Posted on 01/03/2018 12:20:30 PM PST by Red Badger
A closeup view of the skin-stimulating electrodes and earphones used to deliver the specially timed signals. Credit: University of Michigan
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Millions of Americans hear ringing in their ears—a condition called tinnitus—but a new study shows an experimental device could help quiet the phantom sounds by targeting unruly nerve activity in the brain.
In a new paper in Science Translational Medicine, a team from the University of Michigan reports the results of the first animal tests and clinical trial of the approach, including data from 20 human tinnitus patients.
Based on years of scientific research into the root causes of the condition, the device uses precisely timed sounds and weak electrical pulses that activate touch-sensitive nerves, both aimed at steering damaged nerve cells back to normal activity.
Human participants reported that after four weeks of daily use of the device, the loudness of phantom sounds decreased, and their tinnitus-related quality of life improved. A sham "treatment" using just sounds did not produce such effects.
Results from tests in guinea pigs and the double-blind human study funded by the Coulter Foundation validate years of pre-clinical research funded by the National Institutes of Health, including previous tests in guinea pigs.
The U-M team has new NIH funding for an additional clinical trial to further refine the approach. U-M holds a patent on the concept behind the device and is developing it for potential commercialization.
"The brain, and specifically the region of the brainstem called the dorsal cochlear nucleus, is the root of tinnitus," says Susan Shore, Ph.D., the U-M Medical School professor who leads the research team. "When the main neurons in this region, called fusiform cells, become hyperactive and synchronize with one another, the phantom signal is transmitted into other centers where perception occurs.
"If we can stop these signals, we can stop tinnitus," she continues. "That is what our approach attempts to do, and we're encouraged by these initial parallel results in animals and humans."
A dual-stimulus approach to treating tinnitus
The approach, called targeted bimodal auditory-somatosensory stimulation, involves two senses. The device plays a sound into the ears, alternating it with precisely timed, mild electrical pulses delivered to the cheek or neck.
This sets off a process called stimulus-timing dependent plasticity, or STDP, which was first explored in animals and led to long-term changes in the rate at which the nerves fire. The approach aims to re-set the activity of fusiform cells, which normally help our brains receive and process both sounds and sensations such as touch or vibration - what scientists call somatosensory inputs.
Under normal conditions, fusiform cells help our brains focus on where sounds are coming from, and help us tune out sensations that result from the movement of our own head and neck.
But the U-M team's previous work in animals showed that loud noise can trigger a change in the nerve cells' activity - altering its timing so that they fire off synchronized signals spontaneously instead of waiting for an actual sound in the environment.
The toll of tinnitus
These events in animals parallel what happens in humans. After exposure to such things as loud noises, head or neck trauma, or other triggering events, some people develop a persistent sensation that they're hearing sounds like ringing or a grinding noise.
Approximately 15 percent of Americans have some level of tinnitus, but the worst symptoms occur in about 10 percent of sufferers, according to estimates based on interviews with nationally representative samples of Americans. Many of those with more severe tinnitus also have hearing loss.
Some cases are severe. As many as two million people can't work or carry out other daily activities because of the tinnitus itself, or the psychological distress it causes them. Tinnitus is the most common cause of service-connected disability among veterans of the U.S. military.
Current approaches to tinnitus treatment focus include efforts to address the psychological distress it causes, for instance through cognitive behavioral therapy. Other approaches use sound to mask the phantom sounds or attempt to modulate the brain response. For more severe cases, some patients turn to invasive, and therefore riskier, approaches such as deep brain stimulation and vagal nerve stimulation. The current approach provides a novel and unique, non-invasive strategy that aims to modulate and correct the aberrant neural pathways that cause tinnitus.
Study details
Shore and her colleagues are based in U-M's Kresge Hearing Research Institute, which is part of the Department of Otolaryngology at Michigan Medicine, U-M's academic medical center. Co-first authors Kendra Marks, Au.D., David Martel, M.S.E. and Calvin Wu, Ph.D., are all members of the Shore laboratory.
They recruited a particular kind of tinnitus sufferer for their study: those who can temporarily alter their symptoms if they clench their jaws, stick out their tongues, or turn or flex their necks. These maneuvers, Shore says, appear to be self-discovered ways of changing the activity of fusiform cells - providing an external somatosensory signal to modulate their tinnitus.
