3.1 Study synthesis and Data Extraction
The synthesis process of the extracted data involves the collection and summarization of the findings from the primary studies that were included. In the initial round of the search, all studies that focused on EMDR therapy for PTSD were gathered, resulting in a total of 4400 studies. After eliminating duplicate studies, the number was reduced. The second round involved examining the effectiveness of EMDR among patients with PTSD in general. Out of the initial 519 studies, only 97 met the inclusion criteria. Further assessment was conducted on the full text articles, and 65 out of the 97 studies met the criteria for this stage. Finally, after careful evaluation, a total of 8 articles were found to meet all the criteria, as depicted in Figure 1.
A comprehensive systematic review was conducted, including a thorough evaluation of eight published studies that met the specific criteria for inclusion. Among these selected studies, four were classified as randomized controlled studies, while the remaining four were categorized as systematic review and met-analysis studies. Within the scope of all these included studies, it was observed that the primary method of psychotherapy intervention for addressing symptoms of post-traumatic stress disorder (PTSD) was the utilization of Eye Movement Desensitization and Reprocessing (EMDR) therapy.
3.2. Selected Studies characteristics:
Table 1 provides a comprehensive overview of the primary features of the studies that were considered in our analysis. In total, we identified and included 8 studies in our research. Upon further examination, we determined that out of these 8 studies, 4 of them, constituting 50% of the total, were randomized controlled trials, while the remaining 4 studies, accounting for 50%, were review articles. These studies were published within the time frame of 2017 to 2022 and were sourced from various reputable Scopus journals across several countries.
Table (1) Characteristics of the studies included in the Literature
Authors
|
Title
|
Design
|
Major findings
|
Covers et al., 2021
|
Early intervention with eye movement desensitization and reprocessing (EMDR) therapy to reduce the severity of post-traumatic stress symptoms in recent rape victims: a randomized controlled trial
|
RCT
|
EMDR therapy was found to be more effective than watchful waiting in reducing anxiety and dissociative symptoms in the post-treatment assessment
|
Stanbury et al., 2020
|
Comparative Efficiency of EMDR and Prolonged Exposure in Treating Posttraumatic Stress Disorder: A Randomized Trial
|
RCT
|
Results demonstrated a significant decrease in symptoms post treatment for PTSD, depression, anxiety, and stress for both groups, which was maintained at 3 months. At 6 months there was a small increase in symptoms compared to the 3-month time point on the Clinician-Administered PTSD Scale (CAPS) but no significant change in any self-report symptoms EMDR was significantly more efficient than PE. EMDR participants had less total exposure time to traumatic memories when homework hours were included, reported lower SUD scores after the first session, required fewer sessions for the target memory to decrease to near zero distress levels, and processed more traumatic memories.
|
Acarturk et al., 2015
|
EMDR for Syrian refugees with posttraumatic stress disorder symptoms: results of a pilot randomized controlled trial
|
RCT
|
showed that the EMDR group had significantly lower trauma scores at post treatment as compared with the wait-list group. The EMDR group also had a lower depression score after treatment as compared with the wait-list group.
|
Yurtsever et al., 2018
|
An Eye Movement Desensitization and Reprocessing (EMDR) Group Intervention for Syrian Refugees With Post-traumatic Stress Symptoms: Results of a Randomized Controlled Trial
|
RCT
|
The results showed that the EMDR G-TEP group had significantly lower PTSD and depression symptoms after intervention. The percentage of PTSD diagnosis decreased from 100 to 38.9% in the EMDR G-TEP group and was unchanged in the control group. Following the EMDR G-TEP intervention 61.1% of the experimental group no longer had a PTSD diagnosis; this decrease was maintained at 4 weeks follow-up. In the control group the percentage of people who no longer met the diagnostic criteria for PTSD was 10.3% post-test and 6.9% at 4 weeks follow-up. A significant decrease in depression symptoms from pre-test levels was found in EMDR group but not in the control group follow up-test.
