Over 5% of the world’s population – or 430 million people – require rehabilitation to address their ‘disabling’ hearing loss (432 million adults and 34 million children). It is estimated that by 2050 over 700 million people – or one in every ten people – will have disabling hearing loss.
‘Disabling’ hearing loss refers to hearing loss greater than 35 decibels (dB) in the better hearing ear. Nearly 80% of people with disabling hearing loss live in low- and middle-income countries. The prevalence of hearing loss increases with age, among those older than 60 years, over 25% are affected by disabling hearing loss.
Hearing loss and deafness
A person who is not able to hear as well as someone with normal hearing – hearing thresholds of 20 dB or better in both ears – is said to have hearing loss. Hearing loss may be mild, moderate, severe, or profound. It can affect one ear or both ears, and leads to difficulty in hearing conversational speech or loud sounds.
‘Hard of hearing’ refers to people with hearing loss ranging from mild to severe. People who are hard of hearing usually communicate through spoken language and can benefit from hearing aids, cochlear implants, and other assistive devices as well as captioning.
‘Deaf’ people mostly have profound hearing loss, which implies very little or no hearing. They often use sign language for communication.
Causes of hearing loss and deafness
Although these factors can be encountered at different periods across the life span, individuals are most susceptible to their effects during critical periods in life.
Prenatal Period
- Genetic factors – Include hereditary and non-hereditary hearing loss
- Intrauterine infections – such as rubella and cytomegalovirus infection
Perinatal period
- Birth asphyxia (a lack of oxygen at the time of birth
- Hyperbilirubinemia (severe jaundice in the neonatal period)
- Low-birth weight
- Other perinatal morbidities and their management
Childhood and adolescence
- Chronic ear infections (chronic suppurative otitis media)
- Collection of fluid in the ear (chronic nonsuppurative otitis media)
- Meningitis and other infections
Adulthood and older age
- Chronic diseases
- Smoking
- Otosclerosis
- Age-related sensorineural degeneration
- Sudden sensorineural hearing loss
Factors across the life span
- Cerumen impaction (impacted ear wax)
- Trauma to the ear or head
- Loud noise/loud sounds
- Ototoxic medicines
- Work related ototoxic chemicals
- Nutritional deficiencies
- Viral infections and other ear conditions
- Delayed onset or progressive genetic hearing loss
Reference: https://www.who.int/news-room/fact-sheets/detail/deafness-and-hearing-loss