The better to hear you with

Cochlear implants, in addition to conventional hearing aids, are increasingly supplied by the government and health funds to the severely deaf.

By
July 26, 2015 02:27
CONVERSATIONS ARE easier when hearing disabled have a cochlear implant

CONVERSATIONS ARE easier when hearing disabled have a cochlear implant. (photo credit: MED-EL)

Thirty years after the US Food and Drug Administration first approved cochlear implants for adults and 25 years after they were approved for children, more people are taking advantage of the fact that they are included in the basket of services for age groups most likely to need them. There was a small gap in time before the first cochlear implant was performed on Israeli adults, in 1989, at Sheba Medical Center, and in 1991 on children. At present, there are about 300,000 people around the world, and thousands of Israelis – more than half of them children – who have undergone such surgery.

Dr. Yael Henkin, head of the hearing, speech and language center and communication disorders services at Sheba in Tel Hashomer, recalls well the first, pioneering operation at her hospital. A senior lecturer at the department of communication disorders at Tel Aviv University’s Sackler Faculty of Medicine, Henkin has spent most of her professional life researching hearing disorders and treating patients.

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The Tel Aviv-born communications disorders specialist earned all her three academic degrees in communications disorders at TAU, doing her doctorate on auditory cortical neurophysiology and her post-doctoral studies at the University of Michigan.

The implant is an electronic device that restores at least partial hearing to individuals with severe to profound hearing loss who do not benefit from a conventional hearing aid. Implants provide stimulation directly to the auditory nerve, bypassing damaged hair cells in the cochlea that prevent sound from reaching the nerve. The operation does not result in completely restored hearing for the recipient, but it does enable in most cases to perceive sound and speech.

When children or adults lose their hearing after they have acquired language and speech, the perception of speech and sounds after implantation may at first seem quite different from what they remember. After using the cochlear implant for several months or more, they often say they perceive speech to be more natural or closer to their memory of familiar sounds. In general, the younger a child born deaf is implanted, the greater the benefit achieved in speech perception and language development. Children who are born deaf have limited hearing input; they suffer from auditory deprivation.

Most adults suffer from post-lingual hearing loss. “They heard all their lives but suffered trauma or disease in addition to the expected age-related hearing loss. When the benefits provided by hearing aids are not enough, and significant deterioration of speech understanding takes place, a cochlear implant is the solution, Henkin said.

Aside from age or trauma, there are people who suddenly lose their hearing in one ear due to infection, vascular or autoimmune problems. They should rush to the nearest hospital when this happens, as oral or injected steroids can restore the hearing in some cases.

As for adults who get implants, the length of time between the onset of deafness and implantation is a key factor, as those with the shortest period of deafness tend to have better outcomes.

Recipients of implants don’t hear immediately after the operation. “There are acoustical features like changes in frequencies that are important cues for speech understanding that the implants don’t transmit. Speech is therefore degraded and is especially difficult to understand in the presence of background noise. While most patients complain that music is not enjoyable after implantation, they can converse over the phone,” said Henkin.

THE FIRST to benefit from implants were children, who were initially entitled by the basket of health services to a device for one ear, she recalled in an interview with The Jerusalem Post. “Today, they can receive two implants – including the surgery and the rehabilitation and follow-up, which is very intensive during the first year but then less frequent, even though it is really lifelong.”

It took somewhat longer for the basket – which the health funds supply their members with Health Ministry funding – to include implants for adults. “Ideally, an adult with bilateral severe or profound deafness thatand cannot hear well enough with conventional hearing aids, should receive two cochlear implants , but this has not yet been approved.”

Implants are performed today in 10 different Israeli hospitals. Cochlear implant centers programs performing implants are interdisciplinary, requiring surgeons, audiologists, speech-language pathologists, psychologists, social workers and teachers to be on the staff. Hearing loss occurs when the hair cells in the inner ear that vibrate and transmit signals to the auditory nerves leading to the brain are destroyed or don’t exist at all. Cochlear implants bypass the damaged or missing hair cells and convert speech and environmental sounds into electrical signals sent directly to the auditory nerve.

The electronic devices consist of two main components. The first is a small electronic device connected to electrodes inserted into the cochlea (shell-shaped auditory portion of the inner ear). It is inserted under general anesthesia under the skin behind the ear.

The second is external, worn behind the ear, and contains a speech processor, microphone and battery compartment. The microphone captures sound, allowing the speech processor to translate it into distinctive electrical signals. These signals are transmitted across the skin via radio waves to the internal electronic stimulator. The internal stimulator then sends the signals to the electrodes implanted in the cochlea.

The electrodes stimulate the auditory nerve fibers to send information to the brain, where it is interpreted as meaningful sound.

There are varied solutions for all kinds of hearing disabilities, Henkin continued.

“Sheba offers the entire range of hearing solutions, including: hearing aids, CROS systems, FM systems, bone-anchored hearing aids, middle-ear implants and cochlear implants.”

