Causes of Hearing Loss

As you have read in the previous pages, deafness and hearing loss are caused by problems in the outer ear, middle ear, inner ear, or a combination of these.

Outer Ear Problems

Buildup of Earwax - Over time, earwax can block the ear canal and keep sound waves from passing through. Earwax removal can help restore hearing.

Ear Infection, Unusual Bone Growths, Tumours - any of these can cause hearing loss, again, by blocking the passage of the sound waves.

Middle Ear Problems

Ruptured Ear Drum (tympanic membrane perforation) - Loud blasts of noise, sudden changes in pressure, poking an eardrum with an object and infection can cause the eardrum to burst. In turn it then cannot pass on vibrations through the middle ear.

Damaged/Not Functioning Middle Ear Bones - Middle ear bones that cannot vibrate, stop the transmission of vibrations to the inner ear.

Inner Ear Problems

Factors that damage or lead to loss of the hairs and nerve cells in the cochlear include:

• Aging (Presbycusis) - The inner ear breaks down over time
• Loud Noise - Being around loud sounds can damage the cells of the inner ear. Damage can happen by being around loud noises over time or from a short blast of noise, such as from a gunshot
• Heredity - Your genes may make you more likely to have ear damage from sound or from ageing
• Noises on the Job - Jobs where loud noise is constant, such as farming, construction, or factory work, can lead to damage inside the ear
• Noises at Play - Exposure to explosive noises, such as from firearms and jet engines, can cause immediate, permanent hearing loss. Other activities with dangerously high noise levels include snowmobiling, motorcycling, carpentry, or listening to loud music
• Some Medicines (Ototoxic Drugs)- These include the antibiotic gentamicin, sildenafil (Viagra) and certain medicines used to treat cancer, which can damage the inner ear. Very high doses of aspirin, other pain relievers, antimalarial drugs, or loop diuretics can cause short-term effects on hearing. These include ringing in the ears, also known as tinnitus, or hearing loss
• Some Illnesses - Illnesses, such as meningitis, that cause high fever can harm the cochlea

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 including 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

It is quite alarming the many different ways hearing loss can occur. Although some are out of our control, we can take responsibility for our hearing and protect it.

If you would like to read more information about protecting your hearing at work, please click here to go to the Health & Safety Executive guidelines.