|
Valiente-Gómez et al., 2017
|
EMDR beyond PTSD: A Systematic Literature Review
|
SR
|
EMDR therapy could be a useful psychotherapy to treat
trauma-associated symptoms in patients with comorbid psychiatric disorders. Preliminary evidence also suggests that EMDR therapy might be useful to improve psychotic or affective symptoms and could be an add-on treatment
|
Khan et al., 2018
|
Cognitive Behavioral Therapy versus Eye
Movement Desensitization and Reprocessing in Patients with Post-traumatic Stress Disorder: Systematic Review and Meta-analysis of Randomized Clinical Trials
|
SR
|
EMDR is better than CBT in reducing post-traumatic
symptoms and anxiety
|
Wilson et al., 2018
|
The Use of Eye-Movement Desensitization Reprocessing (EMDR) Therapy in Treating Post-traumatic stress disorder A Systematic Narrative Review
|
SR
|
EMDR therapy improved PTSD diagnosis, reduced PTSD symptoms, and reduced other trauma-related symptoms. EMDR therapy was evidenced as being more effective than other trauma treatments, and was shown to be an effective therapy when delivered with different cultures.
|
Wadji et al., 2022
|
Can working memory account for EMDR efficacy in PTSD?
|
SR
|
EMDR has been shown to be effective in the
treatment of PTSD for years, also associated with the reduction of symptoms.
|
3.1.2 Characteristics of all included RCTs based on country and number of participants:
In this review, a comprehensive analysis was conducted on a total of 153 participants, who were selected from four randomized controlled studies. Specifically, the EMDR based intervention group comprised 72 participants, while the control group consisted of 81 participants. It is worth noting that the distribution of these trials was geographically diverse, with 50% being conducted in Turkey (Stanbury et al., 2020 & Acarturk et al., 2015), 25% in the Netherlands (Covers et al., 2021), and the remaining 25% in Australia (Stanbury et al., 2020), therefore, this wide range of locations adds to the robustness and generalizability of the findings.
Table (2): Characteristics of all included RCTs based on country and number of participants
Author/Year
|
Country
|
Number of participants in the EMDR group
|
Number of participants in the control group
|
Covers et al., 2021
|
Netherland
|
29
|
28
|
Stanbury et al., 2020
|
Australia
|
10
|
10
|
Acarturk et al., 2015
|
Turkey
|
15
|
14
|
Yurtsever et al., 2018
|
Turkey
|
18
|
29
|
Total
|
-
|
72
|
81
|
3.1.2 Characteristics of all included review studies based on the number of participants and the number of included studies:
After a thorough synthesis and review of all systematic reviews and meta-analyses included in this study, a total of 2759 participants from four review studies were identified. These participants were drawn from a pool of 48 articles. It is worth noting that the number of included studies varied across the reviews, with a minimum of 6 articles (Wilson et al., 2018) and a maximum of 17 articles (Valiente-Gómez et al., 2017). However, it is important to mention that not all authors reported the exact number of participants included in their studies. As a result, the researchers in this study carefully examined each original article included in the reviews to determine the accurate number of participants included.
Table (3): EMDR Systematic Reviews characteristics based on the number of included studies and total Number of participants:
Author/Year
|
Number of included studies
|
Total Number of participants
|
Valiente-Gómez et al., 2017
|
17
|
976
|
Khan et al., 2018
|
14
|
836
|
Wilson et al., 2018
|
6
|
384
|
Wadji et al., 2022
|
11
|
563
|
Total
|
48
|
2759
|
3.3 Quality of included studies.
3.3.1 Quality of included clinical trial studies:
The quality of 4 included clinical trial studies were assessed using the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool for Quantitative Studies table (2). Each study was evaluated in six domains including Study bias, study design, control of confounders, blinding, data collection method, and withdrawals and dropouts of participants from the study). Based on selection bias domain; all participants in all included studies were agreed to participant in the study prior any intervention and the authors stated that the consents were signed by all participants, furthermore, according to the blinding domain; one randomized control trial (16%) followed a double-blind study design (Stanbury et al., 2020). However, the majority of the included clinical trials applied partial blinding study design (84%). Furthermore, the data in all included studies were collected using tools shown to be reliable and valid, all authors of included studies (100%) reported the number of withdrawals and dropouts participants in their study, however the percentage of participants completed the study in all articles were above 75%. Thus, the overall result after both reviewer discussions showed the 50% of study rated with moderate quality, no study was rated with low quality, and (50%) studies rated as high-quality study.
