Compendium of regional diagnosis in affectations of the brain and spinal cord / Translated by F.S. Arnold.

  • Bing, Robert.
Date:
1913
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Licence: In copyright

Credit: Compendium of regional diagnosis in affectations of the brain and spinal cord / Translated by F.S. Arnold. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    present, little relevance to the subject of regional diagnosis. Special forms, such as transcortical aphasias, visual, tactile, amnesic aphasias, etc., which are developed when Broca's and Wernicke's centres are cut off from each other, from the corti- cal centres for the higher psychical functions {ideation centres), or from the sensory areas, cannot be ascribed to lesions of ordinary type, but must be regarded as depending on many varied and variable interruptions of nerve tracts. The trans- cortical aphasias are, further, probably for the most part intermediate stages of cortical aphasias progressing towards recoverv. The localization of the psychic speech mechanism in the left cortex is the rule only in right-handed individuals. Left-handed persons have their speech area in the right hemisphere. At the same time, cases have been recorded of motor aphasia in left-handed individuals as the result of lesions of the left inferior frontal convolution. It is no matter for surprise, therefore, and no argument against Broca's teaching, if right-handed individuals occasionally fail to become aphasic after destruction of the left inferior frontal convolution ; they must be regarded as exceptional individuals, whose speech centres are on the right side. (It is, indeed, extremely probable that these cortical centres were originally bilateral.) From the point of view of localization, we may sum up what has been said above concerning the study of disorders of speech, as follows : 1. Motor aphasia points to a lesion of the posterior inferior portion of the frontal lobe, on the left side in right-handed individuals, and vice versa. 2. Sensory aphasia points to a lesion of the posterior superior portion of the temporal lobe, on the left side in right- handed individuals, and vice versa. 3. In the rare cases in which these aphasias are pure —i.e., uncomplicated by defects of inner speech, of read- ing and writing—a subcortical lesion, not very superficially situated, may be diagnosed with a high degree of probability. Exceptionally we may have to do with a minimal cortical lesion. 4. The rule of a left-handed locaHzation in right-handed individuals, and vice versa, is subject to rare exceptions.