Featured Research

from universities, journals, and other organizations

Researchers gain insight into 'lazy ear'

Date:
September 30, 2013
Source:
Massachusetts Eye and Ear Infirmary
Summary:
Short-term hearing loss during childhood may lead to persistent hearing deficits, long after basic auditory sensitivity has returned to normal. Researchers have gained new insight into how this works.

Degraded sensory experience during critical periods of childhood development can have detrimental effects on the brain and behavior.
Credit: jacktheflipper / Fotolia

Short-term hearing loss during childhood may lead to persistent hearing deficits, long after basic auditory sensitivity has returned to normal. The processing of sound in the brain is shaped by early experience. New research from Massachusetts Eye and Ear has identified two critical periods occurring shortly after hearing onset that regulate how sounds from each ear are fused into a coherent representation in the brain. Their research is described in Nature Communications.

Hearing scientist Daniel Polley, Ph.D., an investigator at Massachusetts Eye and Ear/Harvard Medical School's Eaton-Peabody Laboratories of Auditory Physiology and collaborators found by inducing a brief, reversible hearing loss at key milestones in cortical development, they identified two critical periods occurring after hearing onset that regulate the maturation of coordinated binaural sound representations. Their work could eventually lead to a better understanding of which periods in a child's development are most crucial to maintain hearing.

Degraded sensory experience during critical periods of childhood development can have detrimental effects on the brain and behavior. In the classic example, a condition called amblyopia (also known as lazy eye) can arise when balanced visual signals are not transmitted from each eye to the brain during a critical period for visual cortex development. In this study, researchers set out to determine how temporary disruption of hearing at precise times in development affect the ability for the brain to hear once hearing is restored.

"The goal of this study was to mimic the moderate, short-term hearing loss that can accompany ear infections in human infants and then study how and when the encoding of auditory signals was disrupted in the brains of developing mice."

Much like starting up a computer, the brain "boots" itself during development beginning with the basic firmware and culminating with higher-level software elements. Unlike a computer, the brain relies on experience from the surrounding sensory environment to complete its startup process. If sensory experience is degraded during these critical periods in early life, as would occur with a visual cataract or conductive hearing loss that can accompany an ear infection, the brain's representation of the sensory world can be distorted in a specific and enduring way, even after the physical deficit in the eye or ear has been corrected. In this study, researchers found that creating a temporary hearing loss one day after hearing begun disrupted the basic alignment of sound frequency selectivity in the mouse cortex, whereas the same manipulation initiated just a few days later interfered with the neural computation of loudness differences between the ears.

"These findings demonstrate that brief bouts of asymmetric hearing loss during very specific points in postnatal development can have a lasting effect on brain circuits that compare and integrate the sound waves that enter each ear," said Dr. Polly. "According to pediatric audiology studies and the latest U.S. census data, approximately 12% of children (or 2.6 million children in the United States alone) will experience at least one bout of otitis media severe enough to cause a brief, mild conductive hearing loss before reaching five years of age. Though our study was conducted in an animal model, these data support a growing body of work that underscores the importance of minimizing hearing loss or excessive environmental noise for healthy infant brain development."


Story Source:

The above story is based on materials provided by Massachusetts Eye and Ear Infirmary. Note: Materials may be edited for content and length.


Journal Reference:

  1. Daniel B. Polley, John H. Thompson, Wei Guo. Brief hearing loss disrupts binaural integration during two early critical periods of auditory cortex development. Nature Communications, 2013; 4 DOI: 10.1038/ncomms3547

Cite This Page:

Massachusetts Eye and Ear Infirmary. "Researchers gain insight into 'lazy ear'." ScienceDaily. ScienceDaily, 30 September 2013. <www.sciencedaily.com/releases/2013/09/130930113845.htm>.
Massachusetts Eye and Ear Infirmary. (2013, September 30). Researchers gain insight into 'lazy ear'. ScienceDaily. Retrieved September 15, 2014 from www.sciencedaily.com/releases/2013/09/130930113845.htm
Massachusetts Eye and Ear Infirmary. "Researchers gain insight into 'lazy ear'." ScienceDaily. www.sciencedaily.com/releases/2013/09/130930113845.htm (accessed September 15, 2014).

Share This



More Health & Medicine News

Monday, September 15, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Respiratory Virus Spreads To Northeast, Now In 21 States

Respiratory Virus Spreads To Northeast, Now In 21 States

Newsy (Sep. 14, 2014) The respiratory virus Enterovirus D68, which targets children, has spread from the Midwest to 21 states. Video provided by Newsy
Powered by NewsLook.com
Shocker: Journalists Are Utterly Addicted To Coffee

Shocker: Journalists Are Utterly Addicted To Coffee

Newsy (Sep. 13, 2014) A U.K. survey found that journalists consumed the most amount of coffee, but that's only the tip of the coffee-related statistics iceberg. Video provided by Newsy
Powered by NewsLook.com
Contagious Respiratory Illness Continues to Spread Across U.S.

Contagious Respiratory Illness Continues to Spread Across U.S.

Reuters - US Online Video (Sep. 12, 2014) Hundreds of children in several states have been stricken by a serious respiratory illness that is spreading across the U.S. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Ebola Batters Sierra Leone Economy Too

Ebola Batters Sierra Leone Economy Too

Reuters - Business Video Online (Sep. 12, 2014) The World Health Organisation warns that local health workers in West Africa can't keep up with Ebola - and among those countries hardest hit by the outbreak, the economic damage is coming into focus, too. As David Pollard reports, Sierra Leone admits that growth in one of the poorest economies in the region is taking a beating. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins