Hearing Loss Overview

Hearing loss is not uncommon.

Hearing loss is not uncommon. In fact, it affects about 48 million Americans, including about one in five teenagers, one in three people aged 65-74 and about half of people 70 and over. Although hearing loss affects us at high rates, only a very small percentage of people who could benefit from hearing aids actually use them. The exact reason for this is largely unknown, however, there are many contributing factors. Firstly, there still exists an unnecessary stigma surrounding hearing loss. Secondly, and perhaps more importantly, hearing loss is extremely gradual, and is often very difficult to detect.

In order to be able to detect and therefore treat hearing loss, it is important to first understand it. Understanding hearing loss starts with understanding the way that healthy hearing operates.

How Hearing Works

Our auditory systems are quite extraordinary. They are complicated, work at lightning speed, and never shut off - even in our sleep! In order to hear even the smallest and most minute sounds, the following process must occur:

  1. Sound waves are collected by the outer ear and travel down the ear canal towards the ear drum.
  2. The sound waves cause the ear drum and three tiny bones located in our middle ear to vibrate at a specific frequency.
  3. The vibrations of these three little bones causes ripples in a special liquid that is located within our spiral shaped cochlea that sits within our inner ear.
  4. The rippling of this liquid moves and bends tiny and delicate hairlike cells that sit atop the liquid.
  5. When these hairlike cells bend and sway along with the rippling liquid, it causes them to transmit the sound waves into electric signals.
  6. The hairlike cells then send these electric signals through the auditory nerve to the brain for processing.
  7. When the electric signals reach the brain, we are then able to process the signals as sounds that we recognize and understand.
ear diagram

It is important to note that this entire process must occur without a hitch in order for us to hear every letter sound in every word.

Types of Hearing Loss

Hearing loss occurs when there is a breakdown in processing anywhere along this process of healthy hearing. Hearing loss is broken down into three basic types: sensorineural, conductive, and mixed.

Sensorineural loss is the most common type, and there are more the 200,000 US cases per year.

Sensorineural hearing loss (SNHL) is a type of hearing loss, or deafness, in which the root cause lies in the inner ear or sensory organ (cochlea and associated structures) or the vestibulocochlear nerve (cranial nerve VIII). SNHL accounts for about 90% of reported hearing loss. Sensorineural hearing loss is permanent. In adults, causes include aging and prolonged exposure to loud noise.

In this type of hearing loss, higher pitched tones may sound muffled. It may become difficult to pick out words against background noise. Treatment includes hearing aids and assistive devices.

Causes of Hearing Loss

Natural Aging

(Presbycusis) Hearing loss is a natural part of growing older. As we age, our delicate hairlike cells slowly begin to decay. Once these cells are lost, they cannot be regenerated.

Excess Exposure to Loud Noises

(NIHL) Noise induced hearing loss is extremely common, and the issue is on the rise. Prolonged exposure to loud noises causes damage to our hairlike inner ear cells.

Ototoxic Medications

Ototoxic medications are over the counter or prescription meds that are known to cause hearing impairment and hearing loss. Some of the most common ototoxic drugs are over the counter pain pills and certain medications associated with chemotherapy.

Diseases or Illnesses

Some diseases, such as Méniere’s Disease have been known to cause hearing impairments. Sometimes, the issue is easily treatable such as hearing loss caused by a sinus infection or severe allergies.