Tinnitus is often referred to as a buzzing, ringing, or hissing sound perceived in one or both ears or centrally within the head. It can be defined as the perception of a constant or intermittent sound without the presence of external auditory stimuli [1-3]. Tinnitus is a very common symptom, with a prevalence of 10%-20% of the world population, which accounts for >70 million people solely in Europe [1,2,4,5]. Most patients with tinnitus have chronic subjective tinnitus, that is, they have experienced tinnitus for ≥6 months, and the tinnitus sound is a phantom sensation of sound without the presence of a physical sound source and is hypothesized to be owing to abnormal neural activity [6-8]. The underlying cause of tinnitus varies widely and can be of an auditory as well as a nonauditory nature [9,10]. Consequently, there is also great variance in the clinical presentation. Some patients can easily ignore the tinnitus sound and do not find it bothersome, while 5%-10% of the patients with tinnitus experience substantial disruptions of daily functioning and health-related quality of life [4,11,12]. These differences are also because of the diversity in comorbidities and associated complaints such as mood changes, anxiety, depression, sleep disorders, concentration problems, and other psychological or emotional issues [4,11,12].

There is no standard rehabilitation trajectory for the treatment of tinnitus as no single tinnitus treatment is beneficial for every patient [13-16]. The tinnitus profile of each patient is unique and needs a tailored, multidisciplinary treatment approach, which can consist of a combination of several treatment forms [13-16]. The current clinical management strategies that are most often recommended include education, counseling, tinnitus retraining therapy (TRT), or cognitive behavioral therapy (CBT) [16,17]. TRT is a combination of sound therapy and retraining counseling, teaching patients about the auditory system and the mechanisms by which tinnitus is thought to arise [18-21]. It aims to induce habituation of tinnitus-induced reactions and tinnitus perception, allowing patients to achieve control of their tinnitus [22]. CBT can consist of multiple aspects such as applied relaxation, positive imagery, cognitive restructuring of negative beliefs about tinnitus, exposure to sounds, behavioral activation, and mindfulness and attention exercises [6,21,23,24]. CBT is often guided by a psychologist who offers support and provides tools to deal with tinnitus [6,21,23,24]. Both TRT [18-21] and CBT [6,21-23] are proven to be effective for alleviating the complaints of tinnitus. However, while both these treatments are effective, they are also costly and time consuming, especially if patients are unable to maintain results and are repeatedly in need of help in whichever form [25-27]. Treatments reducing the need for in-person care by increasing patients’ self-management skills are therefore of high interest.

To address the burden of in-person care of patients with tinnitus, self-management, self-help, and low-contact treatment forms are on the rise. Partially owing to the COVID-19 pandemic, telerehabilitation, that is, delivery of care from a distance, became a necessity rather than an opportunity [28-30]. Studies have shown that low-contact treatment provided from a distance through applications and videoconferencing can be used as a substitution of or an addition to in-person clinical care for several conditions [31-36]. Although real-time telerehabilitation with synchronous video consultations is the most commonly known and used form of telerehabilitation [35,37], this field is not restricted to that. Telerehabilitation is remotely delivering care with any form of technology; this can indeed be by using audio or video communication but also by making use of messaging platforms for guidance, software in smartphone apps with rehabilitative purposes, virtual reality, or a combination of all these forms of technology [38,39]. In the field of audiology and, more specifically, in the field of tinnitus, telerehabilitation in both full and hybrid forms has the potential to be very useful during the entire therapeutic process [29,40,41]. Telerehabilitation has been used as an aid for early screening, initial evaluation, diagnosis, therapy, long-term monitoring, provision of web-based support, etc [40]. For example, in the last decade, computer platforms and smartphone apps increasingly found their way into the treatment of tinnitus, most often in the form of CBT and sound therapy [42,43]. These apps are easy to implement in clinical practice and form easily accessible treatment options. In addition, they might also improve the cost-effectiveness of tinnitus treatment [40,43,44]. As telehealth is a highly dynamic research field, the treatment options for tinnitus in the future world of telerehabilitation will progress even more owing to the advances made in the field of technology [44].

