Exploration of eye movement desensitization and reprocessing in treating posttraumatic stress-disorder in patients with acquired brain injury: a retrospective case series

ABSTRACT

Background: Posttraumatic stress disorder (PTSD) is prevalent in people with acquired brain injury (ABI). Despite the established efficacy of eye movement desensitization and reprocessing (EMDR) for PTSD in general, evaluation studies on EMDR in ABI patients with PTSD are limited.

Objective: The aim of this study is to explore clinical features, treatment characteristics, feasibility and first indications of efficacy of EMDR in adult ABI patients with PTSD.

Method: This retrospective consecutive case series included ABI patients, who received at least one session of EMDR for PTSD between January 2013 and September 2020. PTSD symptoms were measured using the Impact of Event Scale (IES) pre- and post-treatment. Affective distress was measured using the Subjective Units of Distress (SUD) pre- and post-treatment of the first target.

Results: Sixteen ABI patients (median age 46 years, 50% males), with predominantly moderate or severe TBI (50%) or stroke (25%) were included. Treatment duration was a median of seven sessions. Post-treatment IES scores were significantly lower than pre-treatment scores (p < .001). In 81% of the cases there was an individual statistically and clinically relevant change in IES score. Mean SUD scores of the first target were significantly lower at the end of treatment compared to scores at the start of treatment (p < .001). In 88% of the patients full desensitization to a SUD of 0–1 of the first target was accomplished. Only few adjustments to the standard EMDR protocol were necessary.

Conclusions: Findings suggest that EMDR is a feasible, well tolerated and potentially effective treatment for PTSD in ABI patients. For clinical practice in working with ABI patients, it is advised to consider EMDR as a treatment option.

HIGHLIGHTS

• This retrospective consecutive case series (N = 16) explores clinical features, treatment characteristics, feasibility and first indications of efficacy of eye movement desensitization and reprocessing (EMDR) in adult patients with acquired brain injury (ABI) and Posttraumatic stress disorder (PTSD).

• The results suggest that EMDR is a feasible and potentially efficacious treatment for PTSD in ABI patients, as patients demonstrated statistically and clinically significant large sized reductions in PTSD-symptoms after EMDR treatment.

• For clinical practice in working with ABI patients, we advise to consider EMDR as a treatment option.

1. Introduction

Acquired brain injury (ABI) refers to damage to the brain caused by events after birth. Most common causes of ABI are trauma, cerebrovascular incident and hypoxia. Consequences of ABI include long-lasting disorders/problems in cognition, behaviour and emotion (Consortium Cognitieve Revalidatie, 2007). There is increased risk of posttraumatic stress disorder (PTSD) in patients with ABI. Prevalence of PTSD is estimated at 16% after traumatic brain injury (TBI) (Van Praag et al., 2019) and 23% in the first year after stroke (Edmondson et al., 2013).

PTSD can develop after experiencing or witnessing a life-threatening or seriously injuring event and is classified as a trauma-stressor disorder (American Psychiatric Association, 2013). PTSD is characterized by four clusters of symptoms: (1) intrusions, (2) avoidance, (3) negative alterations in cognition and mood, and (4) alterations in arousal and reactivity that start after the traumatic event. Symptoms persist for at least one month and cause significant distress or impairment in social, occupational or other important areas of functioning (American Psychiatric Association, 2013).

PTSD has shown to be related to decreased health-related quality of life and decreased functional outcome in patients with ABI (Haagsma et al., 2015; Stein et al., 2018). In addition, the presence of PTSD in ABI patients is associated with lower return to work (Garrelfs et al., 2015; Glozier et al., 2008; Hedlund et al., 2011; Stein et al., 2018). As only a minority of people with PTSD spontaneously remits within months after onset (Kessler et al., 2017; Morina et al., 2014), awareness of the possible presence of PTSD in ABI patients is important, as well is treatment of PTSD.

