The term hallucinotic eidolia is indebted to the Greek noun eidos, which means image, appearance, idea. It translates loosely as 'hallucination-like image'. The French neologism éidolie hallucinosique was introduced in or shortly before 1973 by the French psychiatrist Henri Ey (1900-1977) to denote a hallucination with a limited duration which manifests itself in a limited part of the perceptual field, typically in the absence of pathology. An example of hallucinotic eidolia is a visual hallucination occurring in the context of * Charles Bonnet syndrome. Given its emphasis on the benign nature of hallucinations such as these, Ey's notion of hallucinotic eidolia bears a certain similarity to the notion of * benign hallucination as formulated by the American psychiatrist Gordon Forrer. In his Traité des Hallucinations, Ey proposes the term éidolie hallucinosique as a substitute for hallucinosis - that is to say, for the term hallucinosis as used by his compatriot Henri Charles Jules Claude (1869-1946) and the German psychiatrist Paul Schröder (1873-1941), both of whom regarded it as a hallucination occurring in the absence of pathology. Ey's desire to propose the new term éidolie hallu-cinosique stemmed from his observation that the term hallucinosis had too many different connotations and from a desire to distinguish between pathological hallucinations (which he referred to as * hallucinations délirantes, or simply hallucinations), and phenomenologically similar percepts occurring in the absence of disease. Ey distinguishes two types oféidolieshallucinosiques, which he calls * phantéidolies and * protéidolies. He uses a related term, *somato-éidolie, to denote what is generally known as a * body schema illusion.
References
Ey, H. (1973). Traité des hallucinations. Tomes 1 et 2. Paris: Masson et Cie., Éditeurs.
Wertheimer, J. (1992). Some hypotheses about the genesis ofvisual hallucinations in dementias. In: Delusions and hallucinations in old age. Edited by Katona, C., Levy, R. London: Gaskell.
Dictionary of Hallucinations. J.D. Blom. 2010.