Study Targets Auditory Processing Problems

It’s not uncommon for parents to complain that their children don’t listen to them. But for some children, it’s not because they don’t want to.

Some children, despite having normal hearing, show difficulties in how the brain processes auditory information. This condition is often referred to as an auditory processing disorder (APD). Because of the APD, a child often demonstrates poor listening behaviors especially in the presence of background noise. The child becomes distracted very easily by other noises and may have trouble recalling auditory information.

At the UT Dallas Callier Center for Communication Disorders, Dr. Jeffrey Martin, assistant professor in the School of Behavioral and Brain Sciences, is conducting research on APD. He recently received an award from the Texas Speech-Language-Hearing Association to study the effects of filtered dichotic words on interaural asymmetry in children at risk for auditory processing difficulties.

A dichotic listening test is a commonly used test that presents two words simultaneously, one in each ear. A score is given for each ear depending on how well the patient is able to correctly recall the information presented in that ear. In most cases, listeners do slightly better with recalling words heard in the right ear as compared to the left ear. The difference between the scores on each ear is referred to as interaural asymmetry.  

The dichotic listening test is used by audiologists to determine if a child has an APD. However, there are concerns that the results from this test may also be influenced by a child’s cognitive and language skills, such as his ability to store multiple test items in memory or his level of familiarity with the information presented during the test.

Because identifying and providing the best treatment is dependent on an accurate diagnosis, Martin’s research will explore different dichotic listening methods that aim to minimize extra auditory factors on performance.

Martin plans to use common words that have been acoustically modified. The words sound muffled or filtered because the higher frequency information has been removed. By removing the higher frequency information, the difficulty of the task can be manipulated without increasing the amount of information that needs to be recalled, which often happens in some traditional dichotic listening tests.  

“Our focus in this study is to examine several experimental variations to the standard dichotic test for the purpose of gaining more informative diagnostic information,” says Martin.

Martin will recruit participants ranging in age from six to 25 years. The study will initially be conducted on participants with normal hearing who do not show signs of APD. The participants will be helpful in determining the expected range of performance with the filtered dichotic words before Martin and his research team applies them to children suspected of having APD.

Future studies will examine patterns in brain activity associated with deficits in this population on dichotic listening tests using electrophysiological and functional brain imaging techniques.

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