Tinnitus masker issues associated with use of tinnitus maskers: the "safe" level of continuous sound depends on the duration of the sound. For maskers worn continuously, or most of the day, a safe level is no more than 70db, in accordance with EPA maximum safe exposure level for 24-hour environmental sound. Maskers louder than 45db or so (the ambient background level of an average home living area) may start to interfere with understanding conversation (about 60db). Masking of high frequency tinnitus (>6,000hz) is difficult because of the resonance characteristics of the human ear as well as high frequency limitations of in-ear devices.
Tinnitus retraining therapy TRT is imputed to work by interfering with the neural activity causing the tinnitus at its source, in order to prevent it from spreading to other nervous systems such as the limbic and autonomic nervous systems. Clients are classified into 5 categories. These categories are numbered 0 to 4, and based on whether or not the patient has tinnitus with hearing loss, tinnitus with no hearing loss, tinnitus with hearing loss and hyperacusis, and tinnitus with hearing loss and hyperacusis for an extended amount of time. The first component of TRT, directive counseling, may change the way tinnitus is perceived.