Tech Page: Lord of the Ringing

Jul 1, 2008 12:00 PM, By Scott Wilkinson

           
 

FIG. 1: The Neuromonics tinnitus treatment relies on a small, portable device that plays customized noise and music to mask the symptoms of tinnitus. The audio signal is programmed by an audiologist or physician according to the patient’s hearing profile.
Photo: Courtesy Neuromonics, Inc.

Among the maladies to which electronic musicians are especially susceptible, hearing damage caused by prolonged exposure to loud sounds is perhaps the most pernicious. When you're young, you normally don't think about the consequences of cranking the amps to 11, but if you do that routinely, you are sure to suffer some form of hearing deficit in your later — or, in some cases, not so later — years.

One of the most common problems that arise from overexposure to loud sounds is called tinnitus (pronounced TIN-ni-tus or tin-NIGHT-us), which is usually described as a ringing in the ears. It can manifest as one or more steady frequencies, hissing, and/or clicking (see Web Clip 1), but these sounds are not being perceived from the outside world. Instead, they are generated within the auditory system. In some cases, the effects are temporary, but for some 12 million Americans, the sounds are a permanent accompaniment to every waking moment, and can range from merely annoying to completely debilitating.

The condition remains mysterious and there is no cure, but recent research has shed some light on its underlying causes. It now seems clear that overexposure to loud sounds, certain kinds of chemotherapy, head and neck trauma, and multiple sclerosis can actually change the activity level of the auditory nerves. This change is then interpreted by the auditory cortex of the brain, which leads the individual to perceive sounds. One theory suggests that tinnitus is the brain's compensation for hearing loss.

To make matters worse, your natural perceptual filters, which normally allow you to focus on one thing while ignoring other stimuli, tend to assign an increasing importance to the “sounds” of tinnitus, constantly bringing them to your attention. This, in turn, raises your level of stress and anxiety, which leads to even more auditory sensitivity and awareness, resulting in a vicious cycle.

Because tinnitus occurs deep within the brain, treating it effectively can be very difficult. However, a company called Neuromonics (neuromonics.com) has developed a new treatment that shows great promise.

Based on the principle of neural plasticity (the brain's ability to form new neural pathways), the Neuromonics system uses an iPod-like device (see Fig. 1) to deliver broadband noise with a frequency and intensity spectrum that's tailored specifically to each user's hearing profile. This is intended to reduce the neural sensitivity that starts the vicious cycle. In addition to the noise component, relaxing music is added to reduce the stress and anxiety caused by tinnitus.

The Neuromonics system addresses the perceptual filters by using systematic desensitization. After several months, the audio signal is adjusted so that the user is momentarily exposed to the tinnitus while in a relaxed state. As a result, the brain is retrained to pay less and less attention to it.

Initial results have been very encouraging. In one recent clinical study conducted at Curtin University of Technology in Perth, Australia, 90 percent of the subjects reported a reduction of 40 percent or more in their tinnitus-related disturbance, with a mean improvement of 65 percent. Further, significant benefits were reported after only two months. After six months, 80 percent of the subjects reported a level of disturbance that was no longer clinically significant, leading to better sleep and a higher level of general well-being.

Clearly, the best way to avoid the trauma of tinnitus is to protect your hearing in the first place. But the Neuromonics treatment could mean that sufferers might finally be able to enjoy life despite the ringing in their ears.

BONUS MATERIAL

Web Clips: Hear audio examples of Tinnitus