Do you remember Spongebob and his ‘Magic conch shell”, where Spongebob pulls a string and the “Magic conch shell” could answer all the questions he has? Do you want to have an all-knowing “Magic conch shell” that could help you make decisions? In one of our class visit, we went to the History of Medicine Museum in one of the medical schools in Paris and there was also a conch shell ear trumpet in the museum. However, the conch shell ear trumpet was not a magic all-knowing shell. Instead, it was a hearing aid that people used in late 19th to early 20th century.
Me standing in front of the eye ball models
The history of hearing aid dates back to 13th century, a time where people use hollowed horns of animals to collect sounds and transmit them back into the ear. In 19th century, the invention of telephone and application of electricity enables the development of hearing aid that both collects and amplifies sounds. In the beginning of 20th century, people were able to develop better sound amplification hearing aid that used vacuum tube technology. However, there was still a problem with the sound amplification, for which the hearing aid was able to amplify all sounds including noise. It may cause an unpleasant experience for users to hear noises. Thankfully, hearing aids were greatly improved in the 21st century. Nowadays, hearing aids had the ability to be programed based on individual’s hearing needs. Moreover, sound could be fine-tuned through hearing aids so that it reduces unwanted sounds transmission (Packer, 2016).
Conch shell ear trumpet
Fine-tuning of sound is an interesting subject and I found a research that investigated the perceptual effects of noise reduction in hearing aids on listeners’ experiences. Unlike other hearing aids research, the Brons, et al. research recruited normal-hearing subjects to hear the babble noise processed by the noise reduction from four different hearing aids. Then, subjects were asked to perform speech-intelligibility tests, listening effort ratings and paired comparison rating regarding perceptual effects of noise reduction, which were noise annoyance, speech naturalness and overall preference.
In all, the research concluded that the overall preference of the normal-hearing listeners under noise-reduction condition was depended on noise annoyance and speech naturalness (Brons, Houben, & Dreschler, 2013). If the experimental result also applies to listeners with impaired hearing, then there would be a need to revision the fine-tuning of noise reduction in hearing aids for better users’ experiences.
I was amazed that conch shell was one of the first hearing aids. I hope people enjoy listening through the roar of ocean!
References:
Brons, I., Houben, R., & Dreschler, W. A. (2013). Perceptual Effects of Noise Reduction With Respect to Personal Preference, Speech Intelligibility, and Listening Effort. Ear and Hearing,34(1), 29-41. doi:10.1097/aud.0b013e31825f299f
Packer, L. (2016, April 25). Hearing aid history: From ear trumpets to digital technology. Retrieved June 8, 2018, from https://www.healthyhearing.com/report/47717-Digital-hearing-aid-history