Tinnitus to the inner ear can cause tinnitus, other apparent causes (e.g., temporomandibular joint dysfunction) are difficult to explain. It may be caused by increased neural activity in the auditory brainstem, where the brain processes sounds, causing some auditory nerve cells to become over-excited. The basis of this theory is that many with tinnitus also have hearing loss. Three reviews of 2016 emphasized the large range and possible combinations of pathologies involved in tinnitus, which in turn result in a great variety of symptoms demanding specifically adapted therapies. Even when tinnitus is the primary complaint, audiological evaluation is usually preceded by
Tinnitus masker the sound is tuned to the pitch, loudness and other qualities of the tinnitus. However, frequencies widely divergent from the tinnitus frequency may also mask the tinnitus, if they are of sufficient loudness. The minimum energy (or loudness) mask is usually one closely matched to the central frequency and bandwidth of the tinnitus. But it has also been discovered that a tinnitus mask close to the frequency of the tinnitus can be ineffective, while a masker with a different frequency or bandwidth effectively masks the tinnitus. This indicates different origins of tinnitus. Tinnitus maskers may use music or natural sounds,