Vogt–Koyanagi–Harada disease Vogt–Koyanagi–Harada disease Vogt–Koyanagi–Harada disease (VKH), also known as Vogt–Koyanagi–Harada syndrome, uveomeningitis syndrome and uveomeningoencephalitic syndrome, is a multisystem disease of presumed autoimmune cause, that affects pigmented tissues, which have melanin. The most significant manifestation is bilateral, diffuse uveitis, which affects the eye. VKH may variably also involve the inner ear with effects on hearing, the skin, and the meninges of the central nervous system. The disease is characterised by bilateral diffuse uveitis, with pain, redness and blurring of vision. The eye symptoms may be accompanied by a varying constellation of systemic symptoms, such as auditory (tinnitus, vertigo, and hypoacusis), neurological
Tinnitus masker amplitude determines the degree of masking achieved. In some cases, the required masking amplitude is so high as to cause discomfort to the user of the sound generator, and the tinnitus is therefore considered unmaskable. The frequency and other characteristics of tinnitus can vary over time, and the shifts can be temporary or permanent. They may also be cyclical. Therefore the optimal tinnitus mask may need to be adjusted periodically, within days, hours, or even minutes. So a fixed recording (i.e. CD, DVD or audio file) of a tinnitus mask is not a very efficacious application. There are also safety