There are three main types of hearing loss, each of which affects a different part of a person's ear. Conductive hearing loss is a result of problems in a person's outer and middle ear, while sensorineural hearing loss (SNHL) is a result of some type of injury or harm to the inner ear. When both types of hearing loss affect a single ear, it is known as mixed hearing loss. Although all three affect a person's ability to distinguish sounds, or hear, the causes, extent and treatments for each of the types can vary widely, as can the treatment success rate.
Conductive hearing loss the first of the types of hearing loss. It is diagnosed when sound is not sufficiently transmitted from a person's outer ear through the middle ear and on to the eardrum. This type of hearing loss commonly results from a cold, ear infection, allergies, earwax buildup or some other blockage of the ear canal. More serious but less common causes can include a perforated eardrum, tumors, or problems with the eustachian tube. Conductive hearing loss can often be remedied with medication, though surgery may be necessary in more serious cases and hearing damage can be permanent.
SNHL happens in the inner ear as a result of damage to the cochlea or nerves that connect the inner ear to the brain. SNHL can be caused by aging, genetics, prolonged exposure to loud sounds, certain drug therapies, and brain trauma. SNHL's myriad potential causes make it difficult to treat. A very small percentage of patients may regain their hearing almost entirely, but the majority of people with SNHL will see only minor improvement with treatment.
Mixed hearing loss — as the name suggests — is a combination of SNHL and conductive hearing loss. An accident or some other trauma may cause both types to occur at the same time. Mixed hearing loss can require varied treatments to achieve the best results, although the patient is more likely to see improvement in his conductive hearing loss than in his SNHL. For this reason, doctors often focus their treatment plan on the patient's conductive hearing loss.
Although the three types of hearing loss have different causes and treatments, it is important for a person to consult with a physician when experiencing hearing loss symptoms. Hearing loss is a problem that rarely gets better on its own. Instead, it often worsens and can lead to irreversible damage.