- The term aschematia comes from the Greek words an (not) and schèma (form, scheme, or topographic map). It translates roughly as an 'inadequate mapping of space'. The term asché-matie was introduced in or shortly before 1905 by the French neurologist Pierre Bonnier (18611918) as an umbrella term for a group of symptoms characterized by an inadequate representation of the space occupied by some part of the body. As Bonnier wrote, "It is the affliction due to which certain parts of ourselves cease to fit in with the notion that we have of our body. When taking up too much space, there is hyper-schematia; too little, hyposchematia;oraplace that is not appropriate, paraschematia." Bonnier proposed the term aschematia as an alternative for the older terms malfunctioning of the somatopsyche and " coenesthesiopathy. All three terms have been used to denote an alteration of bodily object representations due to a lesion to the right parietal lobe. Due to their subjective nature, " hyperschematia, " hyposchematia, and " paraschematia cannot be observed directly in an affected individual. Therefore, diagnostic procedures tend to rely on the indirect evidence provided by the affected individual's drawings. In these drawings, the left side of a clock appears bloated, for example, and the petals on the left side of a daisy tend to be drawn larger, as well as greater in number than on the right side. Aschematia is considered a productive and subconscious manifestation of neglect. It may be accompanied by " negative autoscopy. Aschema-tia is usually classified as a variant of the "body schema illusions.ReferencesBonnier, P. (1905). L'aschématie. Revue Neurologique, 13, 605-609.Rode, G., Michel, C., Rossetti, Y., Boisson, D., Vallar, G. (2006). Left size distortion (hyperschematia) after right brain damage. Neurology, 67, 1801-1808.
Dictionary of Hallucinations. J.D. Blom. 2010.
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body schema illusion — Also known as body schema disturbance, *somato éidolie, *disorder of corporeal awareness, illusion of corporeal transformation, and illusion of corporeal displacement. All six terms are used to denote an illusory change in the size, relation,… … Dictionary of Hallucinations
hyperschematia — Also known as left size distortion. The term hyperschematia comes from the Greek words huper (to exceed a certain boundary) and schèma (form, scheme, topographic map). It translates roughly as overly detailed mapping of space . The term… … Dictionary of Hallucinations
hyposchematia — The term hyposchematia comes from the Greek words hupo (below, beneath) and schema (form, scheme, topographic map). It translates roughly as insufficiently detailed mapping of space . The term hyposchématie was introduced in or shortly before… … Dictionary of Hallucinations
macrosomatognosia — The term macrosomatognosia comes from the Greek words makros (large), soma (body), and gnosis (insight). It translates roughly to experiencing the body as larger . The term was introduced in or shortly before 1963 by the Dutch neurologist… … Dictionary of Hallucinations
microsomatognosia — The term microsomatognosia comes from the Greek words mikros (small), soma (body), and gnosis (insight). It translates roughly as experiencing the body as smaller . The term was introduced in or shortly before 1963 by the Dutch neurologist… … Dictionary of Hallucinations
negative autoscopy — Also known as negative heautoscopy and asomatoscopy. The term negative autoscopy is used to denote a variant of *autoscopy (i.e. the perception of a hallucinated image of oneself) characterized by the transient failure to perceive one s own… … Dictionary of Hallucinations
paraschematia — The term paraschematia comes from the Greek words para (beside, near, resembling, accessory to, beyond, apart from, abnormal) and schema (form, scheme, topographic map). It translates roughly as inadequate mapping of space . The term… … Dictionary of Hallucinations