Lecturer's Précis - Lichtheim
(1885)
"On
Aphasia"
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First published online 11:33 GMT 7th March 2002, Copyright Derek J.
Smith (Chartered Engineer). This version [HT.11 - reinstate lost links] dated 12:00 8th December 2010
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An earlier version of this material appeared in Smith (1996; Chapter 7). It is repeated here with minor omissions but supported with hyperlinks. |
1 - "Lichtheim's House"
In 1885, the German physician Ludwig Lichtheim
(1845-1928) contributed to the localisation debate
by drawing a set of explanatory diagrams showing how the main language centres might be connected up. Like Wernicke,
Bastian, and Charcot before him, Lichtheim placed
auditory memories and motor memories in different centres
(the "A" and "M" centres respectively),
thus:
"We may call 'centre of auditory images'
and 'centre of motor images' respectively, the parts of the brain where these
memories are fixed." (Lichtheim, 1885, p435.)
A third centre, the "B",
or concept, centre (from the German word Begriffe),
took care of the semantic element of the equation. The beauty of the resulting
diagram (Lichtheim's Figure 1 - now affectionately
known as "Lichtheim's house" and reproduced
below) is that a different aphasic syndrome naturally follows damage to any
single pathway or any single centre. Thus [on some rows, onwards links are
provided to the companion "Neuropsychology Glossary"] .....
|
Lesion |
Syndrome |
Further
Detail |
|
motor output pathway (5) |
subcortical motor aphasia |
|
|
acoustic input pathway (7) |
subcortical sensory aphasia |
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acoustic-semantic link (6) |
transcortical sensory aphasia |
|
|
semantic-motor link (4) |
transcortical motor aphasia |
|
|
acoustic-motor link (3) |
conduction aphasia |
|
|
acoustic centre (2) |
sensory (or Wernicke's) aphasia |
|
|
motor centre (1) |
motor (or Broca's) aphasia |
|
|
conceptual centre (B) |
anomic or semantic aphasia |
(NB: The codes in
brackets allow cross-reference to the Figure below.)
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Figure 1 - Lichtheim's "House": Here is a diagrammatic summary of Lichtheim's opinions on how information flows during language processing. The code letters used are A = Acoustic Centre, B = Concept Centre, and M = Motor Centre. The numbers are Lichtheim's originals, and refer back to the lesions named above. The core argument is set out in the following quotation: "The reflex arc consists in an afferent branch aA, which transmits the acoustic impressions to A; and an efferent branch Mm, which conducts the impulses from M to the organs of speech; and is completed by the commissure binding together A and M. When intelligence of the imitated sounds is superimposed, a connection is established between the auditory centre A, and the part where concepts are elaborated, B." (Lichtheim, 1885.) More than a century later, Lichtheim's House remains the reference model of choice during medical school training for the Routine Neurological Examination. See, for example, Fuller (1993). |
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Redrawn from a black and white original in Lichtheim (1885, p436; Figure 1). This version Copyright © 2002, Derek J. Smith. |
2 - "Lichtheim's
Crown"
Lichtheim, incidentally, was also one of the
first to recognise the diffuseness of the semantic
system. In his Figure 7 (shown in Smith, 1996, at Figure 7.5), he divided the Begriffe centre up into a set of distributed but
inter-connected "conceptual centres". This
anticipated Freud's distributed
object concept system, and the increasingly popular modern distributed
memory models, such as (exactly a century later) the attribute domain model of Allport
(1985).
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Figure 2 - Lichtheim's "Crown": Comments as for Figure 1, but noting the physical separation of component elements of the B- system. |
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Redrawn from a black and white original in Lichtheim (1885, p478; Figure 7). This version Copyright © 2007, Derek J. Smith. |
3 - Useful Links
Lichtheim's work was subsequently described by
Head (1926) as being "the high-water mark" of the diagram-making
approach to language localisation. For a more
adventurous modern variant of the basic model, see what we have termed
"McCarthy and Warrington's House" in McCarthy and
Warrington (1984).
References
See the
Master References List
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