|  | Conditions Treatments | Ears Hearing

The History of Hearing Aids

The history of hearing aids begins with crude trumpets and horns that were bulky enough to be used as weapons, and ends with hearing aids so small they are nearly undetectable. Over the years, hearing aids have changed size and shape, but they have never changed their basic function: increase the volume of sound for a hearing impaired user.

  1. Ear Trumpets

    • The first known hearing aids were huge, horn-shaped trumpets with a large opening on one end that collected sound and directed it into the ear. These simple hearing aids provided sound amplification and somewhat improved the signal-to-noise ratio in a noisy room.

    Carbon Microphones

    • The first commercial carbon microphone hearing aids were introduced around 1900. The microphone was worn around the user's neck and connected to an earpiece by numerous wires. These hearing aids were so large that they had to be carried around in special cases, and the batteries typically lasted less than a day.

    Vacuum Tubes

    • Vacuum tubes were used in the hearing aids of the 1920s. They consisted of an ear receiver, a microphone, an amplifier and two batteries so large that they were awkward to carry.

    Over-the-Ear

    • The 1950s ushered in the age of the transistor hearing aids. These "over-the-ear" models combined a microphone with a battery and a transistor all in one unit. The addition of simple on and off switches made the hearing aid small enough to be easily concealed under the wearer's hair.

    In-the-Canal

    • The technological advances of the 1970s and 1980s included integrated circuitry and lithium batteries that allowed for smaller hearing aids with better noise reduction ability. The "in-the-ear-canal" (IETC) models were dropped in the user's ear and were totally hidden from view.

    Digital Processing

    • Hearing aids went digital in the 1990s, providing improved sound quality and greater clarity with even smaller devices. Today's hearing aids typically include adaptive dynamic range optimization (ADRO), which allows the hearing aid to make constant adjustments to access the most useful range of sound.

Ears Hearing - Related Articles