====== Tinnitus ====== >Tinnitus is the perception of noises in the head and/or ear which have no external source. It derives from the Latin word for ringing and those living with the condition may have to endure a ringing, buzzing, hissing, whistling or other noise. The sensation can be constant or intermittent and it can vary in volume.\\ \\ Source : [[https://www.tinnitus.org.uk/what-is-tinnitus|UK Tinnitus Association]] It's estimated that around 30% of the global population have some degree of persistent tinnitus at various stages in their lives. The term is used for a wide range of similar disorders, all of which feature 'audible' disturbances of various kinds. It's believed that the source of the background noise is only rarely due to neural signals coming from the ear itself, but instead it's somehow manifested in the brain's audio processing areas. The exact causes, and the neural mechanisms involved, are unknown. >Whilst we do not know the exact answer to what causes tinnitus, we know that it is not a disease or an illness. It is generally agreed that tinnitus results from some type of change, either mental or physical, not necessarily related to hearing.\\ \\ Source : [as above] Further info : [[https://en.wikipedia.org/wiki/Tinnitus|Wikipedia]] //Note: //As with any other sensory system (natural or artificial) there is always some degree of noise in the signal - so most people experience a very low-level background hiss at all times. Part of which can be the 'thermal noise' of moving air molecules hitting the eardrum.