Author: Dolly Bhargava, M.Spec.Ed.


Technology such as hearing aids, cochlear implants, captioning, assistive listening devices and alerting devices can amplify sounds to help maximize the student’s communication and learning potential at school (Pratt, Heintzelman & Deming, 1993).  With all of the devices described in this section it is crucial that a thorough assessment of the classroom environment is carried out before a device is chosen.  A team approach should be used that consists of the classroom teacher, an assistive technology consultant, audiologist, visiting teacher for hearing, parent, speech-language pathologist, and the student.  A major part of the assessment should include classroom observation to get a thorough understanding of auditory-related concerns.  Based on the assessment, the best possible device to provide an appropriate educational environment for the student should be determined (Smith, Polloway, Patton and Dowdy, 1998).  Also, both teacher and student need to receive appropriate in-service information and on-going follow-up support from a hearing specialist for each of the device/s to gain maximum benefit from it in the classroom. 

This chapter will present technology solutions for students who have a hearing impairment. Access to information and the capacity to interact with that information in a variety of ways is fundamental to a rich curricula experience. Through provision of technology solutions that are viewed as tools, students with hearing impairment have greater opportunity to achieve access, equity and opportunity. 


How Does a Hearing Aid Work?

Fraser (1996) states that “…a hearing aid is an instrument which collects sounds, amplifies them and then directs the louder sounds into the ear” (p. 41).

Hearing aids enable the student to use auditory perception to maximum effect.  It is important to remember that hearing aids are not comparable to eyeglasses (Dugan, 2003).  In other words, unlike eye glasses, which can restore vision to normal, hearing aids do not correct or restore hearing.  Instead they enable the wearer to use his or her remaining hearing more effectively by amplifying sounds (Staab, 2002).

The hearing aid includes the following parts that work together to help the student listen:

  • Microphone – It picks up the sound signal and converts it into electrical energy.  The electrical signal is fed into the amplifier (Fraser, 1996).
  • Amplifier – It progressively boosts the power of the electrical signal through various stages.  The magnified electrical signal is fed into the receiver (Fraser, 1996).
  • Receiver – The receiver converts the electrical signal back into sound energy, which is much louder than the original.  This amplified sound is then fed into the ear canal.  An incoming signal can be boosted as much as 80 dB. For example, a sound entering the microphone at 70dB can be boosted and emerge from the receiver at 150dB (Fraser, 1996).
  • Battery – It is the power source of the hearing aid.  Currently, there are two main types of batteries that are used: zinc-air and mercury.  Zinc-air batteries are more commonly used as they last twice as long and are much more environmentally friendly than mercury batteries (Lysons, 1996).
  • Ear mould – Ear moulds are designed to fit the contour of the ear.  Ear moulds are the medium through which sound travels from the receiver to the student’s ear drum without leaking. Leaking causes feedback in the hearing aid, resulting in a high-pitched whistling sound (Downie, 2000). 

The hearing aid is specifically tailored to meet the needs of the student with hearing impairment.  Factors such as the results of the audiogram, degree of hearing loss, shape of the ear, demands on hearing, situations in which the student communicates, and expense contribute to the selection of the hearing aid (Dugan, 2003).

Most hearing aids have a volume control feature that allows the student with hearing impairment to adjust the volume manually as needed.  If it’s a built-in volume control (automatic signal processing) it adjusts the volume automatically.  According to Fraser (1996), hearing aids are “non selective amplifiers, which means that all sounds within the range of the microphone are amplified equally” (pg. 47).  Initially the student using the hearing aid maybe disturbed or distracted by some everyday sounds, such as other students talking, coughing, sneezing, pencil dropping, paper shuffling or any other sounds in the classroom, especially if they haven’t heard these sounds before.  With time and use of the hearing aid, the sounds become less disturbing (Dugan, 2003).  Please refer to the chapter on Accommodations to help reduce the background noise as much as possible.


Types of Hearing Aids. 

There are several types of hearing aids. Each type offers different advantages, depending on its design, levels of amplification, and size.  Selecting the right type of hearing aid is crucial so that it meets the needs of the individual. For example, the aid is tuned to boost the frequency range(s) where the student’s hearing loss is the greatest (Downie, 2000).  Choosing a hearing aid should be based on a full assessment carried out by an audiologist.  Some hearing aids are equipped with a T-switch (telecoil), which is a magnetic coil that allows for clearer reception of sounds from assistive listening devices such as induction loops and sound amplification systems or telephones (Downie, 2000). 

