Genetics & Auditory Processing

The National Institute on Deafness and Other Communication Disorders (NIDCD) published a study in Human Genetics, August 2007, about auditory processing. An auditory processing disorder, individuals with normal hearing who have trouble making sense of the sounds around them, includes part of the brain that helps us understand what we hear. This is the first study to document that people vary widely in this area largely due to heredity.

Auditory processing enables us to tell the direction a sound is coming from, or the difference between background noise or a voice we should listen to. It plays a role in a child’s acquisition of language and learning ability although that relationship is not well understood. 194 same-sex pairs of twins were studied. They all received a DNA test and a hearing test to confirm their hearing was normal. If a trait was purely genetic, the results should be 100% in identical twins. If the trait was primarily due to environment both fraternal and identical twins should have the same degree of similarity, growing up in the same house.

The results showed that the difference in listening abilities was primarily due to genetic variation, a new piece of information in the understanding of auditory processing disorders.