Authors | Objectives | Participants | PTSD diagnostic tools | Study design | Results | ||||
---|---|---|---|---|---|---|---|---|---|
Type and number | Experimental group | Control group | Type of study | Conditions | Measures | ||||
(Engelhard, van den Hout, Dek, et al., 2011) | Investigate whether double task could provide better desensitization of the traumatic memory | Participants with recurrent intrusive/ disturbing visual images (N = 37) | 1 group (N = 37) | No control group | Yale-Brown Obsessive Compulsive Scale and SCL-90 | Experimental study using computer and behavioural task/measure of an emotionally disturbing auditory memory | Two conditions: recall intrusive images with EM or recall without making eye movements | VAS score on vividness and emotionality | Vividness of intrusive images was lower after recall with eye movement, relative to recall only (t(36) = 2.37, p < .05, d = 0.37), and there was a similar trend for emotionality (t(36) = 2.01, p < .05, d = 0.32). |
(Thomaes et al., 2016) | Examine visual and emotional processing brain regions as well as the activity of the DLPFC during the recall of the traumatic memory recall, with EM relative to recall-only | Participants with current PTSD symptoms (N = 8) | 1 group (N = 8) | No control group | Structured clinical interview and PSS-SR scale | Experimental study using functional magnetic resonance imaging | Two conditions: recall of the traumatic memories with EM and recall without EM | Neural activation in brain regions in response to memory recall during script-driven imagery | EM during recall, compared to recall only, was associated with reducing activity – i.e., less activation of right amygdala and rostral ACC and connectivity in emotional processing in brain regions (T = 3.499, p-uncorrected < 0.005) |
(Sack et al., 2016) | Examine if there is better desensitization with exposure alone, with a double task, or with a visual fixation task | Participants with current PTSD (N = 139) | EM group (N = 47) and EF group (N = 47) | Control group (EC) (N = 45) | CAPS interview based on the DSM-IV | Randomized clinical trial | Three conditions: eyes moving on the therapist’s moving hand (EM), eyes fixating on the therapist’s non-moving hand (EF), and exposure without explicit visual focus of attention as the control condition (EC) | CAPS scores on PTSD symptoms and remission of PTSD diagnosis after EMDR session | Larger symptom decrease in EM and EF than in EC (CAPS: EM = 35.8, EF = 40.5, EC = 31.0) and significantly larger effect sizes (EM: d = 2.06, 95% CI: 1.55–2.57, EF: d = 2.58, 95% CI: 2.01–3.11, EC: d = 1.44, 95% CI: 0.97–1.91); no difference between EM and EF |
(Matthijssen et al., 2017) | Investigate whether auditory memories can be targeted with EMDR in PTSD patients | Participants with current PTSD symptoms (N = 30) | 1 group (N = 30) | No control group | Clinical psychologist/psychiatrist screening using DSM IV-TR criteria | Experimental study with behavioural task/measure of an emotionally disturbing memory | Three conditions: to make EM (VT), to count down (AT), or to stare at a non-moving dot (CC) | SUD score on the emotionality of a disturbing image and reaction time | Emotionality of auditory memory was reduced in the three conditions; however, no difference was found between AT, VT, or the CC [Auditory Memory: [F(2,58) = 2.02, p = .14]; Visual Memory F(2,60) = 0.25, p = .78] |
(Matthijssen et al., 2019) | Examine the extent to which emotionality of auditory hallucination memories could be reduced by dual tasking | Participants with current PTSD symptoms (N = 36) | 1 group (N = 36) | No control group | PSYRATS-AH questionnaire, BAVQ-R questionnaire, SUD score | Experimental study with behavioural task/measure of an emotionally disturbing auditory memory | Three conditions: visual taxation though EM (VT), auditory taxation by counting out loud (AT), and control condition without any additional task (CC) | SUD score on the emotionality of a disturbing image | The active conditions – i.e., making eye movements or counting out loud – showed stronger effects in reducing emotionality of auditory hallucinations compare to the control condition [BF1 = 5.8, model 1: AT (pre-post) = VT (pre-post) > CC (pre-post)] |
(Matthijssen & van Hout, 2016) | Examine the effects of eye movements on positive verbal imagery after an EMDR session | Healthy participants (N = 30) | 1 group (N = 30) | No control group | \ | Experimental study using selected individual negative memory | Two conditions: EM and eyes stationary (ES) | VAS scale on the belief in personality trait and perception checklist scores | No significant differences between the eye movement and the eyes stationary conditions; eye movements did not diminish or enhance the belief of the positive relevant personality trait (F(1, 35) = 0.071, p = .792) |