In the past decades, various low-contact and self-management telerehabilitation treatments were developed for patients with tinnitus to search for an alternative or additional tool for the existing treatment options that are time consuming and costly. The current review aims to make an overview of the research concerning the effectiveness of telerehabilitation interventions for self-management of tinnitus.

The eligibility of the studies was assessed based on the inclusion and exclusion criteria listed in Textbox 1. Studies were included if participants were adult patients (aged >18 years) reporting subjective tinnitus as a primary complaint. The distinction whether the subjective tinnitus of the study participants was either primary or secondary was made after screening the full text as this information is often not included in the abstracts of the studies. The study intervention had to include any possible telerehabilitation intervention for the self-management of tinnitus complaints. Synchronous telerehabilitation interventions, where the remote face-to-face intervention mimics in-person care, were not considered for this review as these interventions do not aim to improve the self-management of patients. The search concluded on October 18, 2021, and no publication date restrictions were imposed.

We consulted PubMed (National Center for Biotechnology Information), ScienceDirect, Scopus, Web of Science, and Cochrane Library in the search of eligible studies.

The search queries were composed using the terms “tinnitus (population) and self-management,” “telerehabilitation,” “smartphone app (intervention),” and their synonyms. Both free terms and Medical Subject Headings terms were included in the search. The complete search queries are included in Multimedia Appendix 1.

All articles collected by the search strategy were screened twice. Two reviewers (SD and AC) independently and blindly performed the eligibility assessment on the title and abstract [46]. Afterward, the blind mode was turned off, and disagreements were discussed and resolved during a consensus meeting (SD, AC, and SM). Articles that were included by both reviewers or received a label “maybe” were considered for the second screening for full text. This second screening was also fulfilled independently by the 2 researchers. After a second consensus meeting and cross-referencing the reference lists of the included articles (SD, AC, and SM), the final articles were obtained (Figure 1) [45].

The included articles were divided into subcategories based upon the different forms of telerehabilitation. In total, 6 subcategories were distinguished, including internet-based CBT (iCBT) with guidance (feedback, monitoring, and support by a psychologist or audiologist), iCBT without guidance, self-help devices, self-help manuals, smartphone apps, and other internet-based interventions. For all studies, information was collected and arranged in data extraction tables per subcategory. Information was organized according to the applicable items of the subdivisions: population, intervention, comparison, and outcome.

The recorded study and population characteristics included author, year of publication, study design, sample size (n), gender distribution (%), mean age and SD (years), type of tinnitus, mean duration of tinnitus, and presence of hearing loss.

The tables of evidence per subcategory had 3 main categories: intervention and comparison, outcome, and results. These categories are subdivided as follows:

The tables were subdivided per subcategory of self-management and telerehabilitation and, in addition, per study design, that is, within each subcategory the studies are separated by trial status.

For the risk of bias (RoB) assessment, the Cochrane RoB2 tool was used. This tool is specifically designed for assessing RoB in randomized controlled trials (RCTs) [47]. However, the domains are, in general, also applicable for other study designs [47]. Most of the included studies are RCTs, and the remaining studies are of diverse study design, making it difficult to compare RoB. Therefore, it was decided to use the RoB2 tool for all included studies [47]. The figures summarizing the RoB conclusions, per domain and overall, were made using RoBvis, an RoB visualization tool by Cochrane [48].

Owing to the heterogeneity in telerehabilitation forms and the differences in chosen outcomes and methodology of the included studies in this review, the reviewers opted not to perform a meta-analysis but to summarize the data in a systematic review. Data were discussed according to the subdivisions mentioned under the Data Items section.

