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TUESDAY, July 22 (HealthDay News) -- Mild memory impairment may be associated with a sound processing disorder called central auditory processing dysfunction, say U.S. researchers.

People with the disorder have difficulty hearing in complex situations with competing noise, such as making out what one person is saying while many people in a group are talking at the same time.

"Central auditory processing dysfunction is a general term that is applied to persons whose hearing in quiet settings is normal or near normal yet who have substantial hearing difficulty in the presence of auditory stressors such as competing noise and other difficult listening situations," according to background information in the study. "Central auditory testing is important in evaluating individuals with hearing difficulty, because poor central auditory ability, per se, is not helped by amplification and requires alternative rehabilitation strategies."

Previous research has found that people with Alzheimer's disease and other types of dementia have central auditory processing dysfunction.

This new study by Dr. George A. Gates, of the University of Washington, Seattle, and colleagues included 313 people, average age 80, taking part in a dementia surveillance program that began in 1994. Of the participants, 17 had been diagnosed with dementia, 64 had mild memory impairment, and 232 had no memory problems.

Three tests were used to assess the participants' central auditory processing. In one test, nonsense sentences were read over the background of an interesting narrative. In the other two tests, separate sentences or numbers were read into each ear simultaneously.

"These central auditory processing test paradigms evaluate how well an individual manages competing signals, a task that requires adequate short-term memory and the ability to shift attention rapidly," the researchers noted.

Participants with dementia and mild memory impairment scored significantly lower on the tests than those without memory problems. The findings were published in the July issue of the Archives of Otolaryngology -- Head & Neck Surgery.

"Central auditory function was affected by even mild memory impairment," the researchers wrote. "We recommend that central auditory testing be considered in the evaluation of older persons with hearing complaints as part of a comprehensive, individualized program to assist their needs in both the aural rehabilitative and the cognitive domains."

More information

The American Academy of Family Physicians has more about age-related memory loss.