Your ability to listen to a phone message in one ear while a friend is talking into your other earand comprehend what both are sayingis an important communication skill thats heavily influenced by your genes, say researchers of the National Institute on Deafness and Other Communication Disorders (NIDCD), one of the National Institutes of Health. The finding, published in the August 2007 issue of Human Genetics, may help researchers better understand a broad and complex group of disorderscalled auditory processing disorders (APDs)in which individuals with otherwise normal hearing ability have trouble making sense of the sounds around them.
Our auditory system doesnt end with our ears, says James F. Battey, Jr., M.D., Ph.D., director of the NIDCD. It also includes the part of our brain that helps us interpret the sounds we hear. This is the first study to show that people vary widely in their ability to process what they hear, and these differences are due largely to heredity.
The term auditory processing refers to functions performed primarily by the brain that help a listener interpret sounds. Among other things, auditory processing enables us to tell the direction a sound is coming from, the timing and sequence of a sound, and whether a sound is a voice we need to listen to or background noise we should ignore. Most people dont even realize they possess these skills, much less how adept they are at them. Auditory processing skills play a role in a childs language acquisition and learning abilities, although the extent of that relationship is not well understood.
To determine if auditory processing skills are hereditary, NIDCD researchers studied identical and fraternal twins who attended a national twins festival in Twinsburg, OH, during the years 2002 through 2005. A total of 194 same-sex pairs of twins participated in the study (138 identical pairs and 56 fraternal pairs), representing ages 12 through 50. All twins received a DNA
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NIH/National Institute on Deafness and Other Communication Disorders