context: If you're very hard of hearing or deaf, a cochlear implant may help you get back the sounds you miss. It isn't a hearing aid, which makes sounds louder. It's a small device that a doctor puts in your ear through surgery. It sends impulses directly to your auditory nerve, which carries sound signals to your brain. The implant doesn't make you hear normally again, but it can help you with sounds. Most people with severe to profound hearing loss can understand speech in person or over the phone better than they did with a hearing aid. It can usually help you know sounds around you, including telephones, doorbells, and alarms. Many people also can pick up on speech in noisy places better than they did with hearing aids, or even enjoy music again. It's for children and adults with sensorineural hearing loss. That condition typically involves damage to tiny hair cells in a part of your inner ear called the cochlea. These hair cells usually pick up the vibrations of sounds and send them to the brain through the auditory nerve. When they're damaged, sound can't reach that nerve. A cochlear implant skips the damaged hair cells and sends signals to the auditory nerve directly. The devices have two parts. One part, the receiver-stimulator, is placed under your skin through surgery. The other, the speech processor, you wear behind your ear like a hearing aid. The outside part is slightly larger than a normal behind-the-ear hearing aid. First, a surgeon puts a receiver under your skin behind your ear through a small cut. The receiver is connected to electrodes, which she'll put into a part of your inner ear called the cochlea. The surgery takes an hour or two, and you'll probably go home the same day. One to 2 weeks after the procedure, your doctor will fit your speech processor. You wear a microphone, which looks like a hearing aid, behind your ear. The processor may be connected to the microphone and worn at your ear, or you might wear it somewhere else on your body, depending on how active you are, your age, or your lifestyle. These processors offer different programs and telephone options. They also can connect to assistive listening devices and other technology you use, like an i Pod. Some have rechargeable batteries, which can lower costs over time. When there are sounds around you, the microphone and processor pick them up and change them into electrical impulses. Then the transmitter sends these coded signals to the receiver under your skin. Next, the receiver delivers the signals to the electrodes inside your cochlea. These electrodes stimulate the auditory nerve, which carries the signals to the brain, where you recognize them as sound. It can be life-changing if you have a serious hearing problem. But the results aren't the same for everyone. Some people benefit more than others. Some of the pros: You may be able to hear speech at a nearly normal level. You may be able to understand speech without lip reading. It's easier to talk on the phone and hear the TV. You may be able to hear music better than before. You can pick up on different types of sounds, including soft, medium, and loud ones. You can better control your own voice so that it's easier for others to understand you. Cochlear implant surgery is very safe, but any operation comes with risks. Problems can include bleeding, infections, and side effects from the medicine that sends you to sleep during the procedure. Other possible complications include: A nerve injury that changes your sense of taste Nerve damage that causes weakness or paralysis in your face Dizziness or balance problems Loss of the hearing you have left Ringing in your ears, called tinnitus Leaks of the fluid around the brain The device doesn't work or gets infected, which may mean you'll have to remove and replace the implant. Meningitis, an infection of the membranes around the brain. It's a rare but serious complication. Children and people with abnormally formed inner ears seem to be at higher risk. The FDA and CDC recommend vaccines for anyone who gets a cochlear implant to lower their risk for the disease. Keep some other things in mind, too: If you have some hearing left, sound may seem "mechanical" or "synthetic," although most people no longer notice this after several months. If you need an MRI, you may first need a simple procedure to briefly take out the magnet in the cochlear implant. But more medical facilities can do these imaging tests without removing the magnet. There's also a type of cochlear implant that has a magnet you don't need to take out in order to have an MRI. Some parts of the device can get damaged if they get wet. You need to take off the speech processor before you bathe, shower, or swim. You also can cover that part with a waterproof case or choose a waterproof cochlear implant processor. Rarely, the implant may stop working, and you'd need surgery to fix the problem. The American Speech- Language- Hearing Association says the device is best for adults who have: Severe to profound hearing loss in both ears Hearing loss after they've already learned speech and language Limited help from hearing aids No medical problems that would make surgery risky A strong desire to hear better A good understanding of what the device will -- and won't -- do for them Also, cochlear implants work better for people who have lost their hearing recently, as well as those who've already used a hearing aid successfully. The FDA says children can get the devices starting at age 1. Most kids who are diagnosed with significant hearing loss as babies get them as soon as possible. A cochlear implant in early childhood exposes children to sound during the critical period when they learn speech and language skills. The devices work best for children who: Have profound hearing loss in both ears Get limited help from hearing aids Are healthy, with no medical problems that would make surgery risky Are ready to learn how to communicate with a cochlear implant Have support from their parents, teachers, and school programs to help them gain hearing skills Are younger than age 5 Join in intensive speech therapy and programs to teach speaking skills A study found that children who got a cochlear implant before 18 months old had major improvements in their hearing, speaking, and learning. But the devices also can help older children who lose their hearing after they've learned to talk. If you have severe or profound hearing loss, a team of experts at a cochlear implant center can help you decide if the device and surgery will work for you. Typically, these experts include an ear doctor called an otologist, an audiologist, a psychologist, a counselor, and a speech-language pathologist. The team works together to check you, do the surgery, and offer follow-up care. You may have tests, such as: An exam of your external, middle, and inner ear to check for infections or other issues Hearing tests such as an audiogram, a graph that charts how you respond to specific sounds A hearing aid evaluation CT or MRI scans to check the inner ear and hearing nerve. These tests will tell your doctor if your cochlea has a normal shape. A physical exam A psychological exam to see if you can handle the changes that come with the implant. This test is more common for children. When you're thinking about getting a cochlear implant, counseling will help you know what you can expect from the device and make sure you understand what it takes to learn how to use the implant. After your surgery, a rehab program may help, too. The goal is to learn how to listen through the implant. Doctors always recommend that children who get implants go through this.