In-the-Ear (ITE) Hearing Aids.  All the components of ITE hearing aids – the microphone, amplifier, receiver, power source – are built into the ear mould itself, which is specifically made to fit the student’s 's ear.  The ITE hearing aid is useful for students with mild to severe hearing loss.  ITE aids can accommodate added technical mechanisms such as a T-switch or telecoil to improve sound transmission.  ITE aids can be damaged by earwax and ear drainage, and their small size can cause adjustment problems and feedback.  ITE aids are not usually recommended for young children because of the size of the ear moulds and also because they will need to be replaced as the ear grows.  Also, the small size of the battery door and volume control may be difficult to adjust (Fraser, 1996; Lysons, 1996).  For more information and an example of an ITE aid please visit http://www.uthearingaids.com/hearaid/inear.htm

Behind-the-Ear (BTE) Hearing Aids.   BTE hearing aids are the most common form of hearing aid for children (Fraser, 1996).  The body of the BTE aid, which is in a small curved case, contains the microphone, amplifier, receiver and battery.  The sound from the receiver in the case is fed through a clear plastic tubing to an ear mould, which fits inside the outer ear.  The sound is transferred from the ear mould into the auditory canal.  BTE aids are used by children of all ages with any degree of hearing loss, mild to profound.  (Staab, 2002).  A t-switch can be installed into the BTE aid to facilitate the use of assistive listening devices and improve sound transmission.  Some models also have a tone and volume control, which is easy to adjust.  Poorly fitting BTE ear moulds may cause feedback, a whistling sound caused by the fit of the ear mould or by buildup of earwax or fluid (Fraser, 1996).  For more information and an example of a BTE aid please visit  http://www.uthearingaids.com/hearaid/behindear.htm

Body Worn Hearing Aids – The microphone, amplifier and battery are inside a case that is carried inside a pocket or attached to clothing or a specially designed harness.  The amplified signal is fed along a thin cord to a receiver which is attached directly to the ear mould (Fraser, 1996).  The body worn hearing aid is of a fairly large size so it is able to incorporate many signal-processing options.  Yet, due to its cumbersome large size and visibility, older students do not commonly use it.  Students with severe to profound hearing losses or very young students or students who cannot use other types of aids (i.e., due to manual dexterity problems) mostly use body worn aids (Esse and Thibodeau, 1995; Lysons, 1996).  For more information and an example of a body worn aid please visit http://www.emedicine.com/ent/topic478.htm

In the Canal (ITC) Hearing Aid - ITC aids are contained in a tiny case that is placed inside the ear canal, with size and shape customized to fit.  They are not visible, offer better acoustics and are easy to maintain.  Students who have mild to moderately severe hearing losses use ITC aids (Esse and Thibodeau, 1995).  However, due to their small size, ITC aids are difficult to handle, adjust and remove, and may not be able to hold additional devices, such as a telecoil.  ITC aids can also be damaged by earwax and ear drainage. They are not typically recommended for young students because they needs to be replaced as the ear grows (American Academy of Otolaryngology, 2002).  For more information and an example of an ITC aid please visit http://www.uthearingaids.com/hearaid/incanal.htm


Benefits of Hearing Aids

The benefits of hearing aids are dependent on the age of onset and the severity of the hearing loss, type of hearing aid used, student’s communication abilities and motivation to use hearing aid.  Hearing aids can enhance quality of life by:

  • Increasing the student’s ability to hear sounds
  • Reducing speech reading effort
  • Reducing communication stress/fatigue level
  • Improving understanding of speech with or without visual cues
  • Promoting independence (e.g. use of the telephone)

          (E-Michigan Deaf and Hard of Hearing, 2002)


Tips for teachers

  • Help students develop realistic expectations of what their hearing aid can do.  For example, Lysons (1996) emphasizes that “not even the best aid can wholly provide the clear discrimination, selectivity and location of sound that is obtained with normal hearing” (p. 99).
  • Help students become familiar with their hearing aid.  For example, they should know how to insert and remove the hearing aid, replace batteries, adjust volume, operate on-off switch, use telecoil or telephone (Lysons, 1996)
  • Encourage students to take care of their hearing aid.  For example, students should wipe the hearing aid regularly with a dry cloth or tissue.  The hearing aid should never be put in water.  Additional information on cleaning the hearing aid will be provided by their hearing aid supplier.
  • Ensure that the material used in activities in which the student is involved does not damage the hearing aid.  For example, chemicals in cosmetics, after-shave, hair spray, perfume, sunscreen and mosquito repellent can damage their hearing aid.  Ask them to remove their hearing aid before applying those products and allow time for the product to dry.
  • Speak to the audiologist for a checklist to assist with troubleshooting for commonly occurring problems with hearing aids.  Below is an example of such a checklist.  Keep it in a location for access by staff.

 

Symptom

Possible Cause

Solution

Whistling or squealing noise while hearing aid is being worn

  • Hearing aid or ear mould not inserted correctly
  • Ear wax blocking the ear canal
  • Earmould tubing split
  • Earmould or in-the-ear hearing aid is too loose
  • Re-insert hearing aid
  • Have the ear canal examined
  • Contact the hearing aid provider
  • Contact the hearing aid provider

No sound

  • Aid not turned on
  • Dead battery
  • Aid in ‘T’ position
  • Tubing blocked with wax or moisture
  • Check that the battery holder is fully closed and the aid is switched ON
  • Replace battery with a new one
  • Switch to ‘M’ position
  • Remove wax or moisture from tubing

Weak sound

  • Volume too soft
  • Moisture or wax partially blocking the tubing
  • Change in hearing
  • Adjust volume control
  • Remove wax or moisture from tubing
  • Have another hearing test

Intermittent Sound

  • Dirty or corroded battery contacts
  • Return aid for service