distorted hallucination

   The term distorted hallucination is indebted to the Latin adjective distortus, which means twisted. It was used in 1894 by the German hallucinations researcher Edmund Parish (1861-1916) to denote a hallucination, typically visual in nature, which consists of an image with distorted or disfigured features. Parish explains the mediation of distorted hallucinations by reference to manipulation or illness of the peripheral sense organs, in combination with a central origin of the hallucinations at hand. Citing as examples sideways pressure to the eyeballs and strabismus due to atropin poisoning, he contends that "the distorted perception of objective impressions (resulting from failure of co-ordination in the eye-muscles) is transferred to the hallucination." The technique of doubling visual hallucinations with the aid of gentle pressure to the eyeballs was developed by the Scottish physicist David Brewster (1781-1868). Whilst seeking to distinguish between sensory and hallucinatory visual images, Brewster applied pressure to the eyeball of a test person, only to find that both types of percepts were doubled in the process.

   References

   Parish, E. (1897). Hallucinations and illusions. A study ofthe fallacies ofperception. London: Walter Scott.