Hearing Impairment

Hearing impairment is the educational term for individuals who are deaf or hard of hearing to the extent that they require special services to achieve optimally in the school environment. Individuals who are deaf cannot process linguistic information with or without a hearing aid. Individuals who are hard of hearing have the residual hearing to use linguistic information with the use of a hearing aid. The age of onset of hearing loss and the severity of the loss will also impact the individual's ability to use language. Individuals who are born deaf are referred to as being congenitally deaf while individuals who lose their hearing later in life are referred to as being adventitiously deaf. The term prelingual deafness refers to deafness that occurs before language develops and is contrasted to the term postlingual deafness which refers to deafness which occurs after language is developed. Hearing loss is measured in terms of decibels (units of loudness) and hertz (pitch). The following classification of hearing impairments is commonly used to describe loss: mild (25-54 dB), moderate (55-69dB), severe (70-89 dB), and profound (90 dB and above). Prevalence estimates indicate that approximately 0.14 percent of the school age population is currently receiving services for hearing impairment.

Familiarity with the parts of the ear and the functions they have will help the student better understand hearing impairments. Although the actual physiology of hearing is quite complex, it can be summarized by understanding the basic roles of the hearing organs. The outer ear (auricle and auditory canal) funnels the sound to the middle ear. The sound waves cause the tympanic membrane to vibrate which in turn causes ossicular vibration. This vibration causes the fluid in the cochlea to circulate and stimulate the hair cells (stereocillia) which send an electrical impulse to the brain. The classification system for hearing impairments is based on the location of the problem. Impairments of the outer ear (e.g., external otitis) and middle ear (e.g., otitis media) are referred to as conductive hearing losses while impairments of the inner ear are referred to as sensorineural hearing losses. A mixed hearing loss is a combination of a conductive and sensorineural loss. Causes of conductive hearing problems include infection, malfunctioning of the ossicles, and other problems. Sensorineural deafness is caused by hereditary influences, viral and bacterial infections, anoxia, head trauma, excessive noise, and other factors.

There are three major types of hearing assessment: pure-tone audiometry, speech audiometry, and specialized tests for infants and children with severe disabilities. In pure-tone audiometric testing, the individual's threshold for hearing is measured at different frequencies (hertz) and intensities (decibels). Speech audiometry refers to measurement of the ability to detect and understand speech. Play audiometry, reflex audiometry, and evoked-potential audiometry are examples of hearing assessments for infants or children with severe disabilities.

The speech and language development of hearing impaired learners in the English language is strongly influenced by the age of onset and the severity of the loss. The majority of individuals with profound hearing loss do not develop intelligible speech. The lack of feedback creates a major obstacle in the production of English sounds. However, this difficulty in the English language does not interfere with the development of fluency in American Sign Language (ASL) which is considered to be the language of the deaf culture. Historically, individuals with hearing impairment were considered to be cognitively deficient instead of cognitively different. Today researchers and educators understand that the intellectual functioning of the deaf population is the same as the hearing population when assessment is conducted in the individual's predominant language). Most children with hearing impairment have major difficulties with academic achievement. Reading achievement appears to be the most severely affected area because of the heavy dependence on the English language. It is interesting to note that deaf children with deaf parents typically fare better academically than do deaf children with hearing parents. In the past, deaf individuals were considered to be socially maladjusted by some researchers because they preferred to socialize with other deaf individuals instead of integrating themselves with the hearing world. However, today it is well known and accepted that wanting to socialize with people who speak the same language is a natural orientation. The value of establishing a bond with others who speak the same language is an important aspect of the deaf culture. Many members associated with the deaf culture believe that deafness is a difference rather than a disability. They are outspoken opponents of technology, such as cochlear implants, designed to assist the deaf in hearing.

There is continuing controversy regarding the best methods for teaching learners with hearing impairment. There are basically three different educational approaches:

1) manualism,

2) oralism, and

3) total communication.

Manualism refers to instruction which focuses on sign language and finger spelling. Oralism involves amplification, speechreading, and speech therapy. Total communication is a combination of manual and oral approaches and includes signing English systems, finger spelling, and sometimes American Sign Language (ASL) as well as the oral techniques above. Members of the deaf culture disagree that signing English systems should be given preference over ASL. They feel that ASL is the natural language of the deaf culture and is therefore the best language to teach hearing impaired students. Proponents of English signing systems believe that this method should be given preference because it matches the language of the written text, thus giving learners a better opportunity to improve reading skills. When bilingualism is involved, there are two different approaches to teaching. One of these models suggests that ASL should be taught to the student before English while the other model recommends that ASL and English be taught at the same time. Different methods of service delivery, from residential schools to full inclusion, are used with hearing impaired learners. Because the incidence of hearing impairment is so low, students who are placed in the mainstream sometimes have socialization problems stemming from communication differences. It is difficult to say that one type of service delivery system is better than another for this population.

Most research has found that recommendations should be made on a case by case basis. Some students with hearing impairment will do well in the regular classroom and other students may do well in residential schools where there is a large peer group for socialization. Recent technological advances in hearing aids, television captioning, telephone adaptations, and computer assisted instruction have made communication more effective and efficient for individuals with hearing impairment.

Early intervention is of critical importance for children with hearing impairments because of language development considerations. The child who is not exposed to language at an early age will have major developmental problems. The key issue with hearing impairment often concerns which language, oral or manual, the child should have exposure to. The issue is further complicated by the language of the parents. If the parents are hearing, it is very difficult for them to learn ASL quickly enough to provide the communicative environment necessary for language development. And if the parents choose an oralist approach, they may find out too late that the child does not have the capacity to develop oral language skills in English --- thus, the child has been deprived of any language. Research has demonstrated that deaf parents have deaf children with fewer problems, probably because the language issue has already been resolved and the communicative environment provided is natural and rich. It appears to be especially important that deaf children with hearing parents be provided with early intervention programs that involve the entire family. Even though the parents may never develop a high level of fluency in ASL, it may well be the only means of communicating with their child. Transition issues for individuals with hearing impairment focus on postsecondary programming and vocational concerns. In the past there have been few choices for postsecondary education for deaf individuals. Gallaudet University and the National Technical Institute for the Deaf where the only choices until the 1980s. Currently there are over a hundred postsecondary programs for these learners to choose from. However, after college or vocational school, deaf individuals face difficult career problems because of communication differences. High rates of unemployment, low wages, and fewer different job opportunities are some of the hurdles which hearing impaired individuals face.