Auditory System

Med Device Monday: BONEBRIDGE by Med-El

Hearing loss is the third most common health problem in the U.S after heart disease and arthritis. It is estimated that about 48 million Americans have some form of hearing loss, often caused by illness, genetics, or other ear-damaging elements that come with a modern lifestyle (e.g. sporting events, airplanes, concerts, and working with heavy machinery). FDA recently granted a de novo request for the BONEBRIDGE device, manufactured by Austrian company, Med-El. BONEBRIDGE is an active bone conduction implant system, and is designed for individuals 12 years and older who have conductive hearing loss, mixed hearing loss, or single-sided deafness.

To understand who should use this device, we need to understand a little more about the types of hearing loss. Hearing loss can be categorized into 4 categories:

  • Conductive: Any problem in the outer or middle ear that prevents sound from being conducted properly.

  • Sensorineural: Hearing loss that results from missing or damaged sensory cells (hair cells) in the cochlea and is usually permanent.

  • Mixed: As the name suggests— is a combination of conductive and sensorineural hearing loss, indicating damage in both the outer or middle ear, and the inner ear.

  • Neural: Neural hearing loss results from the lack of or damage to the auditory nerve, which is a bundle of fibers that carries auditory sensory information from the cochlea to the brain.


Traditional cochlear implants help patients who have sensorineural hearing loss as they replace the functional components of the inner ear (read more about cochlear implants on our blog from May 2016)! Alternatively, BONEBRIDGE is indicated for conductive or mixed hearing loss, which means sound cannot take the natural route through the outer and middle ear to the inner ear. This makes it difficult for the hearing loss sufferer to hear soft sounds and can also lead to the muffling of louder sounds.

Image from www.medel.com/us/bonebridge

Image from www.medel.com/us/bonebridge


BONEBRIDGE transmits sound waves via bone conduction directly to the inner ear, where they are processed as natural sound. The device consists of two components: an externally worn audio processor (called SAMBA), and a surgically-inserted bone conduction implant (called the BCI 601) which lies directly beneath the skin. The audio processor is held directly above the implant using magnetic forces.

Now, let’s get into the specifics of how this device works! Initially, the microphones of the audio processor pick up the sound waves. Then, the audio processor converts those sound waves into electrical signals, which are then transmitted through the skin to the implant. The implant, which is fixed in the temporal bone, converts these electrical signals into mechanical vibrations which are transmitted to the skull. The bone then conducts these vibrations to the inner ear. Signal transmission to the inner ear via bone conduction bypasses the outer and the middle ear, solving the complication of sound’s inability to pass through the natural route that comes with conductive and mixed hearing loss. The inner ear then processes these mechanical vibrations in a way that is similar to the way natural hearing is processed, and transmits nerve signals to the auditory nerve in the brain.

The audio processor is equipped with adaptive directional microphones, which adapts to different environments and individual usage. One of the really cool things about the audio processor (not that the device isn’t already super cool) is that it automatically identifies and minimizes noise interference in situations where there is loud background noise, which can become overwhelming to people who aren’t used to those background noises. The audio processor also comes with a remote control that has wireless connectivity capabilities. Using this remote control, the users can select different programs that have various settings depending on the user’s current environment or activity.

FDA classified BONEBRIDGE under product code PFO as a Class II device with special controls. These special controls include:

1.       Clinical performance testing

2.       Non-clinical performance testing (includes impact testing, mechanical Integrity testing, etc.)

3.       Biocompatibility testing

4.       Sterility of the patient-contacting components of the device

5.       Shelf life of the device

6.       Wireless compatibility, electromagnetic compatibility, and electrical safety

7.       Software verification, validation, and hazard analysis

8.       Labeling

 

We’re so excited to see medical technology like this enter the US market!

Additional Reading:

1.       FDA Classification Order

2.       Video explaining how the BONEBRIDGE works

3.       More info about BONEBRIDGE

4.       More info about the de novo process HERE and HERE

Med Device Monday: Cochlear Implants

I realize the past few Med Device Mondays have focused on devices that help people regain one of their lost or compromised senses, but after something I witnessed recently, I hope you won't mind one more!

Last week I took my car to the car wash for a much-needed cleaning. While waiting for my car, a mother and her young daughter came and sat down on the bench next to me. The girl was no more than four years old, and full of energy and joy. She saw their car emerge from the tunnel and bolted towards it, laughing with excitement as she did.  The mother looked up just in time and yelled after her to "STOP!", since the car was still in motion. The car was moving slowly enough but the girl was on a collision course that would certainly lead to a bruise and some major tears. However, as soon as she heard her mother, the girl froze at the edge of the curb. She turned, smiled demurely at her mother, and returned to the bench for a hug. It was as she walked back towards us that I noticed the girl had cochlear implants behind each ear. The fact that she heard her mother, and that they now chatted to one another sweetly, was a touching and powerful moment to me: as a mother, a neuroscientist, and a regulatory consultant. 

Cochlear implants are FDA regulated and serve as an example of medical devices at their finest. You may have seen the tear-jerker videos on Facebook: a woman hears her husband's voice for the first time. A baby hears its mother's voice for the first time. A person hears their own voice for the first time. These implants are able to assist the profoundly deaf, for whom hearing aids aren't enough. So how do they work? I'll let FDA explain: 

"A cochlear implant is an implanted electronic hearing device, designed to produce useful hearing sensations to a person with severe to profound nerve deafness by electrically stimulating nerves inside the inner ear.

These implants usually consist of 2 main components:

  • The externally worn microphone, sound processor and transmitter system.
  • The implanted receiver and electrode system, which contains the electronic circuits that receive signals from the external system and send electrical currents to the inner ear.

Currently made devices have a magnet that holds the external system in place next to the implanted internal system. The external system may be worn entirely behind the ear or its parts may be worn in a pocket, belt pouch, or harness.

...A cochlear implant receives sound from the outside environment, processes it, and sends small electric currents near the auditory nerve. These electric currents activate the nerve, which then sends a signal to the brain. The brain learns to recognize this signal and the person experiences this as "hearing"."

Read more from FDA about cochlear implants here, and enjoy the videos of cochlear implants changing lives below! (And maybe fall down a YouTube rabbit hole of these videos, as I did.)

A man films his wife as she hears for the first time in years. 

Sarah Churman getting her first device in (click HERE to see her get her second device in). 

Learn about Aria and AB, one of the companies that manufactures these devices: