advertisement

Hearing management

28 May 2019

Study finds how the brain sharpens the hearing of the blind

Researchers found that compared to a sighted person, a blind person's auditory cortex was better able to detect small differences in sound frequency.

Researchers have long wondered why blind people seem to have a sharpened sense of hearing. Now a Seattle team has pinpointed specific brain adaptations that occur in people without sight.

"There's this idea that blind people are good at auditory tasks, because they have to make their way in the world without visual information. We wanted to explore how this happens in the brain," said Ione Fine, a psychology professor at the University of Washington (UW).

More information about sound

Fine is the senior author of a pair of studies in which researchers used functional MRI to detect two specific hearing-related changes in blind people's brains.

Rather than identifying which parts of the brain are most active while listening, the researchers examined the sensitivity of the brain to slight differences in auditory frequency.

One study was published this week in the Journal of Neuroscience and the other in the Proceedings of the National Academy of Sciences.

According to Kelly Chang, the lead author of the Journal of Neuroscience study, the researchers "weren't measuring how rapidly neurons fire, but rather how accurately populations of neurons represent information about sound." Chang is a graduate student in the UW psychology department.

The investigators found that compared to a sighted person, a blind person's auditory cortex was better able to detect small differences in sound frequency.

Using sound to track moving objects

Fine said, "This is the first study to show that blindness results in plasticity in the auditory cortex. This is important because this is an area of the brain that receives very similar auditory information in blind and sighted individuals. But in blind individuals, more information needs to be extracted from sound – and this region seems to develop enhanced capacities as a result."

The other study examined how the brains of people who are born blind or go blind early in life use sound to track moving objects.

The researchers came to focus on an area of the brain called the hMT+, which in sighted people is responsible for tracking moving objects they see. In sightless people, it tracks the sounds of moving objects, such as cars or footsteps, the study authors said.

"These results suggest that early blindness results in visual areas being recruited to solve auditory tasks in a relatively sophisticated way," Fine said in a university news release.

According to Chang, the research showed "that the brains of blind individuals are better able to represent frequencies".

In addition, the findings provide "an idea of what changes in the brain explain why blind people are better at picking out and identifying sounds in the environment".

Image credit: iStock

 

Ask the Expert

Hearing Expert

Minette Lister graduated with a Bachelor of Communication Pathology (Audiology) from the University of KwaZulu-Natal, Westville in 2015. Thereafter, she completed her compulsory year of community service at Phoenix Assessment and Therapy Centre in Durban. In 2017, Minette started working for Thompson and Hoffman Audiology Inc. She is passionate about working with children and adults to diagnose and manage hearing loss using state of the art technology. Minette offers hearing screening programmes for newborn and high-risk babies, as well as school-aged children, in order to decrease the incidence of late or unidentified hearing loss.

Still have a question?

Get free advice from our panel of experts

The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical exmanication, diagnosis and formal advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.

* You must accept our condition

Forum Rules