Hearing Aid History: From Ear Trumpets to Digital Technology.

It is said that time marches on, and one thing is certain: Hearing loss marches right along with it.1 The recorded history of hearing loss goes back hundreds of years, and attempts to correct hearing loss have been in existence since the very first person to cup a hand behind one ear. The good news is hearing aids and other assistive listening devices have come a long way since the first rudimentary attempts at improving hearing. Yes, hearing aid technology is still evolving and is still far from perfect. Well, nothing is perfect in life, as perfection is always an unreachable limit.

Letters to the Deaf: Present-Day Relevance of History's Earliest Social Analysis of Deafness.

Harriet Martineau was a 19th-century sociologist who had a progressive form of deafness. Her 1834 essay, Letters to the Deaf, was the earliest historical document depicting the social challenges of hearing loss. Martineau details complex situations that hard-of-hearing people experienced in the 19th century such as social isolation due to frustrations with communication, physician shortcomings, limited music appreciation, and the stigma of hearing amplification devices. Her descriptions of these experiences are commonly faced by hard-of-hearing people in present-day society. Advancements in technology and recognition of the negative social impact of hearing loss have improved the social experience for the hard of hearing; however, social challenges remain relevant. In this article, we review Letters to the Deaf and note the ways in which this essay provides a dual perspective regarding how much we have advanced as a society and how much we still have to overcome in addressing the social challenges of hearing loss.

Phyllis M. Tookey Kerridge and the science of audiometric standardization in Britain.

The provision of standardized hearing aids is now considered to be a crucial part of the UK National Health Service. Yet this is only explicable through reference to the career of a woman who has, until now, been entirely forgotten. Dr Phyllis Margaret Tookey Kerridge (1901-1940) was an authoritative figure in a variety of fields: medicine, physiology, otology and the construction of scientific apparatus. The astounding breadth of her professional qualifications allowed her to combine features of these fields and, later in her career, to position herself as a specialist to shape the discipline of audiometry. Rather than framing Kerridge in the classic 'heroic-woman' narrative, in this article we draw out the complexities of her career by focusing on her pursuit of standardization of hearing tests. Collaboration afforded her the necessary networks to explore the intricacies of accuracy in the measurement of hearing acuity, but her influence was enhanced by her ownership of Britain's first Western Electric (pure-tone) audiometer, which she placed in a specially designed and unique 'silence room'. The room became the centre of Kerridge's hearing aid clinic that, for the first time, allowed people to access free and impartial advice on hearing aid prescription. In becoming the guardian expert and advocate of the audiometer, Kerridge achieved an objectively quantified approach to hearing loss that eventually made the latter an object of technocratic intervention.

Historical development of active middle ear implants.

Active middle ear implants (AMEIs) are sophisticated technologies designed to overcome many of the shortcomings of conventional hearing aids, including feedback, distortion, and occlusion effect. Three AMEIs are currently approved by the US Food and Drug Administration for implantation in patients with sensorineural hearing loss. In this article, the history of AMEI technologies is reviewed, individual component development is outlined, past and current implant systems are described, and design and implementation successes and dead ends are highlighted. Past and ongoing challenges facing AMEI development are reviewed.

The master hearing aid.

As early as the 1930s the term Master Hearing Aid (MHA) described a device used in the fitting of hearing aids. In their original form, the MHA was a desktop system that allowed for simulated or actual adjustment of hearing aid components that resulted in a changed hearing aid response. Over the years the MHA saw many embodiments and contributed to a number of rationales for the fitting of hearing aids. During these same years, the MHA was viewed by many as an inappropriate means of demonstrating hearing aids; the audio quality of the desktop systems was often superior to the hearing aids themselves. These opinions and the evolution of the MHA have molded the modern perception of hearing aids and the techniques used in the fitting of hearing aids. This article reports on a history of the MHA and its influence on the fitting of hearing aids.

Cognitive hearing science: the legacy of Stuart Gatehouse.

