Tinnitus hum, but it can also arise as a subjective phenomenon from an increased awareness of blood flow in the ear. Rarely, pulsatile tinnitus may be a symptom of potentially life-threatening conditions such as carotid artery aneurysm or carotid artery dissection. Pulsatile tinnitus may also indicate vasculitis, or more specifically, giant cell arteritis. Pulsatile tinnitus may also be an indication of idiopathic intracranial hypertension. Pulsatile tinnitus can be a symptom of intracranial vascular abnormalities and should be evaluated for "irregular noises of blood flow" (bruits). The mechanisms of subjective tinnitus are often obscure. While it is not surprising that direct trauma
Tinnitus retraining therapy called it masking), an integral part of TRT, found no convincing evidence of the efficacy of sound therapy in the treatment of tinnitus. A summary in The Lancet concluded that in the only decent study, TRT was more effective than masking; in another study in which TRT was used as a control methodology, TRT showed a small benefit. A study which compared cognitive behavior therapy (CBT) in combination with the counselling part of TRT versus standard care (ENT, audiologist, maskers, hearing aid) found that the specialized care had a positive effect on quality of life as well as specific tinnitus