Cochlear Implants Answers to Your Questions
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Cochlear Implants Answers to your questions 1 Welcome This guide is designed to give you the information you need when considering a cochlear implant for yourself or someone important in your life. It will help you understand how hearing works, hearing with a cochlear implant and answer some common questions about getting a cochlear implant. YOU’RE NOT ALONE Hundreds of millions of people around the world experience some form of hearing loss. While many can be helped by a hearing aid, more than 75 million people still find the most powerful hearing aids inadequate. DID YOU KNOW? More than 170,000 people around the world have received a Nucleus® cochlear implant. 2 3 How do our ears work? The ear is an amazingly complex but efficient hearing system. The ear is made up of three sections: The whole process only takes OUTER MIDDLE INNER a fraction of a second. Ossicles How do we hear? 3 1 Sound waves are guided down your ear canal by the pinna. Pinna 1 4 2 The sound waves hit your ear drum and it vibrates. 2 Cochlea 3 The small ossicles vibrate with the ear drum, transferring the sound across the middle ear to the cochlea. Ear Drum 4 The fluid inside the cochlea picks up the vibrations and carries them to the thousands of tiny hair cells. These hair cells change the movement into OUTER MIDDLE INNER electrical impulses which are sent The outer ear consists of the pinna The middle ear consists of the ear The inner ear consists of a complicated along the auditory and the ear canal. The pinna is your drum membrane and an air-filled cavity series of channels and chambers. external ear, which captures sound containing three small bones called For hearing, the important organ is nerve to the brain. and funnels it into the ear canal. ossicles. The individual ossicles are the spiral shaped cochlea. Roughly The hearing the hammer (malleus), anvil (incus) the size of a pea, the cochlea contains centre of the brain interprets the and stirrup (stapes) – and they vibrate fluid and about 15,000 tiny hair cells. 3 together when the ear drum moves. Each hair cell is connected to the impulses as sound. 1 4 auditory nerve. 2 4 5 Different types of hearing loss How to read your audiogram There are three basic types of hearing loss: As part of the hearing tests done for you or your at which the frequency can be heard. The closer child, you’ll be given an audiogram, which shows the marks are to the top of the graph, the quieter the hearing profiles for the left and right ears. The the sound that can be heard in that frequency audiogram plots the usable hearing and hearing band. The most important pitches for speech SENSORINEURAL HEARING LOSS loss for each ear. Your audiologist will test sounds fall into the lightly shaded area, which we call one frequency at a time and plot the softest level the ‘speech banana’. Sensorineural hearing loss is often called Sensorineural hearing loss can be caused by: ‘nerve deafness’. It’s caused by damage to • Inherited hearing loss the cochlea, or the nerve pathways between • Ageing (prebycusis) the cochlea and the brain. Sensorineural • Viral infections such as rubella, measles, hearing loss can be mild, moderate, severe, mumps and cytomegalovirus or profound. It can affect one or both ears, • Drugs which damage the hearing system and is usually permanent. • Birth trauma • Complications from premature birth Mild-to-moderately severe sensorineural • Trauma (usually long term exposure to hearing loss can usually be helped with hearing extremely loud noise, commonly called aids or a middle ear implant. Moderately severe industrial deafness) to profound hearing loss can usually be helped with a cochlear implant. CONDUCTIVE HEARING LOSS Conductive hearing loss occurs when there Conductive hearing loss can be caused by: is a problem with the outer or middle ear. • Congenital This means that sound is unable to travel or • Excess wax or a foreign object in the ‘conduct’ from the outer ear to the eardrum ear canal and the tiny bones, or ossicles, of the • Outer ear infection middle ear. A conductive hearing loss may • Chronic ‘glue ear’ or middle ear occur in both ears or just one and can often infection, called otitis media be helped by medical or surgical treatment. • A hole in the eardrum (perforation) The Air and Bone THE AIR CONDUCTION TEST Checks the natural hearing pathway, where sound MIXED HEARING LOSS Conduction Tests travels through the air into the outer and middle ear to reach the cochlea. It’s important to check both the air and bone Mixed hearing loss combines problems with conduction of both ears, to see which part of THE BONE CONDUCTION TEST the conductive pathway (outer and middle ear) the hearing system isn’t working properly. and the cochlea or auditory nerve (the inner Checks the function of the cochlea. A metal band ear). Mixed hearing loss can occur in both ears, with an attachment called a bone oscillator is or just one. placed against the bone behind the ear. Sounds are sent directly to the cochlea through the bone bypassing the outer and middle ear to test the function of the cochlea. 