The U-M device delivers sounds matched to the loudness and pitch of the phantom sounds that each patient hears. It also delivers mild electrical impulses applied to the area of the head involved in the patients' own tinnitus-altering maneuvers.
The crucial timing of the auditory and electrical stimulation came directly from tests in guinea pigs that had noise-induced tinnitus, reported in the new paper. Those tests showed that specific timing between delivery of the two kinds of stimuli was necessary to suppress the hyperactive fusiform cells.
After patients had the device calibrated to their own tinnitus symptoms, they learned to apply its earphones and electrodes for a 30-minute session each day. Half the group received the bimodal sound-and-electricity treatment for the first four weeks, while the other half received just sounds. Then, they all took a four-week break, and started the next four weeks receiving the opposite of what they'd received before. None of them knew which option they got first.
Every week, the patients took a survey about how much their tinnitus was affecting their lives, and a test of how loud their tinnitus sounds were.
Results in human participants
Overall, the loudness of phantom sounds decreased only after the actual, or bimodal, treatment, but not the sham treatment of sound only. For some the decrease was around 12 decibels, about the magnitude of an electric lightbulb's hum. Two participants said their tinnitus disappeared completely.
The quality of life survey - where a low score indicates less impact from tinnitus - is called TFI, and is measured on a 100-point scale. Statistical modeling of the results revealed that, on average, patients experienced significantly reduced scores for the active treatment, though the size of the effect in individual patients varied. On average, scores also stayed lower for weeks after treatment ended. This effect was not significant for the sham treatment.
No patient experienced a worsening of symptoms or quality of life, or other adverse events. Some said their phantom sounds got less harsh or piercing, or became easier to ignore.
"We're definitely encouraged by these results, but we need to optimize the length of treatments, identify which subgroups of patients may benefit most, and determine if this approach works in patients who have non-somatic forms of the condition that can't be modulated by head and neck maneuvers," says Shore.
The research was funded by NIH grants DC004825 and DC00011, and by the Wallace H. Coulter Translational Research Partnership. The device was built at in2being LLC based on patent 9,242,067 granted to U-M in 2016. The device is experimental and not commercially available; potential cost of treatment has yet to be determined.
Explore further: Bilateral tinnitus in men may be hereditary
More information: K.L. Marks el al., "Auditory-somatosensory bimodal stimulation desynchronizes brain circuitry to reduce tinnitus in guinea pigs and humans," Science Translational Medicine (2017). stm.sciencemag.org/lookup/doi/ … scitranslmed.aal3175
Journal reference: Science Translational Medicine search and more info website
Provided by: University of Michigan
Same thing with heavy highway traffic noise in the distance when I go to bed.
I have suffered a lot from this for 25 years. I wonder if they will figure anything out while I am still alive (probably not). Too much loud machinery back in the day.
I told my wife, at least when I die the never ending screeching will stop. Silver lining and all that.
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What other fake news -- aside from that spawned by your maniacal hatred for Apple and its customers -- do you have for us?
The only "Taint" associated with the non-existent "Vagal" nerve is,
"T'a'int no such animule!"!
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"Vagal" is an adjective referring to the Vagus nerve -- which is nowhere near the pelvic region..
(For those interested in fact, see Vagus nerve...)
Thanks for the ring, er ping.
It would be great to have something that works. I went to an audiologist and tried out a tiny hearing aid and it produced some almost inaudible transient noise that I couldn’t really “hear,” but it seemed to reduce my tinitus.
I need to get back to the VA and get one of dang things, but I’m rather used to using that trait. It helps me decide where to sit.
Sounds very much like we both ignored all the loud noises when young and have the same symptoms now. I’m 66 now and have noticed I’m asking more people to repeat themselves and to speak up. Not a good sign. My uncle is 97 and went deaf over the past 4 to 5 years.
Mine is like crickets on a summer’s night most of the time.
Then there are days when it’s like Gregorian chants or Mormon Tabernacle Choir singing the hallelujah chorus for hours in another room.................
There are some people who have it so bad they have an operation to sever the auditory nerve or remove the cochlea in order to get peace and quiet..................
Glad you found some relief.
I’ll have to check into that. Thanks.
