Perhaps the best known name in aphasiology is that of Broca. Not only did Broca write certain papers which turned out to be very important; but also the most intensively studied type of language disorder is named after him, i.e., Broca’s aphasia. Broca expressed his opinions on the loss of language after brain disorder, the issue mentioned above was very popular. In the first quarter of the 19th century the animal studies of Flourens in Paris apparently convinced most researchers that localization was not possible. Bouillaud, however, was not convinces, having received part of his training from Gall. He stated several times, starting in 1825, that language disorders only occur after frontal lesions. Retrospectively, we can say now that the debate entered its decisive phase in 1861, when Broca gave it a last push. Since then the principle of divisibility of the mind and the localization of functions seem to be the generally accepted position.
In 1861, a man named Leborgne died in Broca’s department, the surgical department of the Bicetre in Paris. He had been in that hospital for 21 years but Broca did not see him until 11 April 1861. By then Leborgne was in a very bad condition. However, it was known that apart from a severe speech problem this patient behaved like a perfectly sensible man. The only ‘word’ he could utter was: ‘tan’. Broca presented his patient’s brain on the 18th of April to the Anthropological Society as evidence in support of the thesis of Bouillaud. Four months latter Broca’s paper on the site of language was published, in which he gave a more detailed description of the patient’s history and of his own interpretation of the speech disorder ‘observed’ in this patient. In the paper, Broca elaborates on the different types of language, such as spoken language, mime, and writing. He defines aphemie, as he prefers to call it, as follows: there are cases where the general language faculty remains unaltered, where hearing is intact, where all the muscles, even those of the voice and articulation, obey the voluntary will and where a cerebral lesion abolishes ‘articulated language’ completely. What those patients lack is solely the faculty to articulate words. Broca gives a quite detailed description of what he knew about the patient he refers to as Tan (see picture “Brain of Legborgne”, alias Tan, from the Musee Dupuytren. Note bottling in erect position.). For instance, the man could not write when Broca saw him, nor was his comprehension intact. This suggests that the traditional account of ‘Broca’s aphasia’ is not inspired by this particular patient. In agreement with the clonical picture of Tan, the cerebral lesion Broca observed was rather large. He summarizes it thus: the destroyed organs are the followings: the small marginal inferior convolution (temporo-sphenoidal lobe); the small convolutions of the insula and the part subjacent to the corpus striatum; finally, on the frontal lobe, the inferior part of the transeversal convolution and the posterior half of the two large convolutions, referred to as second and third frontal convolution. Keeping in mind the extended history of symptoms of the patient, Broca attempts to locate the starting point of the lesion. He designates that part where the destruction is most severe as the original locus which presumably was also the cause of Tan’s speech problems. The site thus demarcated was the third frontal convolution. In his conclusions he argues that in this case the principal lesion was probably restricted to the third frontal convolution, but he is not certain whether this holds in general and whether localization on such a small scale was possible.
In his 1865 paper he presented some observations which he had not yet interpreted. Studying ht brains of aphasics he had noted that the extension of the lesion is not always related to the impact on the language. He interpreted this as showing that in some cases (those where there is a huge lesion and only partial loss of speech) the right hemisphere can take over some functions and support the left hemisphere. Broca was uncertain of the extent to which the right hemisphere is capable of speech production and why this take-over does not occur in some patients with relatively small lesions in the left hemisphere.
Considerint the content of the papers Broca wrote on language and the brain, and the fact that almost every general introduction to aphasia refers to Broca, it seems that he has been credited with too much. Broca mentioned that he observed differences in severity of speech disturbances but failed to describe in what respect these patients differ from each other. The way in which Broca inferred from the brain of Leborgne that the third frontal convolution is the site of the faculty of articulated languate would seem unacceptable to any scientifically oriented medical doctor. Therefore, his neuroanatomical work also seems to show sever shortcomings. Why then did Broca, or rather his work on aphasia, become so important? It may be that he formulated some ideas which had been energetically suppressed a few decades before but which by 1860 had become acceptable to wider circles.
Broca, P. 1861b. “Remarques sur le siege de la faculte de langage articule, suivis d’une obserbation d’aphemie (perte de la parole)”. Bulletins de la Societe Anatomique 6:330-57.
---. 1865. “Sur le siege de la faculte de langage articule”. Buletins de la Societe d’Anthropologie 6:377-93.
---. 1863. “Atrophieocmplete du lobule de l’insula et de la troisieme circonvolution du lobule frontale avec conserbation de l’intelligence dt de la faculte du langage articule. Obserbatin par Dr. Parrot”. Bulletins de la Societe d’Anthropologie 8:393-99.
Young, R.M. 1970. Mind. Brain and Adaptation in the Nineteenth Century. Oxford: Clarendon.