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(詳細はhearing aid was created in the 17th century. The movement toward modern hearing aids began with the creation of the telephone, and the first electric hearing aid was created in 1898. By the late 20th century, the digital hearing aid was distributed to the public commercially. Some of the first hearing aids were external hearing aids. External hearing aids directed sounds in front of the ear and blocked all other noises. The apparatus would fit behind or in the ear. The invention of the carbon microphone, transmitters, digital signal processing chip or DSP, and the development of computer technology helped transform the hearing aid to its present form.〔Howard, Alexander. "Hearing Aids: Smaller and Smarter." New York Times, November 26, 1998.〕 ==Ear trumpets== (詳細はdeaf educator John Townshend), the Reynolds Trumpet (specially built for painter Joshua Reynolds) and the Daubeney Trumpet. The first firm to begin commercial production of the ear trumpet was established by Frederick C. Rein in London in 1800. As well as producing ear trumpets, Rein also sold hearing fans, and speaking tubes. These instruments helped amplify sounds, while still being portable. However, these devices were generally bulky and had to be physically supported from below. Later, smaller, hand-held ear trumpets and cones were used as hearing aids.〔Levitt, H. "Digital hearing aids: wheelbarrows to ear inserts." ASHA Leader 12, no. 17 (December 26, 2007): 28-30.〕〔Mills, Mara. "Hearing Aids and the History of Electronics Miniaturization." IEEE Annals of the History of Computing 33.2 (2011): 24-44.〕 Rein was commissioned to design a special acoustic chair for the ailing King of Portugal, John VI of Portugal in 1819. The throne was designed with ornately carved arms that looked like the open mouths of lions. These holes acted as the receiving area for the acoustics, which were transmitted to the back of the throne via a speaking tube, and into the king's ear. Finally in the late 1800s, the acoustic horn, which was a tube that had two ends, a cone that captured sound, and was eventually made to fit in the ear.〔 Toward the late 19th century, hidden hearing aids became increasingly popular. Rein pioneered many notable designs, including his 'acoustic headbands', where the hearing aid device was artfully concealed within the hair or headgear. Reins' ''Aurolese Phones'' were headbands, made in a variety of shapes, that incorporated sound collectors near the ear that would amplify the acoustics. Hearing aids were also hidden in couches, clothing, and accessories. This drive toward ever increasing invisibility was often more about hiding the individual's disability from the public than about helping the individual cope with his problem.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「History of hearing aids」の詳細全文を読む スポンサード リンク
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