Translated Article: EMDR Therapy in the Treatment of Chronic Subjective Tinnitus: A Systematic Review

Chronic subjective tinnitus is a symptom that can affect one or both ears and can cause considerable distress. In subjective tinnitus, the source of this sound is unclear. EMDR, meanwhile, has emerged as an effective and safe approach for many psychiatric disorders. Below, you can read an article systematically reviewing the effectiveness of EMDR therapy for subjective tinnitus, translated and summarized by psychologist Derin Kubilay.

Many researchers use eye movement desensitization and reprocessing (EMDR) as a treatment to alleviate tinnitus symptoms. Given the substantial impact of tinnitus on patients' quality of life, as well as its high economic and societal costs, clinicians are under pressure to identify effective, evidence-based treatments. EMDR may therefore offer a cost-effective and promising single-discipline treatment. This may allow current recommendations and guidelines to be adapted as new information becomes available. Gathering compelling evidence may therefore be one of the first steps toward effective tinnitus management in the future.

Tinnitus: Definition, Prevalence, and Causes

Tinnitus is defined as the perception of sound in the absence of external auditory input. It can significantly affect a person's quality of life. These auditory sensations are commonly described as buzzing, hissing, or ringing, and can be subjective or objective. Objective tinnitus can be attributed to an internal source, such as audible blood flow or muscle contractions, whereas subjective tinnitus is considered a kind of "phantom sound" for which no external sound source can be identified. The prevalence of subjective tinnitus in the adult population is estimated at 10%–15%, but chronic subjective tinnitus develops in 8% to 20% of cases. For a large proportion of patients, these sensations are not perceived as bothersome. However, for approximately 1% to 3% of these patients, tinnitus has a significant impact on quality of life.

Tinnitus can arise from a range of underlying pathologies and conditions. In approximately 50% of cases, tinnitus is associated with otological syndromes, namely hearing loss, acoustic neuroma, Ménière's disease, acoustic trauma, and otosclerosis. Reactions to ototoxic substances and medications; psychogenic conditions such as anxiety, depression, or emotional trauma; neurological disorders; and somatic conditions (e.g., involving the temporomandibular joint or cervical spine) and metabolic diseases (e.g., hyperthyroidism) can also trigger or exacerbate tinnitus. This limited list highlights the importance of a specialized multidisciplinary diagnostic assessment.

Tinnitus and Comorbidity

Tinnitus-related distress is associated with many psychological symptoms, including sleep deprivation, concentration difficulties, depression, and anxiety. Consequently, individuals with this disorder tend to exhibit behaviors such as absenteeism, work interruption or resignation, reduced social interaction, social isolation, and avoidance of daily activities. The impact of tinnitus on patients' lives and the costs of its associated psychological symptoms to affected individuals and society are substantial. An earlier cost study reported an average cost of €6.8 billion attributable to tinnitus in the Netherlands, representing a significant economic burden. Tinnitus severity and duration, age, and co-occurring depressive symptoms were also identified as significant predictors of these costs. The high economic burden is inextricably linked to the lack of an equally effective treatment for tinnitus.

Evidence-Based Treatment

To date, existing systematic reviews of tinnitus treatments (e.g., tinnitus retraining therapy (TRT), cognitive behavioral therapy (CBT), repetitive transcranial magnetic stimulation (rTMS), hyperbaric oxygen therapy, sound therapy, and hearing aids) indicate that there is no single effective approach. No consensus has been reached regarding therapeutic outcome measures and research designs in this area. European tinnitus treatment guidelines recommended a stepped-care approach, with psychoeducation and auditory interventions as the first step. As the next step, they recommend specialized multidisciplinary CBT for tinnitus (CBT4T). However, with these recommended interventions, not all patients report a sufficient reduction in tinnitus symptoms or sustain positive treatment effects over time (i.e., reductions in tinnitus-related impairment and tinnitus severity). The heterogeneity of the tinnitus population makes it difficult to identify the most effective therapeutic pathway and further complicates research into which interventions are most effective for which patients. EMDR sheds new light on tinnitus management and may be a promising treatment for patients with chronic subjective tinnitus.

