In 1825, Jean-Baptiste Bouillaud read a paper at the Royal Academy of Medicine in Paris supporting Franz Gall's theory of a relation between speech and the frontal lobes. Bouillaud argued that if the frontal lobes are crucial to speech, 2 conditions must be satisfied: when the frontal lobes are affected, speech must also be affected; conversely, when the frontal lobes are spared, speech is also spared. Following these principles, he tested and argued in support of Gall's theory by analyzing the data from 2 neuropathological casebooks (Lallemand, 1820-1823; Rostan, 1820 and 1823). We now know that Bouillaud was wrong, since the crucial dichotomy is between the left and right hemispheres and not between the anterior and posterior areas. What is interesting is that the actual data refute Bouillaud's conclusion. We replicated his experiment by reanalyzing the 147 clinical cases described by Lallemand. There were, of course, some cases with frontal lesions and speech disorders; other cases, however, had speech disorders with lesions outside the frontal lobes, and still others had frontal lesions without speech disorders. Although Bouillaud did not notice it, as we expected, almost all patients with speech disorders had a left hemisphere lesion.
Claudio Luzzatti, Harry Whitaker. Jean-Baptiste Bouillaud, Claude-François Lallemand, and the Role of the Frontal LobeLocation and Mislocation of Language in the Early 19th Century. Arch Neurol. 2001;58(7):1157–1162. doi:10.1001/archneur.58.7.1157