Table (4): Effective Public Health Practice Project (EPHPP) Quality Assessment Tool for Quantitative Studies (n= 4)
Study number
|
Study
|
1. Selection Bias
|
2. Study Design
|
3. Control of confounders
|
4. Blinding
|
5. Data Collection Methods
|
6. Withdrawals and Dropouts
|
Total rating score
|
1.
|
Covers et al., 2021
|
1
|
1
|
1
|
2
|
1
|
2
|
2
|
2.
|
Stanbury et al., 2020
|
2
|
1
|
2
|
1
|
1
|
2
|
2
|
3.
|
Acarturk et al., 2015
|
2
|
1
|
1
|
2
|
1
|
1
|
1
|
4.
|
Yurtsever et al., 2018
|
2
|
1
|
1
|
2
|
1
|
1
|
1
|
*Total rating score (1= strong, 2= moderate, 3= weak)
3.3.2 Quality of included review studies.
The quality of all review studies in this review was assessed using a Quality assessment checklist for systematic reviews (AMSTAR 2). According to this review, only one systematic review and meta-analysis study fulfilled all the AMSTAR 2 scale requirements (Khan et al., 2018). As well as the majority of included review studies (75%) did not fulfill all the AMSTAR 2 scale requirements. Indeed the majority of included systematic reviews and meta-analysis showing a low risk of bias (75%) and only one study showed a moderate level of bias (Valiente-Gómez et al., 2017), as well as all included studies showed a high to moderate power of evidence (Table 3). The score varied from 9 (Valiente-Gómez et al., 2017) to 16 (Khan et al., 2018) points, with an average of 12 out of a possible total of 16 points. Items 1, 2, 3,4,5, 6, 9, and 12 were scored as positive for all included reviews. Moreover, items 7, 11, and 16 were scored as positive for 75% of studies; however, items 8, 10, and 13 were not applicable for 50% of systematic reviews.
Table 5: Quality assessment checklist for systematic reviews (AMSTAR 2)
No
|
AMSTAR
Questions
|
Valiente-Gómez et al., 2017
|
Khan et al., 2018
|
Wilson et al., 2018
|
Wadji et al., 2022
|
1
|
Was an “a priori” design provided?
|
Yes
|
Yes
|
Yes
|
Yes
|
2
|
Was there duplicate study selection and data extraction?
|
Yes
|
Yes
|
Yes
|
Yes
|
3
|
Was a comprehensive literature search performed?
|
Yes
|
Yes
|
Yes
|
Yes
|
4
|
Was the status of publication (i.e., grey literature) used as an inclusion criterion?
|
Yes
|
Yes
|
yes
|
Yes
|
5
|
Was a list of studies (included and excluded) provided?
|
Yes
|
Yes
|
Yes
|
Yes
|
6
|
Were the characteristics of the included studies provided?
|
Yes
|
Yes
|
Yes
|
Yes
|
7
|
Was the scientific quality of the included studies assessed and documented?
|
No
|
Yes
|
Yes
|
Yes
|
8
|
Was the scientific quality of the included studies used appropriately in formulating conclusions?
|
NP
|
Yes
|
Yes
|
No
|
9
|
Were the methods used to combine the findings of studies appropriate?
|
Yes
|
Yes
|
Yes
|
Yes
|
10
|
Was the likelihood of publication bias assessed?
|
No
|
Yes
|
Yes
|
No
|
11
|
Was the conflict of interest stated?
|
Yes
|
Yes
|
Yes
|
No
|
12
|
Did the review authors provide a satisfactory explanation for, and discussion of, any heterogeneity observed in the results of the review?
|
Yes
|
Yes
|
Yes
|
Yes
|
13
|
Did the review authors account for RoB in individual studies when interpreting/discussing the results of the review?
|
No
|
Yes
|
Yes
|
No
|
14
|
Authors assess the potential impact of RoB in individual studies on the results of the meta-analysis or other evidence synthesis?
|
NP
|
Yes
|
NP
|
NP
|
15
|
If meta-analysis was justified, did the review authors use appropriate methods for statistical combination of results?
|
NP
|
Yes
|
NP
|
NP
|
16
|
Did the review authors use a satisfactory technique for assessing the risk of bias in individual studies that were included in the review?
