How hearing works and how it fails & Common causes across life
Lesson 1 · 5 min
Based on MedlinePlus en español — Hearing Loss. Original educational summary, read by a medical doctor and confirmed reliable, pending formal approval. Not medical advice.
Learning objectives
- Explain how hearing works and how it fails.
- Explain common causes across life.
How hearing works and how it fails
Sound waves travel through the ear canal and vibrate the eardrum and three tiny bones of the middle ear. These vibrations reach the cochlea in the inner ear, where thousands of tiny hair cells convert them into electrical signals that the auditory nerve carries to the brain. Hearing loss occurs when any part of this pathway is damaged. It is classified as conductive when sound is blocked in the outer or middle ear, sensorineural when the inner ear or nerve is damaged, or mixed when both are involved.
Common causes across life
Age-related hearing loss, called presbycusis, develops gradually as inner ear structures wear out and is one of the most common conditions of older adults. Loud noise damages hair cells permanently, whether from a single explosion or years of exposure to machinery, concerts, or headphones at high volume. Other causes include ear infections, earwax blockage, certain medicines that are toxic to the ear, head injuries, and some genetic conditions.
Key concepts
- How hearing works and how it fails
- Sound waves travel through the ear canal and vibrate the eardrum and three tiny bones of the middle ear.
- Common causes across life
- Age-related hearing loss, called presbycusis, develops gradually as inner ear structures wear out and is one of the most common conditions of older adults.
- Recognizing the signs
- Hearing loss often advances so gradually that family members notice it first.
- Evaluation and options
- A hearing test with an audiologist measures the softest sounds a person can hear at different pitches.