There is robust support for the efficacy of Eye Movement Desensitization and Reprocessing (EMDR) in treatment of PTSD in adults (Cusack et al., 2016; Mavranezouli et al., 2020; Wilson et al., 2018). EMDR is recommended by several guidelines for treatment of PTSD (Department Of Veterans Affairs, D.o.D., 2017; Phelps et al., 2022; World Health Organization, 2013). EMDR is a standardized, protocolled treatment based on the assumption that distress associated with traumatic events is caused by unprocessed information (Shapiro, 2001). During the treatment, the client attends to disturbing material while simultaneously focusing on an external stimulus, i.e. most commonly therapist-directed eye movements, or auditory or tactile stimuli. The distress is reduced during this desensitization process and changes in dysfunctional or negative beliefs occur (de Jongh & ten Broeke, 2011a). Currently, most evidence for the explanation of how EMDR works, supports the ‘working memory hypothesis’. This entails that as a consequence of tasks competing for limited working memory capacity when done simultaneously, negative memories become less vivid and less emotional and are stored in this new way (van den Hout & Engelhard, 2011). There is also evidence supporting other models to explain the mechanisms of EMDR, such as the orienting response, see Landin-Romero, Moreno-Alcazar (Landin-Romero et al., 2018) for a review.

Given the substantial support for the efficacy of EMDR in adults with PTSD, this treatment may also be a suitable treatment for PTSD in ABI, especially since EMDR does not rely heavily on cognitive functions (de Jongh & ten Broeke, 2011a), which are often impaired in patients with ABI. There are some encouraging case reports that suggest EMDR is feasible and efficacious in ABI patients with PTSD (de Roos et al., 2011; Pagani et al., 2018; van Oort & van Zandvoort, 2016; Vink et al., 2016). However, there are, to the best of our knowledge, no controlled studies on the efficacy and feasibility of EMDR in adult patients with ABI and PTSD.

Given the lack of research into the applicability and efficacy of EMDR as a treatment for PTSD in patients with ABI, we performed an explorative study as an initial evaluation. We retrospectively evaluated clinical features, treatment characteristics, feasibility and first indications of efficacy of EMDR in adult patients with ABI and PTSD in a retrospective case series.

2. Method

2.1. Design and participants

The current study was set up as a retrospective case series. We included patients who were treated at the Multidisciplinary Specialist Center for Brain Injury and Neuropsychiatry of GGZ Oost Brabant, the Netherlands, between January 2013 and September 2020. This centre offers multidisciplinary treatment to patients with psychiatric problems and ABI, combining rehabilitation treatment and mental health care.

Patients were included in the current study if they (1) were diagnosed with PTSD according to the criteria of DSM-IV or DSM-5 by clinical evaluation of a psychiatrist or psychologist; (2) were treated with at least one session of EMDR for PTSD; (3) filled out the Impact of Event Scale (Horowitz et al., 1979) prior to and post-EMDR; (4) were > 18 years old. Patients participating in an experimental study on this subject were not included.

All patients provided informed consent. The study was approved by the scientific review board of GGZ Oost Brabant and conducted in accordance with the 1964 Declaration of Helsinki and its later amendments.

2.2. Measurements and procedures

2.2.1. Sociodemographic and clinical information

The following sociodemographic and clinical information was collected from the electronic patient record (EPR): sex, age, in- or outpatient, the ABI (type of and time since ABI), other DSM classifications, PTSD (i.e. the index trauma and time point of traumatic event), EMDR treatment (i.e. therapist, number and frequency of sessions, stimuli used in desensitization, adjustments to standard protocol). Further, total pre-treatment scores on the Outcome Questionnaire-45 (de Jong et al., 2007; Lambert et al., 2004) were collected from the EPR as a descriptive baseline measure of subjective general mental health. The cut-off for clinical significance (i.e. a score below which is considered normal functioning) was set at 56 (Timman et al., 2017). EPRs were checked for adverse advents (e.g. self-harm, suicidal behaviour, necessity for crisis intervention) during the period of treatment with EMDR.

2.2.2. Outcome measures

2.2.2.1. PTSD symptoms

Self-reported symptoms of PTSD were assessed using the Dutch version of the Impact of Event Scale (IES) (Brom & Kleber, 1985; Horowitz et al., 1979). Patients filled out the IES before starting (T0) and after ending the treatment with EMDR (T1) in the context of evaluation of clinical care: the period between filling out the IES (T0) and start of treatment varied as the IES was used either as a screener for PTSD symptoms (after which EMDR treatment was indicated) or as starting point of already planned EMDR treatment. The IES consists of 15 items on a 4-point scale, total score 0–75 (with higher scores representing more symptoms), regarding the amount of distress that one associates with a specific event (i.e. PTSD symptoms of the two factors intrusion and avoidance) in the past week. The IES has been used to screen for PTSD symptoms in ABI patients (Bruggimann et al., 2006; Huenges Wajer et al., 2018; Utz et al., 2019) and demonstrated adequate psychometric properties (van der Ploeg et al., 2004). The cut-off for clinical significance was set at 26 (Rodenburg et al., 2009).