Certainty of study results was examined using the GRADE framework considering the RoB, imprecision, inconsistency, indirectness, and publication bias of the included studies [49].

A total of 555 potentially relevant articles were retrieved from the initial database searches on October 18, 2021 (Figure 1 [45]). Of these 555 articles, 213 (38%) duplicates were removed, resulting in 342 (62%) remaining articles for primary screening. In the primary screening, 81% (277/342) of articles were excluded. The reasons for exclusion are specified in Figure 1. Finally, the full text screening was completed for 59 articles as the full text of remaining 6 articles could not be retrieved. Of these 59 articles, 30 (51%) articles were excluded as 12 (40%) articles were based upon wrong intervention (no telerehabilitation), 17 (57%) articles were based on wrong population (no primary tinnitus complaint or patients aged <18 years), and 1 (3%) article was excluded because of the full text being in a noneligible language. This resulted in a total of 29 eligible articles [50-78]. These articles were divided into subgroups based upon the used form of telerehabilitation as an intervention. Overall, 6 studies were categorized into 2 subgroups, as they compared 2 intervention forms. The level of agreement between both reviewers during the study selection process was 93% for the primary screening and 96% for the screening on full text.

Most of the controlled trials were RCTs with a low RoB arising from the randomization process (D1) [50,53,55,56,58-60, 63,64,66-70,73,74]. Two studies were non-RCTs [61,72]. All controlled trials showed some reasons for concern of RoB owing to deviations from the intended interventions (D2), except for Abbott et al [50] and Chattarjee et al [74]. RoB owing to missing outcome data (D3) was scored “high concerns” and “some concerns” for studies with respectively moderate to high dropout rates and no clearly specified plan on how to handle these missing data. The 3 controlled trials concerning smartphone apps did not provide any information concerning missing data and dropout [72-74]. All controlled studies were rated “some concerns for RoB” in the measurement of outcome (D4) as assessors were not blinded. Most studies did have a full, clear, correct, and specified plan for statistical analysis, suggesting that the concern for RoB in the selection of the reported result (D5) was low. Overall, studies were rated “some concerns” to “high concerns” of RoB. Figure 2 provides the RoB assessment results of the controlled trials.

They did all show some concerns of RoB owing to deviations from the intended interventions (D2). RoB because of missing outcome data (D3) was again scored “high concerns” and “some concerns” for studies with respectively moderate to high dropout rates. All studies specified their statistical analysis beforehand, resulting in low RoB in the selection of the reported result (D5). Figure 3 provides the RoB assessment results of the noncontrolled trials.

A summarization of the RoB scores can be found in Figures S1 and S2 in Multimedia Appendix 2.

In general, the included studies had a low to moderate certainty level according to the GRADE framework [49]. GRADE scores are indicated for each study.

This systematic review aimed to provide an overview of the forms of telerehabilitation available for patients with tinnitus and the effectiveness of these forms. Telerehabilitation might be of great importance to promote the self-management of patients and improve the cost-effectiveness of the treatment [40,43,44]. Currently, the recommended treatments for patients with tinnitus are TRT and CBT, which are tailored to the needs of the patient [16,17]. Although these in-person treatment forms are proven to be effective, they are also time consuming and costly [25-27]. Telerehabilitation might, therefore, form a solution as a replacement of or an aid to the in-person care currently delivered [40,43,44]. In total, 29 articles, that dove into the subject of telerehabilitation, were found eligible for this systematic review. Some of these articles examined multiple telerehabilitation forms [50-78]. Overall, 6 categories of telerehabilitation could be differentiated, namely iCBT with guidance, iCBT without guidance, self-help devices, self-help manuals, smartphone apps, and other internet-based interventions. For every category, evidence was provided stating that this form of telerehabilitation was effective in reducing tinnitus distress and complaints [50-78].

