THE SYMPTOMS AND
COURSE OF DEMENTIA
IN MOST CIRCUMSTANCES, DEMENTIA is a progressive condition that results in an evolving pattern of symptoms, behaviours, functional impairments and disabilities. The nature of an individual's presenting symptoms and the pattern of their evolution will provide clues to the underlying type of dementia. For example, Alzheimer's disease tends to develop almost imperceptibly and progress gradually over a course that may run, on average, for six to twelve years. Vascular dementia has a more varied presentation and course, but a common variant is of relatively sudden onset followed by a stepwise decline over a somewhat shorter timespan than seen in Alzheimer dementia. Because for most persons dementia is a chronic disorder, it is useful to view its course in stages according to the severity of the disease process. Note that these stages should be viewed as only a rough guide, since they are mainly based on the course of Alzheimer's disease, not the other types of dementia. Further, some people may have some features from one stage and other features from an earlier or later stage. 1 There are also many different symptoms of dementia, as listed in Table 4.1.
As with most illnesses, dementia has no set pattern of early symptoms. Presentations can be quite varied, and often are recognised only retrospectively. Furthermore, early symptoms may be subtle and attributable to many causes, a problem accentuated by dementia's relatively slow progression. Currently we have limited knowledge of these earliest symptoms of dementia, and of how