Volume 1

Aphasia and kindred disorders of speech / by Henry Head.

  • Head, Henry, 1861-1940.
Date:
1926
Catalogue details

Licence: In copyright

Credit: Aphasia and kindred disorders of speech / by Henry Head. Source: Wellcome Collection.

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    leave intact those of a different order. Hence the paralysis of voluntary movement, of which we have reported so many examples; and here clinical observation is not in contradiction to physiological experience, because on the one hand animals from whom the cerebral lobes have been removed are incapable of all movement directed by intellectual combinations, and on the other hand, patients incapable of all voluntary movement in consequence of an affection of the brain, can in spite of this execute diverse automatic and instinctive movements; for example, they can withdraw a limb that is pinched, a movement that cannot be evoked simply by the will. Let us not forget that the muscular system is obedient to many different nervous powers. For example, the nervous power which presides over the movements of the internal muscles, such as the heart, the intestinal muscles, etc.; that which rules over the respiratory muscles and all those designated under the name of conservative or instinctive movements; that which governs voluntary movements, reflective, intellectual, all these are essentially different and their respective site has been rigorously determined by modern physiologists. These principles he applied to elucidate the loss of speech produced by a cerebral lesion1. He writes: It is evident that the movements of the organs of speech must have a special centre in the brain, because speech can be completely lost in individuals who present no other signs of paralysis, whilst on the contrary other patients have the free use of speech coincident with paralysis of the limbs. But it is not sufficient to know that there exists in the brain a particular centre destined to produce and to coordinate the marvellous movements by which man communicates his thoughts and feelings, but it is above all important to determine the exact situation of this coordinating centre. From the observations (cases) I have collected, and from the large number I have read in the literature, I believe I am justified in advancing the view that the principal lawgiver of speech is to be found in the anterior lobes of the brain. Let us admit for an instant that this portion of the brain is the site of the nervous principle which presides over the movements of speech; following this hypothesis, it would be necessary that, in those cases where the anterior lobes of the brain were altered, speech should be more or less deranged, and this should be true of the inverse condition also. It would follow moreover, that speech should remain, when the affection occupies other parts of the brain than the lobules indicated. It might be asked how it is that the tongue continues to execute a great number of movements, even in those cases where the anterior portion of the brain is pro¬ foundly disorganised, if it is true that this part presides over the production of speech2. This objection, which I foresaw, is more specious than real. In effect 1 [13L P- H8- 2 [13L P- i69-