What are the different types of hearing loss?

What types of hearing losses are we experiencing today and of these which are the ones that impact most patients in the 55 and over category?

Generally, hearing losses fit into three basic categories:

Conductive - Conductive losses involve the pathway of sound through the outer and middle ear and they include specific conditions associated with collapsed canals, a calcification of the small bones in the middle ear, blocked or deformed passages, trauma etc. In conductive losses, the transmission of sound to the inner ear is impeded. A typical example of this would be otosclerosis or, in common terms, the hardening or stiffening of the bones in the middle ear - which is a condition that is generally surgically correctable (dependent upon age). Conductive losses can also involve tumors or growth in the outer and middle ear such as cholesteatomas. Cerumen accumulation (excessive earwax) in the outer ear is also a conductive component.

Sensorineural Hearing Loss (Nerve Deafness) - In this type of hearing loss, sound is delivered to the inner ear effectively, but the nerve response in the cochlea is not what it should be. This type of hearing loss, is the most common occurrence of all impairments, accounting for approximately 75% to 80% of all losses. Sensorineural hearing loss, or nerve deafness, is usually not operable and some examples of the most common causes of Sensorineural hearing loss are:
- Congenital (at birth)
- Presbycusis (aging)
- Infections and the damage associated with them
- Ototoxia: Oto is Latin for ear and toxia means poison - this is a condition where damage to the nerves occurs due to toxic chemicals or medications. This can happen from over medication with certain types of antibiotics and other drugs, (excessive doses of quinine for example), chemotherapy, etc.
- Acoustic Trauma: Acoustic trauma occurs when there is sudden exposure to loud sound such as gunfire or an explosion.
- Enviro Trauma: This is a term we use for environmental trauma or noise induced loss which is prolonged exposure to excessive noise in the environment or at the workplace. We see this type of loss with people who, over the span of a career, have spent time with excessive exposure to noise such as an ambulance driver, a construction worker working on for example, a pile driving piece of equipment, an aircraft mechanic or engineer ( jet engine noise), a machine shop operator or perhaps a plant manager of a sewing machine facility or weaving or textile plant etc.. Generally, noise induced losses occur over a prolonged period of time of exposure and then oftentimes they evidence the symptoms of loss well after the damage has been done.
- Lesions: Lesions would include conditions such as acoustic neuromas. These are pathologies within the inner ear or along the nerve passageways to the brain. This category could also include trauma to the oval window impacting the fluid filled cochlea or organ of corti which is in the inner ear.
- Heredity: This cause of sensorineural loss obviously includes a family history of sensorineural hearing loss and genetic implications.