Researchers were able to defeat the constant ear-ringing disease tinnitus in rats. And they did it by recalibrating the rodents' brains with the noise. They stimulated a nerve in the rats' necks while playing specific tones over a long period of time. This retrained their brains to interpret that sound properly, reverting neurons back to their original state and preventing the constant maddening ringing from the disease.
It's not well understood what causes tinnitus, but it's thought that the brain might dedicate too many neurons to a certain sound frequency, which causes it to become overwhelming. Hopefully, this treatment will lead to a cure for the condition in humans. Currently there is no treatment for the disease.
Research published in Nature.