Research reveals that temporary hearing deprivation can lead to 'lazy ear'

Mar 10, 2010

Hearing scientist Daniel Polley, Ph.D., an investigator at Massachusetts Eye and Ear Infirmary's Eaton-Peabody Laboratories of Auditory Physiology, has gained new insight into why a relatively short-term hearing deprivation during childhood may lead to persistent hearing deficits, long after hearing is restored to normal. The research, featured on the cover on the March 11 issue of the journal Neuron, reveals that, much like the visual cortex, development of the auditory cortex is quite vulnerable if it does not receive appropriate stimulation at just the right time.

It is well established that 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 development.

"An analogous problem may exist in the realm of hearing, in that children commonly experience a buildup of viscous fluid in the middle ear cavity which can degrade the quality of acoustic signals reaching the brain, which has been associated with a long-lasting loss of auditory perceptual acuity," explains senior study author, Dr. Polley.

Dr. Polley and his colleague Dr. Maria Popescu from Vanderbilt University implemented a method to reversibly block hearing in one ear in infant, juvenile and adult rats then looked at how the parts of the brain involved in hearing were impacted by the temporary hearing loss.

They observed that the temporary hearing loss in one ear distorted auditory patterning in the brain, weakened the deprived ear's representation and strengthened the open ear's representation. The scope of reorganization was most striking in the cortex (and not "lower" parts of the central auditory pathways) and was more pronounced when hearing deprivation began in infancy than in later life. Therefore, it appears that maladaptive plasticity in the developing might underlie "amblyaudio," in a similar fashion to the contributions of visual cortex plasticity to amblyopia.

"The good news about amblyaudio is that it is unlikely to be a permanent problem for most people," concludes Dr. Polley. "Even if the isn't corrected within the critical period, the mature auditory cortex still expresses a remarkable degree of plasticity. We know that properly designed visual training can improve visual acuity in adult patients. We are gearing up now to study whether auditory perceptual training may also be a promising approach to accelerate recovery in individuals with unresolved auditory processing deficits stemming from childhood hearing loss."

Explore further: Long-term effects of battle-related 'blast plus impact' concussive TBI in US military

More information: Popescu et al.: “Monaural Deprivation Disrupts Development of Binaural Selectivity in Auditory Midbrain and Cortex.” Publishing in Neuron 65, 718-731, March 11, 2010. DOI 10.1016/j.neuron.2010.02.019

Provided by Massachusetts Eye and Ear Infirmary

3.7 /5 (3 votes)

Related Stories

Wired for sound: How the brain senses visual illusions

Apr 11, 2007

In a study that could help reveal how illusions are produced in the brain's visual cortex, researchers at the UCSD School of Medicine have found new evidence of rapid integration of auditory and visual sensations in the brain. ...

Lend me your ears -- and the world will sound very different

Jan 14, 2008

Recognising people, objects or animals by the sound they make is an important survival skill and something most of us take for granted. But very similar objects can physically make very dissimilar sounds and we are able to ...

Memory impairment associated with sound processing disorder

Jul 21, 2008

Mild memory impairment may be associated with central auditory processing dysfunction, or difficulty hearing in complex situations with competing noise, such as hearing a single conversation amid several other conversations, ...

Recommended for you

Turning off depression in the brain

1 hour ago

Scientists have traced vulnerability to depression-like behaviors in mice to out-of-balance electrical activity inside neurons of the brain's reward circuit and experimentally reversed it – but there's ...

Rapid whole-brain imaging with single cell resolution

2 hours ago

A major challenge of systems biology is understanding how phenomena at the cellular scale correlate with activity at the organism level. A concerted effort has been made especially in the brain, as scientists are aiming to ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

brant
not rated yet Mar 10, 2010
Lazy eye comes from vaccinations.
It happened to my younger brother right after he was vaccinated.

Now its gone.......

More news stories

Turning off depression in the brain

Scientists have traced vulnerability to depression-like behaviors in mice to out-of-balance electrical activity inside neurons of the brain's reward circuit and experimentally reversed it – but there's ...

Is Parkinson's an autoimmune disease?

The cause of neuronal death in Parkinson's disease is still unknown, but a new study proposes that neurons may be mistaken for foreign invaders and killed by the person's own immune system, similar to the ...