2.2.2.2. Affective distress

In every EMDR session Subjective Units of Distress (SUD’s) were recorded as part of the treatment protocol to assess the level of affective distress in relation to an image of the traumatic event. The SUD is rated on a scale ranging from 0 (absence of distress) to 10 (maximum of distress) (Wolpe, 1969) and is an ongoing measure throughout the delivery of EMDR. For the purpose of this study, the SUD before starting and after ending treatment of the first trauma target (‘Target 1’, i.e. the most distressing image, see Treatment), was used as a measure of effect of EMDR treatment. Adequate psychometric properties have been reported of SUD scores obtained in the context of EMDR treatment (Kim et al., 2008). Full desensitization of a target is operationalized as decline of the SUD to a score of 0–1 (Shapiro, 2001).

2.2.3. Treatment

EMDR treatment was delivered by four clinical neuropsychologists, who all completed an EMDR Europe-approved Basic Training program and were experienced in diagnosing and treating patients with ABI. The number of sessions was based on the patient’s individual needs and judgement of the therapist considering the PTSD. EMDR therapy was delivered using the manualized standard EMDR 8-phased protocol, in Dutch (de Jongh & ten Broeke, 2011a; Shapiro, 2001). Treatment included all eight phases of the EMDR standard protocol, with the only exception being the installation of the safe place or any other form of stabilization. Slight changes in treatment protocol were made by the Dutch EMDR Association during the time frame of the study. See Box 1, Appendix A, for a detailed description of the procedure. Eye movements are the preferred and first stimulus to use, but in case of epilepsy, eye movements are refrained from and other (combinations of) stimuli are used (de Jongh & ten Broeke, 2011b). In case horizontal eye movements are complicated (for instance, due to hemianopia or ocular motoric problems), other stimuli are chosen. The ‘index trauma’ is the traumatic event that is currently most distressing and the subject of intrusion symptoms. One or more targets of this event are treated (first) in EMDR.

2.3. Statistical analyses

2.3.1. Sociodemographic, clinical and treatment characteristics

Descriptive analyses (count, percentage, median and range) were performed to describe sociodemographic (i.e. age, sex), clinical (i.e. type of ABI, months since ABI, type of index trauma, timing of index trauma, in- or outpatient, DSM disorders, OQ45 score, adverse events) and treatment characteristics (i.e. therapist, adjustments to standard treatment protocol, total number of sessions, number of sessions to desensitize the first target, stimuli used in desensitization, drop out).

2.3.2. PTSD symptoms

Descriptive analyses were performed on time span between T0-start of treatment and end of treatment-T1, follow-up time (T0-T1 span in weeks; median, range, IQR) and IES group scores at T0 and T1 (median, range and IQR). Comparative analyses for IES group scores at T0 and T1 were performed with Wilcoxon signed-rank test (because the assumptions of normality were not met upon exploration of the data), and effect size r (r = z/√N) (Rosenthal, 1991). We respectively considered r = .10 as a small, r = .30 a medium and r = .50 as a large sized effect. We counted the number and percentages of patients scoring impaired (i.e. defined as IES score ≥26) at T0 and T1 to assess the clinical significance of individual PTSD symptoms over time. Individual statistically significant change from T0 to T1 in IES scores was determined by computation of the reliable change index (RCI) for the IES (see Appendix B, Box 2). This RCI value reflects the absolute difference required for an individual change score to be regarded as reliable (i.e. unlikely due to measurement error alone). Change was defined as a RCI value exceeding +/−11.31, representing worsened and improved PTSD symptoms, respectively. The number and percentage of patients reporting improved, stable or worsened symptoms were counted. To examine the relationship between follow-up time (T0-T1 span in weeks) and IES change scores (i.e. T0-T1 difference scores), Spearman’s correlation coefficient was used.

2.3.3. Affective distress

Descriptive (median, range and IQR) and comparative analyses (i.e. using Wilcoxon signed-rank test and r for effect size) were performed for SUD group scores of the start and end of treatment of Target 1. We counted the number and percentage of patients reaching full desensitization to a SUD of 0–1 for Target 1 and described the pattern of change in SUD scores for the individuals not reaching full desensitization. Statistical analyses were performed using the IBM Statistical Package for the Social Sciences (SPSS) version 26.0. Alpha was set at .05.

