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Speech
and Hearing Disorders
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/ Speech Impairments / Hearing Impairments -- Definitions / Disorders of the Outer Ear /
/ Disorders of the Middle Ear / Disorders of the Inner Ear / Hearing and Rehabilitation /
Many disorders that affect speech are the result of trauma to the brain; the student should refer to the chapter on neurological disorders to review the affects of cerebral trauma upon speech expression and reception. Certain other physical disorders may also affect the mechanisms of speech; most of these are easily correctable. This section attempts to describe a few of the more common disorders affecting speech.
CLEFT PALATE AND CLEFT LIP
These disorders often occur together are among the more common congenital defects, affecting about one in seven hundred infants. Cleft palate is a congenital disorder of unknown cause in which the roof of the mouth does not close properly during development, leaving a slit, or cleft, in the roof of the mouth. Cleft lip is a fissure in the upper lip; this defect is sometimes called "harelip" because of the similarity of the contour of the mouth with that of a rabbit. Cleft lip may be nothing more than a red line or in extreme cases can extend nearly to the lower eyelid. Both of the disorders affect the mechanism of speech, and are nearly always correctable through plastic surgery, leaving no significant disability.
SHORTENED FRENULUM (TONGUE TIE)
The frenulum is the web-like structure that joins the bottom of the tongue to the midline of the mouth floor. On occasion, the infant is born with a shortened frenulum, or "tongue tie." If detected early, a physician may be able to correct the problem simply by severing the frenulum with a pair of scissors; no anesthetic is needed. Later in life the operation may be performed with local anesthetic. The disorder is usually not a rehabilitation concern.
NASAL BLOCKAGES
Nasal blockages may take one of several forms and may require surgery. Deviated Septum is a faulty development of the cartilage bridge of the nose, and may distort breathing and speech. Surgery may be done on an outpatient basis and almost always corrects the problem. Polyps of the Nasal Passage are believed to be the result of allergic reactions and can grow large enough to block the nasal passages, even to protrude from the nostrils. Treatment usually involves local anesthetic and surgical removal; treatment of allergies may also be undertaken to prevent recurrence. Sinusitis, or infection of the spaces within the head bones, may distort the voice. If the disease is sporadic, antibiotics may remove the infection; however, in chronic cases, surgery to drain sinus or even enlarge them may be necessary. If properly treated, nasal blockages tend not to cause significant residual impairments.
STUTTERING
Stuttering is a disfluency of speech in which the individual may repeat words or parts of words, or may pause for prolonged periods when speaking. The condition may affect as much as one percent of the population of the United States, and is more common in children than in adults. Men are about four times as likely to be affected as women.
The cause of stuttering is unknown, but appears to be related to the development of motor skills. Some persons believe that an environment in which pressure to perform tasks correctly on first trials may lead to anxiety, which affects the development of stuttering. Attempts to change handedness (usually from left hand to right hand dominance) does not cause stuttering to develop, as is often believed.
Stuttering may be brought on in certain anxious situations and may be perpetuated by the stutterer's response to their own stuttering. Since cause is unknown, most medical and rehabilitation texts do not deal contain much information on stuttering. It is believed that the best treatment for the disorder is attention to mental health and avoidance of situations that exacerbate the problem.
Vocationally, persons who are chronic severe stutterers may have difficulty with communication, especially in occupations that require extended interpersonal contact, such as sales or human services. Individuals with severe stuttering problems may find it difficult to obtain and maintain employment in these occupations.
Reduced sensitivity to sound of any type is referred to as a hearing impairment. Unlike many of the disabilities we encounter in rehabilitation, hearing impairments (and speech and visual impairments) mention the specific functional ability that is affected. Other disabilities (spinal cord injury, for example) refer to the part of the body that is injured, diseased, or ill rather than the specific functional effects.
A number of definitions concerning hearing impairments should be discussed. A hearing impairment is any type of disorder in the ability to sense sound, while deafness refers to the inability to hear conversational speech. Hard of hearing refers to persons with hearing problems not as severe as total deafness.
The degree of hearing impairment is usually measured in relation to the decibel level at which an individual is capable of sensing sound.
The mechanics of hearing involve the conduction of sound waves through the outer ear to the middle and ear, where the sound waves are converted into nerve impulses and carried to the brain. Hearing loss may involve any of four classes of problems. Conductive hearing loss involves problems with the conduction of sound waves through the outer or middle ear. Sensorineural hearing loss involves loss of hearing due to defects in the cochlea and auditory nerve of the middle ear. Central Deafness involves lesions to the hearing center of the brain in the cerebral cortex, such as in a stroke or brain injury. Finally, Mixed hearing impairments involve a combination of these problems.
Hearing impairments may be congenital, acquired or advantageous, and for many people the cause of hearing damage is unknown. The following sections are an overview of the anatomical structure of the hearing mechanism and a discussion of common problems which can temporarily or permanently affect hearing.
The outer ear includes the auricles (the part of the ear you see) and the external ear canal, which leads to the eardrum. Glands in the external ear canal produce wax (cerumen) which protects the ear from infection from germs and foreign bodies.
Outer ear disorders rarely cause permanent deafness or hearing impairment. Accumulation of wax in the outer ear canal is often a cause of temporary hearing problems, but are easily cured with appropriate medical intervention. Boils and fungi (otomycosis) may also attack the outer ear, requiring antibiotic treatment and other measures to prevent their spread deeper within the ear.
