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 in 90% of persons but in rare cases, an hour or more. The period of complete silence is usually seconds to about a minute. If the trigger sound is repeated at intervals, tinnitus can be suppressed as long as the repetition lasts. The residual inhibition (RI) effect first noted in 1903: the capacity of a sound of the right frequency and intensity to briefly attenuate or suppress tinnitus. To distinguish the tailored sound used for inhibition from the broadband undifferentiated sound employed in tinnitus maskers, it is usually referred to as the 'trigger' or 'quieting' sound. The trigger sound is