Lecturer's Précis - Wernicke (1874)
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First published online10:35 GMT 11th March 2002, Copyright Derek J.
Smith (Chartered Engineer). This version [2.0
- copyright] dated 09:00 BST 14th June 2018
Wernicke's
(1874) Anatomically Grounded Control Hierarchy
In a pamphlet entitled "The Aphasic
Symptom-Complex" (1874), the German physician Carl Wernicke (1848-1905)
described a counterpart syndrome to Broca's, that is
to say, a condition in which verbal comprehension was severely impaired but the
ability to produce speech was intact. Wernicke reviewed the case histories of
patients with this type of verbal behaviour, and found that all had left
hemisphere lesions affecting the first temporal convolution at the junction of
the left temporal and parietal lobes. Hearing per se was found to be intact,
and so Wernicke placed auditory comprehension in this area.
Specifically, he held the first temporal convolution to be the store of
"sound images" (Klangbilder), the
basis of understanding spoken words after they had been heard. Wernicke also
developed a diagram of the location of his and Broca's
language areas, and of the connections between them. This diagram is reproduced
below, and remains to this day the "standard" left lateral view of
the language areas. It is not strictly speaking an information flowchart
as such, since it purports to be anatomically accurate (which makes it a picture),
however the general approach is important because it formed the basis for Lichtheim's
(1885) more schematic diagram 11 years later. Wernicke was subsequently
criticised by Freud
(1891) and Head (1926) for being too ready to rely on simplistic
diagrammatic explanations of language difficulties.
Wernicke (1874): Here is Wernicke's left lateral view of the language areas. Location b is Broca's area, and location a is Wernicke's area. Pathway a1-a represents the auditory pathway, and pathway b-b1 represents the speech output pathway. What is today called "Wernicke's Area" comprises Areas 22 (secondary auditory) and 39 (angular gyrus) of the left hemisphere. |
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References
Freud, S. (1891). Zur Auffassung der Aphasien. Leipzig: Deuticke.
Head, H. (1926). Aphasia and Kindred Disorders of Speech. Cambridge:
Cambridge University Press.
Lichtheim, L. (1885). On aphasia. Brain,
7:433-484.
Wernicke, C.
(1874). Der Aphasische Symptomencomplex. Breslau: Cohn and Weigert.