Do a google for Tinnitus Retraining Therapy and you will find lots of information, such as http://www.tinnitusformula.com/infoc...ments/trt.aspx

It appears my pitch is very low on the tinnitus scale. At 1108 to 1174, my tinnitus pitch is 1/4th that of common pitches. The higher pitches are the most problematic as they can evoke a fight or flight response. Pitches of 4000 Hrz to over 8000 Hrx are not uncommon. The highest pitch on a piano is 4186 Hrz. This is where many start to hear their tinnitus. Others have multi-pitch tinnitus.

Research suggests that the problem is in the brain's ability to filter out the tinnitus. Only half of those who have measured tinnitus of equal pitch and loudness find it problematic. The therapy is designed to help those with problematic tinnitus learn to ignore or filter out the sounds of the tinnitus. The sounds are still there but are pushed to the back of the list of 'heard' sounds.

Since this filtering mechanism in the brain is often damaged in PCS, it would appear that the therapy may be hap hazzard in its success in the PCS population.