(Voogd & Phelps, 2020) | Examine whether the impact of a working memory task on extinction learning is greater when cognitive load is increased | Healthy participants exposed to PTSD-induced trauma (n = 75) across three groups | Low-load group (N = 24) and high-load group (N = 27) | Control group (N = 24) | \ | Experimental study with induced PTSD using images of snakes associated with peripheral stimulation | Three conditions: low-load condition group, high-load condition group, and without dual task as the control condition | Accuracy scores on a random sequence, SCR response, and reaction times | The conditioned response was stronger in the control group compared to the low-load group [F(1, 46) = 4.24, p = .045, ηp 2 = 0.08] and the high-load group [F(1, 49) = 12.07, p = .001, ηp 2 = 0.20]; also, a stronger cognitive load had a bigger impact on the reduction in the conditioned response compared to the control condition [t(72) = − 3.619, p < .001] |
(Leer & Engelhard, 2020) | Examine the effect of induced EM on memory accuracy on a visual discrimination task | Healthy participants (n = 68) | Group for discrimination test day 2 (N = 34) and group for discrimination test day 1 and day 2 (N = 34) | No control group | \ | Experimental study with induced trauma using two sets of images and a 2-ms electrocutaneous stimulus | Two conditions: recall with EM condition vs. recall without eye movements condition | Shock occurrence prediction, shock expectancy rating score, number of false positive responses, and reaction time of responses | False positive rates in a discrimination task increased in recall with eye movement condition the day after the conditioning phase, compared to the control condition (F(1, 66) = 14.58, p < .001, ηp2 = 0.181) |
(van Schie et al., 2019) | Investigated the effects of dual tasks on intrusive memories following analogue trauma | Healthy participants (n = 76) | 1 group (N = 76) | No control group | \ | Experimental study with induced trauma using word-image association pairs | Three conditions: recall + EM condition, recall + counting condition, and no task (control condition); two different dual tasks to quantify WM (RIR + EM, RIR + counting, or RIR only | VAS score on vividness and emotionality, response latency score, and choice confidence | Cognitive loads of RIR + EM and RIR + counting were higher than RIR only (BFs10 > 2.81 × 1017); hotspot vividness and unpleasantness ratings were not affected by the intervention; WM taxation was not related to decreases in vividness (r = − .19, BF01 = 12.60) or unpleasantness (r = − .04, BF01 = 6.90) |
(van Veen et al., 2020) | Examine if recall + EM results in larger immediate and 24-hour reductions in memory vividness, negative valence, and distress than recall alone | Healthy participants (n = 45) | Recall + EM group (N = 50) and recall only group (N = 50) | No control group | \ | Experimental study with induced trauma using negative autobiographical memory | Two conditions: recall with EM vs. recall without EM | VAS score on vividness, negative valence, and distress ratings; SUIS score on tendency and ease of forming visual images in daily life; ACS score; automated reading span | After four sessions, memory was deflated in recall with eye movements –vividness − 0.90 (− 3.10–1.23); negative valence 0.64 (− 0.76–2.14); distress 0.82 (− 1.17–2.86); memory was inflated in recall alone –vividness − 2.84*(− 4.95 to − 0.71), negative valence − 2.13*(− 3.60 to − 0.70), distress − 3.59*(− 5.57 to − 1.58) After 32 sessions, there was a reduction in both recall conditions for all outcome measures |
(Rackham & Lau-Zhu, 2021) | Investigate whether mental imagery of the 9/11 terrorist attacks following media exposure is dampened by taxing working memory | Healthy participants (n = 45) | 1 group (N = 45) | No control group | \ | Experimental study with PTSD induced using a personally relevant mental image of the 9/11 terrorist attacks | Three conditions: recall + EM, recall + Tetris game, and recall only | 11-point Likert scale on imagery vividness and emotionality | Compared to recall only, dual-task effects (i.e., recall + Tetris and recall + EM) reduced ratings of vividness and emotionality – recall + Tetris, F(1, 28) = 27.90, p < .001, h2 p = .50, 90% CI = [0.26, 0.64]; recall + EM, F(1, 28) = 37.44, p < .001, h2 p = .57, 90% CI = [0.34, 0.69]; this effect vanished in a follow-up (24 h later) test –recall + Tetris, t(14) = 4.75, p < .001, d = 1.22, and recall + EM, t(14) = 5.82, p < .001, d = 1.51) |