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 for hearing loss. Sound generators (masking devices) have received Class II approval from the FDA. However, they are considered to be “experimental, investigational, or unproven” therapies. There is one report of a bone conduction vibration masker that transmits a 60 Hz fundamental with adjustable harmonics up to 1000 Hz. A commercial device based on the phenomenon (Aurex3) was approved by the FDA. A new development in tinnitus management is the use of high audio (10 kHz-20 kHz) or ultrasonic (20-100 kHz) via bone conduction. A 2012 Cochrane Review stated the available studies do not show strong evidence of the efficacy