Tinnitus background noise to one that can be heard even over loud external sounds. The specific type of tinnitus called pulsatile tinnitus is characterized by hearing the sounds of one's own pulse or muscle contractions, which is typically a result of sounds that have been created by the movement of muscles near to one's ear, or the sounds are related to blood flow of the neck or face. Due to variations in study designs, data on the course of tinnitus showed few consistent results. Generally the prevalence increased with age in adults, whereas the ratings of annoyance decreased with duration. Persistent
Black-body radiation logically determined solely by its own internal state. The causal effect of thermodynamic absorption on thermodynamic (spontaneous) emission is not direct, but is only indirect as it affects the internal state of the body. This means that at thermodynamic equilibrium the amount of every wavelength in every direction of thermal radiation emitted by a body at temperature "T", black or not, is equal to the corresponding amount that the body absorbs because it is surrounded by light at temperature "T". When the body is black, the absorption is obvious: the amount of light absorbed is all the light that hits