In search of tinnitus, that phantom ringing in the ears

April 23, 2015, Cell Press
In search of tinnitus, that phantom ringing in the ears
A 3-D image of the left brain hemisphere of a patient with tinnitus (right) and the part of that hemisphere containing primary auditory cortex (left). Black dots indicate all the sites recorded from. Colored circles indicate electrodes at which the strength of ongoing brain activity correlated with the current strength of tinnitus perceived by the patient. Different colors indicate different frequencies of brain activity (blue = low, magenta = middle, orange = high) whose strength changed alongside tinnitus. Green squares indicate sites where the interaction between these different frequencies changed alongside changes in tinnitus. Credit: Sedley, W et al.

About one in five people experience tinnitus, the perception of a sound—often described as ringing—that isn't really there. Now, researchers reporting in the Cell Press journal Current Biology on April 23 have taken advantage of a rare opportunity to record directly from the brain of a person with tinnitus in order to find the brain networks responsible.

The observations reveal just how different tinnitus is from normal representations of sounds in the .

"Perhaps the most remarkable finding was that activity directly linked to tinnitus was very extensive, and spanned a large proportion of the part of the brain we measured from," says Will Sedley of Newcastle University. "In contrast, the brain responses to a sound we played that mimicked [the subject's] tinnitus were localized to just a tiny area."

In the new study, Sedley and The University of Iowa's Phillip Gander contrasted during periods when tinnitus was relatively stronger and weaker. The study was only possible because the 50-year-old man they studied required invasive electrode monitoring for epilepsy. He also happened to have a typical pattern of tinnitus, including ringing in both ears, in association with hearing loss.

"It is such a rarity that a person requiring invasive electrode monitoring for epilepsy also has tinnitus that we aim to study every such person if they are willing," Gander says.

The researchers found the expected tinnitus-linked brain activity, but they report that the unusual activity extended far beyond circumscribed auditory cortical regions to encompass almost all of the auditory cortex, along with other parts of the brain.

The discovery adds to the understanding of tinnitus and helps to explain why treatment has proven to be such a challenge, the researchers say.

"We now know that tinnitus is represented very differently in the brain to normal sounds, even ones that sound the same, and therefore these cannot necessarily be used as the basis for understanding tinnitus or targeting treatment," Sedley says.

"The sheer amount of the brain across which the tinnitus network is present suggests that tinnitus may not simply 'fill in' the 'gap' left by hearing damage, but also actively infiltrates beyond this into wider brain systems," Gander adds.

These new insights may help to inform treatments such as neurofeedback, where patients learn to control their "brainwaves," or electromagnetic brain stimulation, according to the researchers. A better understanding of the brain patterns associated with may also help point toward new pharmacological approaches to treatment, "which have so far generally been disappointing."

Explore further: People with tinnitus process emotions differently from their peers, researchers report

More information: Current Biology, Sedley et al.: "Intracranial mapping of a cortical tinnitus system using residual inhibition" dx.doi.org/10.1016/j.cub.2015.02.075

Related Stories

People with tinnitus process emotions differently from their peers, researchers report

June 25, 2014
(Medical Xpress)—Patients with persistent ringing in the ears – a condition known as tinnitus – process emotions differently in the brain from those with normal hearing, researchers report in the journal Brain Research.

AAO-HNSF clinical practice guideline: Tinnitus

October 1, 2014
The American Academy of Otolaryngology—Head and Neck Surgery Foundation has released the first ever mutli-disciplinary, evidence-based clinical practice guideline to improve the diagnosis and management of tinnitus, the ...

New study brings scientists a step closer to silencing tinnitus

June 16, 2014
New research funded by charity Action on Hearing Loss suggests that tinnitus can be eliminated by blocking signals between the ear and brain, offering hope to suffers that a cure is within reach, with prolonged exposure to ...

Range of cures likely for tinnitus

March 27, 2014
(Medical Xpress)—Tinnitus researchers agree that there may never be a single cure for tinnitus, but instead a range of treatments for different types of tinnitus will be needed.

Brain stimulation aims to speed up tinnitus treatment

June 12, 2013
(Medical Xpress)—A combination of brain stimulation and video games may be the key to speeding up treatment for tinnitus sufferers.

Research gives new hope to tinnitus patients

February 5, 2014
A research project, led by the University of Liverpool and Aintree University Hospital, is giving new hope to patients living with tinnitus.

Recommended for you

Researchers investigate changes in white matter in mice exposed to low-frequency brain stimulation

June 19, 2018
A team of researchers at the University of Oregon has learned more about the mechanism involved in mouse brain white matter changes as it responds to stimulation. In their paper published in Proceedings of the National Academy ...

Cell type and environment influence protein turnover in the brain

June 19, 2018
Scientists have revealed that protein molecules in the brain are broken down and replaced at different rates, depending on where in the brain they are.

Left, right and center: mapping emotion in the brain

June 19, 2018
According to a radical new model of emotion in the brain, a current treatment for the most common mental health problems could be ineffective or even detrimental to about 50 percent of the population.

Often overlooked glial cell is key to learning and memory

June 18, 2018
Glial cells surround neurons and provide support—not unlike hospital staff and nurses supporting doctors to keep operations running smoothly. These often-overlooked cells, which include oligodendrocytes and astrocytes, ...

Electrically stimulating the brain may restore movement after stroke

June 18, 2018
UC San Francisco scientists have improved mobility in rats that had experienced debilitating strokes by using electrical stimulation to restore a distinctive pattern of brain cell activity associated with efficient movement. ...

Neuroscientists map brain's response to cold touch

June 18, 2018
Carnegie Mellon University neuroscientists have mapped the feeling of cool touch to the brain's insula in a mouse model. The findings, published in the June 15 issue of Journal of Comparative Neurology, provide an experimental ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.