Definitions, Identification, and Professionals
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
Author: Dolly Bhargava, M. Spec. Ed.
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 http://www.echalk.co.uk/Science/Biology/InteractiveDiagrams/Ear.htm 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.
- Sound waves are received by the pinna from the environment.
- Sound waves travel through the ear canal.
- 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)
Includes the eardrum, ossicles or three tiny bones(hammer/malleus; anvil/incus; stirrup/stapes) and Eustachian tube.
- Sound waves reach the eardrum.
- The ear drum begins to vibrate and makes the three tiny bones / ossicles to move together.
- 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.
- The vibration of the sound waves causes the cilia to move.
- This movement creates electrical impulses or signals that are sent to the brain via the auditory nerve.
- The hearing centers in the brain interpret these signals as sound and help give them meaning. (Lysons, 2003)
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:
- Type of hearing loss - part of the hearing mechanism that is affected
- Degree of hearing loss - range and volume of sounds that are not heard
- Configuration - range of pitches or frequencies at which the loss has occurred
Type of Hearing Loss
Author: Dolly Bhargava, M. Spec. Ed.
Identifying a Student with Hearing Loss
Author: Dolly Bhargava, M. Spec. Ed.
Niemann, Greenstein & David (2004) describe the impact of a hearing impairment where a child can see people talking but cannot understand what is being said. This results in the child having difficulties understanding the world and in expressing personal needs, resulting in limited interactions and social isolation. Thus, it is important to identify the hearing impairment as early as possible; otherwise the child will also miss out on important educational experiences (Pagliano, 2005). Sometimes hearing impairment can go unidentified partly because it is not immediately visible. A hearing impairment could be so mild that it may it may have gone unnoticed for many years (Smith, Polloway, Patton & Dowdy, 1998). On the other hand, a hearing impairment may develop over time. The student is often the last one to recognise or report a loss in hearing unless it has deteriorated significantly. If the hearing impairment remains undetected, it can result in the student facing a substantial educational disadvantage. The adverse affect of the hearing impairment can create challenges of a personal, academic and social nature for the student and interfere with reaching full potential. Teachers need to be aware of the indicators that signal the possibility that a student has an undiagnosed hearing loss. On a medical note, if the hearing problem is undetected and untreated, it can cause permanent loss of hearing and the long-term consequences for the quality of life can be serious.
Consider the case of Sue, a 10 year old girl who had undiagnosed conductive hearing impairment with a mild hearing loss in her left ear. She thought most of her friends mumbled a lot. Sue stated that she had to strain to listen to them and found it difficult following a conversation, especially in group situations. She would often have to ask her friends to repeat themselves. Often Sue wouldn’t realize that someone was calling her, especially if they were in another room or if it was a very noisy classroom. She would often ask for the volume of the TV or stereo to be turned up or would sit closer to them to hear properly. Without adult awareness, her impairment continued unrecognized.
Table 1 is a simple Yes/No checklist of the signs and symptoms that are indicative of whether a student in your class has a hearing impairment. If any of these behaviours are present, teachers should consider suggesting to the student’s caregivers that they refer the student to a health professional for a formal hearing assessment (Fraser, 1996; Kuster, 1993). Smith et. al. (1998) state “A teacher’s careful observations and referral can spare a student months or years of struggle and frustration” (p. 217).
Possible Sign of a Hearing Impairment
Turning head to position ear in the direction of the speaker
Favoring one ear over another
Using a loud voice when speaking
Mispronouncing words (such as misarticulation of certain speech sounds or omitting certain consonant sounds)
Asking for information to be repeated frequently
Not responding when addressed
Difficulty with following directions or instructions
Seeming distracted and/or confused
Appearing to be inattentive, restless, tired or daydreaming
Distracted easily by visual or auditory stimuli
Lack of, or delayed development of speech and language
Intently watching faces during conversation
Giving incorrect answers to questions
Not startled by loud noises
Preferring to be by themselves (i.e., playing alone rather than with a group, or withdrawing from social situations)
Problems hearing environmental sounds (i.e., doorbell, telephone ringing, people calling and/or talking to the student from behind)
Sitting close to the sound source (i.e.,TV, radio, and/or turning up the volume
(Sources: Adapted from Pagliano (2005), Smith et al. (1998), and Waldron (1996)
Author: Dolly Bhargava, M. Spec. Ed.
