Auditory processing disorder

Auditory processing disorder (APD), also called central auditory processing disorder (CAPD), refers to any of several conditions wherein the brain is unable to interpret accurately some of what is heard by the ear. APD is not caused by a defect in how the ear works but is a disconnect between what is being heard and how it is understood. It occurs in a small percentage of people and is commonly diagnosed in childhood. APD is generally more common in males than in females. It cannot be cured, but it can be treated.

Background

During the 1940s and 1950s, researchers began to understand that what seemed to be learning disabilities in some children were actually caused by issues with how they heard things, particularly speech. Helmer R. Myklebust, a Northwestern University professor and psychologist, began to study children who seemed to have normal or above normal intelligence and an interest in learning as well as normal hearing but were unable to understand some sounds, especially speech. These children misinterpreted what they heard and often spoke little or not at all. In 1954, he published his findings in Auditory Disorders in Children: A Manual for Differential Diagnosis.

In 1963, Myklebust and a number of other prominent researchers in the field gathered for a meeting in Chicago. At this meeting, the term learning disabilities was coined to take in the full range of impediments to learning experienced by children, including APD. In the years since, tests have been devised to identify children who have difficulty understanding what they hear and ways to adapt education to suit their needs. It has also been determined that APD can occur in conjunction with other learning disabilities, such as attention-deficit/hyperactivity disorder (ADHD), and that it can occur in adulthood.

Overview

Due to the work done by Myklebust and others, physicians now know that auditory processing disorder is a hearing problem experienced by about 5 percent of school-age children. It is thought to occur up to twice as often in boys than in girls. Affected individuals have normal hearing as far as the way their ears collect and process sounds. As a result, the person will turn toward a sound and can identify and respond to many sounds, including music, cars, and vacuum cleaners.

However, patients with APD experience an issue with the way the nervous system interprets certain sounds. Researchers are not yet sure exactly how it happens, but the sounds received by the ear become garbled in the process of being interpreted by the brain. This is particularly apparent when a person is trying to understand something spoken, and most noticeable in crowded or noisy settings, such as in a cafeteria or at a sporting event, or in a room with other sound distractions, such as a television playing in the background. The person may have increased problems with words or word sounds that are similar, such as sh and ch, or hat and cat. As a young child grows older, these problems may cause him or her to withdraw from social situations because of feelings of being unintelligent, or out of fear of misunderstanding and making a public and embarrassing mistake.

Some symptoms of APD include being upset or uneasy in noisy places, difficulty following or remembering conversations, increased difficulty responding to conversation in noisy versus quiet places, difficulty following directions, and reluctance to respond to questions. These symptoms can vary in severity. Other learning disabilities, such as ADHD, share some of these symptoms; therefore, a physician will do specific tests to determine if a person has APD.

Diagnosis and Treatment

Physicians are not sure exactly what causes APD to develop. Some theories include trauma such as a head injury, repeated ear infections, and lead poisoning. It is also often difficult to realize that a young child has APD. Since the ear works properly, the child will hear and respond to noises and turn toward a voice, etc., which makes people think the child hears normally. However, the sounds heard by a person with APD are garbled, unclear, and difficult to distinguish. This is complicated by the fact that the child has no basis for comparison and does not realize that he or she is not hearing the same way everyone else does.

For this reason, a child is often seven to eight years old before effective testing can be done by an audiologist (a medical professional who specializes in testing hearing). The audiologist will use specialized equipment to determine how well the child hears in a noisy situation. Tests will also be done to measure the level of auditory memory issues, or how well a child retains what is heard, and the degree of auditory attention, or how long a child can listen to oral speech and instructions. The confusing way speech comes through to a child with APD means he or she sometimes "tunes out" conversations that cause distress because the words are not understood. The audiologist will also test auditory discrimination, or how well the child can distinguish between similar words and sounds. In addition, the child's auditory cohesion will be tested. Auditory cohesion refers to the ability to put together words and meanings to understand more complex language tasks, such as mathematical word problems, jokes and riddles, or conversations with inferences.

In many cases, people with APD can be helped with a device known as a frequency modulation system, or FM system. This system consists of a small microphone and transmitter that is used by a person speaking to the child, such as a teacher or parent. This device boosts the sound of the person speaking so that it is easier for the individual with APD to hear and interpret what is being said.

Other treatments for APD are mainly adaptive, helping the person learn ways to cope with the problem and find ways to compensate for the confusing way sounds are perceived. Younger children are generally better at this because the auditory system and its connections to the brain are not fully developed until the mid-teen years. Techniques that can help manage APD include reducing background noise or leaving noisy environments before attempting conversation, looking directly at the speaker, and asking the speaker to talk a little louder and more slowly so words and sounds are easier to distinguish.

Bibliography

"Auditory Processing Disorder." Learning Disabilities Association of America, INK "https://ldaamerica.org/types-of-learning-disabilities/auditory-processing-disorder/" ldaamerica.org/types-of-learning-disabilities/auditory-processing-disorder/. Accessed 5 Dec. 2016.

"Auditory Processing Disorder (APD)." KidsHealth, HYPERLINK "http://kidshealth.org/en/parents/central-auditory.html" kidshealth.org/en/parents/central-auditory.html. Accessed 5 Dec. 2016.

Bellis, Teri James. "Understanding Auditory Processing Disorders in Children." American Speech-Language-Hearing Association, www.asha.org/public/hearing/Understanding-Auditory-Processing-Disorders-in-Children/. Accessed 5 Dec. 2016.

"Helmer Rudolph Myklebust (1910–2008)." Hammill Institute Preservation Project, 22 Aug. 2012, PERLINK "http://hammill-institute.org/hipp/" hammill-institute.org/hipp/. Accessed 5 Dec. 2016.

"How Hearing Works." Alexander Graham Bell Association for the Deaf and Hard of Hearing, www.agbell.org/Document.aspx?id=138. Accessed 5 Dec. 2016.

Peru, Gina. "Sounds Like Auditory Processing Disorder." ADDitude, www.additudemag.com/adhd/article/8666.html. Accessed 5 Dec. 2016.

Schmitz, Patty Dowd. "Pioneering Presence." Northwestern, Spring 2007, PERLINK "http://www.northwestern.edu/magazine/spring2007/feature/johnson.htm.%20Accessed%205%20Dec.%202016" www.northwestern.edu/magazine/spring2007/feature/johnson.htm. Accessed 5 Dec. 2016

"What Is Auditory Processing Disorder (APD)?" Auditory Processing Disorder Foundation, www.theapdfoundation.org. Accessed 5 Dec. 2016.