3 Hearing Loss Types: Series from Maryville University

Disabling hearing loss affects 5% of the world’s population — 466 million people, more than the population of the U.S. — and the World Health Organization (WHO) expects that figure to nearly double by 2050.

Hearing loss types differ according to their causes. The three hearing loss types are sensorineural hearing loss (SNHL), conductive hearing loss, and mixed hearing loss.

The effects of hearing loss go beyond difficulty with hearing, affecting everything from how people interact to financial demands on individuals and society.

Because hearing loss can have such far-reaching effects, individuals experiencing hearing loss should seek medical attention as soon as they notice a problem. While many types of hearing loss are irreversible, healthcare professionals can help those experiencing hearing loss to improve their hearing.

The three hearing loss types

Hearing occurs when sound waves enter the ear, move through the auditory canal — the passageway from the outer ear — and hit the eardrum, causing it to vibrate. Those vibrations pass to the ossicles, three bones in the middle ear, which amplify the vibrations.

Hair-like cells in the cochlea, an organ that spirals in the inner ear, pick up the vibrations, sending them through the auditory nerve, or cochlear nerve, to the brain. Individuals with normally functioning hearing interpret these vibrations as sound.

Problems with this process can cause hearing loss. Interruptions in the process also can cause deafness or profound deafness.

Hearing loss results in the inability to hear at normal hearing thresholds, 25 decibels or better in both ears, according to the WHO. A whisper is 30 decibels. The WHO defines disabling hearing loss as the inability to hear sounds at 40 decibels in the better hearing ear in adults and 30 decibels in the better ear in children.

About a third of people between 65 and 75 in the U.S. experience hearing loss, according to the Mayo Clinic, and about one in two individuals over the age of 75 have hearing loss.

Those struggling with hearing loss may be experiencing any of three hearing loss types: sensorineural hearing loss, conductive hearing loss, or mixed hearing loss.

Sensorineural hearing loss

Sensorineural hearing loss (SNHL) is the result of damage to the inner ear’s structures or auditory nerve. SNHL is the most common type of hearing loss.

Conductive hearing loss

Conductive hearing loss occurs when something prevents sounds from penetrating the outer and middle ear. Medicine or surgery often can treat conductive hearing loss.

Mixed hearing loss

Mixed hearing loss is a rare condition caused by a combination of issues related to SNHL and conductive hearing loss. Sometimes individuals experiencing SNHL later also develop conductive hearing loss issues.