Hearing is one of the most important senses. It plays a vital part in the learning process. It is held that more than 80% of education is received through hearing (Pagliano, 1994). American Speech-Language-Hearing Association (ASHA) stipulates that hearing impairment can affect children in the following ways:
- It causes delay in the development of receptive and expressive spoken language skills. It also usually causes delay in general language acquisition and receptive and expressive communication. (However, in the minority of deaf children born to signing Deaf families, language and communication skills usually develop at a normal rate.)
- The language deficit can cause learning problems that result in reduced academic achievement.
* Communication difficulties may often lead to social isolation and poor self-concept.
* It may have an impact on vocational choices.
Hearing impairment can impose basic limitations on an individual in terms of
- access to spoken language
- access to environmental auditory experiences
- ease of interacting with a wide range of people, due to the above restrictions.
Difficulty in accessing spoken language may appears to be an obvious result of hearing impairment. On the contrary, there are many variables which affect just how much access a hearing impaired person has to spoken language. As noted earlier, there are different levels of hearing loss; yet, even within these levels many layers exist. For example, two different people may have the same type of hearing loss, the same level of hearing loss and all practical, physiological processes could be almost identical, but they may not have the same access to spoken language. Person A may have acquired the hearing loss post-lingually, which has provided the opportunity to hear and the hearing nerves to be used. Person B may have had to learn to listen without ever experiencing sound, and would have had to learn that sound itself has meaning before beginning to interpret what those sounds mean.
Clear access to speech is contingent upon many variables, including:
- background noise being at a minimum
- well-functioning and optimal hearing technology
- clear speech being expressed by the speaker
Hearing technology continues to improve but still has limitations. One of the limitations is that background noise is not usually completely eliminated when a person with hearing impairment is listening to some source of sound. This means that the important information (i.e., speech) has to be separated from the background noise during cognitive processing.
Clear speech is not exaggerated speech, and the student with hearing impairment uses all the visual and auditory information available to aid understanding of the message. If any of these are exaggerated or distorted, the student has to cognitively explore the possibilities of what was said before trying to repair their misunderstanding of the message. Accents, speech impediments, prostheses (braces), moustaches and beards can all contribute to the challenge of understanding with ease.
Environmental auditory experiences enable hearing students to retrieve information about what is happening in their environment. Hearing students are able to learn incidentally about the world around them and about important functions of language. In contrast, students with a hearing impairment are rarely able to hear enough (without attending to a specific interaction) to learn incidentally from:
- Discussions and interactions between parents, teachers, other adults or peers
- Disagreements or resolutions between these same people
- Television or radio
- Conversations on the telephone.
(Calderon & Greenberg, 2003, p. 179)
Most environmental sounds are very informative. Hearing sounds around the house can indicate where a person is and what that person might be doing. For example, hearing water boiling or the microwave timer lets you know that someone is cooking in the kitchen. Environmental sounds can help you predict what might happen next. For example, hearing the phone ring tells you that someone will get up and move to another area, or start you wondering if that the phone call might be for you. When they hear such things, subconsciously, hearing people make predictions and assumptions without effort. For person with hearing impairment, some of these environmental sounds may be heard and some may not, which in turn means that the appropriate assumptions and predictions may not be made. A student with hearing impairment may not understand why the teacher and all the students are looking out the window, when they heard a car crash on the road outside, or why the teacher stops talking and looks at some other students in the room who have been whispering.
Warnings of danger, such as smoke alarms, fire alarms and car horns are usually given by sound signals, and the student with a hearing impairment may not be aware of the location of the sounds or what they mean. Some of these auditory signals can be supplemented by a range of visual ones, such as flashing strobe lights. These accommodations should be considered by schools with students who are hearing impaired.
All these factors are challenges to students with hearing impairments. While most will be aware of the challenges, they may not always be aware of the strategies they can employ to help them glean information to stay abreast of the happenings in their environment. These strategies can be utilized and encouraged by teachers.
