The research, published in the Journal of Gerontology: Medical Sciences, considered genetic and environmental factors affecting hearing loss with regard to speech recognition, the university in Waltham said Wednesday in a news release.

"This research confirms the importance of genetic factors in age-associated hearing loss, and the need for vulnerable individuals and their families to take extra care to prevent further hearing damage," said Arthur Wingfield, lead author and a neuroscientist at Brandeis.

The study examined 179 identical and 150 fraternal male twin pairs, ages 52 to 60, as part of the Vietnam Era Twin Study of Aging. About two-thirds of the hearing loss in the subjects' better ears could be attributed to genetic factors. In the subjects' poorer ears, about one-half of the hearing loss was genetic, the study concluded.

Wingfield said even mild hearing loss can indirectly lead to drop-offs in cognitive performance because intellectual energy normally used for higher-level comprehension must be re-directed toward efforts to accurately hear someone talk.