For many people with mild to severe hearing loss, hearing aids can help, but which type is best? An audiologist can guide you to a hearing aid that balances your budget and lifestyle. There’s no need to have costly features you don’t need. If you’re concerned about your hearing, schedule a hearing test to learn more.

WHO (the World Health Organization) estimates 1.5 billion people have hearing loss, with that number rising to 2.5 billion by 2050. Writing for livescience.com Sarah Wild explores the history of hearing aids from ear trumpets and vacuum tube models in the nineteenth century to the digital technologies available today. She explains the confusing terms you’ll encounter in your hearing aid search. Wild is an award-winning South African science journalist. You can read her report [here].

There are three primary types of hearing loss, depending on which part of the ear is damaged, according to the American Speech-Language-Hearing Association. The first is conductive hearing loss, in which sound waves cannot reach the inner ear due to fluid, infection, objects or physical damage blocking the ear canal. Sensorineural hearing loss, the second type, occurs when the inner ear itself is hurt by overly loud sounds, drugs, aging, illness or nerve damage. Mixed hearing loss, which is a mixture of the two, is the third type.

Hearing aids are best suited to assist people who have sustained damage to the small sensory cells in their inner ear, called hair cells, said the U.S. National Institute on Deafness and Other Communication Disorders (NIDCD). This is a form of sensorineural hearing loss caused by disease, aging, noise-related injury or certain medicines.

“A hearing aid magnifies sound vibrations entering the ear,” said the NIDCD. “Surviving hair cells detect the larger vibrations and convert them into neural signals that are passed along to the brain. The greater the damage to a person’s hair cells, the more severe the hearing loss and the greater the hearing aid amplification needed to make up the difference.” However, there are limits to how much a hearing aid can magnify sounds, and the hair cells can be too damaged to pick up sounds, no matter how loud they are.