When the Brain Can't Hear: Unraveling the Mystery of Auditory Processing Disorder

by Teri James Bellis

reading decoding (e.g., sounding out words, or word-attack skills),

many children with APD become masters at hiding their disorder.

self-imposed isolation and appears far more preferable and less humiliating to the child than the inevitable overt exclusion by others that they have experienced throughout their lives.

This special talent gives them an outlet for their need to connect with others while, at the same time, providing them with at least one environment in which they feel safe and can succeed.

These tests require a mental age of seven or eight years,

auditory electrophysiology.

Unfortunately, deep sleep may abolish some of the responses from higher cortical regions of the brain that are dependent on consciousness.

left hemisphere of his brain, where actual speech-sound processing takes place.

although his ears were fine, his brain couldn't “hear” certain sounds.

Certainly, if ear infections occur frequently enough at a very young age, the child often misses some of the speech and language input during those periods that are critical for language development. On the other hand, many children have a history of severe ear infections throughout their childhood and exhibit no lasting effects whatsoever.

Furthermore, for many children, ear infections may be “silent”—that is, without evidence of pain or fever—and thus go undetected for a long time.

We do know, however, that many cases of APD are present very early in life, probably at birth. They don't just develop suddenly, unless the child has had some type of head injury, illness, or other trauma that can affect brain function.

Larry's testing revealed a very mild auditory processing deficit specifically in his ability to “fill in” missing pieces of a message—a process we refer to as auditory closure.

Individuals with APD must realize that, just as with other disabilities, some activities will continue to be difficult or impossible, depending on the severity of the disorder.

The dysfunction could be localized, generally, to the language-dominant (or left) hemisphere of the brain, where speech-sound analysis and representation takes place.

More revealing, he could not perform at all during a task that required him not to repeat speech sounds, but to perceive subtle pitch and duration differences in sequences of tones or beeps. This required the right side of his brain to hear the pattern, or acoustic contour, of the tones.

“right-brain” auditory abilities that are responsible for perceiving nonspeech or “musical” aspects of the signal, including those cues that convey tone of voice and assist us in understanding what is meant in relation to what is said.

People with this type of auditory disorder frequently misunderstand the intent of others' communications, often complain of hurt feelings, and may themselves speak in a monotone or with little expression. Often, the cadence or rhythm of their expressive speech is

somewhat distorted, as was Jason's. This type of deficit may affect a person's ability to appreciate humor or sarcasm, to engage in socially appropriate conversational exchang...

nonverbal learning

disability or NVLD.

NVLD can lead to a wide variety of symptoms including social difficulties, depression, difficulty with nonverbal tasks (including math calculation and visual-spatial activities), expressive and receptive prosody (or tone of...

depression frequently co-occurs with right-hemisphere dysfunction,

Importantly, the results of central auditory testing provided information that allowed us to explore further, and ultimately uncover, the underlying problem.

First, not all auditory processing disorders are speech-sound related. A person may be able to tell the difference between speech sounds well, be able to spell and write fluently, yet still exhibit auditory processing problems.

More important, even if a child exhibits a clear auditory processing deficit, that deficit may not be the only, or even the most important, factor contributing to his or her learning or communication problems.

Auditory processing disorders like learning disabilities, occur in males more frequently than in females, but they can and do occur in females.

Furthermore, although the cases discussed so far have exhibited normal hearing sensitivity, auditory processing disorders can coexist with hearing loss, which can make management of the hearing loss more difficult:

Evelyn's difficulties stemmed from the fact that these dichotic listening and tonal patterns tests relied on the ability of both hemispheres of the brain to communicate with one another.

Recent research into auditory processing and aging has indicated that the ability of the two hemispheres of the brain to cooperate—interhemispheric integration—decreases significantly as we age.

Furthermore, the data suggest that this integration deficit, if sufficiently pronounced, may well affect our binaural listening abilities, including the ben...

Evelyn exhibited a third type of auditory processing problem, one in which the issue is neither “left-brain” nor “right-brain,” but rather the way in which the two hemispheres of the brain interact. This common type of APD occurs in children as well as adults.

many people with this type of integration deficit have difficulty with virtually any task that requires cooperation between the two halves of the brain and

may exhibit what are commonly called sensory int...

From an auditory perspective, not only may they have difficulty with understanding speech in noise and telling where a sound is coming from, but they may have difficulty in linking the “left-brain” speech sound and language functions with the “right-brain” tone-of-voice or prosodic cues, resu...

in many cases of APD, physiologic tests such as brain scans, electrophysiology, and magnetic resonance imaging (MRI) fail to reveal any obvious structural or functional damage or dysfunction.

what we do with what we hear.”

Sri loves this quote

Principle number one:When we say auditory processing disorder, we really do mean AUDITORY.

In other words, when we discuss APD, we are referring to a problem or dysfunction in the auditory system—specifically, the central auditory system, or the portion of the system that runs from the ear to the brain.

We are not referring to ear-based auditory problems, such as hearing loss or deafness, although hearing loss will certainly have an impact on the abili...

When we refer to APD, we are referring to primarily an “input” disorder that affects specifically the way auditory information is processed at a variety of levels in the central auditory nervous system.

Principle number two:Hearing, thinking, and attention abilities are still important.

the presence of excellent higher-order memory, thinking, and attention skills provides a person with considerable strengths upon which to draw to compensate for lower-level auditory processing difficulties.

if a deficit also exists in these higher-order abilities, the person's ability to rely on these skills will be lessened, rendering the auditory deficit more destructive.

Principle number three:Not every language or learning problem is an APD.

It must be emphasized that, while APD may affect a child's ability to learn to read or spell, not all spelling or reading disorders are due to APD.

Similarly, although APD in a child will often have a devastating effect on language and speaking abilities, not all receptive or expressive language disorders are due to APD. Finally, although APD may affect problem-solving and socialization abilities, difficulties in these areas may be due to many factors other than APD.

sound-symbol association.

A child's inability to perform invented spelling at a young age may be an early “red flag” of an APD.

Acoustic confusions arise from sounds that are so close together that a child with speech-sound APD would likely hear them interchangeably or not be able to discriminate between them at all. Classic examples of these are consonants such as b, d, g, p, t, and k.