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 with tinnitus have a comorbid psychological injury or illness (e.g., post-traumatic stress disorder, depression, anxiety, obsessive compulsive disorder, stress, dysfunction of the temporomandibular joint, etc.) that can exacerbate the tinnitus. It has been proposed that tinnitus is caused by mechanisms that generate abnormal neural activity, specifically one mechanism called discordant damage (dysfunction) of outer and inner hair cells of the cochlea. The psychological basis for TRT stems from the fact that the brain exhibits a high level of plasticity. In turn, this allows it to adjust to any sensory signals as long as they do not lead to negative effects.