Author: Sarah Stanley
Institution: U.C. Santa Barbara
Date: March 2010
Fans of excessively loud music may soon be able to treat their noise-induced tinnitus with altered versions of the very songs that caused it. Tinnitus, or "ringing of the ears," is characterized by perception of a tone, often of a particular frequency, when no sound is externally present.
In a recent study, listening to recordings of music that were specifically altered according to a patient's tinnitus frequency resulted in improvement in the condition after one year. According to the December, 2009, report in the Proceedings of the National Academy of Sciences (PNAS), improvement was characterized by decreased tinnitus loudness (the main cause of tinnitus discomfort) accompanied by a decrease in brain activity associated with tinnitus.
Of the estimated 50 million Americans who experience tinnitus, 12 million report serious discomfort. The condition has a variety of origins, including head injury, tumors, and, most commonly, excessive exposure to noise. Most sound treatments currently in use merely mask the ringing sound of tinnitus, and there is great demand for treatments, like this one, that could improve tinnitus at a neural level.
In the double-blind study performed in Germany, researchers divided 39 tinnitus patients into target and placebo groups. Each patient then selected musical recordings they enjoyed. Researchers altered, or "notched," each of the target recordings by removing an octave (8 musical notes)-wide range of frequencies centered on the frequency of the corresponding patient's unique tinnitus tone. Placebo recordings were notched by removing several frequency ranges that did not include notes within the tinnitus range.
Patients listened to their notched recordings for about 12 hours per week for a year. Progress was measured by the patients' subjective judgment of tinnitus loudness and by magnetoelectroenchaphaly (MEG) measurements of activity in the auditory cortex, the region in the brain that processes sound, known to be associated with tinnitus. Though the study was continued for one year, patients in the target group already showed significant improvement in tinnitus loudness and tinnitus-associated neural activity after six months.
"The notched music approach can be considered as enjoyable, low cost, and presumably causal treatment that is capable of specifically reducing tinnitus loudness," Dr. Christo Pantev, of the Institute for Biomagnetism and Biosignalanalysis at Westfalian Wilhelms-University,and one of the authors of the study, told BBC News. "It could significantly complement widely-used and rather indirect psychological treatment strategies."
It is thought that tinnitus is caused by reorganization of the auditory cortex in the brain. Because the precise mechanisms involved in generation and maintenance of tinnitus are unknown, the reasons for the success of this treatment remain unidentified. One possibility suggested by the authors of the report is that the absence of auditory input to the neurons associated with the tinnitus frequency depressed their activity, leading to decreased perceived loudness. Or, the tinnitus-associated neurons may have been actively suppressed by neighboring auditory neurons.
The scientists also suggest these auditory mechanisms could work in concert with other neural processes to improve tinnitus. Listening to enjoyable music can release dopamine in the brain. Increased dopamine is associated with increased neural reorganization, which could lead to a decrease in tinnitus severity.
Whatever the underlying explanation, the results of this study are promising for many tinnitus patients, who may be able to significantly decrease the loudness of their tinnitus in a similar, enjoyable manner. But don't use this as an excuse to crank up the volume on your headphones! Noise-induced hearing loss is still a real threat, and was not addressed in this study.
Sources
Okamoto, Hidehiko; Stracke, Henning; Stoll, Wolfgang; and Pantev. Christo. "Listening
to tailor-made notched music reduces tinnitus loudness and tinnitus-related auditory cortex activity." Proceedings of the National Academy of Sciences. 28 Dec. 2009. PNAS doi: 10.1073/pnas.0911268107
"Music therapy 'may help cut tinnitus noise levels'." BBC News 29 Dec. 2009 accessed
16 Feb. 2010 http://news.bbc.co.uk/2/hi/8429715.stm
Sanders, Barbara T. "What is Tinnitus?" Tinnitus Today 24 Sep. 2004: 5-6.