3. Results

3.1. Participant characteristics

Thirty-four patients with PTSD and ABI were treated with EMDR between January 2013 and September 2020. Eleven patients did not fill out an IES pre- and post-EMDR, four patients participated in an experimental study and were therefore excluded from the current study, three patients did not provide consent for study participation. In total, 16 patients were included in the current study.

Table 1 presents characteristics of the ABI patients treated with EMDR who completed the IES at T0 and T1. For more than half (n = 5 TBI, n = 2 stroke, n = 2 other ABI) of the patients, the (circumstance surrounding the) ABI was the index trauma, for example the accident or violent assault causing TBI, the experience of having a stroke, or delusions in a confusional state. In three patients, the A criterion for PTSD according to the DSM-5 was, in contrast to criteria B-H, actually not fulfilled, due to the nature of the traumatic events (classified as ‘other’ in Table 1).

Table 1.

Sociodemographic and clinical characteristics of ABI patients with PTSD treated with EMDR who completed the IES.

Patient characteristics (N = 16)	Number (%)	Median (range)
Male	8 (50%)
Age in years		46 (25–68)
Outpatient	14 (88%)
Type of ABI
TBI moderate/severe	8 (50%)
Stroke	4 (25%)
Othera	4 (25%)
Time since ABI in months		65 (5–354)
Type of index trauma for PTSD ABIb (Other) serious injury or death (of loved one) Sexual abuse Other	9 (56%) 2 (12.5%) 2 (12.5%) 3 (19%)
Timing of index trauma (other than ABI) Prior to ABI Post ABI	2 (13%) 5 (31%)
PTSD main reason for care	6 (38%)
Comorbid DSM disorders and problems
(Neuro)cognitive disorder	16 (100%)
Personality change due to the ABI	6 (38%)
Mood disorder, predominantly depressive disorder	3 (19%)
Personality disorder	0 (0%)
Anxiety disorder (other than PTSD)	1 (6%)
Substance abuse disorder	1 (6%)
Epilepsy	2 (13%)
Occupational problem	6 (38%)
Relational problem Other problem related to the social environment	5 (31%) 3 (19%)
Other problem related to psychosocial circumstances	4 (25%)
OQ45 total score pre-treatment OQ45 total score above clinical cut-off	11 (85%)c	68 (36–105)c

Note: ABI = acquired brain injury; PTSD = posttraumatic stress disorder; EMDR = Eye Movement Desensitization and Reprocessing; IES = Impact of Event Scale; TBI = traumatic brain injury; ^abrain hypoxia, multiple sclerosis, (extirpation of) frontal meningioma, bifrontal cystic encephalomalacia; ^bthe event of or circumstances causing the ABI or the direct consequences of the ABI (for instance the accident/stroke, the violent assault, experiences in ambulance/hospital, or in confusional state/delirium); DSM = Diagnostic and Statistical Manual of Mental Disorders; OQ45 = Outcome Questionnaire 45; ^cdata missing n = 3.

Thirteen percent of the cases (n = 2) experienced the index trauma in their childhood (i.e. prior to sustaining the ABI): both index traumas were single events (sexual abuse and sudden death of a parent).

3.2. Treatment characteristics

All patients were treated by the first author. In most cases, treatment was provided in weekly sessions of a maximum duration of 90 min. Sessions were shortened (with a minimum of 45 min) if, for instance, cognitive dysfunction complicated longer session duration. In one patient therapy during clinical admittance was more frequent and consisted of four sessions a week (on separate days) with therapist rotation of four different psychologists. There were no drop outs of treatment before completion. Table 2 lists treatment characteristics of the included patients.

Table 2.

Treatment characteristics of ABI patients with PTSD treated with EMDR who completed the IES.

Treatment characteristics (N = 16)	Number (%)	Median (range)
Total number of EMDR sessions Number of EMDR sessions to treat Target 1 Stimuli used in desensitization  Eye movements in all sessions  Eye movements in part of sessions  Only other stimulib  Multiple stimuli at once	9 (60%)a 4 (27%)a 2 (13%)a 6 (40%)a	7 (2–14) 3 (1–8)

Note: ABI = Acquired Brain Injury; PTSD = Posttraumatic Stress Disorder; EMDR = Eye Movement Desensitization and Reprocessing; IES = Impact of Event Scale; ^adata missing n = 1; ^bfor instance: auditory bilateral clicks, sensory bilateral buzzers/taps, calculations.

