What is Auditory Neuropathy?
Auditory Neuropathy Spectrum Disorder (ANSD) is a hearing problem in which the ear detects sound normally, but has a problem sending it to the brain.
Someone with ANSD may have trouble telling one sound from another. They may also have trouble understanding speech clearly. The sounds may fade in and out or are "out of sync". Children with ANSD may have hearing responses that vary or worsen over time. A child with ANSD may appear to hear one day and not hear the next. This can be very frustrating for parents and can make a getting final diagnosis difficult. Hearing loss can vary greatly in children with ANSD, from normal hearing to profound hearing loss.
Common Features Seen With ANSD:
- The child has inconsistent responses to speech.
- The child may have a hard time understanding speech. This is especially true in a noisy place.
- The child’s hearing appears to change daily or even hourly.
- The child acts as if they have a hearing loss.
Symptoms can develop at any age. Most children with ANSD are diagnosed in the first months of life.
What Causes ANSD?
The condition likely has more than one cause. It can be inherited genetically or caused by trauma or disease. Many risk factors have been linked to ANSD in children. The most common causes appear to be:
- Lack of oxygen at birth
- Severe jaundice during the newborn period
- Infectious diseases such as mumps
- Immune disorders
- Neurological disorders such as Charcot-Marie-Tooth syndrome or Friedreich’s Ataxia
How is ANSD Diagnosed?
Audiologists use a combination of tests to diagnose ANSD. These tests include auditory brainstem response (ABR), acoustic reflex testing and otoacoustic emissions (OAE). These tests are painless. They can be used in both newborn infants and older children.
Depending upon what test is used for newborn hearing screening, some children with ANSD may pass the first hearing screening in the hospital. This may slow the identification of ANSD. Parents and doctors may not suspect hearing loss right away if an infant’s response to sound changes from day to day.
As children get older, more hearing information becomes available. Ongoing testing may show a poor understanding of speech. It may also show problems with hearing in noisy backgrounds.
Does ANSD Ever Get Better or Worse?
Some newborn babies who have been diagnosed with ANSD improve over time. They may start to hear and speak within a year or two. Other infants stay the same or even get worse. At this time, no tests can tell us if a child’s hearing will change.
What is the Current Treatment for ANSD?
Currently, there is no medical treatment for ANSD. Some children benefit from hearing aids. However, many children get limited hearing aid benefit or no benefit at all. Hearing aids must be set carefully to prevent damage to the parts of the ear that receive sounds normally.
Some professionals recommend the use of remote microphone systems. Remote microphone systems can improve listening in noisy backgrounds.
Some children benefit more from a cochlear implant than from hearing aids. However, no tests are available now to decide whether a child with ANSD might benefit more from a hearing aid or cochlear implant.