Soon it might be possible to have an operation done on one’s ears to restore hearing. It will not, however, involve a laser, as with LASIK. The process will involve attempting to regrow the hair cells located in the cochlea’s Corti. Thus far, such regeneration is only common in birds, reptiles, fish, and amphibians. Mammals are incapable of doing this, so when hair cells die from exposure to loud noise, ageing, or the use of antibiotics; we get cochlear implants or similar hearing devices.

The auditory hair cells are important because they convert vibrations into nerve impulses. When these hairs die, sensorineural hearing loss and balance disorders occur. Animals’ new hair cells grow up from a layer of supporting cells underneath the auditory hair cells. These supporting cells divide and sub-divide until the full complement of hairs is reached. Their hearing is restored to what it was like before. To achieve the same results in humans, laboratories are researching which genes can be manipulated to stimulate re-growth. Someday soon, hearing aids and cochlear implants might no longer be needed.

This type of research has been happening since the late ‘80s, when they discovered birds’ damaged hair cells are spontaneously regenerated. This research has been speeding up recently with the first successfully cultured human eardrum cells. These drums, made from human tympanic membrane tissue gathered from an autopsy, were grown over a scaffold of specially formulated silk. These replicated the human eardrum’s fibrous structure and have the same vibrating abilities. With new surgical procedures, these regenerated eardrums could be implanted successfully.

Researchers at various laboratories will soon start with tests to determine whether the scaffold material is compatible with animals. Within a few years, researchers hope to conduct these same tests in humans. If these tests are successful, they could give a new alternative to millions of hard of hearing people, especially those who might be self-conscious about wearing hearing aids.

About 90 per cent of deafness cases involve damage to the hair cells. It is also hoped that within the next ten years this possible new procedure might prevent these hair cells from dying.

The human ear is a complex but phenomenal sound system, capable of detecting the smallest sounds at an incredibly wide range of intensity and frequency. The structure of the ear can be divided into three major parts, namely the outer ear, or pinna, the middle ear and the inner ear.

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The pinna is responsible for helping to place the location of a sound. It acts as a sound collector and helps channels sound down the ear canal. The outer ear collects sound vibrations, which in turn causes movement of the eardrum. The eardrum is connected to three tiny bones, or ossicles, the malleus, incus and stapes (or hammer, anvil and stirrup).

The middle ear serves to intensify the energy of the sound vibrations and deliver them to the cochlea (inner ear). Inside the cochlea are thousands of tiny hair-like cells connected to the fibers of the hearing nerve. These hairs are sensitive to different frequencies of sound.

Sound vibrations enter the cochlea and cause sound waves to travel through the ear. This causes the basilar membrane to which the hair cells are attached to move. The hair cells then trigger electrochemical signals which travel through the acoustic nerve to the brain where they are recognised as sounds.

A nanobiomaterials company based in Oklahoma, NanoBioMagnetics, Inc, has received a patent to implant nanoparticles in hard of hearing patients’ middle ears. These particles will help the ear to become more responsive to sound vibrations and should allow hearing aids to become smaller. NBMI’s technology may be the first to demonstrate nanochemical tissue movement. It detects sound waves, processes the signals and uses these signals to stimulate an electromagnetic coil, which then transmits a signal that causes the nanoparticles to vibrate. This amplifies the sound and should act much the same as a commercially available electromagnetic hearing aid. The 28 million Americans suffering from hearing loss will eventually benefit from more improved hearing aid devices

The co-inventor of the ‘Method and Apparatus for Improving Hearing’ patent, Charles Seeney, believes that, as “part of an emerging trend” these hearing devices will become smaller. The company started researching and developing this technology between 2002 and 2004 and NBMI plans to find commercial partners for the patent.

Mr Seeney, who is also the CEO and founder of NBMI, revealed that his company is working on a companion hearing aid technology, which is based on sending bioactive materials to the middle ear. Besides their focus on improving hearing, there are various other research projects underway at the M D Anderson Cancer Center in Houston. One of these projects tries to assess the tumor-specific delivery of cancer therapeutics.

The University of Oklahoma and the Massachusetts Eye and Ear Infirmary, an affiliate of Harvard Medical School, played a big role in the development of NBMI’s technology, which is viewed as Oklahoma’s first nanotechnology-based patent for a health-care application.

Many hard of hearing people would prefer to go without normal hearing aids. These people may participate in swimming and fear the water will harm the device. Or there might be worries about the device’s ease of use while sleeping.

Otologics has developed a new kind of hearing aid that will overcome these problems. The device is implanted in the user’s middle ear and uses a microphone to pick up sound signals, which are then processed by electronics. From there, it is sent to a piston against the small bones in the middle ear, which then transmits the vibrations to the inner ear. The inner ear encodes these vibrations as nerve impulses and sends the information to the brain. This method works because it sends sound directly to the cochlea.

This means a chance at a normal life for hard of hearing people. “You can be exposed to environments in which hearing aids have difficulty operating properly”, says Otologics’ CEO José Bedoya.

The challenge in manufacturing a device to implant is to design one that works well under the skin. Mr Bedoya explained that human skin changes throughout the day due to hydration levels and other factors.

The device charges by putting the charger coil on the spot where the implant was made. The average charging time is about one hour each day and the wearer can carry on with normal activities while it charges. The battery lasts for at least five years, after which it needs replacing. The components are sealed together to protect against leaks, so everything except the piston would have to be replaced.

The hearing aid’s phase I clinical trial in 2007 implanted aids into twenty subjects’, who all had moderate to severe hearing loss. The subjects all had slightly worse hearing than with their old hearing aids for the duration of the study, but their satisfaction levels were up. Even though their word-recognition scores dropped by 20 per cent, they felt that the device improved their hearing by making it sound more natural.

There are experts who doubt whether Otologics’ implant is a big improvement. The cost may be prohibitively high. The cost is $19,000 in Europe for the implant alone, while it costs $6,000 for a high-end conventional aid. This implantation device is still in clinical trials in the United States. Another critic, Gerald Loeb, who is a professor of biomedical engineering at the University of Southern California, would prefer implanted hearing aids to outperform conventional ones. Only then, he reckons, would they be worth the extra cost and risk.

He asked an important question: “How big an issue is it to have a little appliance on your ear when the whole world is walking around with cell-phone headsets and iPod earpieces?”

Other experts see great progress being made in implantable microphone design. Joseph Roberson, who is an ear surgeon and the CEO of the California Ear Institute, says, “I listened to a good-fidelity musical signal received by an implantable microphone positioned under half an inch of raw steak.” The functional outcome of the Otologics device, he says, is “roughly equivalent to existing visible external technology.”

However, the phase I study revealed that the Otologics hearing aid technology “serves as a viable treatment alternative for moderate to severe sensorineural hearing loss.” Bedova’s company is addressing the problems found and is preparing for phase II trials. The second trial will test 90 subjects with a revised device.

It seems ‘alpha adopters’ may be the ones most suited to this type of device. Roberson thinks they “are motivated to keep their use of a hearing device a private matter, or those who are intolerant of standard hearing-aid technology.”