are sensory experiences that occur in the absence of real stimuli
Hallucination A hallucination is a perception in the absence of external stimulus that has qualities of real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space. They are distinguishable from several related phenomena, such as dreaming, which does not involve wakefulness; pseudohallucination, which does not mimic real perception, and is accurately perceived as unreal; illusion, which involves distorted or misinterpreted real perception; and imagery, which does not mimic real perception and is under voluntary control.[1] Hallucinations also differ from "delusional perceptions", in which a correctly sensed and interpreted stimulus (i.e., a real perception) is given some additional (and typically absurd) significance.
Misophonia As of 2016 the literature on misophonia was limited.[1] Some small studies show that people with misophonia generally have strong negative feelings, thoughts, and physical reactions to specific sounds, which the literature calls "trigger sounds". These sounds are apparently usually soft, but can be loud. One study found that around 80% of the sounds were related to the mouth (eating, slurping, chewing or popping gum, whispering, etc.), and around 60% were repetitive. A visual trigger may develop related to the trigger sound.[1][3] It also appears that a misophonic reaction can occur in the absence of an actual sound.[1]