Effectiveness of tinnitus therapy using a mobile application

Today, modern technologies are used in all areas of life. Patients are increasingly willing to use unconventional methods of treatment and innovative approaches to problems. Due to a growing interest in new technologies, the developers of mobile applications have created a number of tools that can be useful in medicine, for example for diabetics [1] or asthmatics [2]. There are also applications in audiology, such as noise meters, hearing screening applications, or applications to help treat tinnitus [3].

Subjective tinnitus is an internal sound perceived only by the person themselves [4]. It can be described as a squeak, noise, rumble, humming, buzzing, or crackling. People with tinnitus experience the sound as coming from one or both ears or “in the head” [4]. The presence of tinnitus can have a negative impact on the overall functioning of a patient in their private and professional environment. The phenomenon may give rise to difficulties in concentration, a tendency to fall asleep, and mental disorders such as depression, anxiety, and general irritation [5]. Tinnitus becomes annoying in situations, where the patient cannot accept it, negatively affecting their general quality of life as well as their family [6]. Tinnitus occurs in a large fraction of the population (5–20%) and its incidence increases with age [7, 8]. A recent World Health Organization report suggests there may soon be a significant increase in the population who experiences tinnitus and there will be a growing demand for effective treatments [9].

So far, there is no fully satisfactory and effective therapy for tinnitus. There are no approved pharmaceutical treatments for tinnitus, and patients often use off-label drugs (e.g., anti-vertigo products, antidepressants, sedatives, gingko-biloba extract). Hall et al. [10] showed that most of general practitioners and ENT specialists (> 60%) were dissatisfied with current drug treatments. A meta-analysis of randomized controlled trials revealed some benefits of cognitive behavioral therapy—a medium effect (0.54) for therapist-delivered CBT and a small effect (0.38) for internet-delivered CBT [11]. Wang et al. [12] in their systematic review of sound therapy concluded that it can suppress tinnitus in some patients, but there is still limited evidence of its effectiveness. Currently, when organic disease has been excluded, the standard health care procedure is to provide the patient with sound therapy, cognitive–behavioral therapy, or relaxation therapy [4]. Moreover, sound therapy is often self-help in the hope of alleviating the nuisance of tinnitus for a long time (habituation) or even for a short time (masking).

Sound therapy is a broad term that can be used in many ways. According to the American Tinnitus Association, it is the use of an external acoustic signal to change the perception of tinnitus or one’s reaction to it [13]. This form of therapy does not cure tinnitus, but can significantly reduce the annoyance and negative reactions caused by it [14]. Four mechanisms of sound therapy can be distinguished: masking, distraction, habituation, and neuromodulation [15]. Current clinical practice in our clinic is to a large extent aimed at habituation to tinnitus, i.e., the use of an external signal to reclassify tinnitus as an insignificant sound that the patient should subconsciously ignore. Sound therapy may use various devices, including sound generators, broadband noise generators, or hearing aids [6].

The main rationale for the present study is that, as a result of the common use of mobile devices, mobile applications have been gaining more popularity among tinnitus patients. Mobile applications are tools installed on mobile phones whose principles of operation are practically identical to those of conventional generators. The creators of mobile applications all claim these tools meet their objectives. Unfortunately there is still a lack of research confirming their effectiveness [16, 17]. In March 2016, when this study began, more than 200 tinnitus applications were available on “Google Play” and “App Store” [18]. Although there are a few studies that have evaluated the effectiveness of mobile applications for tinnitus, they are usually based on a very small number of subjects and lack longitudinal outcomes [19, 20]. Another consideration was that, based on the assumption that it is the sound itself which is important, not the device that emits it, one can assume that sound therapy using mobile applications should be as effective as using a classical sound generator. Moreover, findings from one application might be useful for improving others [21, 22].

We, therefore, picked one well-featured and representative mobile application for sound therapy—ReSound Tinnitus Relief. The objective of the current study was to assess its effectiveness over half a year.

The current study shows that continuous use of sound therapy for half a year provided by the mobile application ReSound Tinnitus Relief coincided with a decrease in tinnitus symptoms as measured by THI and TFI. Both questionnaires showed that the biggest changes were in emotional status. This may not be surprising, since emotional and psychological problems are known to go side by side with tinnitus [33, 34]. Studies published so far concerning conventional sound therapy using a sound generator (SG) have shown that such devices can relieve the severity of tinnitus. Rocha et al. [35] showed on a group of 30 patients that SG can be helpful both for people with isolated tinnitus and people with tinnitus and hearing loss. At the 6 month follow-up, the overall results of the THI questionnaire were reduced in the group of people with tinnitus and normal hearing from M = 66.7 (SD = 12.3) to M = 11.6 (SD = 10.0), and in the group with tinnitus and hearing loss, from M = 66.4 (SD = 13.8) to M = 10.1 (SD = 12.9). The observed changes were statistically significant. Another study of 10 people by Suzuki et al. [36] also showed a reduction in the severity of tinnitus as measured by the THI questionnaire. A reduction of at least 20 points was found in 9 people, but due to the small group this result was not statistically significant. In both the above-mentioned studies, behind the ear (BTE) SGs were used, which could have affected the results, because the sounds were emitted through the earphones directly into the external ear canal. The use of sound generators shows promising results and it might encourage patients to choose these devices. However, in compare with mobile applications which are mostly free and easy available, the sound generators are expensive devices. The cost may be the important difference between the sound generator and the mobile application.

