An assessment of hyperacusis, a frequent accompaniment of tinnitus, may also be made. The measured parameter is Loudness Discomfort Level (LDL) in dB, the subjective level of acute discomfort at specified frequencies over the frequency range of hearing. This defines a dynamic range between the hearing threshold at that frequency and the loudnes discomfort level. A compressed dynamic range over a particular frequency range is associated with subjectve hyperacusis. Normal hearing threshold is generally defined as 0–20 decibels (dB). Normal loudness discomfort levels are 85–90+ dB, with some authorities citing 100 dB. A dynamic range of 55 dB or less is indicative of hyperacusis.
Traumatic brain injury, caused by concussive shock, can damage the brain’s auditory processing areas and generate tinnitus symptoms. TBI is one of the major catalysts for tinnitus in military and veteran populations. Nearly 60% of all tinnitus cases diagnosed by the U.S. Veterans Administration are attributable to mild-to-severe traumatic brain injuries.
None of these treatment options are supported by science. Many people are convinced that the herb gingko biloba is helpful, however large-scale studies have been unable to prove this. There are many nutritional supplements claiming to be tinnitus remedies. These are usually a combination of herbs and vitamins, often including zinc, ginkgo, and vitamin B-12.
Exposure to loud noise. Loud noises, such as those from heavy equipment, chain saws and firearms, are common sources of noise-related hearing loss. Portable music devices, such as MP3 players or iPods, also can cause noise-related hearing loss if played loudly for long periods. Tinnitus caused by short-term exposure, such as attending a loud concert, usually goes away; both short- and long-term exposure to loud sound can cause permanent damage.