EMDR Treatment for Tinnitus

Zengin was the first clinician to propose EMDR as a method for reducing tinnitus-related distress (Zengin, 2009). EMDR was first developed by Shapiro in 1987. There is strong empirical support for its use in the treatment of posttraumatic stress disorder (PTSD). It is not recognized by many international organizations, such as the World Health Organization (2013). This scientifically grounded treatment consists of introduction, preparation, bilateral stimulation, assessment, desensitization, installation, body scan, closure, and reevaluation phases, with the use of bilateral stimulation being a key element.

This psychotherapeutic approach is guided by a theoretical model called "Adaptive Information Processing" (AIP). The AIP model proposes that our brains have an innate capacity to process life experiences and achieve an adaptive resolution. However, psychological trauma can create blockages in the information held within the brain. Symptoms develop alongside these disruptions in the processing system. This model suggests that EMDR can enhance the effective processing of these memories, allowing trauma to be processed rapidly and adaptively and current problems to be resolved.

Shapiro (2001) stated that "phantom pain," such as the continued experience of pain in an amputated limb, can be understood as a dysfunctional manifestation of stored somatic memory. EMDR treatment can target somatic memories and pain sensations and reintegrate them. As tinnitus is considered a phantom sound, it can also be compared to phantom limb pain. Evidence has been found for the effectiveness of EMDR in treating somatoform disorders (i.e., phantom limb pain and chronic pain). These disorders have been examined in the context of data showing promising results for EMDR, particularly for phantom limb pain. Recently, several researchers have focused on using EMDR as a treatment for tinnitus. The aim of the present review is to examine the effectiveness of EMDR therapy in treating tinnitus and explore the implications for future clinical studies.

Method

Study Selection

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

Inclusion and Exclusion Criteria

The following predefined inclusion criteria were applied in the eligibility assessment conducted by TL and AG:

Participants. The study population included patients diagnosed with chronic subjective tinnitus by an ENT specialist. The study included more than two patients.

Intervention. An EMDR intervention was used.

Comparator. No restrictions were applied. The study used a design in which EMDR was the active treatment.

Outcome. Measures assessing tinnitus-related distress and quality of life were considered eligible for this review.

Research Design. All clinical studies reporting pre–post assessment results for an EMDR intervention were included in this review. Case studies involving only one patient were excluded from the analysis.

Data Extraction

The following data were extracted from each study:

(a) demographic characteristics of the study population, (b) study inclusion and exclusion criteria, (c) population sample size, (d) tinnitus assessment, (e) characteristics of EMDR treatment (setting, protocol, targets, delivery, and therapist), and (f) outcomes of EMDR treatment. This assessment tool was developed to examine the methodological quality of EMDR studies.

The quality of each study was assessed using the Platinum Standard. This assessment tool was developed to examine the methodological quality of EMDR studies. Evaluating efficacy in EMDR research is the primary focus of this comprehensive assessment tool. A total of 13 criteria were used to analyze treatment-specific aspects of EMDR: clearly defined target symptoms; reliable and valid measures; use of blinded assessors; information on assessor training; manualized, replicable, and specific treatment; random assignment; treatment fidelity; unconfounded conditions; use of multimodal measures; treatment duration; level of therapist training; use of a control group; and reporting of effect sizes.

Quality Assessment

Two authors (TL and AG) independently performed the quality assessment and reached a consensus. The rating scale was applied using a checklist with three response options for scoring items (i.e., 0, 0.5, and 1). The total score classified quality as good (total > 9), fair (8–5), or poor (<5). Following guidelines formulated in a systematic review of assessment tools, not only an overall score but also all 13 domains were reported. An overview of this assessment is shown in Table 1.

Results

Types of Studies

The electronic database search yielded a total of 15 records.

Participants

Two studies reporting on a total of 49 patients with tinnitus met the inclusion criteria. These trials are presented in Table 2. Both studies reported data from a population of patients with chronic subjective tinnitus.

Quality of the Included Studies

The methodological quality of the analyzed articles was rated as fair and good according to the Platinum Standard. Table 1 defines the different criteria for evaluating EMDR studies and links them to scores. Each criterion is reported separately to ensure validity and transparency.

Demographic Information

Primary and secondary outcome measures are summarized in Table 3. Phillips et al. (2019) did not report effect sizes. Therefore, the proportions of patients showing clinically significant improvement (CSI) were compared. The number needed to treat (NNT) was reported. To enable comparison, the study's NNT was calculated and is also provided in Table 3. This derived statistic indicates how many patients need to receive this treatment for one additional patient to achieve a treatment outcome such as the one observed here.