|
No
|
Yes
|
Yes
|
Yes
|
|
Total (yes)
|
9
|
16
|
14
|
10
|
3.4.1 Risk of Bias Assessment of the Included Clinical Trials
The Cochrane Risk of Bias Tool (ROB) was used to assess the potential bias in the trial studies included in this research. The ROB 2 evaluates each domain in terms of the risk of bias identified, which is categorized into three main assessments: Low risk of bias, some concerns of bias, or high risk of bias (Higgins et al., 2019 & Sterne et al., 2019). Therefore, The risk of bias assessment in this study involved a comprehensive evaluation of multiple domains using the ROB 2 framework. This evaluation considered various factors, including how the random sequence was generated, how the allocation was concealed, the level of blinding implemented, the rate at which participants dropped out of the study, and the extent to which the results were selectively reported. By carefully evaluating each of these domains, a determination was made about the potential risk of bias present in the study.
Based on the outcome, after the analyzing of all included Randomized Controlled Trials (RCTs), it was determined that tow studies, accounting for 50% of the total, were found to have a low risk of bias after undergoing assessment with ROB 2. On the other hand, the remaining two studies, also comprising 50% of the total, were found to have some concerns of bias. However, Table (4) offers further details related to the evaluation of each included study, including details regarding the assessment for each domain in ROB 2.
Table (6): Cochrane Risk of Bias Tool for Quantitative Studies (n= 4)
Study number
|
Study
|
Random Sequence Generation
|
Allocation Concealment Method
|
Degree of Blinding
|
Sample Drop
|
Non-Selective Reporting of Results
|
Risk of Bias
|
1.
|
Covers et al., 2021
|
**
|
*
|
*
|
*
|
*
|
Some concerns
|
2.
|
Stanbury et al., 2020
|
*
|
**
|
**
|
-
|
**
|
Low
|
3.
|
Acarturk et al., 2015
|
**
|
**
|
**
|
*
|
*
|
Low
|
4.
|
Yurtsever et al., 2018
|
*
|
*
|
**
|
-
|
*
|
Some concerns
|
*Reported (Some concerns of bias) **Reported in full (low risk of bias). – Not reported (High risk of bias).
3.4.2 Risk Bias for Systematic Review
The risk of bias of the systematic reviews (SRs) that were included in the study was assessed using the ROBIS tool, and the results are presented in Figure (2) and Table (5). The evaluation conducted with the ROBIS tool indicated that all of the review studies included in the analysis had a low overall risk of bias. This suggests that the SRs were conducted in a manner that minimized the potential for bias in their findings. Additionally, the included SRs were found to have clearly stated their research questions in a manner that aligned well with the goals of the overall study. Based on the criteria for determining the eligibility of studies within the field of study, it was found that only 50% of the included studies provided all the necessary information regarding their eligibility criteria. Furthermore, it was discovered that one study was evaluated to have a low risk of bias, while another study (equivalent to 25% of the total) failed to provide clear and specific details about their study's eligibility criteria. Interestingly, none of the reviews reported the registration of a previous protocol, which raises concerns about the transparency and accountability of the research. Additionally, it was observed that all the studies-imposed restrictions on the inclusion of other studies based solely on the language of publication, specifically English language, without offering any justification for this exclusionary approach. This lack of justification further calls into question the validity and comprehensiveness of the research findings. In addition, when it comes to the domain of identification and selection of studies, it is worth noting that half of the reviews that were included in the analysis demonstrated a low risk in this area. However, it is important to highlight that the other half of the reviews did not fully disclose all the pertinent information pertaining to the identification and selection of studies that were ultimately included in their review.
Table (7): Risk of bias assessment with ROBIS tool for all included review studies.
