Tinnitus Retraining Therapy In 1990 Professor Pawel J. Jastreboff of the University of Maryland School of Medicine first published papers describing his "neurophysiological model of tinnitus". Dr. Jonathan Hazell of the U.K. used Jastreboff's principles of tinnitus management, and applied it clinically to his patients. This is the basis of what we call Tinnitus Retraining Therapy (called Auditory Habituation at the time). Tinnitus Retraining Therapy depends on two factors: 1) The property of the central nervous system networks called "neuronal plasticity". Plasticity refers to the fact that our neural networks are not static and can be altered physiologically to a certain degree. 2) Certain pathways traditionally labeled as non-auditory (such as the limbic system and the autonomic nervous system) are considered essential components of tinnitus perception. Tinnitus Retraining Therapy (TRT) has a success rate greater than 80% in substantially improving tinnitus perception and annoyance: Sheldrake(1996); Bartnik, (1999); Heitzman (1999); Herraiz, (1999); Jastreboff (2001); Mc Kinney (1999). That is, patients often report that their tinnitus ceases to be an issue in their lives. This approach employs the temporary use of soft sound, often in the form of broad band "white noise" generators purposely set at a volume that does not mask the tinnitus. The contrast between the tinnitus signal and environmental sounds is thereby decreased, thus facilitating habituation to the tinnitus signal. Habituation means that the subconscious mind is passively retrained to filter out and not respond to the tinnitus signal the same way the subconscious mind naturally filters out the meaningless sound of a refrigerator or a computer fan. Masking "Masking" tinnitus involves partially or completely covering up the tinnitus sounds with other sounds from an external source. In fact, masking raises the threshold of the perception of tinnitus when an external source is presented. In clinical settings, masking is accomplished through the use of wearable noise generators (maskers) or "tinnitus instruments", which are wearable units that function both as a hearing aid and masker. Dr. Jack Vernon and his colleagues at the Oregon Hearing Research Center in Portland introduced the priniciples and concepts behind masking which helped improve the quality of life for literally millions of tinnitus suffers. Costs for masking instruments are based on each case.