Hearing Impairment
Description:
A hearing impairment is a hearing loss that prevents a person from totally receiving sounds through the ear. If the loss is mild, the person has difficulty hearing faint or distant speech. A person with this degree of hearing impairment may use a hearing aid to amplify sounds. If the hearing loss is severe, the person may not be able to distinguish any sounds. There are three types of hearing impairment that occur in young children: ·
Normal hearing in children is defined as the ability to hear sounds in the range of 0–25 decibels (dB). Hearing impairments are classified in the following degrees:
Causes and symptoms:
Conductive hearing impairment: Children develop otitis media because the eustachian tubes that connect the middle ear with the back of the mouth and equalize air pressure and drain fluid are small and easily obstructed. Acute otitis media can result from a respiratory infection such as a cold that causes an inflammation that blocks a eustachian tube. The fluid that builds up in the middle ear is susceptible to bacterial and viral infection. If the blockage persists it causes chronic secretory otitis media, the most common cause of conductive hearing impairment in children.
A painful earache and temporary hearing impairment in one ear are common symptoms of acute otitis media. The symptoms of secretory otitis media develop gradually and fluctuate. They are usually worse in the winter. Symptoms of partial hearing loss from secretory otitis media may go unnoticed for some time and may include the following symptoms:
Sensorineural hearing impairment: Sensorineural hearing impairments result from abnormal development or disorders of the cochlea, the spiral cavity of the inner ear, disorders of the auditory nerve that transmits electrical impulses from the inner ear to the brain, or abnormalities of the auditory center of the brain. Such conditions have a variety of causes. For example, more than 70 known inherited disorders account for about one-half of all severe sensorineural hearing impairments; however, 90 percent of children with congenital hearing impairment are born to parents with normal hearing. In addition, the following problems are associated with sensorineural hearing impairment:
While about 50 percent of congenital hearing impairments have no known cause, prenatal risk factors for congenital hearing impairment include:
A hearing impairment is a hearing loss that prevents a person from totally receiving sounds through the ear. If the loss is mild, the person has difficulty hearing faint or distant speech. A person with this degree of hearing impairment may use a hearing aid to amplify sounds. If the hearing loss is severe, the person may not be able to distinguish any sounds. There are three types of hearing impairment that occur in young children: ·
- Conductive hearing loss, a usually temporary interference with the reception of sound from the outer ear to the middle or inner ear
- Sensorineural hearing impairment, a permanent abnormality of the cochlear hair cells of the inner ear, the auditory nerve, or the auditory center of the brain
- Mixed hearing impairment, a combination of conductive and sensorineural impairments
Normal hearing in children is defined as the ability to hear sounds in the range of 0–25 decibels (dB). Hearing impairments are classified in the following degrees:
- Mild, in which a child hears sounds from 26–40 dB. Speech and conversation are usually unaffected but distant sounds may be difficult to hear.
- Moderate, in which a child hears sounds from 41–70 dB. The ability to form sounds and hear normal conversation is affected.
- Severe, in which a child hears sounds from 71–90 dB. The child requires a hearing aid to hear conversations.
- Profound, in which a child can only hear sounds above 90 dB. A hearing aid may help but the child will not be able to articulate words normally.
Causes and symptoms:
Conductive hearing impairment: Children develop otitis media because the eustachian tubes that connect the middle ear with the back of the mouth and equalize air pressure and drain fluid are small and easily obstructed. Acute otitis media can result from a respiratory infection such as a cold that causes an inflammation that blocks a eustachian tube. The fluid that builds up in the middle ear is susceptible to bacterial and viral infection. If the blockage persists it causes chronic secretory otitis media, the most common cause of conductive hearing impairment in children.
A painful earache and temporary hearing impairment in one ear are common symptoms of acute otitis media. The symptoms of secretory otitis media develop gradually and fluctuate. They are usually worse in the winter. Symptoms of partial hearing loss from secretory otitis media may go unnoticed for some time and may include the following symptoms:
- Immature speech
- Behavioral problems resulting from frustration at not being able to hear well
- Sitting close to the television or turning up the volume
- Poor school performance
- Asthma or allergic rhinitis
- Cleft palate , which impairs drainage of the middle ears through the eustachian tubes (Some 30% of children with cleft palate have conductive hearing loss.)
- Other head or facial abnormalities
- Down syndrome , which is characterized by narrow ear canals resulting in susceptibility to middle ear infections (About 80% of children with Down syndrome have some hearing impairment.)
Sensorineural hearing impairment: Sensorineural hearing impairments result from abnormal development or disorders of the cochlea, the spiral cavity of the inner ear, disorders of the auditory nerve that transmits electrical impulses from the inner ear to the brain, or abnormalities of the auditory center of the brain. Such conditions have a variety of causes. For example, more than 70 known inherited disorders account for about one-half of all severe sensorineural hearing impairments; however, 90 percent of children with congenital hearing impairment are born to parents with normal hearing. In addition, the following problems are associated with sensorineural hearing impairment:
- Craniofacial anomalies
- Down syndrome, in many of which cases the child has some immune deficiency that leads to frequent ear infections resulting in hearing loss
- Problems during or shortly after birth that may damage the inner ear or auditory nerve
- Low birth weigh, below 3.5 lb (1.6 kg)
- Incubator noise affecting premature infants
- Neonatal exposure to aminoglycoside antibiotics
- Bacterial infections such as meningitis during infancy
- Cytomegalovirus (CMV) infection during childhood
- Accidents involving head injuries
While about 50 percent of congenital hearing impairments have no known cause, prenatal risk factors for congenital hearing impairment include:
- Rubella (German measles ) (More than 50% of children born to mothers who contracted rubella during the first ten weeks of pregnancy suffer from congenital malformations.)
- CMV, the most common viral infection in fetuses, a leading cause of congenital deafness (CMV affects 1% or 40,000 newborns annually; about 8,000 of these newborns have birth defects.)
- Other infections, including toxoplasmosis , herpes, syphilis, or flu
- Drug or alcohol consumption
- Drugs that are ototoxins
- Lack of response to loud noises
- Lack of response to voices or noise when sleeping in a quiet room
- Failure to calm down at the sound of the mother's voice
- Failure to make normal baby sounds including cooing by six weeks of age
- Failure to look for the source of a noise by three to six months of alie
- Failure to play with noisy toys , such as a rattle, by four to eight months
- Failure to babble by about six months of age
- Lack of reaction to loud noises
- Failure to imitate sounds
- Lack of response to the child's name during the first year of life
- Failure to vocalize (to imitate simple words, enjoy games that involve speech, or talk in two-word sentences during the second year)
- Failure to understand simple directions during the third year
- Lack of attention
- Turns or cocks head
- Uses gestures
- Lack of speech development
- Works best in small groups
- Monotone quality in voice
- Acts out
- Difficulty in following directions
- Preoccupied with things, not people
- Imitates others
- Responds to noises instead of words
- Reluctant to participate orally