The student with hearing impairment obviously has to consider events and make predictions more consciously than the average hearing student. This can be extraordinarily tiring (Calderon & Greenberg, 2003) and can have the effect of causing the ability to do these very things to deteriorate. On a given day some students may be easily able to understand what the teacher is saying even though there is construction work happening outside, but on another day, may not be able to understand at all.
There are a number of factors that can contribute to ease of understanding, and these are covered in the Accommodations section of this web site.
The student’s ability to access spoken language, environmental auditory experiences, and ease of interaction with others will depend on the type and degree of hearing impairment, self-awareness and acceptance, and on the educational, personal and practical support available.
How do students who are hearing impaired develop an understanding of concepts, communication, and social skills as well as the ability to independently participate in everyday activities? The following areas are underscored by a variety of authors (Marschark, n.d.); Smith, Polloway, Patton & Dowdy (2004); and ASHA (n.d) as some of those that are affected by a hearing impairment:
Early relationships, experience and early learning opportunities of the hearing impaired student will have made a lasting impact upon that student’s ongoing social, language, cognitive, and emotional development.
Communication and language are greatly affected by hearing impairment. Early delay in receptive and expressive communication skills may have an ongoing impact upon the student’s ability to understand, process and use the information being acquired throughout one’s educational life. Individual students with hearing impairment may have varying abilities in their communication abilities. The student may have difficulties with reading or with subjects incorporating jargon specific to that subject, but not used much in everyday language. There may also be difficulties with hypothesizing or with seeing things from another person’s perspective.
Social skills refer to those skills necessary for effective communication with other people. They include both verbal and non-verbal behaviors. Some of the skills include eye contact, proximity, word choice, intonation, ability to read non-verbal cues, facial expressions, take the perspective of another, shift attention, and maintain topic of conversation (Disability News, 2001). Social skills are crucial to our lives for personal, academic and vocational success. A student with a hearing impairment has difficulty with accessing auditory information and expressing ideas in a way that others can understand. The Learning Disabilities Association of Ontario (1999) states that a student with hearing impairment may appear disoriented, distracted, or at times confused because of difficulties with accessing accurate auditory information. The student may try to cope with difficult situations by copying peers or pretending to understand what is going on in the class while actually misunderstanding the situation. The student with hearing impairment may appear to hear normally, when in fact the student can not hear speech sounds clearly enough and is misinterpreting the information. The student may have difficulties pronouncing speech sounds correctly, poor vocal quality, or trouble explaining ideas clearly. All of the above- stated factors can negatively impact social skill development as well as the ability to freely communicate, resulting in the student becoming shy, socially isolated, or displaying behaviors of concern (Learning Disabilities Association of Ontario, 1999).
It is important to be aware of potential areas of difficulty and to note when any confusion or misunderstandings begin to occur. Rectifying confusion or misunderstandings early is imperative in order to ensure the foundational information is understood before placing more scaffolding information on top. One suggestion is offering to give more information or background material to the student, parents, or the visiting support teacher, to preview or review the information being covered. It can be helpful to have students act out or present information visually to enable clearer and deeper understanding of complex information.
Marschark (2002) suggests that these students “may have different knowledge, cognitive strategies and experiences” from hearing students and that we need to support the student with hearing impairment by utilizing skills and acknowledging areas of difficulty (p. 10).
As discussed above, the student may lag behind in achievement in comparison to hearing peers due to the impact of hearing impairment on learning. Therefore, the student may require skills in these areas to be specifically and explicitly taught, along with additional time and opportunities to practice these skills.
Professionals Who Diagnose and Treat Hearing Loss
This section presents information on the assessment process and the various team members that can assist the student. A comprehensive evaluation of the student’s functional hearing needs to take place so that the student receives appropriate intervention and services (Lewis & Allman, 2000). To fully evaluate the hearing condition, abilities and needs of the student, a two-fold approach is required, involving diagnosis and assessment.
Initially, the diagnosis of a hearing impairment is based upon a comprehensive evaluation by a multidisciplinary evaluation team, which includes a physician, an audiologist, and an otolaryngologist or otologist. Table 2 below describes the roles of the various professionals involved in the hearing assessment process and information they can provide to educators to help the student.