The instructions of the standard protocol were comprehensible for the majority of patients. In one patient adjusted instructions, namely simplification of language and presenting instructions in a visual manner, were needed due to aphasia. The Dutch children’s and adolescent’s protocol for EMDR (de Roos et al., 2018) was used as a guideline for these adjustments, and instructions were shortened and simplified to the core of the standard protocol. Adjustments were made in the presentation and rating of the SUD and VOC (which are verbal in the standard protocol), because giving marks or understanding the scale proved difficult. The scale was drawn as a continuum with marks and the SUD/VOC was rated by pointing the scale.

In the majority of patients eye movements were used to tax working memory, although in some cases a switch was made to other stimuli because eye movements proved difficult to perform or seemed to elicit somatic complaints like dizziness. In almost half of the patients multiple stimuli at once were used in desensitization to tax working memory load. No adverse events were reported.

3.3. PTSD symptoms

The IES was filled out within a day prior to start of EMDR in nine patients, within two weeks pre-treatment in three patients and respectively in one, two, three and five months pre-treatment in four patients. The IES post-treatment was filled out within two weeks after finishing EMDR in ten patients, within three to four weeks in four patients and within six to seven weeks in two patients. Median follow-up time (span between T0 and T1) was 16 weeks (range 3–54, IQR = 20.75). No other PTSD treatment was administered between respectively T0 and EMDR, and EMDR and T1.

Median IES score at T0 was 42 (range 33–64, IQR = 16.5). Median IES score at T1 was 6 (range 0–47, IQR = 18.75). IES score was significantly lower at T1 versus T0, z = −3.52, p < .001, ES was large with r = .62. There was no significant relationship between follow-up time and IES change score from pre- to post-treatment, r_S = .15, p = .57.

At T0, all patients had clinically significant scores on the IES (n = 16). At T1, 81% of the patients (n = 13) scored below the cut-off for clinical significance. Figure 1 displays individual scores set against the IES cut-off for clinical significance.

Figure 1.

Individual IES scores of ABI patients with PTSD pre- and post-treatment with EMDR (n = 16).

Note: Plot showing the pre-treatment (X-axis) and post-treatment (Y-axis) individual patient’s Impact of Event Scale (IES) scores. The dashed lines mark the boundaries of reliable change (i.e. +/−11.31). The circle marks the mean group score pre- and post-treatment. Points above the upper boundary of reliable change represent statistically significant deterioration (i.e. reporting more symptoms after treatment as compared to before treatment), triangles within the dashed lines represent no statistically significant improvement over time and squares below the lower boundary of reliable change represent statistically significant improvement (i.e. reporting less symptoms after treatment as compared to before treatment). The dotted lines mark the IES clinical cut-off score of 26, IES scores right of and above these lines are considered clinically significant. Based on Morley and Dowzer (2014).

In 81% (n = 13) of the patients there was a statistically significant improvement over time, represented by the IES change score exceeding the RCI value of −11.31 at T1 compared to T0. There were no patients with positive IES change scores, indicating that no individual showed absolute deterioration from pre- to post-treatment. For all individuals who showed a statistically significant improvement in IES score over time, post-treatment IES scores were no longer clinically significant. Figure 1 displays individual change set against the boundaries of reliable change on the IES.

3.4. Affective distress

Median SUD of Target 1 at the start of treatment was 9 (range 7–10, IQR = 2, N = 16). Median SUD of Target 1 at the end of treatment of Target 1 was 0 (range 0–8, IQR = .88, N = 16). SUD scores were significantly lower at the end of treatment of Target 1 versus the start, z = −3.44, p < .001, ES was large with r = .61. In 14 patients (88%), full desensitization to a SUD of 0–1 of Target 1 was accomplished. In the remaining two patients (12%) no full desensitization was accomplished with SUD scores of respectively 2 (starting at 9) and 8 (starting at 8).