Review
|
Phase two
|
Phase 3
|
|
1. Study
eligibility
criteria
|
2.Identification and selection of studies
|
3. Data collection
and study appraisal
|
4. Synthesis
and findings
|
Risk of bias
in the review
|
Valiente-Gómez et al., 2017
|
low risk
|
*
|
low risk
|
High risk
|
low risk
|
Khan et al., 2018
|
low risk
|
*
|
low risk
|
low risk
|
low risk
|
Wilson et al., 2018
|
*
|
low risk
|
low risk
|
*
|
low risk
|
Wadji et al., 2022
|
High risk
|
low risk
|
*
|
Low risk
|
low risk
|
*= unclear risk
3.5 Standardization of EMDR-based intervention protocol based on included RCTs:
When examining the use of EMDR-based intervention protocols in four randomized controlled trials conducted by (Covers et al.,2021, Stanbury et al., 2020, Acarturk et al., 2015 & Yurtsever et al., 2018), it becomes apparent that there is significant variability in the number and duration of EMDR sessions utilized. Despite conducting a comprehensive review, no standardized protocol for implementing EMDRS has been established. Upon analyzing each study's protocol, it was found that 50% of the trials included only two EMDR sessions (Covers et al., 2021 & Yurtsever et al., 2018), one study utilized a total of six sessions (Stanbury et al., 2020), and the remaining study incorporated seven sessions of EMDR, with one session per week (Acarturk et al., 2015). Moreover, it is important to note that the duration of each session can vary significantly between different study protocols. For instance, when examining two studies (Stanbury et al., 2020 & Acarturk et al., 2015), it was found that each session lasted for 90 minutes. However, in another study conducted by (Covers et al.,2021), the sessions were extended to 210 minutes. Additionally, in a final study conducted by (Yurtsever et al., 2018), each session had a duration of 240 minutes. Interestingly, it was observed that as the number of sessions increased, the duration of each session tended to decrease. This conclusion was drawn after evaluating all the studies included in this analysis.
Table (8) Duration and protocol of employing EMDR intervention.
Author/Year
|
Number of sessions
|
Duration of intervention
|
Duration of each session
|
Covers et al., 2021
|
2
|
4 weeks
|
210 minutes
|
Stanbury et al., 2020
|
6
|
6 Weeks
|
90 minutes
|
Acarturk et al., 2015
|
7
|
7 Weeks
|
90 minutes
|
Yurtsever et al., 2018
|
2
|
3 days
|
240 minutes
|
3.6 The effectiveness of using eye movement desensitization and reprocessing therapy on reducing the severity of symptoms among individuals diagnosed with post-traumatic stress disorder:
After conducting a thorough and comprehensive evaluation of various studies included in this review, it was found that several research studies have been carried out to assess the intensity of symptoms among individuals diagnosed with post-traumatic stress disorder (PTSD) after employing the eye movement desensitization and reprocessing therapy. Taking into account all the studies that were included, a total of eight published studies were analyzed, with a balanced distribution of 50% randomized controlled trials (RCTs) and 50% systematic reviews and meta-analyses. These studies collectively involved a total of 2912 participants. The findings from these studies indicated that eye movement desensitization and reprocessing therapy (EMDR) showed significant improvements in reducing the severity of symptoms among individuals diagnosed with PTSD. To illustrate, a previous RCT conducted by (Covers et al., 2021) to assess the effectiveness of early intervention with eye movement desensitization and reprocessing (EMDR) therapy to reduce symptoms of post-traumatic stress, feelings of guilt and shame, sexual dysfunction, and other psychological dysfunction such as general psychopathology, anxiety, depression, and dissociative symptoms in victims of rape, all participants in EMDR group received a total of two sessions over 2-4 weeks and each session lasted for 210 minutes, based on the study result, EMDR therapy was found to be more effective than watchful waiting in reducing anxiety and dissociative symptoms in the post-treatment assessment.
The second randomized controlled trial (RCT) conducted by Stanbury et al. (2020) aimed to investigate the effectiveness of eye movement desensitization and reprocessing (EMDR) therapy and prolonged exposure (PE) therapy in treating individuals with posttraumatic stress disorder (PTSD). In this study, a group of 10 participants diagnosed with PTSD were recruited for the EMDR-based intervention. Over the course of six weeks, these participants received a total of six therapy sessions, each lasting 90 minutes. The findings of this study revealed a significant reduction in symptoms of PTSD, depression, anxiety, and stress among both the EMDR and PE therapy groups immediately after the treatment. These positive effects were also sustained at the three-month follow-up assessment. However, at the six-month mark, there was a slight increase in symptoms compared to the three-month assessment on the Clinician-Administered PTSD Scale (CAPS). It is worth noting that participants receiving EMDR therapy reported spending less time overall on exposure to traumatic memories when considering the completion of homework assignments.
