-
Part II: From Alzheimer to the Present
- Johns Hopkins University Press
- Chapter
- Additional Information
PART II From Alzheimer to the Present The concept of disease begins with people and their minds. First, the notion of disease, or ‘‘dis-ease,’’ implies that we start with the suffering of an individual human being. Lay concepts of illness are critical to understanding the behavior of patients and their families, and it is these ideas that largely determine what sort of cases come into the view of the clinician. However, once the patient appears before the clinician, it is the professional’s identification of a condition as a disease that dominates society’s models of illness (or at least the public discourse about disease). Thus the scientific concept of Alzheimer disease (AD) begins with the clinical characterization of a pattern of progressive cognitive impairment. This pattern occurring in the elderly has been described in a literature extending back for centuries. The second critical aspect of the development of the initial concept of AD was the application of labels to characterize the disease state. The term dementia, implying loss of mentation, predates AD. Perhaps fifty years before Alzheimer’s time, other clinicians had characterized this loss of cognitive abilities and had begun to differentiate it from other clinical conditions. For example, dementia was differentiated from amentia, or mental retardation; that is, dementia requires normal intellect and a deterioration to an impaired level of thinking ability. Dementia was also differentiated from delirium, which was defined as changes in cognition occurring often acutely in response to medical illness. Thus, the initial characterization of neuropsychiatric diseases depended on the skills of clinicians (or others) to observe individuals and to cluster their symptoms into certain categories. However, the development of methods to examine brain tissue allowed the concept of clinical pathological entities—of which AD is one—to emerge. When 48 Concepts of Alzheimer Disease that conceptual level has been reached, it becomes possible to develop theories about etiology and corresponding strategies for therapeutic intervention. The chapters in this section describe the twists and turns in the development of AD as a clinicopathologic entity from Alzheimer’s time to the present. Certain issues have consistently been at play in this development: the related problems of differentiating the normal from the pathological, and aging from disease; and of sorting out the various roles that psychosocial, environmental, and genetic factors play in producing dementia. Before the late nineteenth century, the techniques to preserve the brain for examination and to process tissue in a way that microscopic evaluation could be conducted did not exist. Alzheimer, however, was practicing at a time when a revolution was occurring in our ability to examine pathological material from patients who suffered from dementia. Moreover, while Alzheimer was applying the techniques of the new field of neuropathology to understanding disease, the rudimentary concepts that would lead to future work on understanding the neurochemical basis of the neurotransmitter alterations in dementia also emerged. The chapter by Heiko and Eva Braak describes the development of effective silver staining techniques in Alzheimer’s time—crucial to Alzheimer ’s discovery of neurofibrillary tangles. The chapter goes on to describe recent developments in knowledge about the nature of the neurofibrillary tangles, including the selective vulnerability to degeneration of particular neurons at specific locations within the brain. Hans Förstl’s chapter describes how the concept of AD was handled in the German neuropsychiatric literature from Alzheimer’s time through the early 1930s. One of the issues that faced clinicians, and continues to face them today, was the differentiation of disease from normality. As they age, many individuals develop changes in cognitive abilities, but for most the changes are fortunately not as severe as for those suffering from AD. Clinicians had a difficult time differentiating normal age-related problems from pathological states. AD was originally conceptualized as a presenile dementia, meaning it occurred in individuals younger than 65. When a person who is 50—Auguste D.’s age was when she started with her symptoms—develops a progressive dementia, this state appears to be more obviously a disease than when it occurs in a person who is 85. But histopathologic study of brain tissue failed to establish solid ground for this distinction. Jesse Ballenger’s chapter describes how the difficulty of establishing a firm basis in brain pathology for the clinical expression of dementia led [3.235.199.19] Project MUSE (2024-03-19 04:01 GMT) From Alzheimer to the Present 49 American psychiatrists to emphasize the role...