Lasers have been in the news in recent years for many medical innovations. Truly, lasers are almost becoming ubiquitous in medical care; everything from eye surgery to spinal surgery to cancer treatment and even cosmetic procedures are taking advantage of the laser’s unique capabilities. And now, for the first time ever, lasers have begun to be used in hearing aids.
The U.S. Food and Drug Administration has just approved the marketing of a new hearing aid called the EarLense Contact Hearing Device that uses a laser diode and direct vibration of the eardrum to amplify sound.
Scientists have known for years that it is possible to “hear” light. In a phenomenon known as the optoacoustic effect, which was discovered by Alexander Graham Bell over a century ago, when certain types of light strike a surface some of the photons are absorbed and their energy is transformed into sound-generating waves. It wasn’t until around 2005, however, that scientists began to look at the ways in which the optoacoustic effect could be used in hearing aids.
In recently concluded clinical trials, 48 patients at four U.S. locations were approved for enrollment and use of the new laser-based hearing technology. One of the criteria for enrollment was that, in order to gauge the difference in patient experience between the two kinds of devices, patients must have previously used an air-conduction hearing aid. Researchers examined both the safety and effectiveness of the laser-based hearing aids at 30 days and again at four months, and found no significant contraindications. As a result, the FDA gave the green light to the sale of the new technology, approving it for adults with mild to severe sensorineural hearing loss.
Here’s how it works. The EarLense Contact Hearing Device has two parts: First, a tympanic membrane transducer (TMT) is placed directly on the eardrum in a non-surgical procedure. Second, a behind-the-ear (BTE) audio processor connects to an ear tip in the ear canal.
When the BTE processor receives the sound waves, it then converts them into to electronic signals, digitally processes them, amplifies them, and sends them to the ear tip. The ear tip is where the laser diode resides. Through the use of the laser diode, those electronic signals are converted to pulses of non-visible, infrared light. Those pulses then shine on to a photodetector in the TMT. At that point the light pulses are converted back into electronic signals which vibrate the eardrum directly.
Although the technology is only approved as of yet for adults with sensorineural hearing loss, which might sound limiting at first, that is not the case. As a matter of fact, more than 90 percent of those who wear hearing aids have sensorineural hearing loss, meaning this new laser technology could have a significant impact. Sensorineural hearing loss is a type of hearing loss in which the cause lies in the inner ear, based on dysfunction or damage to the cochlea, vestibulocochlear nerve or auditory processing centers in the brain. It may be genetic, congenital, noise-induced or age-related. The cause is sometimes not able to be determined, and it is usually permanent and irreversible.
Traditional hearing aids work like tiny speakers that increase the volume on air-conducted sound. Because they are far from the eardrum, they have the same drawbacks as any type of speakers. Distortion, disruptive feedback and poor speech to noise ratio are all problems that traditional hearing aids haven’t yet fully solved. They also struggle to clearly transmit sound in the higher frequency ranges, which is where many of the important consonant sounds lie. The laser hearing aids address these issues, which is why the new technology is being hailed as potentially life-changing for millions of those with hearing loss.
“For the millions of Americans with hearing impairment, hearing aids can significantly improve regular daily communications, as well as overall quality of life,” said William Maisel, M.D., M.P.H., deputy director for science and chief scientist in the FDA’s Center for Devices and Radiological Health. “People with hearing impairment now have a new option that may help improve their hearing by amplifying sounds over a broad spectrum of frequencies.”
Even before coming on board with the company in 2013, EarLense chairman, president and CEO William Facteau knew the cutting-edge technology was different from anything else on the market. “What really attracted me to it were a number of things. It is truly proprietary and differentiated; all the other hearing aids generally use air,” he said. The company has already set its sights on improvements to the device, which will include not only cosmetic changes, but improvements in battery efficiency (the goal is 18 hours with a rechargeable battery) and the addition of audio streaming for the iPhone via low-energy Bluetooth technology.
So could laser technology revolutionize the hearing aid industry? Facteau thinks so. “We believe this could be a real game-changer for hearing-impaired individuals,” he said.