Examines the ears by carrying out a basic hearing screening.
Refers patients to the appropriate health care professionals such as audiologists, otolaryngologists or otologists.
Trained specialist in the evaluation and non- medical treatment of hearing impairment:
Physician specializing in the medical and surgical management and treatment of patients with diseases and disorders of the ear, nose, throat (ENT), and related structures of the head and neck. In the domain of the ear, is trained in both the medical and surgical treatment of hearing, ear infections, balance disorders, ear noise (tinnitus), and congenital (birth) disorders of the outer and inner ear. Pediatric otolaryngologist receives advanced training in the medical and surgical care of children. (Dugan, 2003)
A physician specializing in the medical and surgical diagnosis and treatment of disorders associated with the ear. Pediatric otologists treat children from the newborn period through the teenage years. They have advanced training in the medical and surgical care of children.
Once the referral to the appropriate professional has been made, an audiological examination is performed. An audiological examination is conducted by an audiologist to determine:
- if a hearing loss is present;
- which tones are affected;
- the degree of the hearing loss;
- the type of hearing loss (i.e. conductive, sensorineural, or mixed);
- the best method of treating the hearing loss; including selection of an appropriate hearing aid, if appropriate.
The audiologist then performs several tests in order to obtain an accurate measure of the child’s hearing abilities to determine the existence and extent of the hearing impairment.
When these tests have been completed, the audiologist may conduct more specialized procedures, such as the evaluation of the mechanical functioning of the eardrum and bones of the middle ear (“intermittence teats”), and other measures to assess the function of the cochlea. Alternatively, if deemed necessary, the audiologist will make referrals to other professionals.
After reviewing the child’s information and test results, the audiologist will be able to describe a hearing loss as unilateral (affecting one ear) or bilateral (affecting both ears), the degree of hearing impairment (mild, moderate, severe or profound), and the type of loss (conductive, sensorineural or mixed). The audiologist will make recommendations regarding amplification and provide suggestions on how to best manage the hearing impairment. It is important to remember that every student is an individual and as Scheetz (2000) emphasizes, “One must be careful not to pigeonhole or label someone based on this information” (p. 52). To help the student we need to then individualize the supports that we provide by consulting with other professionals.
Below is information about some of the tests that are performed to assess hearing. They include:
- Otoscopy. Otoscopy is a physical examination of the ear that involves looking into the ear with an instrument called an “otoscope” (or “auriscope”) to examine the structures of the outer ear and the eardrum. Otoscopy can help detect problems such as a hole (perforation) in the eardrum and infections of the middle ear (such as acute Otitis Media, an infection that produces pus, fluid, and inflammation within the middle ear). The nose, nasopharynx (space within the skull that is above the roof of the mouth, and behind the nose), and upper respiratory tract are also examined.
- Tympanometry. Tympanometry measures the ability of the middle ear to conduct sound. It is particularly useful in detecting fluid in the middle ear; Eustachian tube dysfunction (such as negative middle ear pressure); disruption of the ossicles (bones); tympanic membrane (ear drum) perforation; and otosclerosis (abnormal growth of bone in the middle ear). To perform this test, a soft probe is placed into the ear canal and a small amount of pressure is applied. The instrument then measures mobility of the tympanic membrane and its response to the pressure changes. The results of the test are printed as a graph, called a “tympanogram” which can help identify middle ear problems. For example, a flat line on the tympanogram may indicate that the eardrum is not mobile or not vibrating properly due to fluid in the middle ear (Hain, 2002).
The audiologist begins the examination of the child by first taking a case history. The audiologist asks questions about the child’s medical conditions, hearing behaviors, hearing loss in the family, and any concerns of the child and the family.
Audiometry is the testing of a person’s ability to hear sounds at a range of frequencies. This includes air conduction tests, bone conduction tests, and speech audiometry tests. An audiometric test is used to determine the types of sounds the child can and cannot hear.
