Short Description or Definition
Visual hallucinations can be defined as false sensory experiences that occur in the absence of an external stimulus. The spectrum of abnormal visual sensations can range from simple images of dots, lines, flashing lights, or geometric shapes to elaborate and vivid images of people, animals, objects, or scenes.
In contrast to hallucinations, the term visual illusion has been applied to situations in which an external stimulus is present, but the perception of the image is altered in terms of shape, size, number, location, movement, or temporal duration. For example, an individual’s face may seem stretched and distorted, with the abnormal visual image persisting after the person leaves the room.
Although the traditional distinction between hallucinations and illusions is firmly established in the neuropsychological literature, a strict taxonomic separation between these two entities may not be fully justified or relevant owing to...
References and Readings
- Cummings, J. L., & Mega, M. S. (2003). Hallucinations. In Neuropsychiatry and behavioral neuroscience (pp. 187–199). New York: Oxford.Google Scholar
- Jonas, J., Frismand, S., Vignal, J.-P., Colnat-Coulbois, S., Koessler, L., Vespignani, H., Rossion, B., & Maillard, L. (2014). Right hemisphere dominance of visual phenomena evoked by intracerebral stimulation of the human visual cortex. Human Brain Mapping, 35, 3360–3371.PubMedCrossRefPubMedCentralGoogle Scholar
- Tekin, S., & Cummings, J. L. (2003). Hallucinations and related conditions. In K. M. Heilman & E. Valenstein (Eds.), Clinical neuropsychology (4th ed., pp. 479–494). New York: Oxford University Press.Google Scholar