This section provides some basic information about hearing impairment, its treatment, education for children, rehabilitation for adults, training for communication partners, and the relevance of hearing-loss simulation.
Hearing Loss
Children
About 1 child in 1000 is born with impaired hearing, but many others lose hearing as the result of congenital factors or disease. Conductive hearing loss from ear disease and allergy is common in young children. The negative effects of impaired hearing on a child's speech, language, and academic development can be significant. Early identification of the child’s hearing impairment, fitting of hearing aids/cochlear implants, special education, and parent training are necessary to avoid negative consequences.
Older Adults
Hearing loss in older adults is very prevalent. More than 40% of people over the age of 65 experience a hearing loss sufficient to interfere with daily conversation, and an even greater proportion of nursing home residents are hearing impaired. Many older people hear speech without clarity. Acquired hearing loss can result in social isolation, loneliness, and/or depression. Friends and relatives can be trained to avoid or overcome communication difficulties that result from an older person’s hearing loss.
Characteristics of hearing loss
There are two main features of sensorineural hearing loss:
(1) a loss of sensitivity (an inability to hear weak sounds);
and (2) a loss of clarity (an inability to hear small differences between sounds).
Most people with sensorineural hearing loss also experience poorer hearing in the high frequencies and greater interference from background noise.
Treatment, education, and rehabilitation
Medical/surgical
A doctor can easily remove earwax in the outer ear. Antibiotics and decongestants are effective treatments for middle ear disease. A surgeon can insert a grommet in the eardrum to promote drainage and evaporation of fluid. Surgery has been successful in cases of anatomical abnormality or where the middle ear bones have become immobile as the result of otosclerosis.
Hearing aids
Hearing aids are small self-contained amplification systems worn behind the ear, in the outer ear, or in the ear canal. Sound is detected by a small microphone, amplified, and delivered via an earmold to the eardrum. Analog or digital circuitry insures that sound is amplified to listening levels that are matched to the person’s needs and comfort. Most people with moderate-to-severe hearing loss experience communicative benefits.
Cochlear implants
Cochlear implants are special devices designed to restore hearing sensation and perception to a person with an extreme hearing loss. Sound is detected by a head-worn microphone, encoded by a small digital signal processor, and presented directly to the person’s inner ear via an array of surgically implanted electrodes. For people with extreme hearing loss, the ability to perceive speech may be greatly improved.
Assistive listening devices
These are special amplification systems used to enhance communication over the telephone, in noisy places, or at great distances. A microphone is placed at an optimal location near the speaker's mouth, often connected to a small FM transmitter. The person with impaired hearing listens through a cochlear implant, personal hearing aids, or headphones. In most cases, the the negative effects of background noise are reduced, and the received quality of speech is improved.
Lipreading
Most people with impaired hearing watch the speaker’s mouth and face for visible cues as they listen through their cochlear implants, hearing aids, or assistive devices. Lipreading helps a person obtain speech information that is not heard clearly (e.g., place of articulation of consonants), increases a person’s ability to participate in conversation, and reduces communicative effort.
Special education
Educators use a variety of methods to accelerate speech and language learning by children with impaired hearing: parent training during the pre-school years, auditory-verbal techniques to develop listening skills, a quiet/non-reverberant environment to optimise benefit from hearing aids/cochlear implants, good classroom illumination, instruction in small groups, and one-to-one tutoring.
Aural rehabilitation/self-help
Adults with acquired hearing loss often use behavioural strategies to improve their ability to participate in conversation and to reduce stress that they may experience during daily interaction. These include control of the surrounding environment to reduce auditory and visual distractions, management of conversation, self-help through assertiveness, and use of timely requests for clarification.
Communication training
Parents, teachers, family, and friends play an important supportive role. A child or adult with impaired hearing will acquire/maintain spoken language more easily if communication partners produce speech that is consistently audible, visible, and clear. Partners can develop empathy, increase their speech and language clarity, and learn essential communication strategies as the result of training with the HELOS hearing loss simulator.
Parents and teachers are the young child's main communication partners. Most educators recommend that parents and teachers play major roles in the language-development process. Spouses, friends, family, and carers are the older adult’s main communication partners. Most therapists and counsellors recommend that these people actively help to maintain communication.
How easily a child or adult learns to/continues to communicate through speech depends on: (1) what their communication partners say (e.g., short/simple sentences, meaningful context); and (2) how they say it (e.g., clear speech, turn-taking, appropriate responses).
Speech intelligibility
Communication involves the transfer of ideas between people. Not all messages, however, are perfectly received. Intelligibility is the proportion of a message that the receiver can identify correctly.
Speech intelligibility depends on a speaker's voice pitch and level, syllable rate, lip/tongue positions, facial movements, and other factors. Most speakers listen to themselves (but cannot watch themselves) as they talk, and rely on this feedback to decide whether they have spoken clearly. They may pause, speak louder, or exaggerate to compensate - if they feel that a lack of clarity has interfered with communication.
Speech intelligibility depends on what a speaker says. For someone to understand a message easily, the message must be short, contain related words, phrases, and simple language, and fit into the context of the conversation.
Speech intelligibility depends on who is looking and listening. A listener with impaired hearing may perceive some of the message incorrectly - or not at all. What is received may be very different from what was spoken.
Speech clarity
Nearly all people with normal hearing speak with sufficient clarity to converse with other people who have normal hearing. Experience suggests, however, that many people do not speak clearly enough to be heard easily by someone with a serious hearing loss, or to be understood easily by someone who lipreads.
Parents, teachers, family, and carers may develop clear speech and language over many years. They acquire their skills slowly because:
- a speaker cannot hear his/her own speech as someone with impaired hearing does, and thus cannot judge the way it sounds
- a speaker cannot see his/her own mouth while talking, and thus cannot judge the way it looks
- the child or adult with impaired hearing may not provide feedback regarding the speaker’s audibility, visibility, or language clarity
Training partners
Clinicians generally recognize that training partners in conversational skills is vital to the early language development of children and the social rehabilitation of older people with hearing loss. Communication with a child or adult who has a serious hearing loss often requires special knowledge, skill, and patience. As the result of training, communication partners can increase their speech and language clarity.
Most courses in special education or rehabilitative audiology teach their students how to communicate with hearing-impaired children and adults. Some hospitals and community health centres offer similar training to parents, family, and carers.
Information
Training usually includes a review of important principles (see below). A list of strategies like this usually is combined with other training procedures, because an awareness of basic principles alone does not necessarily lead to their use.
Some ways to increase conversational fluency.
- provide amplification
- ensure face visibility
- speak at a short distance
- avoid environmental distractions
- indicate (changes of) topic
- relate messages to the situation
- speak slowly and carefully
- use common words in short, simple sentences
- pause between important thought units
- apply appropriate repair strategies
- check comprehension frequently
Instruction
An experienced teacher or therapist can provide insightful advice about a communication partner's voice and articulation. The instructor analyzes the speaker’s spoken language and suggests how to increase clarity. Similarly, communication training for parents, teachers, and students may include guidance from an observer and coach.
Observation
A communication partner can learn clear speech and language strategies: (1) by observing an experienced teacher or clinician as she communicates with a child or adult with impaired hearing; or (2) by listening through the HELOS hearing-loss simulator while watching video recordings obtained from the point of view of the person with impaired hearing.