Stuart Gatehouse was one of the pioneers of cognitive hearing science. The ease of language understanding (ELU) model (Rönnberg) is one example of a cognitive hearing science model where the interplay between memory systems and signal processing is emphasized. The mismatch notion is central to ELU and concerns how phonological information derived from the signal, matches/mismatches phonological representations in lexical and semantic long-term memory (LTM). When signals match, processing is rapid, automatic and implicit, and lexical activation proceeds smoothly. Given a mismatch, lexical activation fails, and working or short-term memory (WM/STM) is assumed to be invoked to engage in explicit repair strategies to disambiguate what was said in the conversation. In a recent study, negative long-term consequences of mismatch were found by means of relating hearing loss to episodic LTM in a sample of old hearing-aid wearers. STM was intact (Rönnberg et al.). Beneficial short-term consequences of a binary masking noise reduction scheme on STM was obtained in 4-talker babble for individuals with high WM capacity, but not in stationary noise backgrounds (Ng et al.). This suggests that individuals high on WM capacity inhibit semantic auditory distraction in 4-talker babble while exploiting the phonological benefits in terms of speech quality provided by binary masking (Wang). Both long-term and short-term mismatch effects, apparent in data sets including behavioral as well as subjective (Rudner et al.) data, need to be taken into account in the design of future hearing instruments.

Historical background of bone conduction hearing devices and bone conduction hearing aids.

During the last 20 years, bone-anchored hearing aids (Baha(®)) became a familiar solution in the treatment of some types of hearing loss. The aim of this chapter is to present the different historical steps which have permitted the production of this new bone conduction hearing device. The recognition of bone conduction hearing is old and was known at least in Antiquity. During the Renaissance, Girolamo Cardano demonstrated a method by which sound may be transmitted to the ear by means of a rod or the shaft of a spear held between one's teeth: this was the beginning of teeth stimulators to improve hearing, firstly in connection with a musical instrument and then, in the second part of the 19th century, with the speaker. The development of the carbon microphone at the beginning of the 20th century allowed the construction of the bone conduction vibrator placed on the mastoid area, notably supported by eyeglasses since the 1950s. Confronted by various problems, and notably the loss of part of sound in the soft tissue of the external mastoid, the idea to implant the vibrator into the mastoid bone was developed in Göteborg, and the first Baha was implanted in 1977 by Anders Tjellström. From that date, various improvements allowed the development of the actual Baha. These different steps are presented in this study, supported by original documentation.

When mobile communication technologies were new.

In the 19th century, mechanical hearing aids opened up new possibilities for controlling sound waves and managing conversations. Components and ideals from these acoustical instruments became part of the foundation for electroacoustics, the conversion of sounds into "signals". Mechanical hearing aids also set lasting standards for portability and unobtrusiveness in the design of personal communication technology.

Stuart Gatehouse: a personal appreciation.

Stuart Gatehouse worked in the MRC Institute of Hearing Research Scottish Section for 29 years until his untimely death in 2007. The former director records a personal appreciation but also an explanation, for those who did not know him well, of the mixture of qualities that made him an outstanding applied scientist.

Stuart Gatehouse: a brief life.

Stuart Gatehouse was an internationally renowned auditory scientist whose work on basic research, government policy, and clinical practice has directly improved the quality of life of adult hearing aid users. He addressed issues of relevance to the lives of hearing-impaired adults, especially on the impact of a hearing loss on an individual, the management of hearing loss, and the measurement of the benefits offered by hearing aids. He also influenced practice and service delivery and made major contributions to the delivery of audiological services in the United Kingdom, including chairing a report that directly led to their modernization in Scotland. This article describes his life and career.

Stuart Gatehouse: the international perspective.

The international contributions of Stuart Gatehouse are reviewed in three areas: as a scientist, as an advisor to health policy makers, and as a participant in international conferences. He was able, as no other auditory scientist of his time, to bridge the gap between scientific and clinical research. His ability to apply sound scientific principles to issues of clinical importance was most apparent in his work in three main areas of his research: acclimatization to amplified speech, auditory disability and hearing aid benefit, and candidature for linear and nonlinear signal processing.

A historical perspective on digital hearing AIDS: how digital technology has changed modern hearing AIDS.

This article provides the author's perspective on the development of digital hearing aids and how digital signal processing approaches have led to changes in hearing aid design. Major landmarks in the evolution of digital technology are identified, and their impact on the development of digital hearing aids is discussed. Differences between analog and digital approaches to signal processing in hearing aids are identified.