Air conduction tests involve the presentation of beeps and whistle-like sounds, called “pure tones,” through headphones in a soundproof room. Sounds are of varying loudness (intensity measured in dB) and of different pitch (or frequencies measured in Hz) The pure tones go via the air, down the ear canal, through the middle ear into the inner ear. The child is asked to respond when he or she detects a sound (such as by raising a hand or pushing a button). The loudness of each tone is reduced until the child can just hear the tone. The softest sounds the child can hear constitute the hearing threshold. This is marked on a graph called an “audiogram,” which can be used to identify and diagnose hearing impairment (Martin & Clark, 2003).
A bone conduction test involves using a skull vibrator such as a vibrating tuning fork. It is placed behind the ear to measure the softest sounds that the child can hear to test the functioning of the inner ear. The child is asked to respond when detecting a sound produced by the device. As the sound travels through the bones of the skull to the inner ear (cochlea, auditory nerves), the sound sidesteps the outer and middle ear.
Interpretation of Air Conduction and Bone Conduction Results
- If air conduction and bone conduction thresholds are within normal limits, then hearing is normal.
- If the air conduction thresholds indicate a loss and the bone conduction thresholds do not indicate a loss, then a conductive hearing loss is present. In other words a person does not hear normally when sound has to go through the outer, middle and inner ear, but if the sound bypasses the conductive mechanism (i.e. the outer and middle ear), and goes directly to the inner ear, then hearing is normal.
- If there is a loss by both air- and bone - conduction and the abnormal thresholds are essentially similar, then a sensorineural hearing loss exists. In other words, there is a hearing loss by air conduction, such as when the sound goes through the outer, middle and inner parts of the ear. There is the same amount of hearing loss when the sound bypasses the outer and middle ear and goes directly to the inner ear. If there is a loss by both air conduction and bone conduction, but the loss by air conduction is worse than the loss by bone conduction, a mixed hearing loss exists. Both conductive and sensorineural components are present.
This involves presenting the child with a series of simple recorded syllables, words and sentences spoken at various volumes into the headphones. The test is designed to assess speech threshold (i.e., when the child can first hear speech) and the child’s ability to understand speech (Scheetz, 2000). The test requires the child to repeat each word back to the audiologist as it is heard. This provides information on the volume (quantity) of the speech sound that the child can hear and also the quality of the sound (clear vs. distorted) the child hears. The level at which the child can repeat 50% of test materials correctly provides information about the type and degree of hearing impairment (Lysons, 1996). This is useful to determine the candidacy for hearing aid and reaffirm the findings of the pure-tone audiometry test.
Designing the Individual Educational Plan
Once a hearing impairment has been identified, the next step involves creating a plan of action, or the Individual Education Plan (IEP), that meets the abilities and needs of the student. It is important to do this by using a team approach. Table 3 below describes the various team members. The team can be comprised of a variety of educational specialists, such as a certified teacher and assessment professionals. The team also includes a variety of other health professionals such as Occupational Therapists, Audiologists, and Speech and Language pathologists. The composition of the team will depend on the needs and abilities of your student. Hence your team may not necessarily include all the people listed below.
Visiting teacher or Hearing Support Teacher
- Assesses and evaluates the needs of each child
- Explains the impact of hearing impairment to staff and students without a hearing impairment in terms of current and future implications
- Assists teaching staff understanding of audiological equipment (such as sound amplification technology)
- Offers support to the student (such as note-taking, assisting with concerns related to academic work, social matters, audiological issues, speech, listening, language and literacy goals)
- Provides advice on adaptations to the school environment needed for the student
- Assists with educational programming for the student
- Providesadvice to teaching staff regarding instructional and classroom management strategies
- Liaises and consults with parents and outside agencies
- Develops daily living skills (educational skills such as writing, and self-help skills such as washing, dressing, eating)
- Advises on special equipment, aids and adaptations to the environment to maximise independence.
- Assesses student’s gross-motor skills (ability to sit, stand or walk)
- Recommends exercises to develop motor skills, increase flexibility, balance and coordination
- Provides mobility aids
- Provides psycho-educational assessments
- Identifies student’s learning style and educational needs
- Addresses learning, behavior and emotional concerns
- Provides counseling as needed.
