Auditory performance in competing acoustic signals listening to different messages in each ear. Auditory performance with degraded acoustic signals the ability to understand the whole message when part of it is missing, such as what happens in background noise. If a person has difficulty performing auditory processing skills, often they will have difficulties that are noticeable to others. Some common symptoms of APD include:. ADP testing is typically scheduled for a 2-hour time period.
The time is divided into 3 segments: the first half-hour is spent obtaining a thorough case history, and hour is necessary for testing, and the last half-hour is used to explain the results. If necessary, the session can be scheduled as two separate visits. Testing is completed in a sound-proof booth by an audiologist.
We begin with a basic hearing test to rule out hearing loss as the cause for the difficulties. We prefer to conduct testing in the morning, when clients are well-rested. We use that knowledge to let the bottom up processing centers know what the brain wants and needs from the incoming signal. The brain then forms an expectation of what should be the incoming signal and makes its final decisions as to what is heard i.
This occurs for both linguistic material as well as non-linguistic material. For linguistic material, the brain has some ideas of what it expects to hear. For example, you meet someone and initially you expect them to say some greeting.
However, we also hear noises and recognize the noises. For example, you are expecting a person to arrive at your house around 2pm, and at pm you hear three banging sounds coming from the direction of your front door.
You process this as the person you expect to come to your house, so you go to the door and open it and greet your friend. Thus, we have expectations already in our language centers of cortex and in our cognitive thinking centers of cortex. Many speech-language pathologists and psychologists today still hold to auditory processing being a top down based function. Treatment is then focused on improving the language and cognitive functions of the person so identified.
If the voice sounds like or the person you expect, and the person says the name you were expecting, your decision is that the person at the door is the person you were expecting.
The second choice is if the voice is unrecognized and the person says a name that does not match the person you were expecting, the top centers rethink and change their decision.
In this second case, the decision is to look out the window or through the peep hole to see who is at the door. Thus, as you can see, bottom up processing started the process while top down processing became involved and they worked together to identify who is at the door. Now consider this second situation. Let us consider listening in a very noisy restaurant. The person you are with starts discussing a topic for which you have no initial clue, you use a great deal of bottom-up processing to get the first clues to identify the topic.
The bottom-up is not merely from the auditory system but is also from our visual system. Pointing, showing something, body language, etc. If we get clear auditory and visual signals, we switch from primary bottom-up to primary top-down processing. But, once we have guessed what might be the topic, we validate our decision based on the next bottom-up processing we receive. With all the noise in the restaurant, the incoming bottom up signal is distorted.
We heavily rely on bottom up processing to verify the words we think were hear as the person is speaking. But, language cues and our language knowledge stored in memory another system in the brain help us comprehend the message.
What I hope this information indicates is that both top-down and bottom-up processes are critically important in the accurate and appropriate processing of auditory information we receive.
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