Ears

Developments in prosthetic technology for ears is primarily invested in alleviating the difficulties for those of impaired audial capacity.

Ancient Hearing Aids

Manufactured hearing aids date back to the time of the ancient Greeks, who would use seashells to amplify their hearing.

There was little variance between the time of the Greeks to the 19th century. Almost two thousand years had only minorly affected the design of hearing aids. Rather than be made of seashells, 19th century hearing aids were commonly made of wood or metal.

  

Hearing "trumpet" common in the 19th century

 
During the 19th century is when the design of hearing aids began to change. Disgruntled with the “undignified” trumpet designs, royals began to implement hearing thrones. The thrones had open chambers at the ends of the armrests and hollow tubes that carried the sound to the ears of the monarch sitting in the throne.
 
 But while royalty had their thrones, it was not until the late 1800′s that the common people had access to alternative hearing aids. A major revolution in hearing aid design came when French inventor Clarvox Lorgnette created a system that attached a narrow tube to a pair of spectacles.
 
 
 
 

Clarvox Lorgnette's design

 

 Dawn of the Electronic Hearing Aid

It wasn’t until 1898 that a successful electronic hearing aid was developed. The device was created by Miller Reese Hutchinson and sold for $400. Called the Akoulathon, it required that it be set on a table for use, making it impractical for travel.

 Only three years later in 1901 Hutchinson solved the portability issue with the first portable electronic hearing aid, the Acousticon.

 
 
 

Miller Lee Hutchinson

The early 1920′s saw a shift back from Hutchinson’s Acousticon to the cumbersome, but more reliable table models. However, thanks to the use of vacuum tubes the devices were more compact and accurate than ever before. The earliest hearing aid model to use vacuum tubes was the Vactuphone invented in 1921 by Earl Hanson.

In 1933 the Bone Conductor was invented. Rather than amplify sound through air as its predecessors did, the Bone Conducter vibrated bones in the ear, bypassing the injured area. However, the vibrations also caused headaches, due to which the Bone Conducter never became a popular choice for the hearing impaired.

Throughout the 1930′s and 1940′s there were very little new approaches to hearing aid technology. Rather than innovation, companies focused on revisions. The goal was to develop the most portable hearing aids possible, but manufacturers repeatedly struggled with issues of size and weak battery life.

In 1948 the world of electronic hearing aids was transformed by the invention of the transistor. The transistor was far smaller in size than the cumbersome vacuum tubes common in the day. Additonally, the transistor was far more energy effecient. Thus developers were able to drastically reduce the size and increase the quality of hearing aids available to their customers, as well as dramatically lower their production costs.

 The first device to use the transistor was a hybrid device that contained both vacuum tubes and transistors called the Sonotone Model 1010.

 
 

The Sonotone Model 1010

By 1953 transistor-only hearing aids were released and the vacuum tube was never used again.

 By 1956 the design of the hearing aid was shrunk down to a tiny device worn over the ear.

 
 

1956 Behind the Ear Hearing Aid

1961 introduced the first hearing aids to be placed inside the ear canal.

 
 

1961 In the Ear Hearing Aid

There have been no major changes in hearing aid technology since the 1961 introduction of the in the ear hearing aid. Hearing aid development simply has slightly reduced the size and cost of the devices. Today hearing aids can be installed inside the ear canal and be so miniscule that they are impossible to detect by sight alone.

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