How do we hear sounds?
Before getting into the details of hearing through bone conduction and the use of bone conduction headphones for tinnitus, let’s first review how we as humans hear sounds:
- Sound waves, which are vibrations, enter the outer ear and travel through the ear canal to the middle ear, where the eardrum is located
- The sound waves hitting the eardrum cause the eardrum to vibrate. This in turn sends vibrations to three tiny bones in the middle ear called the malleus, incus, and stapes
- The three bones of the middle ear then increase the vibrations further and send them to the cochlea (the spiral-shaped structure filled with fluid) in the inner ear
- Vibrations cause the fluid inside the cochlea to move, which creates a traveling wave against the basilar membrane (an elastic outer covering that runs from the beginning to the end of the cochlea)
- Hair cells (sensory cells on the basilar membrane) are then set in motion. Those near the wide end of the cochlea detect higher-pitched sounds, while those towards the center detect lower-pitched sounds
- Movement of the hair cells triggers the opening of nearby pores that causes chemicals to rush into the cells and create an electrical signal
- The auditory nerve carries the electrical signal to the brain, which processes it as a sound that we recognize and understand
How do we hear sounds through bone conduction?
While we normally hear sound through vibrations against the eardrum, in bone conduction, sound waves vibrate on the bones of the head and jaw, bypassing the eardrum and transmitting the sound directly to the inner ear.
Bone conduction headphones do not cover the ears, and therefore, allow the wearer to still hear the sound of their environment and the sound of their own voice.
Many report the following practical uses for bone conduction headphones:
- Can maintain awareness of surroundings (eg, listening for traffic)
- Can still hear while having a conversation
- Avoids damaging, high sound levels of standard headphones
- Can be worn with hearing aids
- Since they don’t rely on the eardrum, make good headphone options for individuals with hearing loss (which usually results from damage to the eardrum)
- Can be used as a method for masking tinnitus
How might bone conduction headphones help with tinnitus?
One method of tinnitus treatment is to use sound masking devices that produce music, white noise, pink noise, or ambient sounds to distract from or cover tinnitus sounds.
Bone conduction headphones can be used as tinnitus maskers for those who find tinnitus relief with environmental/ambient sounds, music, or speech (eg, podcasts).
Furthermore, many tinnitus sufferers report that, since standard headphones generally block external noise, wearing them can make tinnitus sounds seem louder. Standard in-ear headphones can also worsen hearing loss and tinnitus. Using bone conduction headphones on the other hand, would likely remedy these issues as they leave the ears free and unblocked.
As every person’s experience with and causality of tinnitus is different, it is always a good idea to speak with your healthcare provider who is treating you for tinnitus about using bone conduction headphones.
- National Institute on Deafness and Other Communication Disorders (NIDCD). How Do We Hear? https://www.nidcd.nih.gov/health/how-do-we-hear. Updated January 2018. Accessed June 2020.
- Manning C, et al. The Effect of Sensorineural Hearing Loss and Tinnitus on Speech Recognition Over Air and Bone Conduction Military Communications Headsets. Hearing Research. 2017;349:67-75.
- Dauman R. Bone conduction: An Explanation for this Phenomenon Comprising Complex Mechanisms. Eur Ann Otorhinolaryngol Head Neck Dis. 2013;130(4):209-213.
- U.S. Department of Veterans Affairs. How to Manage Your Tinnitus: A Step-by-step Workbook. https://www.ncrar.research.va.gov/Education/Documents/TinnitusDocuments/HowToManageYourTinnitus.pdf. Accessed June 2020.
Images courtesy of Visual Hunt.