4. Discussion

This retrospective case series explored clinical features, treatment characteristics, feasibility and first indications of efficacy of EMDR as a treatment for PTSD in adult ABI patients. All patients included in the current study were, in addition to the diagnosis PTSD, diagnosed with a neurocognitive disorder according to the DSM-classification. Only in one of the patients adjustments of instructions in the standard protocol for EMDR were made. These adjustments were in line with the Dutch children’s protocol for EMDR in which instructions are simplified and presented in a visual manner. No adverse events were reported. There was no exacerbation of PTSD-symptoms measured by the IES. There were significant and large reductions in PTSD-symptoms on a group level, as well as individual statistically and clinically significant reductions in PTSD-symptoms in the majority of patients. This was corroborated by significant reductions in affective distress (SUD) reported by ABI patients in relation to the most disturbing traumatic image during the course of EMDR treatment. Overall, results suggest that EMDR treatment is feasible and seems to be efficacious in reducing PTSD-symptoms in ABI patients.

It has been suggested that symptoms of ABI (e.g. cognitive impairments, problems with emotion regulation, impulse control) and physical problems (e.g. headache or problems with vision or other senses) may limit patients’ ability to engage in or benefit from psychological PTSD treatments (Kennedy et al., 2007; Tanev et al., 2014). On the other hand, it can be stated that EMDR is a straightforward, relatively short psychotherapy, which does not rely heavily on cognitive functions, and painful memories do not have to be extensively discussed (de Jongh & ten Broeke, 2011a). This is one of the first studies demonstrating that EMDR treatment indeed is feasible as well as promising with regard to its efficacy in patients with ABI, cognitive disorder and PTSD. Although no controlled studies are available on the efficacy and feasibility of EMDR in patients with ABI and PTSD, controlled studies are available of EMDR on PTSD symptoms in other patient groups with comorbid disorders, like severe psychotic disorder (van den Berg et al., 2015), autism (Lobregt-van Buuren et al., 2019) and intellectual disability (Karatzias et al., 2019; Mevissen et al., 2017). In those studies, EMDR was also shown to be feasible, acceptable, and effective (van den Berg et al., 2015) or potentially effective (Karatzias et al., 2019; Lobregt-van Buuren et al., 2019; Mevissen et al., 2017).

This study has some limitations that need to be noted. The most important limitation is the lack of an experimental design which facilitates the exclusion of threats to the validity of our findings (e.g. regression to mean, lack of control group, selection bias etc.). For instance, the time point at which the IES was administered varied significantly. Although we found no relationship between the change in IES-scores and the time span between pre- and post-EMDR IES, and no other PTSD-treatment was offered between pre- and post-IES, we cannot rule out any effects from non-PTSD-specific treatments (e.g. cognitive rehabilitation). However, the significant reduction in affective distress, measured during the EMDR sessions, suggests that EMDR is producing a treatment effect.

Secondly, we established PTSD classification by clinical diagnosis and solely used self-report instruments to establish PTSD symptoms post-treatment, whilst taking a structured clinical diagnostic interview is considered the gold standard in diagnosing PTSD in general. In addition, the diagnostic interview appears to distinguish symptoms of psychopathology better from symptoms of ABI than self-report questionnaires, and is less affected by ABI-related problems such as memory deficits (Cnossen et al., 2017). Future research should therefore incorporate structured clinical diagnostic interviews, such as the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) (Weathers et al., 2018), to diagnose PTSD and to serve as a primary outcome measure.

Third, as the study is an initial, clinically based evaluation, we included patients with various kinds of index traumas, for instance the ABI itself, childhood trauma and sexual assault and with various kinds of ABI. We did not assess whether any of our patients met the criteria of the International Statistical Classification of Diseases and Related Health Problems, 11th revision (ICD-11), diagnosis of complex PTSD (Maercker et al., 2022), which was being proposed at the time of the study. It is still unclear whether complex PTSD requires a different treatment approach than described in the existing international treatment guidelines for PTSD, namely with extra preparatory, stabilizing interventions (Cloitre et al., 2010; Maercker et al., 2022). We could not examine this in our study. However, results of recent randomized controlled trials suggest a different treatment approach may not be required (Oprel et al., 2021; van Vliet et al., 2021).

Further, we did not include performance-based measures of cognition, i.e. from neuropsychological tests. Studies of psychotherapy of PTSD showed that more proficient pre-treatment performance on standardized neuropsychological measures of memory was associated with better treatment response (Haaland et al., 2016; Nijdam et al., 2015; Scott et al., 2017). Research is needed to examine to what extent pre-treatment cognitive performance moderates treatment effect in patients with ABI and what the minimum level of cognitive function is to engage in EMDR. Also, psychological treatments for PTSD have been shown to improve memory functioning (Susanty et al., 2022). It would be interesting to include pre- and post-treatment measures of cognitive performance in studies on psychotherapy for PTSD in patients with ABI, to learn more on the relative contribution of PTSD to cognitive disorders in this group.

A final limitation is that the participants included in our study may not be fully representative of ABI patients in general, as our population had more comorbid psychiatric disorders than the ABI-population in general (Mitchell et al., 2017; Whelan-Goodinson et al., 2009). However, although the patients in our study had comorbid psychiatric and/or cognitive disorders, results nevertheless suggest EMDR treatment is feasible and potentially effective. Therefore, we presume that EMDR treatment is feasible and potentially effective in ABI patients with PTSD and less psychiatric comorbidity. Future randomized controlled research should now address the subject.

In conclusion, the results of this evaluative retrospective case series suggest that EMDR is a feasible and potentially efficacious treatment for PTSD in ABI patients. The study included a diversity of ABI patients, mostly with moderate or severe TBI or stroke, with comorbid psychiatric and/or cognitive disorders. Treatment was well tolerated, relatively short and few adjustments to the standard protocol for EMDR were required. For clinical practice in working with ABI patients, we advise to consider EMDR as a treatment option. In case adjustments to the standard EMDR protocol are necessary because of cognitive disorder or aphasia, the children’s EMDR protocol and presenting instructions in a visual way may be helpful.

Appendices.

Appendix A

Box 1. Dutch EMDR standard protocol Before the first treatment session the therapist discusses treatment rationale, psychoeducation, and addresses treatment planning. The next sessions focus on the patients’ traumatic memory or memories. The patient is asked to concentrate on specific aspects of the traumatic memory, particularly (1) its most distressing ‘image’ (i.e. the target); (2) the cognition associated with it, that is, the patient's negative or dysfunctional belief of him- or herself; (3) the accompanying emotions, physical responses and Subjective Units of Distress (SUD). At the core of the EMDR technique is the principle of taxing the working memory in each individual case, preferably by eye movements. This is operationalized by having the patient focus on the therapists horizontal hand movements in front of the patient at eye level or a horizontally moving light on an EMDR light bar, and/or audio tones (irregular clicks) bilaterally through headphones, and/or tactile stimuli (taps, for instance) while the patient is mentally confronting the most disturbing part of the traumatic event. The patient is asked to focus on the stimuli while holding the distressing image in mind. After about 30 s the distracting stimuli are paused and the patient is asked what comes up. The therapist lets the patient know he/she should focus on that and continues desensitization (i.e. offers working memory taxing stimuli). This is continued until there is no more change in the patient report (i.e. twice the same association in a row) or after 5–10 min. Then the image is brought into recollection and the patient assesses the SUD associated with the image. The patient is asked to focus on the image and name what is distressing in the image. The procedure then continues with desensitization. This continues until the SUD is 0. By asking questions, the therapist checks the specific memory of the patient for other distressing images, and, when present, those are also desensitized. Next, the validity of cognition (VOC) of the positive cognition in relation to the image (i.e. the counterpart of the negative cognition) is assessed (on a scale of 1 (completely false) to 7 (completely true)) and desensitization is applied until VOC is 7. When there is enough time, a body scan is done to assure there is no more distress associated with the image. In case there are other distressing memories of the event about which intrusions exist, the protocol is repeated as described above. In case there is also anticipatory fear and avoidance behaviour, for instance fear of a future debilitating stroke and avoiding being alone, a ‘flashforward’ (Logie & de Jongh, 2014) is applied. Desensitization is applied as described above on the image of the anticipatory fear as if it were a memory. When appropriate, a future template is installed of a realistic avoided situation. To help foster closure, each session ends on a positive note. Homework between sessions is not a standard part of EMDR and was not applied.

Appendix B

Box 2. Computation of the reliable change index (RCI) for the Dutch version of the Impact of Event Scale following the method of Jacobson and Truax (1991) Step 1. Compute standard error of measurement SEm = s √ 1-rxx, with s = 20.4 and Cronbach’s α = .96 (van der Ploeg et al., 2004) SEm = 20.4√1−.96 = 4.08; Step 2. Compute Sdiff Sdiff = √ 2 (SEm2), with SEm = 4.08 Sdiff = 5.77 Step 3. Compute RCI RCI = Sdiff * 1.96, with Sdiff = 5.77 RCI = 11.31

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The participants of this study did not give written consent for their data to be shared publicly, so due to the sensitive nature of the research supporting data is not available.