Senility is a disease commonly referred to as dementia. It affects 4 million Americans every year and is a major cause of disability in old age (Bunch, 1997, p. 106). Its prevalence increases with age (Bunch, 1997, p. 106). Dementia is characterized by a permanent memory deficit affecting recent memory in particular and of sufficient severity to interfere with the patient's ability to take part in professional and social activities (Bunch, 1997, p. 106). Although the aging process is associated with a gradual loss of brain cells, dementia is not part of the aging process (Horton and Smart, 1984, p. 320). It also is not synonymous with benign senescent forgetfulness, which is very common in old age and affects recent memory (Bunch, 1997, p. 106). Although the latter is a source of frustration, it does not significantly interfere with the individual activities (or what the individual considers trivial.) Furthermore, patients with benign forgetfulness usually can remember what was forgotten by utilizing a number of subterfuges, such as writing lists or notes to themselves and leaving them in conspicuous places (Horton and Smart, 1984, p. 320). Individuals with benign forgetfulness also are acutely aware of their memory deficit, while those with dementia - except for in the early stages of the disease - have no insight into their memory deficit and often blame others for their problems.
In addition to the memory deficit interfering with the patient's daily activities, patients with dementia have evidence of impaired abstract thinking, impaired judgement, or other disturbances of higher cortical functions such as aphasia (the inability to use of comprehend language), apraxia (the inability to execute complex, coordinated movements), or agnosia (the inability to recognize familiar objects) (Bunch, 1997 p.107).
Dementia may result from damage to the cerebral cortex, as in Alzheimer's disease, or from damage to the subcortical structures, such as white matter, the thalamus, or the basal ganglia. Although memory is impaired in both cortical and subcortical dementias, the associated features are different (Bunch, 1997, p. 107). In cortical dementias, for example, cognitive functions such as the ability to understand speech and to talk and the ability to perform mathematical calculations are severely impaired (Bunch, 1997, p. 107). In subcortical dementias, on the other hand, there is evidence of disturbances of arousal, motivation, and mood, in addition to a significant slowing of cognition and of information processing (Bunch, 1997, p. 107).
Alzheimer's disease, the most common cause of presenile dementia, is characterized by progressive disorientation, memory loss, speech disturbances, and personality disorders (Bunch, 1997, p. 107). Pick's disease, another cause of dementia, is more common in women (Bunch, 1997, p.107). In the early stages of Pick's disease, changes in personality, disinhibition, inappropriate social and sexual conduct, and lack of foresight may be evident - features that are not common in Alzheimer's disease (Bunch, 1997, p. 107). Patients also may become euphoric or apathetic (Bunch, 1997, p. 107). Poverty of speech is often present and gradually progressive to mutism, although speech comprehension is usually spared (Bunch, 1997, p.107). Pick's disease is characterized by cortical atrophy localized to the frontal and temporal lobes (Bunch, 1997, p.107).
Vascular dementia is the second most common cause of dementia in patients over the age of sixty-five and is responsible for 8 percent to 20 percent of all dementia cases (Bunch, 1997, p. 107). It is caused by interference with the blood flow to the brain (Bunch, 1997, p. 107). Although the overall prevalence of vascular dementia is decreasing, there are some geographical variations, with the prevalence being higher in countries with a high incidence of cardiovascular and cerebrovascular diseases, such as Finland, and Japan (Bunch, 1997, p. 107). About 20 percent of patients with dementia have both Alzheimer's disease and vascular dementia (Bunch, 1997, p. 107). Several types of vascular dementia have been identified (Bunch, 1997, p. 107).
Multiple infarct dementia (MID) is the most common type of vascular dementia (Horton and Smart, 1984, p.320). As its name implies, it is the result of multiple, discrete cerebral infarcts (strokes) that have destroyed enough brain tissue to interfere with the patient's higher mental functions (Horton and Smart, 1984, p.320). The onset of MID is usually sudden and is associated with neurological deficit, such as the paralysis of weakness of an arm or leg or the