« PreviousContinue »
noticed a certain number of curious observations bearing upon this interesting subject, I have thought it not a useless task in this short essay to give a résumé of the labours of scientific observers in various parts of the world, who are endeavouring to elucidate this complex question, adding thereunto the result of my own personal experience, the clinical history of my own cases being given with a considerable amount of detail.
From time immemorial loss of speech, unconnected with any other paralytic symptom, must have been noticed; but it is only of late that the diagnostic value of this symptom has been recognised, and its pathology attempted to be explained; and it is probable that early observers may have confounded paralysis of the tongue from disease of the hypoglossus, with that loss of the memory of words, and inability to give expression to the thoughts which characterise aphasia.
It has been stated that Hippocrates confounded aphasia with aphonia ; I am inclined, however, to think that the reputation of the Father of Medicine has suffered from the fault of his English translator, for in his . Epidemics'* he describes a disease characterised by sore throat and hoarseness of voice, using the phrase “golloi pápvyyas énóvnoаv povaż kakoúpeval,” the last two words of which have been erroneously rendered in English “loss of speech !” In another place Hippocrates clearly distinguishes between loss of speech and loss of voice, by employing the words “ üvavdos” and “ápovos" in the description of the same case.
The following passage from Sauvages shows that the distinction was clearly understood by him: “Aphonia
* Hippoc. de Morb. Pop.,' lib. iii, sec. ii, p. 80, edit. Innys.
est plenaria vocis suppressio. Mutitas (quibusdam alalia) est impotentia voces articulatas edendi, seu sermonem proferendi.”
As this subject has more particularly engaged the attention of French pathologists during the last few years, it is most convenient to consider first their researches.
The minute anatomy of the surface of the brain not being to my knowledge described in any English author with the same amount of detail as occurs in M. Broca's description, I have condensed the following account from his work, “Sur le Siège de la Faculté du Langage Articulé.”
The anterior lobe of the brain comprises all that part of the hemisphere situated above the fissure of Sylvius which separates it from the temporo-sphenoidal lobe, and in front of the furrow of Rolando, which divides it from the parietal lobe. The direction of the furrow of Rolando is nearly transverse; starting from the interhemispheric median fissure, it descends almost in a direct course, but with some slight flexuosities, terminating below and outside of the fissure of Sylvius, which it meets almost at a right angle, behind the posterior border of the lobe of the insula; in front this furrow is bounded by the transverse frontal convolution, and behind by the transverse parietal convolution.
The anterior lobe is composed of two stories or divisions, one inferior or orbital, formed by several convolutions called orbital, which lie on the roof of the orbit; the other superior, situated beneath the frontal and under the most anterior part of the parietal. This superior division of the anterior lobe is composed of four fundamental convolutions called the frontal convolutions ; of these, one is posterior, the others are anterior. The posterior, slightly tortuous, forms the anterior boundary of the furrow of Rolando; it is therefore almost transverse and ascends from without inwards from the fissure of Sylvius to the great median fissure which receives the falx cerebri; it has been variously described as the posterior, transverse, or ascending frontal convolution. The three other convolutions of the superior division are very tortuous and complicated; they have all an anteroposterior direction, and, running side by side, extend from before backwards over the whole length of the frontal lobe, terminating behind at the tranverse frontal, into which convolution they all three enter; they are distinguished by the names of first, second, and third frontal convolutions. The first and second frontal convolutions call for no special remark, but the precise relations of the third are important. This convolution, by its superior border, is contiguous to the second frontal in its whole length; in reference to its inferior border, the anterior half is in contact with the most external orbital convolution, whereas the posterior half is free, and forms the superior border of the fissure of Sylvius, which separates it from the temporo-sphenoidal lobe. In consequence of this latter relation, the third frontal is sometimes called the superior marginal convolution, the name of inferior marginal being given to the superior convolution of the temporo-sphenoidal lobe, which forms the inferior border of the fissure of Sylvius.
In drawing asunder these two convolutions which bound the fissure of Sylvius, the lobe of the insula is exposed, which covers the extra-ventricular nucleus of the corpus striatum. The result of these relations is,
that a lesion which is propagated from the frontal to the temporo-sphenoidal lobe, or vice versâ, will pass almost necessarily by the lobe of the insula, and from thence, in all probability, it will extend to the extraventricular nucleus of the corpus striatum, seeing that the proper substance of the insula which separates the nucleus from the surface of the brain is composed of only a very thin layer. *
As far back as 1825 Bouillaud placed the faculty of articulation in the frontal lobes of the brain, which he considered to be the organs of the formation of words and of memory; and he stated that the exercise of thought demanded the integrity of these lobes; he also collected 114 observations of disease of the anterior lobes accompanied by lesion of the faculty of speech.
Audral, who has investigated the subject very fully, analysed 37 cases, observed by himself and others, of lesion of one or both of the anterior lobes, and found that speech was abolished 21 times, and retained 16 times; when the lesion was unilateral, however, he has not stated on which side the morbid condition existed. He has also collected 14 cases where speech was abolished without any alteration in the anterior lobes, but where the lesion existed in the middle or in the posterior lobes. He cites the case of a woman, eighty years of age, who, three years before entering the hospital, was suddenly deprived of speech, without lesion of the intelligence, motion, or sensation, and still retaining the power of walking about; she presented, however, signs of organic disease of the heart, and died at last
* Vide Plate facing title page.
of pulmonary apoplexy. At the necropsy there was found in the left hemisphere, softening of cerebral substance on a level with, and external to, the posterior extremity of the corpus striatum; and in the right hemisphere, a similar softening at the junction of the anterior and posterior half of the hemisphere.*
Then comes Dr. Dax, who places the lesion exclusively in the left hemisphere; basing his theory on the fact that when the subjects of aphasia are at the same time hemiplegic, the paralysis is always on the right side, his essay containing no less than 140 observations in support of his views.
His son, Dr. G. Dax, following in the wake of his father, wrote an essay, in which, whilst confirming the theory as to the lesion being in the left hemisphere, he localised it more especially in the anterior and external part of the middle lobe.
The ne plus ultra of pathological topography, however, was reserved to M. Broca, who defines the seat of lesion in aphasia to be “the posterior part of the third frontal convolution of the left hemisphere!” M. Broca's views are detailed at some length in the proceedings of the Paris Anatomical Society for 1861, and the following is a brief summary of the two cases upon which he has founded his somewhat startling theory.
A man named Leborgne, 50 years of age, and epileptic, was admitted into the surgical ward of M. Broca, at Bicêtre, for phlegmonous erysipelas, occupying the whole of the right lower limb. When M. Broca questioned him about the origin of his disorder, he only answered by the monosyllable “ Tan,” repeated
**Clinique Médicale,' chap. iv, observ. xvii.