Hearing loss and tinnitus are becoming increasingly common due to an aging population and a rise in noise-induced hearing loss, resulting in significant medical and social costs. As of 2018, the population with hearing loss in Korea is estimated to be around 8.09 million [1]. Hearing loss limits communication, academics, and work, increases the risk of accidents, and is associated with cognitive decline and dementia, necessitating active auditory rehabilitation [2]. The use of hearing aids can slow cognitive decline, reduce the incidence of dementia [3], promote social activities, decrease depression, and contribute to economic independence [4].

However, the usage rate of hearing aids remains low [5]. In the United States, only 20% of the population that needs hearing aids actually uses them, while in Korea, only 12.6% of patients with moderate or greater hearing loss use hearing aids. Additionally, only 0.47% of patients with mild hearing loss, who do not have moderate hearing loss but still require hearing rehabilitation, use hearing aids [6]. One reason for the very low usage rate of hearing aids among patients with hearing loss is the high cost of hearing aids [7]. To address this issue, the use of personal sound amplification products (PSAPs) is also recommended as an alternative to overcome accessibility problems caused by the high price of hearing aids [8].

With the widespread use of smartphones, apps equipped with sound amplification and hearing test functions have been developed and are actually being used [9]. These apps can be used on various mobile devices and provide sound amplification and noise control functions, increasing interest in the usefulness of mobile devices for auditory rehabilitation [10]. These apps include multi-channel amplification, compression and expansion, and noise reduction algorithms [11]. Since most can be downloaded for free, they can be an alternative for patients with hearing loss who are reluctant to use hearing aids due to economic reasons [12].

Previous studies have suggested that PSAPs significantly improve listening in quiet environments, but their effectiveness may be limited in noisy environments [13]. Additionally, smartphone hearing aid apps (SHAA) are gaining attention as a cost-effective alternative and are reported to potentially help improve speech recognition in hearing-impaired patients, but there is still a lack of systematic analysis on their effectiveness and limitations [14]. Public awareness surveys have shown that while people know that PSAPs are different from hearing aids, many are not familiar with SHAAs [15,16]. As the use of these devices increases, there is a growing need for clear guidelines on SHAA and PSAP.

This study aims to comprehensively analyze the effectiveness and limitations of SHAA and PSAPs, which are gaining attention as alternative devices to hearing aids for patients with hearing loss, and to provide clear guidelines on their use. The study was conducted with the support of Patient-Centered Clinical Research Coordinating Center (PACEN) from 2019 to July 2024 [15-22]. It was designed as a multi-center, prospective, randomized study involving five university hospitals in Korea. It utilized a crossover design to compare the subjective and objective efficacy and side effects of hearing aids with either SHHA or PSAPs, involving a total of about 370 participants. The study results, roundtable discussions conducted by PACEN, and recent research findings will be reviewed to propose clinical guidelines. Roundtable discussions were conducted by 7 otology experts and 1 layperson who represent the consumers. They discussed the definition of PSAP and suggest the minimal requirement for the PSAP for using the hearing loss patients.

These guidelines clearly outline the factors hearing-impaired patients should consider when selecting devices and provide basic instructions to support practical and effective auditory rehabilitation.

The field of hearing loss management and auditory rehabilitation is continuously evolving, with new technologies constantly emerging [10]. Therefore, it is necessary to continuously evaluate the technological advancements and costeffectiveness of SHAA and PSAP to improve the guidelines. Updated guidelines reflecting the latest technologies can provide more effective and appropriate auditory rehabilitation solutions for hearing-impaired patients. New research and data following technological advancements will play an important role in updating and supplementing future guidelines.

This study has several limitations. First, clinical practice guidelines are typically developed based on a systematic review of the scientific evidence, supplemented by expert consensus and accompanied by a graded recommendation system. These guidelines should be updated regularly to reflect new evidence and evolving clinical practices. To date, this guideline will be revised through a more rigorous systematic review process, incorporating updated recommendations and graded levels of evidence on a regular basis. Second, SHAAs may have performance differences depending on the smartphone’s hardware and software, which may affect the accuracy of the study results. However, despite these limitations, this study comprehensively presented the effectiveness and limitations of devices by analyzing data considering various smartphone models. Third, there is a lack of data on the actual usage environment due to insufficient noise processing technology in PSAPs, and there is a lack of analysis of the long-term effects and side effects of prolonged use. Nonetheless, the study is significant in clearly defining the usage conditions of PSAPs and specifically analyzing their limitations, particularly in noisy environments. Fourth, the study was limited to university hospitals in a specific region, which may affect the generalization of the results. However, even within a limited environment, this study provided reliable data, which offers important information for evaluating the usefulness of devices in specific environments.

Future research directions should focus on continuously evaluating the technological advancements and cost-effectiveness of SHAA and PSAP. In particular, technological development to improve effectiveness in noisy environments and additional research on the long-term effects and side effects of devices are needed. Additionally, studies that include diverse regions and populations are needed to derive more generalized results and provide practical data for improving auditory rehabilitation solutions. Improving guidelines reflecting the latest technologies will contribute to providing more effective and appropriate auditory rehabilitation solutions for hearing-impaired patients. Such research is expected to provide fundamental data for the advancement of hearing loss management and auditory rehabilitation fields.

This study evaluated the effectiveness and limitations of SHAA and PSAP, providing practical and safe usage guidelines for hearing-impaired patients. Hearing aids have been confirmed to be effective across mild to moderate hearing loss and are reliable devices that operate stably in various auditory environments. In contrast, SHAA and PSAP are useful only under certain conditions and show limited effectiveness, especially for moderate or more severe hearing loss or in noisy environments.

Hearing aids are recommended as the first choice for hearing-impaired patients, while SHAA or PSAP may be considered when hearing aids are difficult to use. This study clarifies the appropriate usage conditions and selection criteria for each device, supporting hearing-impaired patients in selecting more effective and suitable auditory assistance devices. Future research needs to evaluate the technological advancements and cost-effectiveness of SHAA and PSAP, improve their effectiveness in noisy environments, and analyze long-term data. This study is expected to provide foundational data for the advancement of hearing loss management and auditory rehabilitation fields.