6 7 WHEN HEARING AIDS ARE NO LONGER EFFECTIVE When people with severe-to-profound hearing loss don’t benefit from hearing aids, Why hearing aids medical experts consider a cochlear implant to be a more effective long-term solution. can’t work for everybody Why cochlear implants Hearing aids help a lot of people with hearing loss. are different However they can’t help everyone. Internal Implant Unlike hearing aids, cochlear implants don’t just amplify sounds. They mimic the natural For many people with severe-to-profound sensorineural hearing loss hearing function of the inner ear through in both ears, even the most advanced hearing aids can be like listening electronic stimulation. The system has two to a loud, badly tuned radio. While you can certainly hear the broadcast, parts – an external sound processor and the it’s broken up and hard to understand. actual cochlear implant. Incoming sounds That’s because hearing aids simply make sounds louder, which doesn’t are processed into electrical signals and then always make them clearer. In fact, understanding complex sounds like transmitted directly to the hearing nerve, speech can actually be even more difficult. bypassing the damaged parts of the inner ear. HOW A HEARING AID WORKS These signals are sent to the The microphone in the hearing aid picks up sound internal implant, via the coil. and sends it to the amplifier where it makes it louder. 2 External Sound Processor 1 These implulse are sent to the brain where 3 they are perceived as sound. 1 4 4 3 The hearing nerve delivers the signal to the brain, sound is heard. 3 2 2 Motion transferred to the cochlea fluids is converted into electrical impluses by tiny hair cells inside the cochlea. The implant converts the signals to electrical impulses and sends them along an electrode array in the cochlea. The receiver of the hearing aid sends the amplified sound down the ear canal, causing the The external sound processor captures sounds eardrum and the middle ear bones to vibrate. and converts them into digital signals. 8 9 The sooner you receive a cochlear implant, the sooner you can start Is a cochlear implant hearing, interacting and enjoying your life to the full. right for you? Instead of the isolation and loneliness that often accompanies significant hearing loss, you can look forward to rediscovering the activities that you may have abandoned because of your hearing. You won’t just reconnect with the world of sound, but with Ask yourself, when you use a hearing aid: a whole wide world of enjoyment and opportunity. • Do you have to ask people to repeat themselves, even in one-on-one conversations Performance with cochlear implants compared in a quiet room? with best-aided testing with hearing aids* 100 • Do you depend on lip-reading to help you understand what’s being said? Average Performan ce 84 Over Time 80 • Do you avoid social activities because you don’t always know what’s being said 80 75 – and are worried about responding incorrectly? 70 pre-implant (with hearing aid(s)) 65 • Are you exhausted at the end of the day because listening takes so much concentration? 60 ect 56 r 3 months after implant • Are you having a hard time keeping up at work? or C % 40 • Is it hard for you to talk on the phone, and does that make you avoid answering 6 months after implant or using your phone? 20 17 • Is listening to music no longer enjoyable? 13 12 months after implant 0 HINT (Quiet ) 60dB HINT (Noise) 60dB *In patients with moderate to profound hearing loss Average Scores If you answered yes Cochlear implants can deliver rapid improvements over hearing aids, especially in the crucial area of speech recognition. Studies have shown that, on average, to any of these adults can achieve 75% sentence understanding after using a cochlear implant for just 3 months and 80% after 6 months, compared to 13% previously, when questions, you may using just their hearing aids.1 be a good candidate It’s important to realise that not all hearing losses are the same. Results can vary and people may experience different hearing outcomes with their cochlear for a cochlear implant. implant. You should talk to your hearing professional about your individual situation and raise any questions or concerns you might have.