How eye movements affect unpleasant memories: Support for a working-memory account

Background: Eye movement desensitization and reprocessing (EMDR) is an effective psychological treatment for posttraumatic stress disorder. Recalling a memory while simultaneously making eye movements (EM) decreases a memory’s vividness and/or emotionality. It has been argued that non-specific factors, such as treatment expectancy and experimental demand, may contribute to the EMDR’s effectiveness. Objective: The present study was designed to test whether expectations about the working mechanism of EMDR would alter the memory attenuating effects of EM. Two experiments were conducted. In Experiment 1, we examined the effects of pre-existing (non-manipulated) knowledge of EMDR in participants with and without prior knowledge. In Experiment 2, we experimentally manipulated prior knowledge by providing participants without prior knowledge with correct or incorrect information about EMDR’s working mechanism. Method: Participants in both experiments recalled two aversive, autobiographical memories during brief sets of EM (Recall+EM) or keeping eyes stationary (Recall Only). Before and after the intervention, participants scored their memories on vividness and emotionality. A Bayesian approach was used to compare two competing hypotheses on the effects of (existing/given) prior knowledge: (1) Prior (correct) knowledge increases the effects of Recall+EM vs. Recall Only, vs. (2) prior knowledge does not affect the effects of Recall+EM. Results: Recall+EM caused greater reductions in memory vividness and emotionality than Recall Only in all groups, including the incorrect information group. In Experiment 1, both hypotheses were supported by the data: prior knowledge boosted the effects of EM, but only modestly. In Experiment 2, the second hypothesis was clearly supported over the first: providing knowledge of the underlying mechanism of EMDR did not alter the effects of EM. Conclusions: Recall+EM appears to be quite robust against the effects of prior expectations. As Recall+EM is the core component of EMDR, expectancy effects probably contribute little to the effectiveness of EMDR treatment.

Section: Discussionmentioning

confidence: 79%

“…Simultaneously performing these tasks therefore reduces the sensory quality of the memory, making it less vivid and less emotional. It is likely that, after EMDR, the less rich, degraded memory is reconsolidated into long-term storage which may explain long-term effects (Gunter & Bodner, 2008; Nader & Hardt, 2009; van den Hout & Engelhard, 2012). …”

mentioning

confidence: 99%

Exploring expectation effects in EMDR: does prior treatment knowledge affect the degrading effects of eye movements on memories?

Littel

Schie

Hout

2017

“…Previous studies have repeatedly shown positive effects for dual tasks on vividness and emotionality ratings of autobiographic memories (e.g. Gunter & Bodner, 2008; Leer et al, 2014; van den Hout et al, 2011). However, contrary to previous research, neither dual-task TGP1 nor dual-task TGP2 reduced vividness and emotionality ratings.…”

Section: Discussionmentioning

confidence: 93%

“…The beneficial effects of dual tasks have been found in healthy volunteers retrieving a negative autobiographical memory when performing eye movements (e.g. Leer, Engelhard, & van den Hout, 2014; van den Hout et al, 2011, 2012), drawing complex figures (Gunter & Bodner, 2008) and mental arithmetic (Engelhard, van den Hout, & Smeets, 2011). In addition, the effectiveness of Eye Movement Desensitization and Reprocessing (EMDR) for PTSD has been explained by WM theory (van den Hout & Engelhard, 2012).…”

Section: Introductionmentioning

confidence: 99%

Development and testing of TraumaGameplay: an iterative experimental approach using the trauma film paradigm

Asselbergs

Sijbrandij

Hoogendoorn³

et al. 2018

Background: Vivid trauma-related intrusions are a hallmark symptom of posttraumatic stress disorder (PTSD), and may be involved in its onset. Effective interventions to reduce intrusions and to potentially prevent the onset of subsequent PTSD are scarce. Studies suggest that playing the videogame Tetris, shortly after watching aversive film clips, reduces subsequent intrusions. Other studies have shown that taxing working memory (WM) while retrieving an emotional memory reduces the memory’s vividness and emotionality. Objective: We developed TraumaGameplay (TGP), a gaming app designed to reduce intrusions. This paper describes two successive experiments to determine whether playing TGP without memory retrieval (regular TGP) or TGP with memory retrieval (dual-task TGP) reduces intrusion frequency at one week compared to a no-game control. Method: For both experiments, healthy university students were recruited. Experiment 1: 92 participants were exposed to a trauma film and randomized to (1) regular TGP1 (n = 31), (2) dual-task TGP1 (n = 31) or (3) control (n = 30). In experiment 2, 120 healthy students were exposed to a trauma film and randomized to (1) regular TGP2 (n = 30), (2) dual-task TGP2 (n = 29), (3) recall only (n = 31) or (4) control (n = 30). Results: We found no significant difference between conditions on the number of intrusions for either playing regular TGP or dual-task TGP in both experiment 1 and experiment 2. Conclusion: Our results could not replicate earlier promising findings from preceding experimental research. Several reasons may underpin this difference ranging from the visuospatial videogame used in our experiments to the method of the experiment to the difficulties of replicability in general.

“…focusing attentional, dividing attention, planning). Thus, according to such an interpretation of the working memory theory (Van den Hout & Engelhard, 2012), working memory load rather than modality is the crucial component (Gunter & Bodner, 2008). Moreover, working memory theory also implies a dose–response relationship with stronger effects for more demanding tasks, which has indeed been found in empirical studies (Engelhard, Van den Hout, & Smeets, 2011; Van den Hout & Engelhard, 2012).…”

mentioning

confidence: 99%

Tetris and Word games lead to fewer intrusive memories when applied several days after analogue trauma

Hagenaars

Holmes

Klaassen

et al. 2017

Background: Intrusive trauma memories are a key symptom of posttraumatic stress disorder (PTSD), so disrupting their recurrence is highly important. Intrusion development was hindered by visuospatial interventions administered up to 24 hours after analogue trauma. It is unknown whether interventions can be applied later, and whether modality or working-memory load are crucial factors. Objectives: This study tested: (1) whether a visuospatial task would lead to fewer intrusions compared to a reactivation-only group when applied after memory reactivation four days after analogue trauma exposure (extended replication), (2) whether both tasks (i.e. one aimed to be visuospatial, one more verbal) would lead to fewer intrusions than the reactivation-only group (intervention effect), and (3) whether supposed task modality (visuospatial or verbal) is a critical component (modality effect). Method: Fifty-four participants were randomly assigned to reactivation+Tetris (visuospatial), reactivation+Word games (verbal), or reactivation-only (no task). They watched an aversive film (day 0) and recorded intrusive memories of the film in diary A. On day 4, memory was reactivated, after which participants played Tetris, Word games, or had no task for 10 minutes. They then kept a second diary (B). Informative hypotheses were evaluated using Bayes factors. Results: Reactivation+Tetris and reactivation+Word games resulted in relatively fewer intrusions from the last day of diary A to the first day of diary B than reactivation-only (objective 1 and 2). Thus, both tasks were effective even when applied days after analogue trauma. Reactivation-only was not effective. Reactivation+Word games appeared to result in fewer intrusions than reactivation+Tetris (objective 3; modality effect), but this evidence was weak. Explorative analyses showed that Word games were more difficult than Tetris. Conclusions: Applying a task four days after the trauma film (during memory reconsolidation) was effective. The modality versus working-memory load issue is inconclusive.