Editing Agnosia (section)

== History ==
The term "agnosia" comes from the [[Ancient Greek]] ἀγνωσία (''agnosia''), "ignorance", "absence of knowledge". It was introduced by [[Sigmund Freud]] in 1891:<ref>"Freud 1891">Freud, Sigmund, Zur Auffassung der Aphasien, Vienna, 1891, p. 80</ref> "For disturbances in the recognition of objects, which Finkelnburg classes as asymbolia, I should like to propose the term 'agnosia'." Prior to Freud's introduction of the term, some of the first ideas about agnosia came from [[Carl Wernicke]], who created theories about [[receptive aphasia]] in 1874.  He noted that individuals with receptive aphasia did not possess the ability to understand speech or repeat words.  He believed that receptive aphasia was due to lesions of the posterior third of the left [[superior temporal gyrus]].  Due to these lesions, Wernicke believed that individuals with receptive aphasia had a limited deafness for certain sounds and frequencies in [[speech]].<ref name="Goldstein1974">{{cite journal|last1=Goldstein|first1=Marvin N.|title=Auditory agnosia for speech ("pure word-deafness")|journal=Brain and Language|volume=1|issue=2|year=1974|pages=195–204|issn=0093-934X|doi=10.1016/0093-934X(74)90034-0}}</ref>

After Wernicke, came Kussmaul in 1877 who attempted to explain why [[auditory verbal agnosia]], also known as word deafness, occurs.  Contrary to Wernicke's explanations, Kussmaul believed auditory verbal agnosia was the result of major destruction to the first left temporal gyrus.  Kussmaul also posited about the origins of [[alexia (acquired dyslexia)]] also known as word blindness.  He believed that word blindness was the result of lesions to the left angular and [[Supramarginal gyrus|supramarginal gyri]].<ref name="Goldstein1974" />

Heinrich Lissauer shared his ideas about agnosia after Wernicke and Kussmaul.<ref name="Goldstein1974" /> In 1890, he theorized that there were two ways in which object recognition impairment could occur.  One way in which impairment could occur was if there was damage to early perceptual processing or if there was damage to the actual object representation.  If the actual object representation was damaged, this would not allow the object to be stored in visual memory, and therefore the individual would not be able to recognize the object.<ref>{{cite journal|last=Vecera|first=P. S|author2=Gilds, S. K|title=What processing is impaired in appreceptive agnosia? Evidence from normal subjects|journal=Journal of Cognitive Neuroscience|year=1998|volume=10|pages=568–580|doi=10.1162/089892998562979|pmid=9802990|issue=5|s2cid=21568462}}</ref>  During the time of Wernicke, Kussmaul and Lissauer there was little known about the [[cerebral cortex]].  Today, with new [[neuroimaging]] techniques, we have been able to expand our knowledge on agnosia greatly.<ref name="M.S.Burns (2004)" />