Internet-based interventions for adults with hearing loss, tinnitus and vestibular disorders: a protocol for a systematic review

Chronic auditory conditions can be debilitating and greatly reduce quality of life [1]. They generally fall into three broad categories, namely hearing disability, tinnitus and vestibular disorders. The impact of hearing loss is often multifactorial and not isolated to reduced hearing and increased listening effort. For example, it can negatively impact on the ability to communicate, which amplifies social isolation, and can lead to relationship difficulties and reduced well-being [2, 3]. In addition, the presence of uncorrected hearing loss increases the risk of cognitive decline and dementia [4, 5]. For those with troublesome tinnitus, many aspects of daily life may be disrupted, leading to sleep and concentration difficulties, and indirect psychosocial effects, including feelings of hopelessness, irritability, frustration, anxiety and depression [6, 7]. Loss of vestibular function can cause imbalance, dizziness and an increased risk of falls [8]. This can affect the ability to carry out activities of daily living such as walking and driving. There is an increased dependence on others and decreased life satisfaction [9].

Auditory-related conditions are prevalent with around 15% of the world’s population having some degree of hearing loss [10]. In addition, hearing loss of greater than 20 dB was found to be the second most common impairment, from a systematic review investigating 310 diseases [11]. At least 10% of the adult population have tinnitus, as seen from studies across the globe, for example from Italy [12], Korea [13], New Zealand [14], the UK [15, 16] and the USA [17, 18]. The prevalence of dizziness has been reported to be 20–30% among adults [9, 19]. Although hearing loss, tinnitus and vestibular disorders can occur in isolation, they often co-occur and are associated with otological pathologies such as otosclerosis, Ménière’s disease, cerebellopontine angle lesions (such as vestibular schwannoma) and superior semicircular canal dehiscence [20]. In addition, the prevalence of auditory-related conditions generally increases with age [21‐23]. This is a concern as the proportion of elderly people is rising [24]. These disabilities add to the healthcare and societal economic burden. Unaddressed hearing loss poses an annual global cost of $750 billion dollars [25]. The annual cost of tinnitus interventions in the UK was calculated to be £750 million in total and the annual societal costs relating to tinnitus was calculated at £2.7 billion [26]. In the USA, the annual economic burdens of unilateral and bilateral vestibular disorders were found to be $3531–$13,019 per patient [27].

As these are chronic long-term conditions, ongoing management over a period of years or decades is often required [25]. Interventions to prevent, identify and address hearing loss, tinnitus and vestibular disorders can be cost-effective [28‐30] and can bring great benefit to individuals in reducing the adverse impact these difficulties have [31‐33]. The standard intervention for hearing loss involves the provision of hearing aids within an audiology clinic [34]. Although hearing aids can help reduce the negative consequences of hearing loss, the uptake and adherence are suboptimal, even in countries where the provision of hearing aids is free at the point of use [35]. Despite moderate-to-strong evidence that vestibular rehabilitation is an effective treatment for peripheral vestibular disease [36], less than 3% of eligible primary care patients with dizziness ever received vestibular rehabilitation [37]. Moreover, the structure, provision of, and access to tinnitus services vary greatly depending on demographic location [38].

