Auditory Processing Disorder: A neurological deficit that affects how the processes spoken language.
ASHA's Position Statement on Central Auditory Processing Disorder "Central auditory processing disorder (CAPD) refers to difficulties in the processing of auditory information in the central nervous system (CNS) as demonstrated by poor performance in one or more of the following skills: sound localization and lateralization; auditory discrimination; auditory pattern recognition; temporal aspects of audition, including temporal integration, temporal discrimination (e.g., temporal gap detection), temporal ordering, and temporal masking; auditory performance in competing acoustic signals (including dichotic listening); and auditory performance with degraded acoustic signals".
The Central Auditory Nervous System
The pathway that sound takes from the ear up to the temporal lobe of the brain.
Major Structures Involved:
- Auditory Nerve: connects the hair cells of the inner ear to the CN
- Cochlear Nucleus
- Superior Olivary Complex: 80% of fibers cross over here
- Lateral Lemniscus
- Inferior Colliculus
- Medial Geniculate Body
- Auditory Radiations: Fibers that connect the MGB to the AC
- Auditory Cortex in the Temporal Lobe
Regions of the Brain:
-Hearing Information is received and processed inside the Temporal Lobe.
- Broca's Area is used for speech.
There is much controversy surrounding Auditory Processing Disorder (APD). The following is a list of agreed upon facts.
-There is a breakdown in receiving, remembering, understanding and using auditory information
-Hearing ability in not impaired
-There is a neurological cause
-The child's ability to listen is somehow impaired
Lesions in Brain:
Certain disorders are associated with lesions in specific parts of the human brain. The picture demonstrates the different damages and diseases that result in specific neurologic disorders.
What is needed for Normal Auditory Processing:
-Auditory Awareness: The ability to detect or become aware of a sound or speech signal
-Auditory Discrimination: The ability to recognize a sound. Auditory discrimination also allows the listener to hear the difference between two different sounds.
-Localization: The ability to track a sound in space.
-Listening in Noise: The notion of how well one can attend to a signal and ignore background noise.
-Phonological Awareness: The ability to recognize that words are made up of a variety of sound units.
-Auditory Memory: The ability to process, recall and analyze orally presented information
-Sequencing: Ability to keep a list of things in order.
-Closure: The ability to fill in the blanks, exposure to sound and repetition is needed in order to have this skill
Common behaviors seen in children with APD:
-Sound Discrimination errors
-Trouble following directions
-Distracted easily by background noise
-Oral and written expression deficits
-Auditory memory problems
-Difficulty with reading
-Listening for only a short duration of time
Auditory Processing and Reading:Children with APD often have trouble with reading.
Reading difficulties are often due to trouble with:
-Sound-Symbol Association: Difficulty associating a sound with a letter
-Sound Blending: Difficulty blending individual sounds to form a word
Video Clip: Auditory Processing Disorder and Dsylexia
Assessment of APD:
-Most testing is not done until the 1st grade
-Speech Language Patholgist: Assessment of Language
-Audiologist: Assessment of Auditory Processing
-Pschologist: Assessment of Cognitive and Behavior abilities
-Occupational Therapist: Assessment of Sensory Systems
Accommodation and Modification Strategies for children with APD:
-Keep directions simple
-Only tell one step at a time
-Give directions both orally and visually
-Maintain eye contact while speaking
-Limit background noise
-Provide specific opportunities that practice skills to build vocabulary, rhyming, segmenting and blending words
ASHA suggested intervention of APD:
-Interdisciplinary approach to therapy involving Audiologist, SLP, and other professionals
-Treatment and management goals are highly individualized to client
-Treatment should include both top down and bottom up approaches to therapy
-Top down approach provides compensatory strategies designed to minimize the impact of APD, by strengthening higher order resources
- Bottom up approach is designed to enhance the acoustic signal and to train specific auditory skills.
-Direct skills remediation, compensatory strategies and environmental modifications should all be used
Treatments available for Auditory Processing: National Institute on Deafness and other Communication Disorders
- Auditory trainers are electronic devices that allow a person to focus attention on a speaker and reduce the interference of background noise. They are often used in classrooms, where the teacher wears a microphone to transmit sound and the child wears a headset to receive the sound. Children who wear hearing aids can use them in addition to the auditory trainers
- Environmental modifications such as classroom acoustics, placement, and seating may help. An audiologist may suggest ways to improve the listening environment, and he or she will be able to monitor any changes in hearing status.
- Exercises to improve language-building skills can increase the ability to learn new words and increase a child's language base.
- Auditory memory enhancement, a procedure that reduces detailed information to a more basic representation, may help. Also, informal auditory training techniques can be used by teachers and therapists to address specific difficulties.
- Auditory integration training may be promoted by practitioners as a way to retrain the auditory system and decrease hearing distortion. However, current research has not proven the benefits of this treatment.