Tinnitus background noise to one that can be heard even over loud external sounds. The specific type of tinnitus called pulsatile tinnitus is characterized by hearing the sounds of one's own pulse or muscle contractions, which is typically a result of sounds that have been created by the movement of muscles near to one's ear, or the sounds are related to blood flow of the neck or face. Due to variations in study designs, data on the course of tinnitus showed few consistent results. Generally the prevalence increased with age in adults, whereas the ratings of annoyance decreased with duration. Persistent
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.