Discussion of the Studies

Design

Both eligible studies used pretest and posttest assessments. The study by Phillips et al. (2019) had no control group, whereas Rikkert et al. (2018) used a waitlist control group in their pilot study. The use of a control condition is one of the criteria recommended by the Platinum Standard for assessing the methodological quality of an EMDR study. This delayed-treatment design provides an indication of therapeutic change and controls for the possible effects of the passage of time, but it cannot rule out nonspecific treatment effects, such as expectancy and the attention provided by a therapist willing to listen to and support the patient. The timing of follow-up assessment differed, with follow-up scheduled at either 3 or 6 months.

Sample Size

The study by Phillips et al. (2019) included 14 patients, and the study by Rikkert et al. (2018) included 35 patients. In both prospective clinical studies, the study population consisted of patients with diagnosed tinnitus who required urgent psychiatric treatment and had no serious mental health condition.

EMDR Protocol

The main distinction between the two studies lies in the protocols used. Rikkert et al. (2018) used only the standard EMDR protocol, whereas Phillips et al. (2019) used the standard protocol to process tinnitus-related memories but developed another protocol, called "tEMDR," to target current tinnitus. The study population exhibited symptoms unrelated to any history of trauma. Rikkert and colleagues adopted a trauma-focused approach using the standard EMDR protocol, with targets consisting of distressing tinnitus-related memories and traumatic experiences that evoked feelings of helplessness. However, although the focus of the Rikkert study was on traumatic memories, the significant reduction in tinnitus-related distress could not be explained by a reduction in PTSD symptoms, as PTSD scores decreased only minimally. This indicated that somatic symptoms, namely tinnitus sensations, could be processed by desensitizing emotional associations, memories, and experiences.

Treatment Duration

Treatment duration was compared across the two studies. Therapy lasted between 540 and 600 minutes, consisting of six 90-minute sessions and ten 60-minute sessions. The number of sessions varied depending on the treatment effect.

Level of Therapist Training

Therapists' level of training and the availability of supervision may affect treatment outcomes. Level II has been identified as appropriate for evaluating efficacy in EMDR research.

Treatment Targets

Both studies processed distressing memories associated with tinnitus, although their approaches appeared to differ. Phillips et al. (2019) focused on the tinnitus-specific experience after processing traumatic memories, if any were present. Comparing the two protocols revealed no fundamental difference in treatment targets. During the desensitization and reprocessing phase, patients were asked to focus on an external bilateral stimulus, such as visual (eye movements) or tactile stimulation. These stimuli were used in both studies.

Symptom Improvement

Comparable outcome measures were not used; however, a comparison can be made based on the percentage showing improvement in the two pilot studies. The study by Rikkert et al. (2018) showed a significant reduction in tinnitus-related distress after treatment in 51.4% of participants, with a stable effect at the 33-month follow-up. In the study by Phillips et al. (2019), 57.1% of participants reported less tinnitus-related distress after treatment, and this effect increased 6 months after treatment (64.3%). An important point to note is the difference in study design: the Phillips study had no control group, whereas the study by Rikkert and colleagues used a waitlist control condition. These figures should therefore be interpreted cautiously in this context.

Primary Outcome Measures

Tinnitus Functional Index (TFI). The TFI was developed to assess tinnitus-related distress and the impact of tinnitus symptoms on daily life (i.e., intrusiveness, sense of control, cognitive interference, sleep problems, hearing problems, relaxation, quality of life, and emotional state). A total of 18 of the 35 patients experienced CSI, and this effect remained stable after 3 months.

Tinnitus Handicap Inventory (THI). Instead of the TFI, Phillips and colleagues used the THI to investigate reductions in tinnitus-related distress after treatment (i.e., functional, catastrophic, and emotional subscales).  A total of eight of the 14 patients reported significant improvement after treatment, and nine patients experienced a positive treatment effect after 6 months.

Secondary Outcome Measures

Mini Tinnitus Questionnaire (Mini-TQ).

This self-report measure scored tinnitus-related distress across specific domains: emotional and cognitive distress, intrusiveness, sleep disturbances, somatic complaints, and auditory perceptual difficulties. A significant reduction in tinnitus was detected after EMDR treatment

Symptom Checklist-90 (SCL-90). This checklist was developed to assess psychological distress and was used in the Rikkert study. A statistically significant reduction in psychological distress was found after the EMDR intervention.

