The main parts of the ear are the outer ear, the eardrum (tympanic membrane), the middle ear, and the inner ear.

The sinuses are cavities, or air-filled pockets, near the nasal passage. They are lined with mucous membranes.

A hearing problem may be suspected in a child who is not responding to sounds or who is not developing language skills appropriately.

Sensorineural hearing loss involves the inner ear or its connection with the brain. Conductive hearing loss involves the middle or outer ear.

Hearing loss in babies is rare in this country, but when it does occur, it's important to diagnose it early. Undetected hearing loss can delay speech and language development.

One type of hearing screening test for newborns uses a tiny, flexible plug that is inserted into the baby's ear. The other type of test uses electrodes attached with adhesive to the baby's scalp.

A child's hearing loss may be helped with hearing aids or cochlear implants. Training in sign language and lip reading is another option.

Hearing aids can help improve hearing and speech, especially in children with hearing loss in the inner ear caused by damaged hair cells or a damaged hearing nerve.

Experts say today's small music players pose a big risk of hearing loss. One reason: The "earbuds" used with iPods and other MP3 players fit into the ears, not over them.

Here are guidelines on speech and language development that may help you decide if your child is experiencing hearing problems.

One sign of possible hearing loss is an infant who does not move or jump when a loud sound is made.