Types of hearing loss
Types of hearing loss include:
- Mixed (conductive and sensorineural combined)
Conductive Hearing Loss
Conductive hearing loss can be acquired or congenital. With conductive hearing loss, sounds aren’t adequately conducted through the outer ear canal to the eardrum and the tiny bones, or ossicles, of the middle ear. Conductive hearing loss typically results in one’s inability to discern faint sounds, and conversations may sound muffled or distant. Conductive hearing loss can manifest itself on its own or be accompanied by sensorineural hearing loss. Most conductive hearing loss affects all hearing frequencies evenly, yet typically do not result in severe hearing loss and can often be resolved by medical or surgical treatment.
Conductive hearing loss often occurs with middle ear infection (otitis media) and ostosclerosis (abnormal growth of bony tissue in the middle ear). Many conditions of this type can result from fluid build-up in the middle ear as a result of colds, allergies, inadequate functioning of the eustachian tube, a perforated eardrum, impacted earwax, ear canal infection, the presence of foreign matter in the ear, and the absence or malformation of a person’s ear canal, middle ear or outer ear. Children suffering from recurring ear infections or persistent middle ear effusion (fluid behind the eardrum) usually have at least some conductive hearing impairment.
Sensorineural Hearing Loss
Sensorineural loss can be acquired or congenital and is caused by malfunction of the cochlea. Congenital sensorineural hearing impairment may occur due to genetic factors, premature birth, or lack of oxygen at birth.
Although there are a variety of causes that may lead to sensorineural hearing loss, the most common is Prebycusis, which can be described as an age related deafness. Excessive exposure to noise can also be a factor that leads to sensorineural hearing loss. A sensorineural hearing loss is generally irreversible, and often produces the following side effects:
- Tinnitus (a ringing or buzzing in the ear or head)
- Recruitment (oversensitivity to loud sounds)
- Decreasing word recognition ability
If left untreated, a sensorineural hearing loss will worsen in most cases and lead to a greater reduction in word recognition ability.
Sensorineural hearing loss is determined through a hearing evaluation which consists of a series of tests that define an individual’s hearing ability. Once an evaluation has been performed, a specialist can then determine if a hearing instrument(s) is required. Some less common possible causes of sensorineural hearing loss include head injury, meningitis, acoustic neuroma, and some types of infectious disorders such as mumps and measles.