Tinnitus activity in the limbic system and autonomic nervous system, thus increasing tinnitus awareness and annoyance. There are two types of tinnitus: "subjective tinnitus" and "objective tinnitus". Tinnitus is usually subjective, meaning that there is no sound detectable by other means. Subjective tinnitus has also been called "tinnitus aurium", "non-auditory" or "non-vibratory" tinnitus. In very rare cases tinnitus can be heard by someone else using a stethoscope, and in less rare – but still uncommon – cases it can be measured as a spontaneous otoacoustic emission (SOAE) in the ear canal. In such cases it is objective tinnitus, also called "pseudo-tinnitus"
Tinnitus retraining therapy called it masking), an integral part of TRT, found no convincing evidence of the efficacy of sound therapy in the treatment of tinnitus. A summary in The Lancet concluded that in the only decent study, TRT was more effective than masking; in another study in which TRT was used as a control methodology, TRT showed a small benefit. A study which compared cognitive behavior therapy (CBT) in combination with the counselling part of TRT versus standard care (ENT, audiologist, maskers, hearing aid) found that the specialized care had a positive effect on quality of life as well as specific tinnitus