The third randomized controlled trial (RCT) conducted by (Acarturk et al., 2015) aimed to investigate the impact of Eye Movement Desensitization and Reprocessing (EMDR) in reducing symptoms of post-traumatic stress disorder (PTSD) and depression among Syrian refugees. The study included a total of 14 participants in the EMDR intervention group, who received seven therapy sessions lasting 90 minutes each over a period of seven weeks. The findings of the study revealed that the EMDR group exhibited significantly lower trauma scores after treatment compared to the wait-list group. Additionally, the EMDR group also displayed lower depression scores following treatment in comparison to the wait-list group.
In a recent study conducted by (Yurtsever et al., 2018), researchers aimed to explore the effectiveness of EMDR G-TEP in treating symptoms of post-trauma and depression and preventing the development of chronic PTSD in a group of refugees living in a refugee camp. The study consisted of 18 participants who were assigned to the EMDR intervention group. These individuals received two therapy sessions, each lasting 240 minutes, over the course of three days. Additionally, they were followed up for a period of four weeks. The findings of the study revealed that the participants in the EMDR group experienced a significant reduction in PTSD and depression symptoms following the intervention. Specifically, the percentage of participants diagnosed with PTSD decreased from 100% to 38.9% in the EMDR group, while remaining unchanged in the control group. Furthermore, after the EMDR intervention, 61.1% of the participants in the experimental group no longer met the diagnostic criteria for PTSD, and this improvement was sustained at the four-week follow-up. On the other hand, in the control group, only 10.3% of individuals no longer met the diagnostic criteria for PTSD after the post-test, and this number decreased to 6.9% at the four-week follow-up. The study also found a significant decrease in depression symptoms in the EMDR group when compared to the control group during the follow-up period.
In four separate review studies exploring the impact of eye movement desensitization and reprocessing therapy (EMDR) on individuals diagnosed with post-traumatic stress disorders (PTSD), it was consistently demonstrated that EMDR effectively reduces the severity of PTSD symptoms. To further illustrate this point, a previous systematic review conducted by Valiente-Gómez et al. in 2017 investigated the effectiveness of EMDR therapy. This particular review analyzed a total of 17 articles involving 976 participants. The findings of the review indicated that EMDR therapy has the potential to serve as a valuable form of psychotherapy for addressing trauma-related symptoms in patients with psychiatric disorders.
In a second review study conducted by Khan et al. in 2018, the objective was to compare the effectiveness of Cognitive Behavioral Therapy (CBT) and Eye Movement Desensitization and Reprocessing (EMDR) in alleviating post-traumatic symptoms, anxiety, and depression among individuals diagnosed with Post-Traumatic Stress Disorder (PTSD). This comprehensive review examined a total of 14 articles that encompassed a significant sample size of 836 participants. The results of this study revealed that EMDR exhibited superior outcomes compared to CBT, specifically in reducing post-traumatic symptoms and anxiety levels.
In a study conducted by (Wilson et al., 2018), the goal was to thoroughly examine the effectiveness of Eye Movement Desensitization and Reprocessing (EMDR) therapy in treating Post-Traumatic Stress Disorder (PTSD) through a systematic and narrative review of Randomized-Controlled Trials. This review included a total of six studies that utilized randomized controlled designs and involved a combined total of 384 participants. The findings of this review revealed that EMDR therapy not only improved the diagnosis of PTSD but also led to a reduction in PTSD symptoms as well as other symptoms related to trauma. Furthermore, the study also highlighted that EMDR therapy was found to be more effective compared to other treatments for trauma and was shown to be beneficial when utilized across different cultural contexts.
Finally, in a recent systematic review conducted by (Wadji et al. in 2022), the objective was to comprehensively examine the existing research on the role of dual tasking in Eye Movement Desensitization and Reprocessing (EMDR) treatment for Post-Traumatic Stress Disorder (PTSD). This review encompassed a substantial body of literature, consisting of 11 articles and involving a total of 563 participants. Through analysis and synthesis of these studies, the findings of this extensive review shed light on the long-standing efficacy of EMDR in addressing PTSD. Over the years, numerous studies have consistently demonstrated that EMDR therapy yields positive outcomes in alleviating the distressing symptoms. Moreover, the researchers discovered a promising association between EMDR treatment and a notable decrease in PTSDs symptoms.