Author: Dolly Bhargava, M. Spec. Ed.

Hearing plays an important role in student development and daily performance.  Hearing impairment occurs when there's a problem with or damage to one or more parts of the hearing mechanism.  It is identified as one of the ten most prevalent causes of disability in the United States.  The U.S. Department of Health and Human Services (1991) reported that five percent of children 18 years and under have a hearing loss.  A student with a hearing impairment is part of a heterogeneous group whose one common characteristic is some degree of hearing loss.  To effectively teach students with hearing impairment, teachers need to become familiar with hearing related concepts.  The purpose of this chapter is to briefly outline the nature of hearing impairment and provide you with useful current definitions.  The chapter will provide you with information on how we hear, how hearing is assessed, ways of identifying students with hearing impairments in the classroom and discuss their learning characteristics.  Some information on the several types of professionals who can be of assistance in diagnosing and educating students with a hearing impairment will also be provided.

The Individuals with Disabilities Education Act (IDEA), defines “hearing impairment” and “deafness” separately.  Hearing impairment is defined as an “impairment in hearing, whether permanent or fluctuating that adversely affects a child’s educational performance.”  Deafness is defined as a “hearing impairment that is so severe that the child is impaired in processing linguistic information through hearing, with or without amplification.” 

Components of the Ear

The organ of hearing is the ear and it is composed of three major parts: the outer, middle and inner ear.  It is important to understand the basic anatomy of each part and how it works before reading about the different types of hearing impairments.  Refer to for a diagram of the ear.  The anatomy and contribution of each part of the ear has been described below:

Outer Ear

Includes the external visible part of the ear (pinna) and the ear canal.

What does it do?
  1. Sound waves are received by the pinna from the environment.

  2. Sound waves travel through the ear canal.
  3. Sound waves make their way to the beginning of the middle ear called the ear drum (thin membrane that separates the outer ear from the middle ear).                                                     (Dugan, 2003; Scheetz, 2000)

Middlen Ear

Includes the eardrum, ossicles or three tiny bones(hammer/malleus; anvil/incus; stirrup/stapes) and Eustachian tube.

What does it do?
  1. Sound waves reach the eardrum.

  2. Ear The ear drum begins to vibrate and makes the three tiny bones / ossicles to move together.
  3. These bones help sound move into the inner ear.

The middle ear is filled with air and for optimal hearing the air pressure inside the middle ear and outside of the ear needs to be the same.  The Eustachian tube connects the middle ear to the back of the nose.  The Eustachian tube helps keeps the air pressure in the middle ear equal to the air pressure in the environment.  (Dugan, 2003; Fraser, 1996)

Inner Ear

Includes a snail-shaped, fluid filled structure called the cochlea, tiny hair cells (cilia) and the auditory nerve, which travels from the inner ear to the brain.

What does it do?
  1. The vibration of the sound waves causes the cilia to move.

  2. This movement creates electrical impulses or signals that are sent to the brain via the auditory nerve.
  3. The hearing centers in the brain interpret these signals as sound and help give them meaning. (Lysons, 2003)

Some Definitions

A hearing impairment results when there is a problem in one or more components of the hearing mechanism.  When describing hearing impairment, three attributes are considered:

  1. Type of hearing loss (part of the hearing mechanism that is affected)
  2. Degree of hearing loss (range and volume of sounds that are not heard)
  3. Configuration (range of pitches or frequencies at which the loss has occurred).