Is There Such a Thing as a Lazy Ear?

The phenomenon of a lazy eye is well known; a small percentage of children either have this problem at birth, or they develop it in the first few months of life. Usually only one eye is affected; it turns inwards and the child is said to have a squint. As the information from the outside world isn’t the same in both eyes, the brain tends to favour the eye that is straight and the other eye is ignored. This then causes fewer nerve connections to develop along the visual pathway from the ‘lazy eye’ and this reduces vision.

It is now being suggested that a very similar thing can happen with the ear. Children who suffer multiple ear infections and often have an excess of fluid in the inner ear could be at risk. Conditions such as otitis media are common in childhood, causing pain and distress. The fluid that builds up inside the ear is the result of the body’s immune response trying to deal with the repeated infections but, because the inner ear is a closed space, it becomes trapped.

How Fluid in the Ear Affects Hearing

The inner ear transmits vibrations from the air and converts them to vibrations through fluid and, ultimately, into nerve signals that are then interpreted by the brain. When the ear becomes blocked with thick, sticky mucus, pus and dead immune cells, the transmission of sound vibrations is not very efficient. If you have this type of ear infection sounds appear muffled and, as the problem worsens, partial temporary deafness is common.

How the Ear Becomes Lazy

In small children, just as in the visual pathways, connections are forming in the nerve pathways between the ear and the brain. If hearing is reduced in one ear due to particularly bad ear infections and fluid build up, the brain sort of forgets about that ear as far as hearing goes. Even when the infection clears up, or is treated successfully and the fluid subsides, the reduction in hearing remains. The child has developed a lazy ear.

Preventing and Treating a Lazy Ear

Research showing that the ear as well as the eye can become lazy if it doesn’t receive the same amount of stimulation by picking up sounds is very new. Publication of the findings of American researchers was published in March 2010. It will take time for the findings to be checked out in larger clinical trials and studies but the researchers think that their research may lead doctors to treat ear infections in children much more aggressively.

If ear infections can be cleared up more quickly, before the hearing deficit lasts for long enough to cause a lazy ear, the problem could be avoided. It is more difficult to see how a lazy ear that has already arisen in a young child could be treated. If the problem was a lazy eye, it is fairly straightforward to cover up the good eye and allow the poorer eye to receive more stimulation. Reducing the ability of the good ear to pick up noise would be more difficult and would involve wearing a very efficient noise reducing ear plug in the good ear, rather than a simple eye patch.

Could a Lazy Ear Recover?

The researchers who have studied how the hearing works say that young children have great plasticity in their nervous system, particularly in the pathways that are stimulated by visual images or sound. This lasts until about the age of eight. This means that children who have suffered bad ear infections and who show some signs of impaired hearing in one ear could be treated successfully if that treatment is done sooner rather than later. The ability for new nerve connections to be made in the auditory nerve pathway reduces after that age, and is very limited in adults.