On the other hand, a systematic review by Sereda et al. [37] showed that there was no evidence that one type of sound therapy device (i.e., hearing aid, SG, or combination hearing aid) was more effective than the other. Our study showed that there was a statistically significant difference in the perception of tinnitus after the use of sound therapy via a mobile application. Mobile applications are more flexible devices than sound generators. Thanks to the ability to update and modify a mobile application, it is easier for patients to customize the tool to their individual needs. Greater availability and low cost (most mobile apps are free) can also help achieve better results. A wide selection of free apps allows the user to experiment with each, so the patient can choose the best one for their own needs.

There are only a few studies on the use of mobile applications in tinnitus therapy [38]. For example, Henry et al. [19] developed one and tested it on a group of 25 people for 8 weeks. The recorded general changes in the average TFI results were small, but almost one-third of the users (8 out of 25), obtained a reduction of 13 points or more. According to the authors of the TFI questionnaire, a decrease of 13 points or more reflects a change that may be significant for a given person. The sounds best rated by the participants of this study were: ocean waves, rain, fan, and frogs. Mehta et al. [39] used standardized tools (THI questionnaire and a visual analog scale) to assess the impact of the HyperSound tinnitus application. According to a visual analog scale, a significant reduction in loudness and severity of perceived tinnitus was obtained. The THI questionnaire showed a decrease in overall mean score from 43 (SD = 30) to 39 (SD = 29), but these results were not statistically significant (p = 0.06), probably caused by the small sample size (n = 11). The observation time was very short (5 min) and there was no information about the long-term effects of the therapy.

There are also distinct groups of tinnitus sufferers who have profound hearing loss in one ear (called single-sided deafness, SSD) or in both ears. Cochlear implants (CIs) prove to be a very effective treatment which restores their ability to hear [40]. There is also the side-effect that a CI reduces tinnitus in around 90% of subjects and even eliminates it in around 20% [41‐44]. These numbers might be improved even further, and therefore, CI users might also be potential users of mobile applications for tinnitus. In fact, Tyler and colleagues used the same app as the one in the current study (ReSound) on CI subjects [20]. The investigation focused mainly on the acceptability of the presented sounds. According to the CI users, the most acceptable sound was rain and waves on rocks. For 90% of study participants the therapy was satisfactory, but only 16 people took part. It was also found that using an application on a mobile phone was more convenient for patients than using tablets or computers. The participants said that the application "provided them with a wide variety of sounds" and the signals provided by the implant were acceptable.

The studies above describe preliminary tests of mobile applications and innovative devices used today to reduce tinnitus severity. The results might be generally classed as satisfactory, although it is not possible to compare them accurately because of small samples and different methodologies. In our study we found a decrease in tinnitus severity as measured with the THI questionnaire. General severity slightly decreased after 3 months of sound therapy with the ReSound application and it decreased significantly after another 3 months. This change was particularly apparent in the negative emotions associated with tinnitus. Many researchers emphasize that tinnitus is associated with lowered mood, irritability, and increased stress [45, 46]. In this context, the results of this study can be considered particularly encouraging. Our research showed that reduction of negative emotions occurred faster than in the reduction of the Functional subscale, where change was only noticeable after 6 months. The Functional subscale concerns aspects such as concentration, sleep problems, limiting social contacts due to tinnitus, and others—i.e., cognitive strategies and patterns of behavior that are more difficult to change than emotions and so require more time. Clinically important change (improvement) in tinnitus severity measured with the THI was found in 12% and 54% of the participants after 3 and 6 months, respectively. The effect seems quite encouraging when compared, e.g., to the effect of an intervention combining counselling and hearing devices shown by Gudex et al. [47]. After 1 month of intervention it was found that 27% of the tinnitus subjects showed a clinically important change on the THI and 24% after 2 years.

Similarly to THI, a reduction in tinnitus severity was also demonstrated by TFI, where the overall rating slightly decreased after 3 months and decreased significantly after another 3 months. It is worth noting that the biggest changes were recorded in negative emotions, which is consistent with the THI results and increases the reliability of the results. The sense of control over tinnitus increased significantly after just 3 months and remained stable. Psychologists emphasize that the sense of control over health is an important factor [34, 48]. It seems particularly beneficial for tinnitus patients to have a tool by which they can readily relieve themselves of chronic and troublesome discomfort. Tinnitus control by means of an external agent has a positive effect on self-empowerment and improves the psychological functioning of the sufferer. We found clinically important improvement in tinnitus severity measured with the TFI in 27% of the participants after 3 months and in 58% of the participants after 6 months. The effect was comparable or even better than that revealed by Jacquemin et al. [49]. In this study authors found that the improvement in tinnitus treatment (High-definition transcranial direct current stimulation) was significant for 50% of the responders who underwent 6 sessions of neuromodulation 7 weeks earlier. So, our result is comparable and serves as additional evidence for the effectiveness of tinnitus therapy using a mobile application.

As in the case of THI, TFI also showed beneficial (although more delayed) effects of the sound therapy on functional aspects of tinnitus such as cognition, sleep, hearing, and relaxation. For these aspects, it was necessary to wait over 3 months for positive effects, which also indicates the need for careful planning of mobile device therapy and to convince the patient that systematic and long-term use of the application is needed.

This study involves the largest number of people in terms of published studies to date. The results from standardized questionnaires from a group of 52 patients indicate that the tested application may contribute to tinnitus reduction. However, to be able to draw more certain conclusions, the study needs to be conducted in a more controlled environment. The questions which arose during analysis of the data are a catalyst for improving the protocol. The current study is being continued, and now includes a control group and more accurate monitoring of the experimental group.