- visual perseveration
- Also known as perseveration. Both terms are indebted to the Latin verb perseverare,which means to maintain or to keep on stating. The term visual perseveration was introduced in or shortly before 1949 by the British neurologist Macdonald Critchley (1900-1997) to denote the illusory reoccurrence of visual percepts after the stimulus-object has moved out of focus. As Critchley explains, "This experience is not ordinarily a persistent one, but is intermittent. Only very rarely can it be demonstrated at will. There are two main varieties, namely: (1) visual perseveration in time, or paliopsia; and (2) illusory visual spread, a visual extension, expansion, and elongation; in other words, a kind of spatial perseveration of objects seen." A third variety of visual perseveration is the *trailing phenomenon. As to the pathophysiology of visual perseveration, it has been suggested that the visual parietal regions may be involved. Visual perseveration is commonly classified as a * reduplicative phenomenon or as a type of *metamorphopsia (which is itself classified as a * sensory distortion). Conceptually, it is related to reduplicative phenomena occurring in any of the other sensory modalities. Thus perseveration in the auditory modality is referred to as auditory perseveration or *palinacusis, and perseveration in the tactile or somatosensory modality as perseverative somaesthetic sensation or * palinaesthesia. Irrespective of the sensory modality involved, perseveration tends to be associated in an etiological sense with * aurae occurring in the context of paroxysmal neurological disorders such as migraine and epilepsy and with the use of *hallucinogens such as LSD and mescaline. The term perseveration is also used in psychiatry to denote a formal thought disorder characterized by the aimless repetition of words, sentences, or themes.ReferencesCritchley, M. (1949). Metamorphopsia of central origin. Transactions ofthe Ophthalmologic Society of the UK, 69, 111-121.Critchley, M. (1953). The parietal lobes. London: Edward Arnold & Co.ffytche, D.H., Howard, R.J. (1999). The perceptual consequences of visual loss: 'Positive' pathologies of vision. Brain, 122, 1247-1260.Klee, A., Willanger, R. (1966). Disturbances of visual perception in migraine. Acta Neurolog-ica Scandinavica, 42, 400—114.Santhouse, A., Howard, R., ffytche, D. (2000). Visual hallucinatory syndromes and the anatomy of the visual brain. Brain, 123, 2055-2064.
Dictionary of Hallucinations. J.D. Blom. 2010.
Look at other dictionaries:
illusory visual perseveration — see illusory visual spread … Dictionary of Hallucinations
perseveration — see visual perseveration … Dictionary of Hallucinations
illusory visual spread — Also known as illusory visual perseveration. Both terms were introduced in or shortly before 1949 by the British neurologist Macdonald Critchley (1900 1997) to denote a type of visual perse veration characterized by the visual extension,… … Dictionary of Hallucinations
polyopia — Also known as polyopsia. Both terms stem from the Greek words polus (much, many) and opsis (seeing). They refer to the perception of an image that repeats itself within the visual field. The ensuing coexistence of various similar images within … Dictionary of Hallucinations
reduplicative phenomenon — The term reduplicative phenomenon is indebted to the Latin noun reduplicare, which means to double. It is used as an umbrella term for a group of illusory perceptual phenomena characterized by the perseveration, reduplication, or reoccurrence… … Dictionary of Hallucinations
metamorphopsia — The term metamorphopsia comes from the Greek words metamorphoun (to change the form) and opsis (seeing). It translates roughly as seeing an altered form . It is not clear who introduced the term, but it appears in a medical lexicon as early as … Dictionary of Hallucinations
trailing phenomenon — Also known as trailing effect and tracers. The first two terms were introduced in or shortly before 1971 by the American psychiatrist and addiction specialist Harvey Asher to denote a visual phenomenon which is associated with the (prior) use… … Dictionary of Hallucinations
palinopsia — pali·nop·sia (pal″ĭ nopґse ə) [palin + opsia] visual perseveration; the pathologic continuance or recurrence of a visual sensation after the stimulus is gone … Medical dictionary
Glossary of psychiatry — In this glossary of psychiatric terms, mostly Greek, secondly French and German and some English terms, as used in psychiatric literature, were defined. We have included many other terms with the passage of time and aim to broaden this article to … Wikipedia
Mental status examination — Intervention ICD 9 CM 94.09, 94.11 The mental status examination in the USA or mental state … Wikipedia