Hearing aids, which are state subsidized, can be replaced every three years in children and every four years in adults. As for implants, users undergo at least two implants in a lifetime because they wear out, and become more advanced. “The companies give a 10-year guarantee on a cochlear implant, while the health funds provide new internal parts if they fail,” Henkin said.

While profoundly deaf Israelis are much better off than deaf individuals in countries that don’t pay for cochlear implants or even hearing aids, the Health Ministry does not have a budget for implants when adults and children are deaf on only one side. “Some think that hearing in one ear is enough, however, current evidence shows that especially in children, hearing with one ear has significant negative implications on development of speech, language, and communication skills,” said Henkin, who just returned from a week-long conference on cochlear implants in California. But she is well aware that there are legitimate priorities in the health system.

An implant, surgery and rehabilitation costs some $20,000, but studies have proven that the procedure is cost effective, as it turns hearing-disabled people into well-functioning children and tax-paying individuals who don’t need assistance.

THERE ARE also countries even more advanced that Israel in the provision of hearing aids. “I visited Scandinavia and saw that the state provides devices to the whole population that need them – and they are the best, most advanced available,” said Henkin.

“Audiological services and devices offered in Israel are advanced and state-of-the-art. However, only children (under 18 years) and older adults (over 65) may purchase them in a subsidized price. The others get less help unless they are recognized by the National Insurance Institute as being hearing impaired.

They get a disability payment, but not all adults with hearing problems receive them,” she pointed out.

There is, said Henkin, a small (and shrinking) number of families or individuals who turn down cochlear implants to which they are entitled.

“In the past, there were parents didn’t want to hear about such intervention. I remember years ago that I went to a cochlear implant conference in Washington, DC, and parents of hearing-impaired children demonstrated outside against the implants,” recalled Henkin. “Increasingly, deaf parents who use sign language want their children to have devices.”

Cochlear implants have been supplied here even to Palestinian children in Gaza. “There were years that we in Sheba worked with the Peres Peace Center, which subsidized implants for children, but the budget for this [has] declined since. Some Gaza children are treated in eastern Jerusalem hospitals that get donations from implant companies and foreign donors.”

SHEBA WAS the first hospital in the country to perform universal screening tests on newborn babies for hearing problems. In 1997, it pioneered the practice of universal screening of all babies soon after birth. “The Health Ministry accepted our model in 2010, and now all newborns undergo mandatory screening.” Since then, nearly 1,000 children and adults have received implants at the Tel Hashomer medical center.

This is important, she adds, because it identifies possible hearing problems very early so they can be treated early. Infants and toddlers who have hearing aids or, if necessary, cochlear implants will develop language much more easily.“There is a window of opportunity in children; if they get an implant after their fourth birthday, the benefits will be limited.”

Both researchers and commercial cochlear implant companies around the world are developing better, more-sensitive and smaller devices. The first ones were larger, more obtrusive and less effective, but today they are smaller and more sensitive.

DR. RONEN Perez, head of the otology unit in the ear, nose and throat (ENT) and head-neck surgery department (directed by Prof. Jean Yves Sichel) in Jerusalem’s Shaare Zedek Medical Center, is a surgeon who actually conducts the cochlear implantation operations.

The implant center performs about 40 annually in patients of all ages; 75% of them are babies or children. The department began two decades ago as a small unit, but since then, it grew and developed over time, reaching its current scope – a full-fledged department with experts in all ENT fields, including complex, innovative operations.

The Shaare Zedek cochlear implant center specializes in complex and challenging cochlear implantation cases. These include patients with anatomical malformations of the cochlea and temporal bone, patients deafened from meningitis with an ossified blocked cochlea and revision surgeries. In all these cases, there is an increased risk that the electrode array may be improperly positioned in the cochlea or outside of it. In the malformation cases, real-time imaging (fluoroscopy) is used during the surgery to verify that electrodes are inserted into the right place.

“Implant devices used to be clumsy and large with only one electrode. Today, they are smaller and have 12 to 22 electrodes for more sensitivity. One has to modulate them to determine which electrode stimulates which nerve fiber,” Perez explained. More sophisticated devices are sometimes implanted over time to replace old ones. The devices were originally invented by teams in the US, Australia, France and Austria.

The operation usually takes about 90 minutes.

The newer implants are waterproof, but patients usually remove the external part when they shower or swim. Infections, said the ENT specialist, are rare.

His patients represent the diverse population in Israel. Among them are Orthodox Jews, new immigrants from North America and Arab children whose parents are consanguineous (first cousins who marry) and pass down genetic diseases including those involving hearing loss.

As for the possibility of completely curing deafness (which cochlear implants don’t do) by regenerating damaged hair cells, Henkin and Perez both conclude that it will take years to do this. “In the beginning, there was a lot of too-optimistic talk about this, but since then it has declined.”


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