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 in the central auditory system, and therefore cause tinnitus. The most common cause of tinnitus is noise-induced hearing loss. Such hearing loss may also be present in a hidden form, i.e., in persons showing a normal audiogram. Hearing loss may have many different causes, but among tinnitus subjects, the major cause is cochlear damage. Ototoxic drugs can also cause subjective tinnitus, as they may cause hearing loss, or increase the damage done by exposure to loud noise. Those damages can occur even at doses that are not considered ototoxic. Over 260 medications have been reported to cause tinnitus as a