To understand how hearing aids work, it is important to understand how the human hearing system works when no problems are present.
Here are some key facts about our hearing system:
✔ Our ears are shaped to pick up high frequencies best. The high frequency (high pitch) sounds are the important ones that help us understand speech. Consonants like “s,” “h,” and “f,” have higher frequencies and convey most of the meaning of what we say. Someone who cannot hear high-frequency sounds will have a hard time understanding speech.
✔ The middle ear (eardrum and 3 small bones) transmits the sound to the inner ear, which has tiny sensory (hair) cells. These cells play an incredible role in shaping information for the auditory (hearing) nerves.
✔ The auditory nerves carry the information through the “central” auditory system, where the interpreting of sound takes place. Different sounds wind up in different areas of the auditory cortex (brain) where decisions are made about whether someone is asking us a question, crying for help, telling a joke, etc.
This process all occurs within a few seconds of words being spoken, and we can have all of this happening while multiple distractions are occurring. For example, music can be playing, dishes clattering and other people can be talking. Our brains decide how much of that other sound is important.
How Hearing Aids Work
A hearing aid is a small electronic device that you wear in or behind your ear. All hearing aids contain 3 basic components: a microphone, amplifier, and speaker. The hearing aid receives sound through the microphone, which converts the sound waves to electrical signals and sends them to an amplifier. The amplifier increases the power of the signals and then sends them to the ear through a speaker.
Hearing aids will be programmed to amplify the pitches where hearing loss is present.
Hearing aids are primarily useful in improving the hearing and speech comprehension of people who have hearing loss that results from damage to the small sensory cells in the inner ear, called hair cells. This type of hearing loss is called sensorineural hearing loss. The damage can occur as a result of disease, aging, or injury from noise or certain medicines.
A hearing aid magnifies sound vibrations entering the ear. Surviving hair cells detect the larger vibrations and convert them into neural signals that are passed along to the brain. The greater the damage to a person’s hair cells, the more severe the hearing loss, and the greater the hearing aid amplification needed to make up the difference.
Essentially, hearing aids can profoundly help your hearing and help retrain the central auditory system of the brain by sending sound to the ear. It is important to keep hearing sounds in everyday life whenever possible, as there can be negative consequences to “auditory deprivation”, or lack of sound. Treating hearing loss early helps the brain maintain speech understanding, resulting in a better outcome.