The term extracampine hallucination is indebted to the Latin words extra (outside) and campaneus (field). It was introduced in or shortly before 1903 by the Swiss psychiatrist Eugen Bleuler (1857-1939) to denote a hallucination that is experienced by the affected individual as being outside the range of ordinary perception. The term extracampine hallucination is usually applied to the visual modality, i.e. to "visual hallucinations experienced at the back of the head or at other locations outside the regular visual field. In his original paper on the subject Bleuler also mentions two cases of "tactile extracampine hallucination, one involving a man who felt spurts of water on the back of his hands, and another involving a woman who claimed that she could feel on her skin the movement of mice crawling inside a wall. As pointed out by the Russian neurologist Johann Susmann Galant (1893-1937?), it is not entirely clear whether these case reports are commensurable with the concept of the extracampine hallucination. After all, both individuals experienced tactile hallucinations within the boundaries of their regular sense of touch. It would have been different if they had claimed, for example, that they could feel jets of water or the crawling of mice inside their brain (which has no tactile sense ofits own). Perhaps Bleuler's inclusion of these examples can be explained by reference to his theoretical supposition that the brain is actively involved in the outward projection of percepts, and that the occurrence of extracampine hallucinations may therefore be regarded as proof of the fallability of the mechanism responsible for this outward projection. Both of Bleuler s examples of the tactile extracampine hallucination would seem to comply with this hypothesis.
References
Bleuler, E. (1903). Extracampine Hallucina-tionen. Psychiatrisch-neurologische Wochenschrift, 25, 261-264.
Galant, S. (1924). Das Halluzinationsproblem und die Algohallucinosis. European Archives of Psychiatry and Clinical Neuroscience, 70, 187-215.
Sato, Y., Berrios, G. (2003). Extracampine hallucinations. The Lancet, 361, 1479-1480.
Dictionary of Hallucinations. J.D. Blom. 2010.