WHAT IS AUDITORY IMPAIRMENT?
Auditory impairment is the partial or total inability to hear. Also known as hearing impairment, this condition includes permanent or fluctuating hearing problems. Auditory impairment can range from slight and mild to severe and profound.
Approximately three in 1,000 infants are born with auditory impairment, making it the most common birth defect. Recognizing hearing problems early is important since unacknowledged hearing impairment can adversely affect a child’s academic performance and social development.
CAUSES & RISK FACTORS
What causes auditory impairment?
Auditory impairment occurs when there is a problem with a structural part of the ear, the nerves coming into the ear, or the neurological part of the brain to controls hearing. The ear consists of three sections: the outer ear, the middle ear, and the inner ear.
The outer ear is composed of the pinna portion we see on the sides of our heads, the ear canal, and the tympanic membrane that leads to the middle ear. The middle ear consists of the eardrum and three bones called ossicles (individually known as the hammer, anvil, and stirrup) that direct vibrations of the eardrum to the inner ear. The inner ear consists of a tiny organ known as the cochlea that either amplifies sound or sends sound along the auditory nerve to your brain. In addition, the inner ear also has semicircular canals that help the body with balance.
All of these components create pathways between the outer ear and the neurological pathway known as the auditory (hearing) system. Problems with this pathway or any of its components can result in hearing impairment or hearing loss.
What are risk factors for auditory impairment?
The most common causes of auditory impairment in newborns are genetic defects. Causes of hearing impairment in infants and older children can include conditions like ear infections (secretory otitis media), injury, and even the accumulation of earwax.
For example, some risk factors in newborns include:
- Low birth weight
- Low blood oxygen levels
- Infection before birth
- Skull abnormalities
- Some antibiotics
- Bacterial meningitis
- Extensive use of the ventilator
Risk factors in older children include:
- Chronic infections
- Childhood diseases before vaccines
- Head injury that involved loss of consciousness
- Fluid buildup near eardrum
- Repeated exposure to loud noises or loud music
If you have concerns about any of the risk factors, schedule a hearing screening, doctor’s evaluation, or tympanometry with your pediatrician or a referred audiologist.
SIGNS OF AUDITORY IMPAIRMENT
- At 0-4 months, the baby does not startle or cry at loud noises
- By 4-8 months, the baby does not turn for the source of sound, smile at familiar voices, or babble
- By 8-14 months, the baby does not respond to his or her own name or use simple words like “mama” or “dada”
- By 14-24 months, the child does not develop simple vocabulary or follow basic commands
Signs of Auditory Impairment in Toddlers or Older Children
- Child turns and responds upon seeing parents but not upon hearing their voices
- Child does not respond to the sound of his or her name (this may be mistaken for ignoring or not paying attention, but it could be a sign of impairment or hearing loss)
- Child seems to hear some sounds better than others
- Delayed or unclear speech
- Child thrives at home but struggles in school (this may result from inability to hear instructions or peers in unfamiliar environments)
- Child frequently says “huh” or turns up volume on devices
What are the common types of auditory impairment?
Audiologists describe sound in terms of loudness or intensity (measured in units called decibels or dB) as well as frequency or pitch (measured in units called hertz or Hz). Problems in any of these areas can fall under the common types of hearing impairment.
The Five Main Types of Hearing Impairment
- Conductive Hearing Loss – This occurs when part of the outer or middle ear prevents sound from going to the inner ear. Many cases of conductive hearing loss are mild to moderate and result from temporary conditions (such as illness or infection). Physicians treat most cases with medicine or surgery.
- Sensorineural Hearing Loss – This occurs when there is a problem with the inner ear, cochlea cells, or hearing nerve. For children with this condition, sounds may seem muffled or impossible to hear at some frequencies. The condition can also affect speech.
- Central Hearing Loss – A rare form of hearing loss in which the cochlea is working fine but neurological pathways do not function as expected.
- Mixed Hearing Loss – This impairment occurs from conductive and sensorineural origins, requiring combined treatment plans.
- Auditory Neuropathy Spectrum Disorder – This communication disorder means that the brain cannot organize sound in a way the child can understand.
Four Degrees of Hearing Impairment
- Mild – The child can hear standard voices and sounds but struggles to hear softly spoken words or sounds.
- Moderate – The child may hear no sounds spoken at normal level and requires sounds to be amplified.
- Severe – The child hears no sounds at normal level and only some loud sounds.
- Profound – The child cannot hear any speech and may only hear very loud sounds.
Other Ways to Describe Hearing Impairment
- Unilateral or Bilateral – Auditory impairment can occur in one ear (unilateral) or both ears (bilateral).
- Prelingual or Post-lingual – This refers to whether auditory impairment occurred before a child learned to speak (prelingual) or after (post-lingual)
- Symmetrical or Asymmetrical – Hearing impairment can be the same degree in area in both areas (symmetrical) or different degrees and areas (asymmetrical).
- Progressive or Sudden – This describes whether auditory impairment becomes worse over time (progressive) or occurs very quickly (sudden).
- Fluctuating or Stable – These terms describe auditory impairment can get better or worse with time (fluctuating) or remain the same (stable).
- Congenital, Acquired, or Delayed Onset – Although many cases of hearing impairment are present at birth (congenital), some happen as the result of illness or injury (acquired) or gradually show up later in life (delayed onset).
How can I help my child diagnosed with an auditory impairment?
Fortunately, there are ways to help a child with auditory impairment. All babies should have a hearing screening by 4 weeks old. Children should have a screening sometimes during toddler years, before staring school, and any time there is a concern about their hearing.
After diagnosis, there are a number of early childhood intervention (ECI) and special services for children with hearing impairment. Early intervention services create custom treatment plans for your child and family. These plans usually include a team of experts that can help your child learn unique ways to communicate such as sign language, speech reading, or exact-language hand speech. The team may also help implement and educate parents about the latest technology for hearing loss. These devices can include hearing aids, cochlear implants, bone conduction implants, amplification devices, assistive listening devices, telecommunication devices (TDD), or personal frequency modulation (FM) systems. Experts can also recommend medical intervention if required (such as medication or surgery).
Types of professionals who work directly with children include audiologists, speech-language pathologists, communication-disorder specialists, and special education teachers. Be sure to ask questions during each session for the best way to approach your child’s specific condition. In addition, early childhood intervention also includes family support services to help your household understand children with hearing differences and to help your infant or toddler thrive.