A twin study of auditory processing indicates that dichotic listening ability is a strongly heritable trait.

We administered tests commonly used in the diagnosis of auditory processing disorders (APDs) to twins recruited from the general population. We observed significant correlations in test scores between co-twins. Our analyses of test score correlations among 106 MZ and 33 DZ twin pairs indicate that dichotic listening ability is a highly heritable trait. Dichotic listening is the ability to identify and distinguish different stimuli presented simultaneously to each ear. Deficits in dichotic listening skills indicate a lesion or defect in interhemispheric information processing. Such defects or lesions can be prominent in elderly listeners, language-impaired children, stroke victims, and individuals with PAX6 mutations. Our data indicates that other auditory processing abilities are influenced by shared environment. These findings should help illuminate the etiology of APDs, and help to clarify the relationships between auditory processing abilities and learning/language disorders associated with APDs.