles of trauma exposure are lacking. Additionally, time since trauma and a clear memory of the trauma are yet to be examined as predictors of PTSD and CPTSD. We analyzed trauma exposure as reported by a general population sample of Israeli adults (N = 834), using latent class analysis, and the resultant classes were used in regression models to predict PTSD and CPTSD operationalized both dimensionally and categorically. Four distinct groups were identified: child and adult interpersonal victimization, community victimization-male, community victimization-female, and adult victimization. These groups were differentially related to PTSD and CPTSD, with only child and adult interpersonal victimization consistently predicting CPTSD and disturbances in self-organization. When modeled dimensionally, PTSD was associated with the child and adult interpersonal victimization and adult victimization groups, whereas only the child and adult interpersonal victimization group was predictive of PTSD when operationalized categorically. The roles of time since trauma and a clear memory of the trauma differed across PTSD and CPTSD. These findings support the use of trauma typologies for predicting PTSD and CPTSD and provide important insight into the distribution of trauma exposure in the Israeli population.

When Patients Overreport Symptoms: More Than Just Malingering

Mental-health patients may report more symptoms than they actually experience. Experts and laypeople often view this overreporting as a sign of malingering. We show that there are multiple pathways to symptom overreporting: carryover effects from previous tests that lower the threshold for answering affirmatively to symptom items, suggestive misinformation that escalates symptom reports, inattentive responding that promotes indiscriminate endorsement of symptoms, and personality traits that bias symptom reports in an upward direction. A one-sided focus on malingering may distract from a research agenda that may contribute to knowledge accumulation in this domain.

Psychophysiological reactivity, coping behaviour and intrusive memories upon multisensory Virtual Reality and Script-Driven Imagery analogue trauma: A randomised controlled crossover study

BACKGROUND

Peri- and post-traumatic factors predict the differential development of stress-associated mental disorders. Prospective designs assessing these risk factors in real-time under controlled experimental conditions can overcome limitations of retrospective designs. Therefore, we aimed to investigate multi-sensory, experimental analogues of a traumatic experience delivered in Virtual Reality (VR) or Script-Driven Imagery (SDI).

METHODS

In a randomised controlled crossover design, differences in the induced analogue trauma symptoms between multi-sensory analogue trauma by either VR or SDI versus a neutral condition were assessed in 127 non-clinical participants.

RESULTS

Analogue symptoms (psychophysiological responses, coping behaviour and intrusive memories of the experimental trauma) increased following analogue trauma in both VR and SDI, with more analogue symptoms for VR. Psychophysiological arousal was in general higher in VR.

LIMITATIONS

The analogue trauma situation of a car park fire that was used may be infrequent in real life.

CONCLUSIONS

Multisensory (vision, olfaction, hearing) analogue trauma in VR and SDI offers a useful tool for the induction and real-time assessment of peri- and post-traumatic risk factors for analogue stress-associated psychopathology. VR was more effective in inducing analogue symptoms than SDI, even though the latter might be more personalised. New experimental models for studying trauma exposure and responses may contribute to a better understanding of risk factors and help to identify and protect individuals at risk.

Imagining trauma: Memory amplification and the role of elaborative cognitions

BACKGROUND AND OBJECTIVES

Trauma victims, such as war veterans, often remember additional traumatic events over time: the "memory amplification effect". This effect is associated with the re-experiencing symptoms of post-traumatic stress disorder (PTSD), including frequent and intrusive images of the trauma. One explanation for memory amplification is that people gradually incorporate new, imagined information about the trauma with what they actually experienced, leading to an amplified memory for what actually happened. We investigated this proposal here.

METHODS

Participants viewed highly negative and graphic photographs and recorded their intrusions. Critically, we instructed some participants to elaborate on their intrusions-that is, we asked them to imagine details about the trauma beyond what they actually witnessed. We assessed memory for the traumatic photos twice, 24-h apart.

RESULTS

The elaboration condition experienced fewer intrusions about the photos compared to the control condition. Furthermore, the elaboration condition were less susceptible to memory amplification compared to controls.

LIMITATIONS

The use of negative photos allowed experimental control, however does not permit generalization of our findings to real-world traumatic experiences.

CONCLUSIONS

Our findings suggest that effortful imagination of new trauma-related details leads to a reduction in intrusions and an increased tendency to not endorse trauma exposure over time. One explanation for this finding is that elaboration enhanced conceptual processing of the trauma analogue, therefore reducing intrusions. Critically, this reduction in intrusions affected participants' tendency to endorse trauma exposure, which is consistent with the reality-monitoring explanation for memory amplification.