- Provides family support and counseling
- Supports the family in accessing community services
- Assists the student in accessing programs in the community
Speech/ Language Pathologist
- Assesses communication skills
- Provides communication intervention (Receptive skills intervention may include awareness of sound, localization of sound, discrimination of sound differences, recognition of sound and comprehension of speech. Expressive skills intervention may include developing breath control, vocalization, voice patterns and sound production. Social skills intervention could involve support with making friends, requesting clarifications, problem solving skills and developing a positive self concept.)
In conclusion, teachers can work with a variety of professionals to plan an appropriate educational program that will help the student with hearing impairment participate successfully in the classroom. This chapter has provided an overview of hearing impairment by detailing information on how we hear, how hearing is assessed, ways of identifying students with hearing impairments in the classroom, and learning characteristics of students with hearing impairments. Additional information has been provided on the types of professionals who can be of assistance in diagnosing and educating students with a hearing impairment.
- ASHA (n.d.) Types of Hearing Loss. Retrieved February, 15, 2005 from http://www.asha.org.
- ASHA Task Force on Central Auditory Processing Consensus Development (1996). Central auditory processing: current status of research and implications for current practice. American Journal of Audiology, 5 (2): 41-54.
- Calderon, R. & Greenberg, M. (2003). Social and Emotional Development of Deaf Children: Family, school and program effects. In M. Marschark & P.E. Spencer (Eds) Oxford Handbook of Deaf Studies, Language and Education. (pg 177 –189). Oxford ; New York : Oxford University Press.
- Disability News. (2001, April 2). I should have stayed in bed. Retrieved April 1, 2005 from, http://www.redwoods.edu/district/dsps/newsletter/Spring-01/htm. (no longer available)
- Dugan, M. B. (2003). Living with hearing loss. Washington, D. C.: Gallaudet University Press.
- Fraser, B. (1996). Supporting children with hearing impairment in mainstream schools. London : The Questions Publishing Company.
- Hain, T.C. (2002). Hearing Testing. Retrieved February, 15, 2005 from http://www.tchain.com/otoneurology/testing/hearing_test.htm#tympanometry (no longer available)
- Kuster, J. M. (1993). Experiencing a day of conduction hearing loss. Journal of school health, 63, 235-237.
- Learning Disabilities Association of Ontario. (1999). Literacy project: A listing of learning disability groupings. In An introduction to Learning and Employment Assessment Profile (LEAP) and Learning disabilities.
- Lysons, K. (1996). Understanding hearing loss. London ; Bristol, Pa. : J. Kingsley Publishers.
- Marschark, M. (2000). Looking beyond the obvious: Assessing and understanding deaf learners. Invited address to the 3rd International Conference Action Communication Formation Pour la Surdite [ACFOS], Paris.
- Marschark, M., Lang, H. G. & Albertini, J. A. (2002). Educating deaf students : from research to practice. Oxford ; New York : Oxford University Press.
- Martin, F. N. & Clark, J. G. (2003). Introduction to audiology (8th Ed). Boston : Allyn and Bacon.
- Niemann, S., Greenstein, D. & David, D. (2004). Helping children who are deaf : family and community support for children who do not hear well. Berkeley, Calif.: Hesperian Foundation.
- Northern, J. L. & Downs, M. P. (2002). Hearing in children (5th Ed.). Philadelphia, PA : Lippincott Williams & Wilkins.
- Pagliano, P. (2005). Using the senses. In Ashman, A. & Elkins, J. (Eds.). Educating children with diverse abilities (2nd Ed) (pg 319-359). Frenchs Forest, N.S.W. : Pearson Education Australia.
- Scheetz, N. (2000). Orientation to deafness (2nd Ed). Boston, MA :Allyn and Bacon.
- Schwatz, S. (Ed.) (1987). Choices in deafness: A parents guide. Kenington, MD: Woodbine House.
- Smith, T. C., Polloway, E. A., Patton, & J. R., Dowdy, C. A. (1998). Teaching students with special needs in inclusive settings (2nd Ed). Boston : Allyn and Bacon.
- US Dept of Health and Human Services (1991). Healthy people 2000: National health promotion and disease prevention objectives. DHHS Publication No. 91-50121. Washington, DC: US Government Printing Office, Superintendent of Documents.
- Waldron, K. A. (1996). Introduction to a special education: The inclusive classroom. Albany, NY: Delmar Publishers.