context: About 37.5 million American adults have trouble hearing. The loud music of your youth or simply aging may be to blame. But there are many more reasons why you might not hear things the way you want to. Medicine or surgery can treat some types of hearing loss. Others are permanent, but hearing aids or implants can help. It only takes a few minutes for a doctor to figure out which type you have. Hearing loss falls into three basic groups: Conductive hearing loss is a mechanical problem with your ear. Sound has trouble moving from the outer ear to the eardrum and middle-ear bones. Medicine or surgery may help. Sensorineural hearing loss ( SNHL) comes from nerve damage in your inner ear. It's usually permanent. A hearing aid or cochlear implant may make things better. Mixed hearing loss is a combination of both. Usually, a structural problem or disease in your outer or middle ear brings this type of temporary hearing loss. Causes include: Too much earwax: Doctors call this cerumen obstruction. Using a cotton swab can push the wax deeper into your ear. When it builds up, you don't hear as well. Your doctor can easily get rid of the wax during an office visit. Swimmer's ear: Your doctor may call this otitis externa. Water causes this infection of the outer ear canal. If your ear swells a lot, you might lose some hearing. Something stuck in the ear canal: Tiny buttons or beads -- even pieces of cotton from ear swabs -- can get stuck in the ear. Doctors often see this in children. If a bug is stuck in your ear (uncommon, but it does happen), you may have a hard time hearing and your ear may be very itchy. Fluid in your middle ear: This may happen if you have an ear infection, cold, allergies, or other upper respiratory illness. You can also get it if your Eustachian tubes (which drain fluid) stop working. A hole in your eardrum: When your eardrum is perforated, it can't pick up sound vibrations like it usually can, so you lose hearing. Birth defects: Sometimes, the outer ear canal appears malformed at birth. This is atresia. The ear canal may also be missing or have failed to open at birth. Surgery can reconstruct the ear. Otosclerosis : An abnormal bony growth forms around a bone in your middle ear. This keeps it from vibrating in response to sound. Cholesteatoma: This is a noncancerous clump of skin in your middle ear. You may get one if your eardrum collapses. It can damage your ear and lead to more serious problems. This is the most common form of permanent hearing loss. If you have this, sounds may seem garbled or muted. Faint sounds can be unclear. Conversations in a crowded room can be hard to hear. Even loud sounds, like a person's voice, may seem muffled. There are many causes: Aging: Simply growing older may make sensorineural hearing loss more likely. You may hear a doctor say "presbycusis." This is age-related hearing loss. It tends to run in families. You may first notice trouble hearing high-pitched sounds. Noise exposure: You may also hear this called "acoustic trauma." Long-term exposure to loud noises damages your ears. Noisy environments that involve loud tools, engines, weapons, even music events raise your odds. For example, 15 minutes at a rock concert is enough to harm your ears. Wearing ear protection can help save your hearing. Head injury. It can cause both sensorineural and conductive hearing loss. Sudden changes in air pressure: Things like scuba diving or riding in an airplane while it lands may cause fluid in the inner ear to shift, causing a leakage or rupture. This may lead to inner ear nerve damage. Acoustic neuroma : This noncancerous tumor affects the nerve that sends signals between the inner ear and brain. Hearing loss, the main symptom, is slow to occur and happens in just one ear. Autoimmune inner ear disease: This rare condition causes various levels of hearing loss in both ears, which slowly gets worse over weeks to months. You may also have ringing in the ears and a feeling of fullness in the ears. Meniere's disease: This chronic condition can cause hearing loss that comes and goes, along with ringing in the ears (tinnitus) and vertigo. Other causes of sensorineural hearing loss include: Diseases of the central nervous system Ear structure problems The growth of bone in your middle ear, called otosclerosis Most of the time, this type happens slowly. It can happen suddenly, but that's rare. When it happens, doctors believe a viral infection of your inner ear or hearing nerve may be to blame. Hearing loss typically affects one ear. If yours comes on suddenly, it's a medical emergency. Medicine may be able to treat it. If you or a loved one notices changes in your hearing, see a doctor or audiologist. Hearing loss is common with aging, but sometimes it's a sign of a serious condition. It can also be a side effect of some medications.