Research in rats suggests that stimulating a nerve in the brain could help stop persistent ringing in the ears
American scientists claim to have developed a cure for tinnitus, a condition that causes incessant ringing in the ears. Researchers have found that by stimulating the part of the brain that causes the disorder they were able to make the ringing go away – at least for, er, rats.
According to a study published in Neuron earlier this month (via the Daily Swarm) tinnitus is not just the result of damage or obstruction in the ear – it is brought on by the brain, which overcompensates for lost hearing. After brain scans of 22 people at Georgetown University in Washington DC, scientists found that tinnitus occurs when one part of the brain tries to produce sounds to replace missing frequencies, and another fails to stop the unwanted sound – ringing – from reaching the auditory cortex.
In a separate paper, published last week in Nature, scientists at the University of Texas at Dallas experimented with rats, "resetting" their brains by stimulating a major cranial nerve, called the vagus. "Unlike previous treatments, we're not masking the tinnitus, we're not hiding the tinnitus," co-author Michael Kilgard told AFP. "We are eliminating the source of the tinnitus."
Kilgard and his colleagues electrically stimulated the vagus nerve in rats, which runs from the brain's medulla to the abdomen. This releases chemicals such as acetylcholine and norepinephrine, which can encourage changes in the brain. By pairing the stimulation with a high-pitched tone, the scientists were apparently able to halt the rats' tinnitus for more than three months.
Around one in 10 British adults suffers from tinnitus, which can be provoked by numerous sources - including listening to loud music. In the United States, there are 23m sufferers. These include 40% of military veterans, which requires the government to spend around $1bn in payments to tinnitus sufferers each year.
According to the lead author of the Dallas study, Dr Navzer Engineer, human trials will begin in Europe "in the coming months".
via Retuning the brain may cure tinnitus, finds study | Science | guardian.co.uk.
The vagus nerve is one of the 12 cranial nerves, the paired nerves that attach to the undersurface of the brain and relay information to and from the brain. Cranial nerve fibers conduct impulses between the brain and other parts of the brain and various body structures, mostly in the head and neck. The vagus nerve - the longest of the cranial nerves - also extends to organs in the chest and abdomen. (The word vagus comes from a Latin word for "wandering.')
Some cranial nerves bring information from the senses (like touch or sight) to the brain (sensory) and some control muscles (motor). Other cranial nerves, like the vagus, have both motor and sensory functions. The vagus nerve serves many organs and structures, including the larynx (voice box), lungs, heart and gastrointestinal tract.
Depressed? Just Stimulate Your Vagus Nerve
... Practitioners of yoga may already be enjoying the benefits of vagus nerve stimulation. The vagus nerve supplies motor and sensory parasympathetic fibers to virtually everything from the neck down to the first third of the transverse colon. Governing things like the heart rate, digestion, sweating and skeletal muscles, it's easy to see how any basic yoga routine can stimulate this pivotal channel between the mind and body.
But it turns out that the vagus nerve is involved with many other, less obvious activities associated with yoga, like chanting and pranayama.
The acts of chanting, both listening and vocalizing, stimulate the vagus nerve through muscle movements in the mouth, like those important to speech and those that work the larynx for breathing. The nerve also connects to vocal chords and receives some sensation from the outer ear; thus the acts of vocalizing and listening can influence it. ... the most refined practice for yogic stimulation of the vagus nerve may be pranayama ...
One of the big things it does, is get the parasympathetic nervous system to kick in. It balances out the whacked, adrenaline-crazed sympathetic nervous system, and gets us to chill out. It can head anxiety attacks off at the pass. It can cancel panic before gets hold of you. It tames the tigers of agitation and edginess, and soothes jangled nerves.
One suggestion about how to stimulate your vagus nerve:
... You just breathe. Breathe deeply. Slow the breath and pay attention to the feeling of the breath moving through your nostrils and into you lungs. Fill your lungs up, so that they press against the inside of your chest cavity and stimulate the vagus nerve, which will in turn tell your system to ratchet it down a bit… send a little of the good stuff through our hormonal pathways, and reward us wonderfully for the effort we’ve put out. Do it for three breaths… or five… or ten. Do it for a minute… or two… or five. But do it. The more you try it, the more you’ll like it. I sure do.
I'll try it. Do I create a pitch close to the one I hear when I stimulate the vagus nerve?