New hearing aid uses lasers, direct eardrum stimulation

Hearing aids have been around since the very end of the 1800s, but surely none of the first users imaged that the devices would eventually use lasers. On September 29, 2015, the FDA approved a new type of hearing aid for marketing that combines laser pulses and direct eardrum stimulation to amplify sound. The EarLens Contact Hearing Device™ (CHD) has received an indication for use in adults with mild to severe hearing impairment.

How does it work?

This device depends on two different parts working in unison. A tympanic membrane transducer (TMT) is placed on the eardrum (non-surgically) while an audio processor sits on the outer ear. The audio processor is connected to an ear tip containing a laser diode, which is placed into the ear canal. When the behind-the-ear (BTE) processor receives external sound waves, it converts them to low electronic signals that are sent to the ear tip. The signals are converted to pulses of light, which shine onto the TMT’s photodetector. The photodetector converts the light back into electronic signals and then transmits the sound vibrations onto the ear drum.

How is it different?

There are already multiple types of hearing aids. Some sit in the ear (ITE), some in the canal (ITC) and some behind the ear.  Older analog hearing aids simply amplified sounds, and some users struggled with them because all sounds were equally amplified by the device’s microphone. Some of these aids are programmable to hold separate settings for various environments, but they are not as sensitive to sounds as digital aids. Digital aids contain a chip that analyzes sounds based on the environment and user’s degree of hearing loss. The microphone amplifies sounds with an adjustment for volume and pitch, as well as feedback.

The EarLens, by contrast, is custom molded to the eardrum. The sounds are amplified by direct stimulation of the eardrum. The FDA believes that this is a new option for amplifying sounds over many frequencies.

Safety and effectiveness

The EarLens was studied over a four-month period for safety and effectiveness. The trials assessed residual hearing stability, amplification gain, and improved word recognition. Users’ ability to hear sentences in background noise with the device was compared to listening without any amplification. After a month of using the device, the 48 subjects experienced word recognition improvement by about a third. They also experienced a significant functional gain in the high frequency range. A maximum of 68 decibels was gained in the 9000-10,000 Hz range, which the FDA notes is not usually achieved with conventional hearing aids. There were some ear canal abrasions experienced, mainly due to the ear tip or forming the impressions. However, no serious adverse events were reported.

Who pays?

Medicare does not cover routine hearing exams or hearing aids. Part B will cover some diagnostic hearing exams if a doctor order these tests (20 percent of the Medicare-approved amount, along with the Part B deductible). Some Medicare Advantage plans may have some sort of hearing coverage. Only a few private insurance companies cover hearing aids, although three states (Arkansas, New Hampshire, and Rhode Island) require coverage for adults. This can be a problem for patients who suffer hearing loss, as prices can range up to thousands of dollars for one aid.

A House bill was introduced in March 2015 (H.R. 1653) proposing to repeal the Medicare hearing aid exclusion. After it was introduced, the Government Accountability Office (GAO) was instructed to study financial aid programs for hearing aids, as well as related examinations for patients suffering hearing loss.