October 21, 2016 -- Lia Best
Hearing aids are becoming smaller and yet more powerful with every advancement in technology. You might be wondering, how can they fit all of that technology in such a tiny space? What exactly goes inside a hearing aid?
In all hearing aids you will find these 5 basic components: a microphone, an amplifier, a battery, a loudspeaker and a computer chip that is programmed by the audiologist. The microphone picks up the acoustic signal in the environment and converts it to an electrical signal. Most hearing aids have more than one microphone to pick up sound in a more directional manner, which prioritizes sound coming from the front of the listener. The sound becomes analyzed by the computer chip. The processed sound is then sent to the amplifier. The amplifier sends the signal to the loudspeaker which emits the sound into the ear canal towards the tympanic membrane where it can then be processed by the inner ear. In most new hearing aids there is the addition of a 6th component – the wireless antenna for connecting to other wireless devices (e.g. cell phones).
Today’s hearing aids are digital devices which means the “natural” sound waves are converted into digital bits (0,1) that will be processed by the hearing aid. This digital signal processing allows audiologists to have much more control over the settings in the hearing aids. Instead of having devices that “amplify all sounds,” we can selectively amplify only the frequencies where the hearing loss occurs to protect your ears from further damage. We can selectively enhance soft speech while leaving loud speech alone, which makes for a more comfortable sound environment. We can adjust how quickly or effectively the hearing aid deals with background noise. In addition, the hearing aid can better distinguish between different types of “noise.” It will adapt differently based on whether the background noise is a continuous sound, such as a car engine, or whether it’s a more variable sound such as music or other speech.
This is a fascinating time to be entering the world of hearing aids because with every new advancement in computer technology, hearing aids will continue to benefit. According to Starkey “the processing power of the printed circuit board inside a Halo hearing aid is magnitudes greater than the computers aboard the Apollo 11 space shuttle that landed on the moon.”