Tinnitus: Ringing in the Ears : Part 2

by Food and Drug Administration (FDA)

(Page 2 of 2)

Paul Guth, a pharmacologist who researches hearing and balance mechanisms at the Tulane Medical School, New Orleans, says side effects of lidocaine in tests to treat tinnitus included amnesia, slurred speech, and fainting. Guth's research has been into medications that target the hearing system. One such drug, aminooxyacetic acid (AOAA), had reached clinical trials in controlling epileptic seizures and seemed to be safe in humans. A former student, Richard Bobbin, reported to Guth he found AOAA also had a measurable effect on endocochlear potential, an electrical voltage output essential to the function of the inner ear. A reduction in the endocochlear potential reduces activity in the auditory nerve, studies showed. Bobbin reported AOAA lowered endocochlear voltage potential in laboratory animals, so Guth tested it on 70 people with tinnitus. Fourteen patients reported some relief, he found. However, 10 of those who were helped also reported side effects that led Guth to search for other drugs that also could reduce endocochlear potential.

Furosemide, a potent diuretic prescribed for people who have very severe kidney damage, also was tried on tinnitus patients. Reported side effects for kidney patients included tinnitus and transitory hearing impairment, but Guth found that when furosemide was given in reduced dosages intravenously to 37 volunteers with tinnitus, half of them reported they believed it helped, so Guth continued testing furosemide in oral doses on nine patients. Seven of the nine volunteered to continue taking the medication, an indicator that they must be getting some relief, he said.

Alprazolam (trade name Xanax), a central nervous system depressant prescribed for anxiety disorders, has been reported to have helped a small number of tinnitus patients. And it introduced another line of questioning. What is the relationship between depression and tinnitus? Is tinnitus a cause or result? Dobie's research indicates that antidepressant medications, particularly tricyclic antidepressants, have helped convert people who are suffering from tinnitus into people who are dealing with it. Dobie adds that other patients referred to him have benefited from relaxation techniques, biofeedback (conscious effort to control involuntary body functions such as breathing and heartbeat), and other forms of therapy that show them how better to live with tinnitus. Hypnotism has been tried for relief of the mental stress caused by tinnitus, but no positive results are documented.

Technology also may have some answers for tinnitus sufferers. Directing a small charge of electricity into the auditory nerve has shown some promise in silencing tinnitus. Of 20 persons tested with electrical nerve stimulation at the Washington Medical Center in Seattle, only one was helped, but that person was helped dramatically, according to Dobie.

If electrical nerve stimulation continues to show promise, surgically implanted stimulators may become a technology for the future in tinnitus treatment. Meantime, a more elementary electronic device is already helping some. It's the tinnitus masker. Using an external noise source to mask the rush, the ringing, or the roar of tinnitus has been effective for about 70 percent of the 500 people that St. Louis audiologist Hopmeier has treated for tinnitus during the past 10 years.

The principle in masking is much the same as when you realize you are no longer bothered by routine office noises, ventilator fans, or traffic sounds. Masking is based on the mind's ability to ignore external noises that become familiar or monotonous. It's easier to ignore an external sound than an internal one, Hopmeier points out.

Vernon became interested in masking in 1977 after the chance discovery by a patient that he could not hear his tinnitus when he stood near a waterfall, and that the water's sound was an acceptable and welcomed substitute for tinnitus. But the best masking sound is not the "white noise" of a waterfall, according to audiologist Hopmeier. That would interfere with the wearer's ability to understand speech, he says. So, following a hearing and perception test that Hopmeier describes as his way to determine a "sensation level," to indicate the amount of stress the person is experiencing due to his or her tinnitus, a masking device is customized that is most pleasing and helpful for the wearer.

More than 90 percent of people who come to Hopmeier with tinnitus also have some impairment to hearing that they either had not recognized or did not think was significant. Their concern had become focused on their tinnitus, he explains. Sixty percent of the tinnitus masking devices he has fitted have been combined with a hearing aid, and for some people the devices are fitted in both ears, depending on the amount of hearing loss and the patient's perception of the tinnitus' location. Dual-purpose hearing and masking devices have separate volume and on-off controls. Hopmeier says most users eventually become less dependent on the masking and more on the hearing aid, which offers a natural masking effect. The hearing aid's own amplification of voices and other sounds in the environment draws the user's attention away from his or her tinnitus, Hopmeier explains.

Some of the relief that masking gives tinnitus patients may be psychological, according to Dobie. For some tinnitus sufferers, just knowing they have their masking device available to use if they want seems to provide reassurance and relief. Dobie, Vernon and Hopmeier agree that the lack of control over this unwanted noise in their heads is the distressing aspect of tinnitus that leads most people to seek help.

Masking devices require FDA approval because they present a potential for risk of injury to the ears or long-term hearing impairment due to overstimulation from the continuous and sometimes loud masking noise. Five brands and nine models of tinnitus masking devices have approval for marketing from FDA.

James L. Parkin, a Salt Lake City otolaryngologist, observes that "tinnitus is an irritating symptom for both the patient and the physician. The patient is annoyed most by the problem during times of fatigue or anxiety. He is concerned that it indicates serious mental or physical illness. The physician is annoyed because his diagnostic efforts may not reveal a well-defined cause for the complaint."

Tinnitus. It ... happens.

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