Almost funny, both my paternal grandparents were deaf. My parents were concerned I would be born deaf. No, great hearing.
Until the tinnitus came knocking on the door when I was 50-51.
At the time we just took the loud noises as part of life. The consequences of all that noise wasn’t being looked at by researchers as I recall.
Both of my paternal grandparents were born deaf. I sometimes wonder if there might be a hereditary component to my tinnitus.
I keep forgetting to ask about it.
Fanbois are pure Buzzkill.
I read that doesn't usually help. They end up deaf and still hearing the screeching. It is theorized that the issue is a mis-wiring in the brain.
Doesn’t work. Tinnitus is created in your brain and has nothing to do with your hearing.
I've got the high pitch. Used to describe it as similar to the high freq sound from old color tv sets.
Still up there and I think some lower freq thrown in.
Would l o v e to get rid of it.
The first one, though both are used frequently............
Here is a 1979 Popular Science article How to Protect Yourself from Shop Noise.
OSHA (as much as we hate government intrusion) was responsible for beginning hearing protection in 1971. Unfortunately, that was too late for us -- it would have been nice growing up in an era when the hazards were understood.
Some interesting background on regulatory efforts:
Hearing Conservation in the US: A Historical Perspectiv
The US Occupational Safety and Health Administration (OSHA) Noise Exposure Regulation became effective in 1971.1 Since 1983, OSHA's regulation has included an amendment to require specific components related to hearing protection, audiometric testing, and training. This amendment has become known as the 'Hearing Conservation Amendment.'
How effective have these regulations been in preventing hearing loss in the workplace? There is no brief, or abbreviated way to answer this question. Simply, the complexity of the problem and the complexity of the solution, beg a detailed analysis.
In 1971, when the original regulation became effective, events and policies made the practice of hearing conservation a fuzzy notion to plant management - and a low priority to others! In 1971, OSHA's intention was to 'remove the hazard' or 'remove the worker' when noise exposure reached a time-weighted average (TWA) of 90 dB. Importantly, hearing protection (accomplished through the use of hearing protection devices, HPDs) was to be used only as an interim measure until feasible engineering or administrative controls could be implemented.
However, during the 1970s, the word 'feasible' became a significant point of controversy in the new regulations and the burden of proof to show technical and economic feasibility (i.e., cost-effectiveness) rested squarely on OSHA's shoulders. This new burden, combined with diminishing resources, compelled OSHA to change strategies and enforcement policies. This was the beginning of the problem.
The ink had hardly dried on the new OSHA regulations when NIOSH published its first criteria document in 1972 for occupational noise exposure. The agency - which is an advisory arm of the federal government - immediately called upon OSHA to lower the permissible exposure level (PEL) from 90 dB to 85 dB TWA and to make other proactive changes to protect hearing in the workplace.
In 1974, the Environmental Protection Agency (EPA) issued its famous 'Levels' document which established criteria to protect the public health from the effects of noise - not just regarding speech communication and human comfort, but also on hearing.3 Based on this document, the EPA also called for OSHA to lower its PEL. Later that year, OSHA actually issued a proposed revision to make some of these changes. But the political climate was not right and the proposed changes 'fell on deaf ears.'
my hearing aid now has a setting for tinnitus. it emits a sound that matches the various sounds of tinnitus in my ears. this somehow cancels out the tinnitus and makes it easier to live with. I’m told that eventually I’ll stop hearing the tinnitus entirely. so far it just makes it easier to live with.
I imagine industry fought noise regulations pretty hard. The executives weren’t the ones losing their hearing.
I worked with a guy who spent time in the army, artillery.
He was given a medical discharge for hearing loss. He started wearing hearing aids at the age of 28.
That is a nice summary of hearing protection.
Hopefully our grandchildren won’t have to suffer from work related hearing problems.
They will probably develop their own set of workplace hazards.
Glad it helps.
Definitely going to check into the hearing aids.
I have to ask people to repeat themselves but ONLY CERTAIN PEOPLE. I had a hearing test a couple of weeks ago and was told that I DID NOT need a hearing aid, my hearing loss is so minimal that it would not make a real difference. I noticed that I had zero problem understanding what the technician said. My conclusion was that I work with some people who speak and with some others who only mumble and slur as if they were drunk.
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