In an attempt to increase access to treatments and improve outcomes of rehabilitation for auditory-related disabilities, Internet-delivered interventions have been developed [39‐42]. These interventions have generally focused on providing self-help techniques for behavioural change by means of a structured programme. Within the field of audiology, they have been developed to improve hearing aid use and/or reduce hearing disability [43]; reduce tinnitus distress through techniques such as cognitive behavioural therapy [44]; or improve balance function through vestibular rehabilitation [45]. These programmes generally last 6–10 weeks and may be independent of professional support (unguided) or offer some form of support (guided). The intervention content usually consists of a range of modules (6–21 chapters) with interactive elements such as quizzes and worksheets. Internet interventions for auditory-related conditions have a relatively short history with the first trials conducted in the field of tinnitus [42]. As such, evidence of their efficacy and effectiveness is still being sought. In 2010, Swanepoel et al. [46] conducted a broad-spectrum systematic review to identify telehealth applications for screening, diagnosis and interventions in audiology. In this review [46], the use of Internet-based interventions was only identified for tinnitus and not for hearing loss and vestibular disorders. Since then, additional studies related to Internet-based interventions in the fields of tinnitus have been published as well as in the fields of hearing loss and vestibular disorders. With this emergence of new evidence, an updated review is warranted. Within the hearing domain, there has been a systematic review investigating the efficacy of computer-based auditory training [46], but not Internet-based training. Reviews in the field of tinnitus have investigated the efficacy of cognitive behavioural therapy (CBT) for tinnitus [47], tinnitus management [48] or self-help tinnitus interventions [49]. No recent review has focused solely on Internet interventions for tinnitus. Moreover, systematic reviews for vestibular rehabilitation were found [50], but these were not specific to Internet-based interventions. Reviews that have investigated Internet interventions have either explored a specific health conditions (e.g. anxiety) or a variety of general health problems [51]. In view of the lack of an up to date and comprehensive review of the role of Internet interventions for auditory conditions, the current review protocol was designed. The aim of this protocol is to investigate the effects of Internet-based interventions for adults with hearing loss, tinnitus and vestibular disorders. This will include determining the efficacy of Internet-based interventions, referring to the extent to which an intervention produces a beneficial result under ideal conditions, as well as their effectiveness, which is the extent to which a specific intervention, when used under ordinary circumstances, does what it is intended to do [52]. The main research question was formulated following consultation with researchers in the field: what is the effect of Internet-based interventions for adults with hearing loss, tinnitus and vestibular disorder? Taking this broad-spectrum approach has disadvantages such as mixing different disorders which may have different intervention effects [53]. This approach is required due to the more recent nature of audiological Internet interventions and to provide a more comprehensive overview of these interventions and to identify whether further reviews with a narrower scope are indicated.

This systematic review was prospectively registered with the International Prospective Register of Systematic Reviews (PROSPERO number CRD42018094801). The methods selected were guided by the Preferred Reporting Items for Systematic reviews and Meta-analyses for Protocols (PRISMA-P) [54, 55] (see Additional file 1). In the event of differences between the protocol and the completed review, these amendments will be presented together with the date of amendment, description of the change, rationale and consequence of these modifications.

The limited availability, accessibility and affordability of hearing healthcare have recently been highlighted [84]. Applications of technological advances have been incorporated as a way of improving healthcare. Internet interventions are one such example that have been used recently for auditory-related conditions. In view of recent developments, assessing the evidence-based supporting an Internet-based intervention format is important. This planned review is thus of value to establish the current effects of Internet interventions within audiology. This information is required to assist the future planning of accessible evidence-based audiological healthcare services. This review will thus be of value to stakeholders and clinical services and help guide further research. It is also important to help consumers of these interventions to know their possible effects. The previous review conducted in 2010 [46] included all telehealth application within the scope of audiology from screening through to diagnosis and treatment. This present review will focus only on Internet-based interventions within audiological telehealth applications. Although this scope is more focused, it is still a broad-spectrum approach by including Internet-based interventions for hearing loss, tinnitus and vestibular disorders. Mixing different disorders which could have different intervention effects is a limitation but was selected as audiological Internet interventions do not have a long history. There is therefore the possibility that there will be too few studies available to draw valid conclusions from if the focus is on individual disorders. If enough studies are found further suggestions for follow-up reviews with a narrow scope will be made. Due to the relative newness of audiological Internet interventions, treatment credibility may not yet be established from both patients’ and clinicians’ viewpoints. This review may aid knowledge regarding the effects of these interventions. There is also the danger that optimal sample sizes have not being recruited as treatment credibility may not yet be established. Hence, the review will include the reporting of low powered studies. The drop-out rates in the included studies may also be high, introducing further bias. Moreover, the possibility that the interventions will have been developed and conducted by the same research groups and this potential source of bias will be considered. This review will be limited to English due to time and financial constraints. This may introduce the risk of publication bias, and the results need to be interpreted with this consideration. Limitations of this search strategy include the language restrictions and financial constraints preventing an expert to do the database searches. Despite these limitations, this review is important for the future planning of accessible, affordable and evidence-based interventions for distressing symptoms related to having hearing loss, tinnitus or vestibular disorders.