As CBT is one of the most recommended evidence-based treatments for patients with tinnitus, it is not unusual that most studies took a closer look at iCBT. iCBT has proven to be effective for the treatment of posttraumatic stress disorder, anxiety, and depression [81-83]. The effectiveness of iCBT with guidance was also affirmed for the tinnitus treatment by 17 studies [50-67]. Most often, CBT is offered by a trained psychologist; however, in the 7 studies from the research group of Beukes [51-57], patients received guidance offered by an audiologist [6,21-23]. An interesting limitation of these studies concerning iCBT was the high dropout rates. Dropout from iCBT was also a concern when it was researched in the treatment of populations other than patients with tinnitus [81-83]. It is hard to differentiate whether patients did not complete follow-up assessments because they did not achieve the expected results and dropped out or because they did improve and did not find it necessary to receive further help and examination. Therefore, it is not certain that, in general, iCBT with guidance will be as beneficial as predicted for every patient. The high dropout rates for iCBT with guidance group forecast the same for iCBT without guidance group. This is because patients have to work autonomously to fulfill the modules of the iCBT course and do not receive motivational messages, feedback, support, or any form of additional guidance.

The current understanding of predictors of dropout is limited [83]. An important point of discussion that needs to be highlighted is that, according to previous research and clinical experience, CBT is a treatment form that might be susceptible for dropout by nature even as in-person care [84]. Further research is needed to assess why adherence and retention rates are low in iCBT and whether the reasons for dropout in in-person CBT are equivalent. Some of the included studies offered hypotheses for the high dropout rates. First of all, iCBT might not be engaging enough despite regular therapeutic encouragement [50,52]. In addition, it is highly demanding and time consuming for the patients [50,54,62]. Patients with lower levels of initial tinnitus distress appeared to be less motivated and more likely to drop out or be a nonresponder [50,51,55,65]. Finally, the attitude of the patient toward the treatment and the personality of the patient might be of great influence. Patients with an open personality, with a hope of improvement, and who believed the treatment was credible did show the best results [61,63,64,67]. It needs to be noted, however, that patients expecting positive results of treatment are often also patients who are likely to improve. Future iCBT interventions should address the barriers of lack of time, motivation, and engagement and should emphasize the link between efforts and results to the patient. The iCBT content has to be more engaging and should consist only of the most essential modules to limit the time investment. Options that need further exploration are, for example, increasing the interactivity, enhancing visual education material rather than plain text, implementing rewards within the program, or other ideas to increase compliance.

Internet-based intervention programs, such as iCBT, as well as others such as iACT, have been of great interest since the past decennia owing to the great advancements made in technology and the accessibility of the internet. Although iCBT and other CBT-based self-help treatments are a frequently researched topic in the world of telerehabilitation, the use of self-help devices is not a topic of research. In addition, the evidence for existing in practice therapies that are in need of a self-help device is limited compared with the evidence available concerning the effectiveness of CBT. In this review, only 2 studies with a small sample size examined the use of a self-help device. However, self-help devices form a window of opportunity to reduce the need for in-person care in treatment forms where several sessions are required to possibly achieve results. A risk involved with self-help devices is that not all patients are disciplined enough to perform the required treatment sessions at the requested time. For these categories of telerehabilitation through other internet-based interventions, the dropout rates for self-help manuals and self-help devices were most often not reported. Smartphone apps are more practical and portable than self-help devices. Almost every adult uses a smartphone in daily life. How convenient would it be if patients with tinnitus could use the device they already keep on them, their smartphone, as a treatment tool? Not only in the field of tinnitus, but in medicine and rehabilitation in general, the use of smartphone apps to offer treatment from a distance is on the rise and forms the newest trending topic in the field of medicine [85,86]. The same evolution is observed in the field of audiology. In the past years, the number of smartphone apps developed has increased widely. Some of these apps target the treatment of tinnitus, most often in the form of sound therapy [42,43]. Sound therapy, delivered through a smartphone app, appeared to be effective in reducing tinnitus distress. An important note, however, is that the smartphone apps were only tested in smaller sample sizes. Although the previous forms of telerehabilitation observed high dropout rates, the dropout rates for the use of smartphone apps were not reported, except for 2 studies. Henry et al [75] reported a dropout rate of 8% and Tyler et al [78] reported a dropout rate of 23.1%.

