Hearing loss in adults: causes, tests and hearing aids, a review

Hearing loss can affect adults of any age. For some people it is temporary and treatable, and for others it is permanent. This review brings together information from the NHS, the US National Institute on Deafness and Other Communication Disorders (NIDCD), the US CDC and the World Health Organization (WHO).

1. Introduction

The NHS describes hearing loss as a common condition that becomes more frequent with age, and notes that it may be treatable or permanent ^[1]. The WHO estimates that nearly 2.5 billion people will have some degree of hearing loss by 2050, and that nearly 80% of people with disabling hearing loss live in low- and middle-income countries ^[4]. Disabling hearing loss means loss greater than 35 decibels in the better ear ^[4].

Hearing loss can affect one ear or both, and it can be mild, moderate, severe or profound ^[4]. It is not always easy to tell that your hearing is getting worse, so other people may notice it before you do ^[1].

2. Signs and symptoms

The NHS lists these common signs ^[1]:

• Difficulty hearing clearly, especially in noisy places
• Often asking people to repeat themselves
• Turning the television or music up louder than other people need
• Trouble hearing on the phone or following a conversation
• Feeling tired or stressed from the effort of listening

The NIDCD adds that people may struggle to hear doorbells, smoke alarms and warnings, and may feel left out in group settings, which can lead to isolation ^[2]. In children, hearing loss can affect speech, language and school progress ^{[1, 3]}.

3. Causes and risk factors

The cause depends on the pattern of the loss. The NHS describes these examples ^[1]:

• Gradual loss in both ears: usually ageing or long-term exposure to loud noise.
• Ear infection: may bring earache, fever, itching, pressure or discharge, along with hearing difficulty in one ear.
• Earwax build-up: can cause a blocked feeling or itching.
• Perforated eardrum: a hole in the eardrum. Sudden loss can follow an ear infection, a very loud noise or a change in air pressure, such as flying.
• Labyrinthitis or Ménière's disease: can cause sudden loss with dizziness, a spinning feeling called vertigo, or ringing in the ears (tinnitus).

The NIDCD notes that age-related hearing loss, called presbycusis, is linked with changes in the ear and the nerve pathways to the brain, and that high blood pressure, diabetes, some genes and certain medicines that can harm hearing may add to the risk ^[2]. About one in three people aged 65 to 74 has hearing loss, and nearly half of those over 75 have difficulty hearing ^[2].

Noise is a major and avoidable cause. The CDC explains that hearing loss can follow a sudden very loud sound close to the ear or repeated exposure to loud noise over time, from sources such as fireworks, power tools, lawn mowing, sports crowds and concerts ^[3]. The WHO adds that over 1 billion young adults are at risk of permanent, avoidable hearing loss from unsafe listening ^[4].

4. Diagnosis and tests

The NHS advises seeing a doctor rather than guessing the cause yourself. If the doctor cannot treat the cause, you may be referred to a hearing specialist for more tests and treatment. Some pharmacies and opticians offer free hearing tests ^[1]. The NIDCD says hearing care providers include family doctors, ear, nose and throat doctors (ENT specialists) and audiologists, who specialise in measuring hearing loss. It also describes a short self-screening questionnaire, and suggests a hearing check if several answers point to trouble ^[2]. The CDC advises people to recognise early signs of noise-induced hearing loss and to get their hearing tested if they are at risk ^[3].

5. Treatment and management

Treatment depends on the cause. The NHS says a doctor may treat an infection, or treat earwax with ear drops or removal. For lasting loss, hearing aids make sounds louder but do not restore normal hearing, and some people need a hearing implant. Helpful extras include amplifiers for the phone and television, and flashing or vibrating alarms ^[1].

The NIDCD describes hearing aids worn in or behind the ear. In the United States the Food and Drug Administration created an over-the-counter category in 2022 for adults with mild to moderate loss. If such a device does not help, or if loud sounds are hard to hear, the loss may be more severe and a hearing professional should be seen ^[2]. Cochlear implants, which are surgically placed, are for people with severe or profound loss ^{[2, 4]}. The WHO also lists speech and language therapy, sign language, assistive technology and counselling as part of rehabilitation ^[4].

6. Prevention and self-care

The NHS suggests these steps ^[1]:

• Wear ear protection around loud noise.
• Keep music at a comfortable volume.
• Never put fingers or objects, including cotton buds, into the ears.
• In conversation, reduce background noise, face the speaker and ask them to slow down.

The NIDCD says scientists do not yet know how to prevent age-related hearing loss, but noise damage can be limited by avoiding loud sounds, limiting time in them and using earplugs or earmuffs ^[2]. The WHO adds that vaccination, treating common ear conditions and safe listening habits help prevent avoidable loss ^[4].

7. Special groups

Early identification matters most for babies, school-age children, older adults, workers in noisy places and people taking medicines that can harm hearing ^[4]. The WHO states that nearly 60% of childhood hearing loss is due to avoidable causes ^[4].

8. When to see a doctor

See a doctor if your hearing is slowly getting worse, or has not returned after an ear infection or earwax has been treated ^[1]. Ask for an urgent appointment, or call a health helpline, if you have sudden hearing loss in one or both ears, hearing that worsens over days or weeks, or hearing loss with earache or ear discharge, because it may need quick treatment ^[1].

In an emergency, call your local emergency number (112 in India, 911 in the United States).

9. Conclusion

Hearing loss is common, often gradual, and has many causes, from earwax to ageing and loud noise. Checking hearing early, protecting the ears from noise and using suitable devices can help reduce the effects of hearing loss. Your doctor decides which tests and treatment are right for you.