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 retraining therapy TRT is imputed to work by interfering with the neural activity causing the tinnitus at its source, in order to prevent it from spreading to other nervous systems such as the limbic and autonomic nervous systems. Clients are classified into 5 categories. These categories are numbered 0 to 4, and based on whether or not the patient has tinnitus with hearing loss, tinnitus with no hearing loss, tinnitus with hearing loss and hyperacusis, and tinnitus with hearing loss and hyperacusis for an extended amount of time. The first component of TRT, directive counseling, may change the way tinnitus is perceived.