For a child, hearing and speech are essential tools of learning, playing and developing social skills.

Children learn to communicate by imitating the sounds they hear. If they have a hearing loss that is undetected and untreated, they can miss much of the speech and language around them. This results in delayed speech/language development, social problems and academic difficulties.

Hearing loss, in varying degrees, affects two in every 100 children under the age of 18.

Excessive noise is especially hazardous for young children. It does to hearing what tobacco smoke does to lungs and the sun to skin: cumulative damage for life, irreversible and untreatable. Young children have more potential years of noise exposure ahead of them than older children and adults, making prevention more important. Their ear canals are smaller and sound pressure entering the ear is greater. This increases noise levels at the higher frequencies, the frequencies crucial to language development. Noise is a leading cause of hearing loss. Statistics suggest that the incidence of hearing loss is increasing and occurring at younger ages.

How loud is too loud? The loudness of a sound is measured in decibels (dB). Zero dB is the softest sound the normal human ear can hear. Generally, sound above 85 dB is considered harmful. Normal conversation is about 60 dB. The longer the exposure to loud noise the greater the risk of damage. More than 15 minutes of exposure to 100 dB is unsafe. Genetic and other determinants make some individuals more vulnerable than others.

Infants cannot articulate discomfort from noise. Older children and adults have the option of covering their ears or distancing themselves from excessive noise. Warning signs are discomfort and pain or ringing in their ears. Assume that crying infants in noisy surroundings may be reacting to noise and remove them from the situation.

Excessive noise affects health and behaviour. Children living near airport runways are more likely to have hearing deficits than children living in quiet neighbourhoods. Hearing deficits, even very mild ones, subtly interfere with language acquisition, reading and learning skills, and social interactions. Hearing deficits increase the likelihood of behaviour problems in class and of problems with cognitive and emotional development.

Avoidance is the best way to protect young children's hearing. But most cases of noise-induced hearing loss are caused by repeated exposure to moderate levels of noise over many years, the kind that are difficult to prevent-traffic.. and industrial sources, for example. Reducing exposure generally requires action by local governmental authorities.

Earplugs are generally ineffective in young children. It is difficult to place earplugs into infants' small ear canals and to make them form an airtight fit. And earplugs often fall out. Moreover, many infants seem to find them uncomfortable and remove them. Earplugs are a choking hazard for small children.

Specialized earplugs are available for air travel. Makers of such earplugs claim that the plugs not only reduce noise but also minimize earaches caused by the rapid changes in atmospheric pressure as aircraft ascend and descend. These earplugs slow the movement of air into and out of the outer ear, giving the inner ear more time to adjust to the pressure changes. Models are available for children as young as one year of age. Many parents say that these earplugs suffer from the same problems as do regular earplugs.

Noise-reducing earmuffs or children's ear defenders offer the best solution. Young children seem to prefer kids ear defenders to earplugs; many seem to actually enjoy wearing them. They are lightweight, can be adjusted, have wide, foam-filled cushions to ensure that the set doesn't squeeze uncomfortably and that there is plenty of space for the earlobes. Sizes are available for children, infants and even babies.