Fearful Asymmetry: Bouillaud, Dax, Broca, and the Localization of Language, Paris, 1825–1879 by Richard LeBlanc (review)

Neurology is the medical specialty par excellence that celebrates its early luminaries. The story of those who led to our understanding of language disorders is a prime example. Richard LeBlanc, neuro-surgeon and physician-scientist at the Montreal Neurological Institute (MNI), has woven together an authoritative and engaging story of the leading role played by the French school of neurology in the latter half of the nineteenth century and the important contributions from Germany and England. He ends with more recent intraoperative observations by Penfield and colleagues.

The title reflects the vigorous neurological debates in Paris necessary to overcome the prevailing view of Xavier Bichat that symmetrical organs, including the brain, had unitary function. Those debates were the culmination of centuries of speculation about brain function beginning with Leonardo and the medieval view that the ventricles were the seat of the soul. René Descartes moved outside the ventricles and suggested the pineal as the chosen site. Thomas Willis followed his remarkable drawings of the cerebral vasculature with the suggestion that the higher faculties of reason and memory resided in the folds of the cortex.

The phrenologists enter the story in Vienna in the 1780s. Gall speculated that personal attributes, personality traits, and moral character resided in specific areas of the brain. The degree of development in those areas would be reflected in the dimensions of the overlying skull. Although his techniques fell out of favour, his speculations evoked the interest of Bouillard and Broca and were the beginning of contemporary understanding of cerebral localization.

Jean-Baptiste Bouillard has been a neglected figure and is featured appropriately by LeBlanc. Bouillard's careful study of patients led to descriptions of partial disturbances of language and lively debates at the Royal Academy of Medicine. The second half of the nineteenth century was a time of ongoing clinical observation, pathological examination, and unrelenting debates concerning the nature of language and its cerebral localization, including vigorous but unenlightening exchanges concerning sex and racial differences in brain size.

Paul Broca entered the scene in 1861 during a debate at the Royal Academy of Medicine. Later, in 1863, he published a paper describing six patients with aphemia (used in Modern Greek to mean infamy). It was later changed to aphasia (which refers to loss of speech). Baillarger drew attention to the emotional aspects of Broca's aphasia. Trousseau, Dax senior, Bouillard, and Broca pursued lively debates in the clinic and in the literature about the cerebral localization of speech. Bichat's generally accepted doctrine of identical function in symmetrically paired organs weighed heavily early on in those debates but abridged papers by Dax published in the Weekly Gazette in April 1865 finally established left-hemisphere language dominance.

LeBlanc then takes us on a carefully documented tour of the disagreements, clinical examples, and tissue examinations we associate with a variety of clinicians and pathologists, notably Baillarger, Brodmann, Cécile and Oskar Vogt, and Constantin von Economo. Attention to the neuroanatomical features underlying cortical function was provided by Meynert and Wernicke, who identified regions necessary for the understanding and interpretation of spoken words (word deafness). Dejerine later identified damage to the angular gyrus as the cause of word blindness.

John Hughlings Jackson, a young neurologist at the London Hospital, was the main English contributor to this early history of the localization of language. Jackson's particular interest was studying what he termed two aspects of language – the intellectual aspect that suffers in aphasia and the emotional aspect or "the ability to exhibit states of feeling." Debate continued on both sides of the channel about the anatomic location of various aspects of language disturbance.

LeBlanc ends with reference to the in vivo work of Wilder Penfield and Lamar Roberts, at the time a fellow at the MNI. Herbert Jasper, a neurophysiologist who documented EEG changes arising from cortical stimulation during surgery, was an important co-investigator. Those stimulation...