Hearing Loss: Causes, Types and Treatment

Types of hearing loss

Hearing loss is graded by how loud a sound must be to be heard, in decibels (dB). On the scale commonly used in the US, normal hearing is 15 dB or better, mild loss 26 to 40 dB, moderate 41 to 55 dB, moderately severe 56 to 70 dB, severe 71 to 90 dB and profound above 90 dB.

Common causes of hearing loss

Ear wax

Wax blocking the canal causes muffled hearing, fullness and sometimes ringing. It is common in older adults, hearing aid users and people who use cotton swabs, which push wax deeper. See ear wax impaction.

Fluid and infection in the middle ear

Middle ear infections and fluid behind the eardrum (otitis media with effusion) are the commonest cause of hearing loss in children. Adults get it after colds, with blocked Eustachian tubes, or after flying.

Damaged or perforated eardrum

A hole in the eardrum from infection, injury or pressure causes conductive hearing loss, often with ringing. Repeated infections can scar the eardrum (tympanosclerosis) or erode the tiny middle ear bones, and a skin cyst (cholesteatoma) can grow behind it. See eardrum perforation.

Age-related hearing loss (presbycusis)

Gradual, symmetrical loss of high-pitched sounds, starting from about age 50 to 60. People notice difficulty following speech in noisy places and confusing consonants like "s", "f" and "th". It affects about a third of adults over 65 and about half of those over 75. See presbycusis.

Noise-induced hearing loss

Loud noise damages the hair cells in the cochlea. It can follow one explosive sound or years of exposure to machinery, music or firearms. Sounds above about 85 dB (heavy traffic, a lawnmower) can cause damage with long exposure. Ringing in the ears is often the first sign.

Sudden sensorineural hearing loss

A rapid drop in hearing in one ear, over hours to 3 days, often noticed on waking or when using the phone, sometimes with a pop, fullness, tinnitus or dizziness. Most cases have no identified cause; viral infection or reduced blood flow to the inner ear are suspected. Sudden sensorineural hearing loss is often mistaken for wax or a blocked ear, so it is frequently missed.

Other causes

• Meniere's disease: episodes of spinning vertigo, fluctuating low-pitched hearing loss, tinnitus and ear fullness. See Meniere's disease.
• Otosclerosis: abnormal bone growth fixing the stapes bone, causing slowly progressive conductive loss in young and middle-aged adults.
• Acoustic neuroma: a benign tumor on the hearing and balance nerve, causing one-sided hearing loss and tinnitus.
• Medicines toxic to the ear: some antibiotics (aminoglycosides), cisplatin chemotherapy, and high doses of loop diuretics or aspirin.
• Infections: meningitis, mumps, measles and congenital CMV.
• Genetic hearing loss: about half of hearing loss present at birth is genetic.
• Head injury.

Hearing loss in one ear

One-sided (asymmetric) hearing loss is more likely to have a specific cause, such as wax, infection, perforation, sudden hearing loss, Meniere's disease or acoustic neuroma. It should always be assessed, and a sudden onset is urgent. A simple check doctors use is the tuning fork test: in conductive loss the sound seems louder in the bad ear; in sensorineural loss it is louder in the good ear.

Symptoms that come with hearing loss

How hearing loss is diagnosed

1. History: speed of onset, one or both ears, noise exposure, medicines, family history, and other symptoms.
2. Otoscopy: looking at the canal and eardrum for wax, fluid, perforation or scarring.
3. Tuning fork tests to distinguish conductive from sensorineural loss.
4. Audiogram: a hearing test in a soundproof booth measuring the quietest sounds you can hear at different pitches, through headphones (air) and a bone vibrator (bone).
5. Tympanometry: measures eardrum movement to detect fluid or a perforation.
6. MRI scan for one-sided sensorineural loss or tinnitus, to rule out acoustic neuroma.
7. Newborn hearing screening and specialist tests for babies and young children.

Treatment

• Wax: softening drops, irrigation or microsuction by a clinician.
• Infection and fluid: antibiotics for some infections; ear tubes for children with persistent fluid and hearing loss.
• Perforated eardrum: most heal on their own within weeks; persistent holes are repaired with tympanoplasty.
• Otosclerosis and cholesteatoma: surgery.
• Sudden sensorineural hearing loss: steroids by mouth or injected through the eardrum, ideally started within 2 weeks and best within days. About half to two-thirds of people recover some or all hearing.
• Hearing aids: the main treatment for permanent loss. Over-the-counter hearing aids are available in the US for adults with perceived mild to moderate loss; prescription aids fitted by an audiologist suit more complex or severe loss.
• Cochlear implants: for severe to profound sensorineural loss when hearing aids give little benefit.
• Bone-anchored devices for some conductive or one-sided losses.
• Assistive technology: captioning, phone amplifiers, TV streamers and alert systems.

Treating hearing loss helps communication and is linked with lower risks of social isolation and, in research studies, slower cognitive decline in at-risk older adults.

Preventing hearing loss

• Keep sound at safe levels: if you have to shout to be heard, it is too loud.
• Use earplugs or earmuffs around loud machinery, concerts and firearms.
• Follow the 60/60 rule for headphones: no more than 60 percent volume for 60 minutes at a time.
• Do not put cotton swabs or objects in your ears.
• Keep children's vaccines up to date (measles, mumps, meningitis).
• Have your hearing tested if you are over 50 or regularly exposed to noise.

Frequently asked questions

What is the most common cause of hearing loss?

In adults, age-related hearing loss and noise exposure are the most common causes of permanent loss. Ear wax is the commonest cause of temporary loss. In children, fluid behind the eardrum from ear infections is the most common cause.

Is sudden hearing loss an emergency?

Yes. Sudden hearing loss, especially in one ear, should be assessed within 24 to 72 hours. Steroid treatment works best when started early. Many people assume it is wax or a blocked ear and wait too long, which reduces the chance of recovery.

Can a hole in the eardrum cause hearing loss and tinnitus?

Yes. A perforated or scarred eardrum vibrates less efficiently, causing conductive hearing loss, and often ringing. An ENT doctor diagnoses it by examining the ear with a microscope and doing an audiogram and tympanometry. Many holes heal on their own; others are repaired surgically.

Can hearing loss be reversed?

Conductive hearing loss from wax, fluid, infection or eardrum damage often can be reversed. Sudden sensorineural hearing loss sometimes recovers with prompt treatment. Most age-related and noise-induced loss is permanent, but hearing aids and implants restore much of the ability to communicate.

How do I know if I need a hearing test?

Get tested if you often ask people to repeat themselves, struggle in noisy places, turn the TV up louder than others like, hear ringing, or family members mention it. Anyone over 50, or exposed to loud noise at work, benefits from regular testing.