Hearing loss symptoms can broadly be defined as resulting from any one (or more) of the following factors:
- The aging process
- Ear infections
- Genetic conditions/syndromes
- Exposure to noise
- Medications that are toxic to the auditory system
- Head or ear trauma
- Diseases
Generally, the causes of hearing loss symptoms are categorised by which part of the auditory system is not working or has been damaged. There are three basic types of hearing loss: Conductive hearing loss, Sensorineural hearing loss and Mixed hearing loss.
Conductive hearing loss occurs when sound is not conducted efficiently through the ear canal to the small bones of the middle ear.
Sensorineural hearing loss occurs when there is damage to the inner ear (cochlea) or to the auditory nerve (pathway from the cochlea to the brain).
The term Mixed hearing loss is used to describe a hearing loss that is a combination of conductive and sensorineural loss – in other words affecting both the outer/middle and inner ear.
Causes of Conductive and Sensorineural hearing loss include:
Conductive Hearing Loss | Sensorineural Hearing Loss |
Middle and outer ear infections | Age-related hearing loss |
Collection of fluid in the middle ear (glue ear in children) | Noise exposure |
Perforated eardrum | Viral infections of the inner ear (e.g. mumps or measles) |
Impacted earwax | Diseases e.g. multiple sclerosis |
Absence or malformation of the outer ear, ear canal, or middle ear | Infections or inflammation of the brain or brain covering – e.g. meningitis |
Presence of a foreign body | Acoustic neuroma, a benign (non-cancerous) tumour affecting the auditory nerve |
Otosclerosis (fusion of the bones of the middle ear) | Drugs toxic to the auditory system |
Benign (non-cancerous) tumours | A brain tumour |
Genetic syndromes e.g. Teacher Collins Syndrome |