- In the Outer Ear: Ear wax build-up, infections that cause swelling, a growth in the ear canal, injury or birth defects can restrict hearing in the outer ear.
- In the Middle Ear: Fluid build-up is responsible for the most common infections in the middle ear. Fluid in the middle ear prevents the bones from processing sounds properly. Tumors, both benign and malignant, can also result in hearing loss in the middle ear.
- In the Inner Ear: Aging effects and long-term noise exposure cause damage to the cochlea (hearing organ), vestibular labyrinth (which regulates balance), or the auditory nerve (nerve that sends sound signals to the brain).
Other causes of hearing loss include:
- Presbycusis: age-related hearing loss, such as having difficulty hearing in noisy places, having trouble understanding what people are saying or not registering softer sounds.
- Meniere’s Disease: an inner ear disorder that causes hearing loss, vertigo/dizziness and sometimes ringing.
- Heredity and Genetic Causes: many diseases and syndromes that are either genetic or hereditary can cause hearing loss. Some, like rubella (German measles) occur when a pregnant mother has the disease, which causes hearing loss in the baby. Other, rarer types of hereditary and genetic causes include CHARGE Syndrome, Connexin 26 disorder, Goldenhar Syndrome,Treacher Collins Syndrome, Usher Syndrome, and Waardenburg Syndrome.
- Otosclerosis: a hereditary disorder caused by growth of spongy bone tissue in the middle ear. This results in abnormal sound transmission through the middle ear bones causing muffled hearing.
- Cholesteatoma: a benign growth starting in the middle ear that erodes bone and the eardrum.