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TWO: Neuropathology and Symptomatology in Alzheimer Disease: Implications for Caregiving and Competence
- Johns Hopkins University Press
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mc h a t e r t w o Neuropathology and Symptomatology in Alzheimer Disease Implications for Caregiving and Competence Roger A. Brumback, M.D. Alzheimer disease (AD) is one of many conditions that produce the clinical syndrome of dementia,which is the insidiously progressive loss of intellectual , cognitive, and social abilities (Brumback & Leech, 1994). Dementia can occur at any age (e.g., adrenoleukodystrophy causing dementia in late childhood ) (Riva, Boca, & Bruzzone, 2000). However, the term dementia is most often used to describe conditions affecting adults past the fourth decade of life, of which Alzheimer disease is the most common dementing disorder (Fratiglioni et al., 1991; Evans et al., 1989; Evans et al., 1991; Bachman et al., 1993; Brumback & Leech, 1994; Kukull & Ganguli, 2000). Dementia must also be distinguished from senility, a term used in the late eighteenth century to imply age-related mental infirmity (Oxford English Dictionary, 1971). During the nineteenth and twentieth centuries that term developed the connotation of cognitive incompetency occurring in all older people at a specific age, in particular at age sixty-five years (Brumback & Leech, 1994). This chapter describes the current understanding of the progression of the symptoms in AD, correlating them with the progression of the neuropathologic process. Neuropathology and Symptomatology 25 m Dementia as a Clinical Syndrome Dementia is the result of the progressive loss of brain functioning due to reduced functional connectivity of the billions of synapses linking neurons in the brain. This loss of neuronal interconnectivity can be the result of either or both physiologic impairment of neuronal and synaptic activity or pathologic destruction of neurons, axons, dendrites, and synapses. Behavioral assessment of dementia has involved the use of a wide variety of rating scales (Gottfries et al., 1982; Shader, Harmatz, & Salzman, 1974; Spiegel et al., 1991; Rosen, Mohs, & Davis, 1984; Overall & Schaltenbrand, 1992; Blessed, Tomlinson, & Roth, 1968; Schmitt et al., 1997; Morris, 1993; Reisberg et al., 1982; Reisberg et al., 1987; Cole & Dastoor, 1983; Schneider et al., 1996; Knopman et al., 1994; Tariot et al., 1995; Cummings et al., 1994; Cohen-Mansfield, 1986; Reisberg, 1988; Lucas et al., 1998). These scales have been used to quantify cognitive function and, by implication of a change in value from normal, the severity and the rate of progression of dementia (Milberg, 1996; Malloy et al., 1997). The MiniMental State Examination (MMSE), originally developed by Folstein and colleagues (1975), is the scale most often used (Malloy et al., 1997) (table 2.1). It consists of a series of thirty tasks to be performed by the patient, scored from 0 (lowest) to 30 (highest). Normal individuals usually achieve a score of 25 or higher (although some normal individuals can score as low as 21). Scores of 20 or lower indicate varying degrees of severity of dementia (scores of 10 to 20 for moderate dementia and 9 or lower for severe dementia). In chapter 16, Scheirton refers to this examination as a useful tool for distinguishing the kinds of educational interventions that can assist the patient and family caregivers during early, middle, and late stages of the disease. Individuals with neurodegenerative dementias such as Alzheimer disease progressively experience a linear decrease of 2 to 4 points per year in score on the MMSE. Similar linear deterioration of function over time has been identified with most of the other rating scales developed to assess dementia. The fallacy in using such linear scales (which assign a single overall number to brain function) is the implication that the brain is a homogenous organ. In contrast to the brain, the kidney (like most other organ systems in the body) is a homogeneous organ composed of millions of units (nephrons) that all perform the same functions. [34.230.84.106] Project MUSE (2024-03-19 12:54 GMT) table 2.1. Mini-Mental State Examination (MMSE) Items Correlated with Cognitive Function and Brain Areas Basic Instructions Item for Scoring Major Cognitive Function Tested Associated Brain Area Ask a series of questions about time and place Name three common objects (examples include “ball,”“apple,”“table,” “penny,”“cigarette,”“car,”“door”); pronounce each word carefully; have patient immediately repeat all three and record success; then repeat each until patient learns all three; tell patient to remember these words for the future Serial 7’s (starting at 100 serially subtract 7); stop after 5 answers Spell the word world backwards Ask the patient to recall the three object words memorized earlier 1. What year is it? 2. What season are we in? 3. What...