A History of Neuropsychology. Группа авторов

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СКАЧАТЬ Agraphia from 1861 to 1965

      Victor W. Henderson

      Departments of Health Research and Policy (Epidemiology) and of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA

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      Abstract

      Studies of alexia and agraphia have played historically important roles in efforts to understand the relation between brain and behavior. In the second half of the 19th century, works by Paul Broca and Carl Wernicke led to the concept of delimited cortical centers in the left cerebral hemisphere concerned with discrete aspects of spoken and written language. These specialized centers were linked by white matter pathways. Charlton Bastian, Jean-Martin Charcot, Sigmund Exner, and Jules Dejerine championed center–pathway models of reading and writing. Dejerine played a dominant role, rejecting the idea of a left frontal lobe center that mediated writing and proposing a unique, specialized role for the left angular gyrus in both reading and writing. In 1891 and 1892, he detailed the symptoms of alexia and agraphia that resulted from injury to the left angular gyrus and from the isolation of the left angular gyrus from visual input required for reading. During the early 20th century, his work and that of other so-called diagram makers was confronted and largely discredited by Pierre Marie, joined later by Henry Head and Kurt Goldstein. In the 1960s, the center–pathway model was resurrected and refined by Norman Geschwind. He drew upon foundational works of Dejerine, Hugo Liepmann, and others to describe syndromes resulting from cortical disconnections and, in doing so, helped to establish a framework for the modern discipline of behavioral neurology.

      © 2019 S. Karger AG, Basel

      Introduction

      Aphasia is an acquired disorder of language defined principally by deficits in speech and speech understanding. Reading and writing are the visual counterparts of spoken language. Disorders of reading and writing, viz., alexia and agraphia, are often considered in relation to the language impairments of aphasia. Studies of aphasia, alexia, and agraphia play a historically important role in understanding the relation between brain function and complex behaviors.

1861 is a useful starting point for the history of alexia and agraphia. This is the year in which the French surgeon and anatomist Paul Broca (1824–1880) described his first case of aphemia (Broca’s aphasia) [1]. A convenient place to conclude is 1965, when Boston neurologist Norman Geschwind (1926–1984) ushered in the modern era of brain-behavior studies with his publication on cerebral disconnection syndromes [2]. Aspects of this topic have been reviewed [3, 4].

      Broca proposed an anatomical center within the cerebral cortex that mediated articulate language. This model, expanded by others to accommodate reading and writing, came to include several cortical centers with discrete functional roles, interconnected by subcortical white matter pathways. As in Broca’s original case, the role of a center was inferred from symptoms after tissue destruction within a delimited cortical area. The role of a pathway was often inferred from the function of centers that it connected. Early proponents of the center–pathway model included Wernicke, Bastian, Charcot, and particularly Dejerine, who provided a key theoretical framework for alexia with and without agraphia. Opposing views were espoused by Hughlings Jackson and later by Marie, Head, and Goldstein. Geschwind’s work represented a rediscovery and elaboration of earlier models in the mode of Broca and his successors.

      Setting the Stage

Franz Gall (1758–1828), an accomplished neuroanatomist linked to the pseudoscience of phrenology, observed physical features of the head and related these to mental faculties. While still a student, he famously associated protruding eyes with an excellent memory for words. During the early 19th century, Gall described regional anatomical variations in the human brain, which he associated with mental abilities and behaviors observed during life [5]. He proposed cerebral organs as the morphological substrates for an intellectual faculty, psychological trait, or moral tendency. Thus, Gall reasoned that brain tissue behind the orbits represented organs for word memory and language sense, and their enlargement led to protruding eyes [5]. Gall did not identify organs for writing or reading. His controversial doctrines were popular throughout the 19th century but were opposed by the Catholic Church and by the scientific establishment.

Beginning in 1825, the French physician Jean–Baptiste Bouillaud (1796–1881) reported series of patients who had lost the ability to speak but understood what was said to them. At autopsy, he described areas of injury within the anterior (frontal) lobes, and Bouillaud proposed that a “special cerebral center…distinct and independent” (p 42) was responsible for speech [6]. This interpretation accorded with Gall’s organ for language sense, which Gall had located within a more delimited portion of the anterior lobes [5].

Building on Bouillaud’s work, Louis Victor Marcé (1828–1864) in 1856 described patients whose speech or writing was impaired; 2 patients wrote well despite speaking poorly [7]. By way of explanation, Marcé proposed that the agent responsible for speech coordination, but not the agent for writing coordination, had been damaged. These cases implied that a brain faculty coordinated the graphic representation of ideas, the formation of letters, and the assembly of letters into syllables and words. The role of this writing faculty was analogous to the speech center described by Bouillaud [6]. Marcé recognized, as had Bouillaud, that speech and writing were usually impaired together after brain injury. He reasoned that the speech and writing faculties were separate but intimately connected, but Marcé did not propose anatomically distinct centers.

      1861: Broca’s Aphemia

Bouillaud’s notion of a speech center in the anterior lobes was refined by Broca. In 1861, members of the Anthropological Society of Paris, co-founded by Broca the year before, debated the relation between intelligence and brain size. Noting that the brain is a complex organ, a debate participant – Bouillaud’s son-in-law Ernest Auburtin (1825–1893) – asked whether different parts of the brain should be considered separately. He mentioned a patient who had lost speech but who retained the ability to understand and, further, he predicted that an autopsy would eventually confirm a softening (stroke) within the anterior lobes in accordance with Bouillaud’s ideas [8].

      By remarkable coincidence, a man with similar symptoms was admitted to Broca’s surgical service at the Bicêtre hospital 8 days later. Years before, he had lost his ability to speak, and he was paralyzed on his right side. He died of infection shortly thereafter, and Broca reported clinical and autopsy findings to the Anthropological Society [1]. His patient “understood almost all that one said to him” (p 236), and Broca interpreted this finding as evidence that intelligence was spared. The autopsy showed that “the frontal lobe of the left hemisphere was softened in most of its extent,” particularly affecting “the middle part of the frontal lobe of the left hemisphere” (p 237) [1]. СКАЧАТЬ