To understand ANSD, it’s helpful to review how the ear hears. Hearing begins when sound waves that travel through the air reach the outer ear, or pinna, the part of the ear that’s visible. The sound waves go through the ear canal into the middle ear, which includes the eardrum (a thin layer of tissue) and three tiny bones called ossicles. The sound causes the eardrum to vibrate. The ossicles amplify these vibrations and carry them to the inner ear.
The inner ear is made up of a snail-shaped chamber called the cochlea, which is filled with fluid and lined with four rows of tiny hair cells. When the vibrations move through this fluid, the outer hair cells contract back and forth and amplify the sound. When the vibrations are big enough, the inner hair cells translate them into electrical nerve impulses in the auditory nerve, which connects the inner ear to the brain. When the nerve impulses reach the brain, they are interpreted as sound.
In addition to assistive listening devices, kids with ANSD often can benefit from learning visual communication skills. American Sign Language (ASL), Cued Speech, and Signed Exact English are three types of visual communication techniques. You’ll work with the medical team to determine which is the most appropriate for your child.