The middle ear contains the eardrum (tympanic membrane) and three bones called the malleus, incus, and stapes (hammer, anvil, and stirrup), collectively known as the ossicles. Sound waves striking the eardrum cause the three bones to strike a fluid-filled portion of the inner ear called the cochlea, where the sound waves are transformed into nerved impulses by the movement of the fluid. This fluid also is the source of the body’s sense of balance.
Ruptured Eardrum, from loud noises, rapid changes in air pressure, or careless insertion of objects into the ear, is a common problem of the middle ear. Most ruptured eardrums heal spontaneously within a few weeks, but occasionally surgery is necessary to repair the lesion. Prognosis for ruptured eardrum is excellent, provided that the ossicles are not damaged.
Infections of the middle ear are common and were once a major cause of concern. Otitis Media is the term referring to infection of the middle ear canal; if fluid builds in the middle ear the condition is called by the name Serous Otitis Media. With modern antibiotic treatment, this condition is not as serious as it once was, but still requires prompt treatment as it can affect hearing if allowed to go untreated. Mastoiditis is the major complication of untreated middle ear infection. The infection finds its way to the mastoid bone between the outer and middle ear. This condition was once a major cause of deafness but like otitis media may usually be cured with application of antibiotics. Alternative treatment involves surgical removal of the mastoid bone.
Otosclerosis is the development of bony spurs in the middle ear causing the ossicles to ankylose (fuse together). Surgery may be performed to correct the defect or hearing aids may be used to aid hearing. The severity of the condition ranges from no effect significant upon the hearing to total hearing loss.
The inner ear (ear labyrinth) contains the cochlea, which have previously been described, and the auditory nerve, which transmits impulses concerning sound and balance to the brain.
Presbycusis (literally meaning “old hearing”) are the effects of degenerative changes with aging on the inner ear. Presbycusis affects the neural pathway and initially causes a loss in the ability to hear higher pitches. The ability to discriminate words is affected. Presbycusis is a common problem of older individuals and is progressive and incurable.
Meniere’s Disease is a disorder that usually appears in the 50’s or 60’s and involves dizziness (vertigo), fluctuating hearing loss, and ringing in the ears (tinnitus) caused by a loss of inner ear pressure. Hearing loss affects lower frequencies first and proceeds to higher frequencies. The disease can cause considerable discomfort, but usually only involves one ear (90% of the time) and only results in total deafness in about one in ten cases. Treatment may involve drugs to fight vertigo, a low salt diet to prevent fluid retention and reduce inner ear pressure, or surgery to sever the auditory nerve in severe cases.
Toxic Agents and Infections can affect the interior structure of the cochlea or auditory nerves and cause permanent deafness. Drugs such as nicotine, quinine, aspirin, and certain antibiotics have been known to cause permanent deafness in some situations. Denatured alcohol is a common toxic agent that may cause damage to the inner ears. Various infections, such as meningitis, many childhood diseases, and high fevers in the mother prior to birth may permanently damage the inner ear. These conditions were once major causes of deafness but with immunization and improved prenatal care hearing damage from these causes are less common.
A procedure that has become more common in recent years is the surgical implantation of cochlear implants. The implant is a sound-activated electronic device that is implanted in the ear that sends electrical stimuli to the auditory nerve. Cochlear implants allow for sound sensation, but do not restore normal hearing. The implants are intended as an aid to lip-reading and other alternative communication modalities for individuals with profound deafness.
For the rehabilitation counselor, it is important to understand the extent of hearing loss that an individual has sustained and the remaining functional hearing capacity. Together with this, the extent to which hearing may be improved through the use of hearing aids or other devices. Hearing aids may rest in the ear canal or over the ear, or be attached to eyeglasses or to the body or belt. Some of the newer devices allow for interfacing with electronic devices such as telephones. Other assistive devices, such as Telecommunication Devices for the Deaf (TDDs) allow for visual encoding of incoming and outgoing telephone messages.
Communication for individuals who have profound hearing impairments may involve the use of lip reading, American Sign Language (ASL) or Signed Exact English (SEE). ASL is recognized by linguists to be a distinct language from English with its own grammar and syntax, while Signed Exact English is based upon the spoken English language. ASL is more commonly spoken by individuals who are born with hearing impairments or acquire them early in life; SEE by those with impairments acquired later in life.
When communicating with an individual with a hearing impairment, remember to speak to them rather than the interpreter-much of what is "heard" is acquired through reading your lips. Be sure that the room is well lit and do not eat, smoke or chew gum.
Communication will be the most significant functional disability. Practically all of the daily communications an individual must undertake at home, at work, and in the community will be affected. Assistive devices and alternative communication may be helpful; writing instead of speaking and the use of interpreters when possible are helpful aids. Those things heard by most people must be seen or felt by individuals who have severe hearing impairments. Flashing lights or vibrating devices may be substituted for doorbells, telephone ringers, or alarm clocks. If a workplace depends heavily on intercoms, a modification must be made to allow the individual to receive this information in an alternative format. Access to a TDD will be critical for individuals who must use the telephone in employment.
Environmental conditions are a major concern in job placement. Lighting must be adequate to allow the individual to substitute visual stimuli for auditory cues, but should not be so bright as to cause the individual to need to blink or squint an excessive amount. Noisy environments should be avoided, as extremely loud noises may damage what remaining hearing an individual possesses. Background noise may be amplified by a hearing aid and minimize its usefulness. Even things such as wooden floors in an office may increase noise pollution.