Auditory Processing Disorder

The auditory cortex is the part of the temporal lobe that processes auditory information in humans and many other vertebrates. It is a part of the auditory system, performing basic and higher functions in hearing, such as possible relations to language switching. It is located bilaterally, roughly at the upper sides of the temporal lobes – in humans, curving down and onto the medial surface, on the superior temporal plane, within the lateral sulcus and comprising parts of the transverse temporal gyri, and the superior temporal gyrus, including the planum polare and planum temporale (roughly Brodmann areas 41 and 42, and partially 22).

Section 1
Biological Understanding

“Auditory processing”—We are hearing this term be referenced more and more, and an increasing number of children are being identified as having an ” auditory processing disorder.” But what does it actually mean? How can you have normal hearing and have an auditory processing disorder?

 

First, let’s define “hearing.” The “peripheral hearing mechanism,” as it is referred to, includes the outer ear—where sound waves are collected, the middle ear—where sound is converted to mechanical energy, and the inner ear—containing the cochlea. Traditional hearing tests (audiograms) and tympanograms assess the integrity of this system. If this system is intact and functioning well, then your hearing should test normal.

 

But what happens when the signal leaves the inner ear? Basically it travels along the auditory nerve, through the brainstem, and eventually reaches the brain. Auditory processing, simply defined, is what happens along this pathway and what the brain does with the auditory signal from the ears. It has a number of different aspects, listed and enumerated differently by different authors. Below we list and define aspects of auditory processing that we have found to be relevant to the children with whom we work. Also listed are additional functions that are closely tied to auditory processing.

Aspects of Auditory Processing

  1. Auditory attention—being able to “tune in” to auditory input.

  2. Auditory discrimination—the ability to distinguish between different sounds or words.

  3. Auditory sequential processing—how many pieces of information one can listen to (receive), store, recall, and utilize. Related to auditory memory. Often tested in terms of digit spans.

  4. Auditory tonal processing—the correct processing of sounds or tones; related somewhat to auditory discrimination, but takes it a step further; has a significant impact on language processing.

  5. Auditory memory—ability to store and recall auditory information.

  6. Auditory sensitivity—perception of sound loudness; hypo-sensitive individuals have a reduced response to sound in their environment, even when hearing is “normal.” Hypersensitive individuals over-respond to “normal” sounds, often perceiving typical environmental sounds as bothersome or too loud.

  7. Auditory figure-ground processing—ability to attend to and process an auditory stimulus in the presence of background sound.

  8. Language processing—processing the meaning of verbal input. This is not true auditory processing. It is the next step after auditory processing occurs.

  9. Temporal processing—related to the “time” aspect of the auditory signal; rate of processing.

Section 2
Video Resources

Section 3
Related Website

Nemours KidsHealth

Auditory Processing Disorder (for Parents)

NACD International

Webmd.com

Auditory Processing Disorder: Symptoms, Cause, and Treatment