Toronto Rehabilitation Institute
A small (4.8 cm long), curved electronic device designed to fit behind the helix (outer rim) of the ear. It consists of two primary parts: A transparent, yellow-tinted curving canal called an ear hook, and an electronics enclosure. The ear hook is attached to the enclosure by a threaded connection.
The plastic electronics enclosure is tan on the flat sides, with a darker brown colouring along the perimeter. As with similar devices, the controls are located on the outer edge, with a door for the battery compartment at the base of the enclosure.
The ear hook of this example has a bright red wax guard in place.
This hearing aid did not have an earpiece in place, but it could have been used with an earmould such as the examples in this collection.
Accession Number: 2025.rehab.24
Alternative Name:
Primary Materials: Plastic
A label under a clear filter along the inner edge of the artifact reads as follows: “UNITRON// 236774// S F/X P Pro”
Printed on the door to the battery compartment: “CЄ 0543// UNITRON// CANADA 2002″
Dimensions (cm): Height = 3.5, Width = .8; Length = 4,8.
A hearing aid is a device designed to amplify sound so that it is audible to a person with hearing loss.
A behind the ear (BTE) hearing aid is a type of electronic hearing aid that locates the electronics enclosure behind the helix (outer rim) of the ear. In this format of BTE hearing aid, sound is transmitted through a tube to an ear mould that matches the user’s ear canal.
A digital hearing aid is a more recent form of electronic hearing aid that uses digital signal processing to amplify sound in a manner tailored to an individual’s hearing abilities.
This item is in good condition, but retains patches of debris in recesses and corners despite a careful cleaning. It does not have an associated ear piece.
Associated Instruments:
Unitron Industries. Kitchener, Ontario, Canada.
Date of Manufacture: c. 2002
This artifact was among a number artifacts related to audiology and optometry collected from the Toronto Rehabilitation Institute at 130 Dunn Avenue on December 6, 2017.
Levitt, Harry. “A Historical Perspective on Digital Hearing Aids: How Digital Technology Has Changed Modern Hearing Aids.” Trends in Amplification 11, no. 1 (2007): 7–24.
Mills, Mara. “Hearing Aids and the History of Electronics Miniaturization.” IEEE Annals of the History of Computing 33, no. 2 (2011): 24–45.
Virdi, Jaipreet. Hearing Happiness : Deafness Cures in History. Chicago: The University of Chicago Press, 2020.
Virdi, Jaipreet. “Deaf Futurity: Designing and Innovating Hearing Aids.” Medical Humanities 50, no. 4 (2024): 678–84.
Unitron. “About Unitron” Commercial Webpage. (Archived 29 April, 2025)
Unitron is a Canadian hearing aid manufacturer based in Kitchern, Ontario. The company was founded in Newfoundland by Rolf Strothmann and Rolf Dohmer, who began their business in electronics sales and repairers before developing hearing amplification instruments. In 1964, they founded Unitron Industries and moved their business to Kitchener soon after.
The “behind the ear” (BTE) format of electronic hearing aid first emerged in the late 1950s. The small format was made possible by the development of transistors. integrated circuits, and button cell mercury batteries. At this stage, all electronic hearing aids were analogue.
Digital Hearing Aids
Developmental work on an all-digital programmable hearing aid began in the late 1970s with the availability of array processors capable of performing the parallel processing necessary for real time digital processing of audio. However the technology of the day limited the practical size of a device. In 1982, digital signal processing (DSP) chips appeared that made wearable devices possible. These featured processes such as active noise cancelling and nonlinear methods of enhancing the speech signal, for instance by lowering high speech frequencies, for people with severe high-frequency hearing loss. (Leavitt 2007, 10)
The first behind the ear (BTE) digital hearing aid was introduced around 1989 by The Nicolet Corporation, though it was not a commercial success. This period also saw a switch to programmable hearing aids whose performance could be tailored to an individual’s hearing. The first practical BTE programmable digital hearing aids, with DSP ships that were efficient enough to achieve a reasonable battery life, arrived in the 1990s. For patients used to the older generation of analogue BTE hearing aids, the transition to digital involved a profound and disorienting change in perception. For a firsthand account, see Virdi 2020, 258-260.
Design Considerations
Disability scholars have analyzed such devices for values that their design embodies. Virdi 2024 gives a good overview of this discussion and cites its many contributors. For some, the process of miniaturization, the standardized, medicalized aesthetic of flesh-coloured devices and clear earpieces, embodies the a social stigma surrounding deafness–a stigma not seen, for instance, in corrective eyewear, which is, by nature, more visually intrusive yet is commonly viewed as a fashion accessory. The discrete, medicalized aesthetic of hearing aids has, in recent years, been challenged by disabled designers who have modified their own devices and collaborated with manufacturers in producing appealing designs that challenge the stigma surrounding disability technology. (Virdi 2024, 682-683)
- Donated to UTSIC