The Causes and Symptoms of Hearing Loss
Types of Hearing Loss continued...
Sensorineural hearing losshappens most often from damage to the hair cells in the inner ear. Other causes include damage to the nerve for hearing, called the auditory nerve, or the brain. It’s usually happens as you get older, but it also can happen because of noise exposure, chemotherapy, radiation, trauma, and your genes.
Mixed hearing lossis a combination of conductive and sensorineural hearing loss, meaning that there may be a problem in the outer or middle ear and in the inner ear or auditory nerve. Mixed hearing loss can happen after a head injury, long-term infection, or because of a disorder that runs in your family.
Hearing loss can affect one or both ears. It can happen suddenly or gradually get worse over time. If you notice sudden hearing loss, you should see an ear, nose, and throat specialist as soon as possible.
Hearing Loss Causes
When your hearing is normal, sound waves enter your outer ear and cause your eardrum and middle ear bones to vibrate. The sound waves then travel through your inner ear, which is a shell-shaped, fluid-filled tube called the cochlea. As the fluid moves, it sets in motion thousands of tiny hairs that convert the sound vibrations into nerve impulses. Those impulses go to your brain where they are processed into sounds you can recognize.
Hearing loss happens when there's a problem with the structures of the ear that process sound. Any of these conditions can lead to hearing loss:
- Age. As people get older, the structures in the ear become less elastic. The tiny hairs get damaged and can’t respond to sound waves as well. Hearing loss can get worse over several years.
- Loud noise. The blare of power tools, airplanes, or loud music on headphones, for example, can damage the hair cells in the cochlea. How much hearing you lose depends on the volume of the sound and how long you were around it.
- Ear infections. They can make fluid build up in the middle ear. Usually the hearing loss from an ear infection is mild and goes away shortly. But if you don’t treat them, they can lead to serious long-term problems.
- Perforated eardrum. An ear infection, loud sounds, head trauma, or intense pressure in the ear from flying in an airplane or scuba diving can damage the eardrum, leaving a hole that may or may not heal. Depending on the size of the hole, there may be mild or moderate hearing loss.
- Cholesteatoma. This is a collection of skin that you can get in the middle ear when the eardrum collapses or when skin grows through a hole in the eardrum. Cholesteatomas grow over time and can lead to hearing loss by destroying the middle ear bones or, rarely, the inner ear.
- Illnesses or infections. Measles, mumps, tertiary syphilis, and meningitis are just a few of the conditions that can cause hearing loss.
- Meniere’s disease. Symptoms of this inner ear disorder include dizziness, hearing loss that comes and goes, ringing in the ear, or fullness in the ear. Hearing loss in Meniere’s disease usually gets worse but only involves one ear.
- Tumors. Cancer or benign tumors can cause severe hearing loss. This includes acoustic neuroma (vestibular schwannoma), paraganglioma, and meningioma. People who have one might also have numbness in their face or weakness and ringing in their ear.
- An object stuck in the ear. When something’s in your ear that shouldn’t be, it can block hearing. Earwax can sometimes build up and harden, which can make it hard to hear.
- Malformed ear. Some people are born with poorly formed ears.
- Trauma. Injuries such as a skull fracture or a punctured eardrum can cause severe hearing loss.
- Medications. Some types of drugs -- including some antibiotics (erythromycin, kanamycin, neomycin, streptomycin), large amounts of aspirin, chemotherapy drugs (carboplatin, cisplatin), and Vicodin (in large amounts) -- can cause hearing loss. Sometimes hearing will return once you stop taking the drug. In most cases the hearing loss is permanent.
- Genes. Scientists have found genes that make people more prone to severe hearing loss, particularly as they age. Most of the time, genetic hearing loss is diagnosed at birth, but it can show up later.
- Autoimmune disorders. Lupus and rheumatoid arthritis, for example, may affect hearing. It’s one of the main features of several autoimmune disorders, including Cogan’s syndrome, Wegener’s granulomatosis, and Behcet’s disease.