番茄社区

CHICAGO – Tinnitus might be overcome with behavioral therapy approaches, researchers suggested here at the annual scientific sessions of the Radiological Society of North America.

In an experiment involving healthy college students subjected to artificial white noise to simulate tinnitus, most were able to use biofeedback to reduce the impact that the noise was having on their ability to perform tasks, said Matthew Sherwood, PhD, of Wright State University in Fairborn, Ohio.

For their study, the researchers had 18 healthy volunteers with normal hearing undergo five fMRI-neurofeedback training sessions. Study participants were given earplugs through which white noise could be introduced for periods of time. The earplugs also served to block out the scanner noise. To obtain functional MRI results, the researchers used single-shot echoplanar imaging, an MRI technique that is sensitive to blood oxygen levels, providing an indirect measure of brain activity.

"We started with alternating periods of sound and no sound in order to create a map of the brain and find areas that produced the highest activity during the sound phase," Dr. Sherwood said. "Then we selected the voxels that were heavily activated when sound was being played."

He explained that the experiment was based on "the idea ... that in people with tinnitus there is an over-attention drawn to the auditory cortex, making it more active than in a healthy person. Our hope is that tinnitus sufferers could use neurofeedback to divert attention away from their tinnitus and possibly make it go away."

The subjects in the study participated in a neurofeedback training phase while inside the MRI scanner. They received white noise through their earplugs and were able to view the activity in their primary auditory cortex as a bar on a screen. Participants were instructed to watch the bar during the relax period and actively attempt to lower it by decreasing primary auditory cortex activity during the lower phase.

The researchers gave the participants techniques to help them do this, such as trying to divert attention from sound to other sensations like touch and sight. "Many focused on breathing because it gave them a feeling of control," Sherwood said. "By diverting their attention away from sound, the participants' auditory cortex activity went down, and the signal we were measuring also went down."

He said the researchers demonstrated that they could "use this nerve biofeedback technique to control the primary auditory cortex. We found that this control rapidly increased and was sustained by our experimental group."

Sherwood noted that his findings are being extrapolated from healthy volunteers as a way of benefiting people with tinnitus – a ringing noise heard in the ears by some people that is difficult to find with imaging or other modalities. About 1 in 5 people report varying degrees of tinnitus. Tinnitus often correlates with other conditions such as hearing loss. "It is a subjective condition. There is no way to test for tinnitus; there is no way to prove you have tinnitus; it is very difficult to treat," he told 番茄社区.

"I have experienced that ringing noise in my ear, but I wouldn't call it tinnitus. It think that more people experience this than they will admit," he said.

Max Wintermark, MD, of Stanford University, who wasn't involved in the study, told 番茄社区 that "for many patients, tinnitus is a truly debilitating condition which does impact on their way of life. And really, there is no well established treatment for tinnitus.

"We do an imaging work-up to see if we can find what is causing the tinnitus, and for a few patients we can find a cause but for the others we just can't find any reason," Wintermark said.

He called the study elegant: "I like the idea that they are using neurofeedback to measure the degree of the white noise so that the subjects in the study could use that information and develop strategies and decrease the way their brain perceives the white noise in the experimental treatment."

Although it involved a small number of subjects, he said, "if there is something here that can help these patients it would be a very big advance."

"If these healthy volunteers could reduce their perception of the white noise through behavioral therapy techniques, then perhaps this can be taught to patients with tinnitus so they can get relief from their symptoms," he said. "This is the next step in the research. This is an area where we need progress."

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