The apparent, often strong subjective perception of an object or event when no such stimulus or situation is present; may be visual, auditory, olfactory, gustatory, or tactile. [L. alucinor, to wander in mind]
auditory h. a symptom frequently observed in a schizophrenic disorder consisting, in the absence of an external source, of hearing a voice or other auditory stimulus that other individuals do not perceive.
formed visual h. h. composed of scenes, often landscapes.
gustatory h. the sensation of taste in the absence of a gustatory stimulus; may be seen in temporal lobe epilepsy.
haptic h. the sensation of touch in the absence of stimuli; may be seen in alcoholic delirium tremens.
hypnagogic h. h. occurring in the period between wakefulness and sleep; one of the components of narcolepsy.
hypnopompic h. vivid hallucinations that occur when wakening from sleep; occurs with narcolepsy, but grouped with hypnagogic h.
lilliputian h. h. of reduced size of objects or persons.
mood-congruent h. h. in which the content is mood appropriate.
mood-incongruent h. h. that is not consistent with external stimuli; content is not consistent with either manic or depressed mood.
olfactory h. false perception in smell.
stump h. phantom limb
tactile h. false perception of movement or sensation, as from an amputated limb, or crawling sensation on the skin.
unformed visual h. h. composed of sparks, lights, or bursting spheres of light.
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