Auditory Processing In-Depth

White fluffy cloud border on black background.

What Exactly is Auditory Processing, and What Causes the Disorder?

Auditory processing is responsible for cleaning up the incoming auditory message and preparing it for language processing. Receptive language can only apply appropriate meaning to the incoming message if auditory processing has done its job. There are 4 primary Auditory Processing skills necessary for efficient communication:

  • Auditory Figure Ground (Words-in-Noise): Ignoring background noise, automatically determining relevant vs. irrelevant auditory information in a listening environment without purposeful effort.
  • Auditory Closure (Distorted Words): Cleaning up the incoming message if it is missing parts, distorted, accented, or coming in too rapidly.
  • Dichotic Listening (Competing Words): Coordinating and synchronizing the information coming in from both ears.
  • Temporal Processing: Understanding tonal differences in speech and discrete timing and frequency separations between similar sounds in language.

Understanding Auditory Processing Disorder

Sensory processing pyramid with explanatory text.

The pyramid above illustrates the importance of the foundational skills. Listeners with Auditory Processing Disorder (APD) have foundational breakdowns of auditory information, causing bottom-up effects on the higher-order skills (language and executive function). When there is an auditory deficit, the information delivered to the receptive language center is unclear, making it difficult for it to apply the correct meaning. It’s like in the old game of “Telephone,” where the first person is like the incoming auditory message, the next 10 people are like auditory processing of that message, and the last person is receptive language. In the game, the resulting message is some hilarious, jumbled-up version of the initial message. It’s not fun when that’s how one listens every day.

Auditory processing skills develop rapidly from birth to 18 years of age with clear auditory experiences. The causes of APD are largely unknown, but we do know that certain medical histories may suggest a higher risk of APD due to “auditory deprivation” (pockets of unclear auditory experiences). These include chronic ear or sinus infections, allergies or frequent illness, and hearing loss.

Consistent, clear auditory experiences are necessary to enhance increased neural firing and connectors that myelinate (fatten up) the auditory nerve during the developmental period. The fatter the nerve, the faster information travels. The faster information travels, the more efficient the nerve handles auditory information and the less surface area that is occupied in the cortex to perform a specific auditory function. When auditory processing is underperforming, one of two subjective outcomes typically occurs: the listener either withdraws (appearing inattentive—looking like inattentive ADD) or acts out (appearing defiant, disobedient, hyperactive, etc.). As a result, many APD sufferers are misdiagnosed with more “high order” deficiencies when the root problem is really more foundational. Treatment of APD often results in bottom-up improvement in these behaviors, but sometimes the effect is more significant, requiring specific therapy for those conditions after the APD issues have resolved. Treatment for those higher-order deficits before treating APD often results in slow or minimal progress in those interventions because of the foundational gaps that APD can cause.