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 The patient is taught the basic knowledge about the auditory system and its function, the mechanism of tinnitus generation and the annoyance associated with tinnitus. The repetition of these points in the follow-up visits helps the patient to perceive the signal as a non-danger. Measuring the efficacy of TRT is beset by confounding factors: tinnitus reporting is entirely subjective therefore not reliable; tinnitus or at least subjects' perception of it varies over time and repeated evaluations are not consistent. Researchers have noted that there is a large placebo component to tinnitus management. In many commercial TRT practices, there is a