Central Auditory Processing Disorder, or CAPD (also sometimes referred to as Auditory Processing Disorder, or APD), is a complicated hearing disorder based not in the ears' inability to hear sounds, but on the brain's inability to process and interpret them correctly. The person with Central Auditory Processing Disorder hears sounds correctly but something adversely affects the way their brain recognizes and interprets the sounds, especially the sounds associated with speech. The disorder is thus characterized by a lack of coordination between the ears and the brain.
Central Auditory Processing Disorder affects as many as 2% to 5% of school-age children, and as many as half of the children are diagnosed as having a learning disability. One of the characteristics of Central Auditory Processing Disorder is that children who have it have difficulties recognizing subtle differences between the sounds of similar words, even though they have no problem hearing the words. This inability to understand words often becomes worse in noisy environments, but is not as present in quiet environments.
This can make Central Auditory Processing Disorder hard to detect. A child that can hear and intrepret speech well in a quiet environment will generally have no problems passing a hearing test administered in a quiet environment. As a result, their audiogram results may appear normal, but they may nevertheless have difficulties distinguishing similar words, locating where sounds are coming from, recognizing repetitive patterns in high and low sounds, or hearing more than one person's voice at a time.
The symptoms of Central Auditory Processing Disorder also tend to appear in other areas of life, as the child struggles to deal with not being able to understand people speaking to them or around them. The disorder may manifest itself in a difficulty following instructions, being easily distracted by loud noises, appearing forgetful or disorganized, or slow to develop reading, spelling and language skills. Since standard hearing test for these children often yield normal results, these indicators are often mistaken for other disorders such as ADHD or depression. In reality, CAPD can be present alone or combined with these other disorders, presenting a difficult diagnostic challenge.
It is important for these children's development that problems with CAPD be identified early so that treatment and correction of the difficulties can begin as soon as possible. A standard hearing test doesn't rule out CAPD. If you detect any of these signs in your children, schedule a professional hearing test that can replicate the conditions where the child struggles.