Adults with hearing challenges often do not seek traditional solutions provided by ear-level amplification devices for a variety of reasons including cost/benefit factors related to poor hearing aid quality.1 The consensus report, “Hearing Health Care for Adults: Priorities for Improving Access and Affordability,” published by the National Academies of Sciences, Engineering, and Medicine in 2016 encouraged the development of innovative technologies, with particular attention to “compatibility and interoperability of hearing technologies.”2 It recommended FDA regulation of a new category of over-the-counter (OTC) hearing devices to address the affordability of hearing technology. Although advanced digital signal processing algorithms are available in some of the more affordable OTC products, dissatisfaction with hearing in noise remains a problem in large part because the speech signal cannot be optimally separated from the background noise when the microphone(s) are located at the user’s ear.
It is fortuitous that advancements in smartphone technology coincided with the urgency to improve the accessibility and affordability of hearing technology and have emerged as viable solutions for communication in noise. The number of people using smartphone technology has steadily increased from 1.06 to 3.8 billion in the last decade.3 In addition to the ability to access multiple microphones to improve signal processing, the smartphone can serve as a remote microphone that can be strategically placed close to the talker so that the signal-to-noise ratio (SNR) is improved and communication is significantly facilitated in noisy environments.4 The benefits of remote microphone technology (RMT) are well documented for early wireless protocols via FM transmission5 and current protocols via 2.4 GHz technology.6
So, it seemed that the stars were aligning for improving hearing health care accessibility and affordability; however, a significant hurdle remained: The smartphone solution required technical sophistication particularly with connectivity to ear-level receivers, which was likely an unfamiliar experience for the target population. Smartphone market penetration is greater than 80 percent for people aged 75 years and below in a recent MarkeTrak survey, yet the use of connectivity features such as streaming was reported by only 13 percent of the respondents.7 Hardly a day goes by without an email announcement or social media post about new wireless technology or an app that is designed to facilitate communication not only for those with reduced sensory input but even for those with normal sensitivity that need to communicate over distance, in background noise, or in different languages. Consumers are faced with information overload when considering smartphone platforms (IOS, Android), wireless protocols (proprietary 2.4 GHz, induction loops, Classic Bluetooth, Bluetooth LE), purchase options (big box, clinic, internet), hearing aid connections (made-for-iPhone, MFi; made-for-all phones, MFA), and other transducer styles (earbuds, noise-canceling headphones).
The hearing care professional (HCP) is ideally suited to address the gap between the affordable solution and the required technology sophistication. As the “hearing health care travel agent,” the HCP can navigate the maze of options towards the development of a successful “wireless accessibility plan.” First, the HCP must determine the status of current communication challenges via a comprehensive assessment, e.g., the TELEGRAM, to determine the scope of the plan.8 Next, the HCP must think beyond “a single device” and consider the connectivity options that address employment, education, social, entertainment, and family communication goals.9
As the maze was rapidly expanding, researchers at the University of Texas at Dallas (UTD) recognized the value of a single component, the smartphone, to serve as the hub for connectivity. In 2016, a collaborative team of UTD researchers focused on convenient solutions to improved communication in noise employing smartphone technology. The combined efforts of two University of Texas at Dallas Research Labs, Hearing Health Lab and the Statistical Signal Processing Research Laboratory, resulted in an open-source research platform for speech processing and hearing improvement funded by The National Institute of the Deafness and Other Communication Disorders of the National Institutes of Health (5R01DC015430-05).
The engineering team developed noise-filtering and speech-enhancement apps that use the built-in microphones of a smartphone which can be conveniently placed near the talker. The audiology team tested the apps on both Android and iOS-based smartphones with currently available MFA/MFi hearing aids or wired/wireless earphones. Some of the features include displaying the direction of the speech source, suppressing the background noise, and improving speech quality and perception.10-12 These features are accomplished through conventional signal processing methods as well as the deep neural network and machine learning techniques. By training the software to recognize noisy speech through evaluation of massive databases of clean speech and noise environments encountered in typical daily life, models were developed and applied in real-time to improve speech perception.13
Evaluation of the smartphone apps when processed through one manufacturer’s MFA hearing devices connected to an iPhone showed improved speech recognition in noise on average of 22.21 percent for people with impaired hearing and 33.56 percent for those without hearing loss when compared to listening without the apps.4 In addition, comparisons of the smartphone app with available smartphone features such as “Live Listen” on the iPhone have shown equivalent benefits.14 The algorithms, user guides, technical documentation, and audio/video demos are available to the research and HCP communities on the team’s research lab website. Supported by the UTD research, the benefits of using the smartphone to assist those with hearing challenges will hopefully encourage HCPs to present the smartphone as the hub of basic “Wireless Accessibility Plans” to their patients when simplicity and affordability are paramount to success.
AUTHOR ACKNOWLEDGMENTS: This work was supported by The National Institute of the Deafness and Other Communication Disorders (NIDCD) of the National Institutes of Health (NIH) under award number 1R01DC015430-05. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
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