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 [HT.1 - transfer of copyright] dated 18:00 14th January 2010

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.

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.