Self-Rating Inventory for Posttraumatic Stress

Disorder (SRIP).

Only a minimal decrease in SRIP scores was found over time. No significant effect was detected. Therefore, the reduction in tinnitus-related distress could not be explained by a reduction in PTSD symptoms.

Beck Depression Inventory (BDI). The BDI was used in the Phillips study to measure depression severity. These scores showed a significant reduction in depressive symptoms after treatment, with a seven-point decrease (p  = .0098). This effect was maintained after 6 months.

Beck Anxiety Inventory (BAI). The BAI screened for clinical anxiety and assessed anxiety symptoms. No clinically significant improvement was observed.

Summary of Strengths and Limitations

Strengths of the Included Studies

All authors reported clinical and statistical improvement in tinnitus symptoms and strong treatment effects at the latest available follow-up. The reviewed studies had several strengths. The multicenter nature of the study by Rikkert et al. (2018) demonstrated the generalizability of the treatment outcome. These researchers also noted that using multiple therapists limited therapist bias. The use of a delayed-treatment group can control for spontaneous improvement and fluctuations.

Therapists and participating patients were blinded to assessment results. A manualized treatment protocol, session checklists, and video-recorded sessions enhanced treatment fidelity. Furthermore, a significant reduction in tinnitus-related distress was achieved after treatment, and this effect was maintained after 3 months. The reported effect sizes were also comparable to those in previous tinnitus studies. A feature discussed in the study by Phillips et al. (2019) was the development of a specialized EMDR protocol (tEMDR). This protocol met the needs of patients with tinnitus, including through its use of a "present-oriented focus." The notable effects of tEMDR remained stable after treatment and at 6 months.

Limitations of the Included Studies

Some limitations of the reviewed studies warrant discussion and point toward implications for future research. The within-group design used in the study by Rikkert et al. (2018) raises the question of whether nonspecific effects (e.g., positive attention, hope, and expectancy) explain small changes. The study by Philips et al. (2019) also lacked an independent control group. The number of patients was much smaller than in the Rikkert study. Treatment effects should therefore be interpreted cautiously and in this context. Nevertheless, these preliminary studies have clear clinical relevance, as more than 50% of patients achieved significant improvement.

Research Implications

This systematic review comprises two relevant studies. Analyses and comparisons are difficult because of the heterogeneity of the outcome measures used by Rikkert et al. (2018) and Phillips et al. (2019). Variability in assessment tools limits the ability to obtain clear evidence about actual treatment effects. Nevertheless, the percentages showing improvement (e.g., 51.4% versus 57.1%) are comparable, and derived scores from NNT calculations (e.g., 1.95 versus 0.82) were available, indicating that a similar number of patients needed to be treated for one additional patient to benefit.

Recommendations for Future Research

The promising results of both EMDR studies highlight the value of future randomized controlled trials with an adequate control group, a substantial sample size, and standardized EMDR procedures. In addition, future research should focus on using not only subjective outcome measures but also objective measures. This is because no association has been found between certain aspects of tinnitus, such as tinnitus loudness and pitch, and tinnitus-related distress. A randomized controlled trial protocol examining the value of EMDR in tinnitus treatment was recently published. This study incorporated a comparison of two therapies—TRT + CBT as the evidence-based control treatment and TRT + EMDR as the experimental treatment—along with the use of the original EMDR protocol and both subjective and objective measures. These data may provide more detailed insights into the effectiveness and mechanisms of action of this treatment in patients with tinnitus.

Conclusion

EMDR has been proposed as a potential treatment for patients with tinnitus, as positive effects have previously been reported in two pilot studies. This review suggests that EMDR may be a promising treatment for patients with moderate to severe tinnitus symptoms. Furthermore, tinnitus-related somatic sensations, emotions, experiences, and memories can be successfully desensitized using EMDR. Replication using both waitlist and active control conditions is warranted.

Reference:

Luyten, T., van Rompaey, V., van de Heyning, P., Van Looveren, N., Jacquemin, L., Cardon, E., Declau, F., Fransen, E., De Bodt, M., & Gilles, A. (2020). EMDR in the Treatment of Chronic Subjective Tinnitus: A Systematic Review. Journal of EMDR Practice and Research, 14, 135 - 149.