by Krista Galyen

There are two main factors (among the many factors) when considering the impact of a hearing loss on a child: onset (time) of loss and type of loss. Each factor will aid in determining the impact on the child’s education. However, two students with similar onsets and types of hearing loss could be performing at different levels at school. After all, hearing children perform differently as well.

The Sounds of a Hearing Loss

To give you a general idea of what a child with a hearing loss hears (or does not hear), below are some sound files in .wav format. Continue Reading

by Krista Galyen

The simple act of understanding an audiogram can give many insights into a child. One will learn what that student hears as well as a partial understanding of what they are comprehending. One will also gain insights into why the child speaks and behaves the way they do, and why that impacts other areas of their education. Understanding an audiogram is a simple yet useful tool.

Parts of an Audiogram

First, an audiometer is used to test a person’s hearing. It makes different pitches (frequencies) from low to high at different volumes (measured in hertz, Hz). These are printed across the top of the audiogram. The loudness or intensity of the sound is measured in decibels, or dB. These are printed vertically on the audiogram. When looking at an audiogram, think of the frequencies like the keys on a piano: lower sounds are to the left, higher sounds are to the right. Continue Reading

by Krista Galyen

The Outer Ear

The pinna helps gather sound and directs it down the ear canal (external auditor meatus) toward the eardrum. The sound vibrations cause the eardrum, or tympanic membrane, to vibrate. The outer ear ends at the tympanic membrane.

The Middle Ear

The middle ear consists of a small air-filled space. Inside this space are three small bones. These three small bones, called ossicles, form the ossicular chain. Each bone fits tightly into the next one. It is possible for them to become disarticulated and move out of position. This may happen from a very strong hit to the head. Each part of the ossicular chain has a specific name. The hammer (malleus) receives the sound vibrations from the tympanic membrane. The vibrations are then passed to the anvil (incus). The vibrations are finally passed to the stirrup (stapes).

The eustachian tube is another part of the middle ear. It allows air in or out of the middle ear when a person swallows or yawns. When the eustachian tube is not functioning properly, it can cause a hearing loss. If either the middle ear or the outer ear is not working, a person has a conductive hearing loss.

The Inner Ear

The cochlea and semicircular canals are the two main parts of the inner ear. The cochlea is a snail-shaped organ where vibration is changed into nerve energy. The cochlea has three compartments that are separated by two thin membranes. Four rows of hair cells stick out from one of the membranes. As the stapes vibrates back and forth, it changes the fluid pressure inside the cochlea. The change in the fluid causes the hair cells to bend. The bending of the hair cells changes the vibration into a nerve impulse. The nerve impluse travels through the auditory nerve to the portion of the brain that receives and understand the nerve iimpulse from the ear. If any part of the cochlea is not working, a person has a sensorineural hearing loss.

A Neat Fact: The semicircular canals are attached to the outside of the cochlea. They help with balance and the feeling of movement. For example, when a person spins around and around, the fluid in the canals give you the feeling of movement. When you stop spinning, the fluid in the canals is still moving and it takes the fluid a while to cease moving. That is what gives a person the feeling of being dizzy. Neat, huh!

More Sites on How the Ear Works:

Anatomical Tour of the Ear: http://www.earaces.com/anatomy.htm

Anatomy of the Ear: http://www.hope4hearing.org/anatomy.htm

How We Hear: http://www.audiologyawareness.com/hhelp/howhr.htm

How’s That? The Aural Mechanics: http://www.audiology.org/consumer/guides/aural.php

Interactive Anatomy of the Ear: http://earfoundation.org/anatomy.html