However, there are some limitations for the studies included in this systematic review. All included studies scored some to high concerns of RoB. As a result, the included studies are of low to moderate certainty. Furthermore, a comparison of effectiveness among studies was not feasible owing to the variety of questionnaires used to measure the level of tinnitus complaints, severity, or distress. In addition, some crucial confounding parameters were not considered by all studies. Only a minority of studies concerning iCBT in this review observed the proportion of participants with hearing loss or how many patients used hearing aids. However, how these studies define the presence of hearing loss was often not clarified. The studies concerning other telerehabilitation forms such as self-help manuals, self-help devices, and smartphone apps did seldomly define the percentage of participants with hearing loss. Hearing loss is an important risk factor for developing tinnitus [1]. In addition, there are patients with audiometrically normal hearing who experience tinnitus [1,87,88], but tinnitus severity and distress are known to be significantly worse in patients with tinnitus with hearing loss in comparison with patients with tinnitus without hearing loss [89]. Therefore, hearing loss might be an important confounding variable to consider. An audiometric examination of patients with tinnitus is therefore of value when researching patients with tinnitus.

Although hearing loss is an important confounding factor to keep in mind, other factors also need to be considered. First, gender plays a role in how patients perceive their tinnitus [90-95]. Men show less tinnitus-related distress compared with women [90-92]. Consequently, they might react differently to treatment [94]. Second, the prevalence of chronic tinnitus increases with age and older patients scored the loudness, annoyance, and distress of the experienced tinnitus higher [96,97]. As a consequence, the age of the patient might have an influence on how beneficial a treatment is. Third, the mental state of the patient, which can be measured using, for example, the Hospital Anxiety and Depression Scale, might be important. Tinnitus is known to be closely associated with anxiety, depression, stress, sleeping problems, etc [95,98,99]. The more serious these comorbidities are, the worse is the prognosis of the tinnitus [99]. These additional complaints severely influence the choice of the therapeutic plan [95,98,99]. Subsequently, hyperacusis is often a comorbid complaint of tinnitus patients, resulting in higher tinnitus severity and mental distress [100]. Finally, some patients might have neck or jaw complaint and this somatosensory afference might influence their tinnitus. This is referred to as somatic tinnitus or somatosensory tinnitus, often characterized by simultaneous onset or increase and decrease of tinnitus and the neck or jaw complaints [101,102]. The presence of somatic tinnitus requires an adapted treatment approach. Physiotherapy can be used to reduce the neck or jaw complaints and can consequently alleviate the tinnitus [103]. All the factors mentioned earlier might have an impact on the effectiveness of a treatment and should therefore be considered in future research.

The results of this systematic review indicate that overall, there is low to moderate quality evidence that telerehabilitation in the form of iCBT with or without guidance, self-help manuals, self-help devices, smartphone apps, and other internet-based interventions effectively reduces tinnitus severity and distress. Telerehabilitation might form an alternative or additional tool to the recommended in-person care that patients currently receive. This review accentuated, however, that the greatest barrier to the success of telerehabilitation is the lack of compliance to treatment. Factors such as lack of time, engagement, motivation, and openness of the patient resulted in participant dropout and should be considered. In addition, it was noted that all included studies showed some to high concerns of RoB resulting in low to moderate certainty of the statements concerning the effectiveness of the telerehabilitation treatment forms. Future research should consider limiting the RoB and should further explore which factors are most likely to cause the lack of compliance and how clinicians can counteract these factors. Owing to the advances in technology made every day, telerehabilitation will keep evolving and therefore remains a trending topic to follow-up.