Abnormal Psychology

Cognitive Disorders 701

What Is Dementia?

Dementia is the general term for a set of cognitive disorders that is characterized

by defi cits in learning new information or recalling information already learned

plus at least one of the following types of impaired cognition (American Psychiatric

Association, 2000):

• Aphasia.In dementia, aphasia often appears as overuse of the words thing and it

because of diffi culty remembering the correct specifi c words.

• Apraxia.Problems with executing motor tasks (even though there isn’t anything

wrong with the appropriate muscles, limbs, or nerves) can lead to problems dress-

ing and eating, at which point self-care becomes impossible.

• Agnosia. People with dementia may not recognize friends, family members, or

even the face in the mirror.

• Executive function problems. These problems lead to diffi culties in planning, initi-

ating, organizing, abstracting, and sequencing or even in recognizing that one has

memory problems. (These problems arise primarily in dementia that affects the

frontal lobes.) These defi cits can make it impossible to meet the demands of daily

life. Mrs. B. evidenced some diffi culties in tasks that required executive functions.

We discussed aphasia, apraxia, and agnosia earlier, in the context of effects of

brain damage on cognition. Unlike the effects of a stroke or a head injury, however,

dementia is not caused by an isolated incident. Rather, it arises over a period of

time, as brain functioning degrades; symptoms of dementia often change over time,

typically becoming worse, but sometimes remaining static or even reversing course.

To be diagnosed as having dementia, a person must have cognitive defi cits se-

vere enough to impair daily functioning, and these defi cits must contrast with a

prior, more adaptive level of functioning. Table 15.7 summarizes the DSM-IV-TR

diagnostic criteria for dementia.

Mild symptoms of dementia may go unnoticed in people whose cognitive func-

tioning started out at a very high level. Such a patient may detect his or her compro-

mised ability to function, but neuropsychological testing is likely to show that the

patient’s abilities are within the normal range for his or her age—and so the early

signs of dementia would go undiagnosed (Harvey, 2005a). Most people with demen-

tia are over 65 years of age when symptoms emerge, and in these cases, DSM-IV-TR

specifi es that the disorder has late onset. When symptoms begin before age 65, the

disorder is said to have early onset. Early onset, particularly before age 50, is rare

and is usually hereditary (Ikeuchi et al., 2008).

Depending on the specifi c mental processes that are impaired, a patient with

dementia may

• behave inappropriately (for instance, tell unsuitable jokes or be overly familiar

with strangers);

Table 15.7 • DSM-IV-TR General Diagnostic Criteria for Dementiag

A. Multiple cognitive defi cits are present, including the following:

1. memory impairment (new learning or recall) and


2. one or more of aphasia, apraxia, agnosia, or executive dysfunction.

B. The cognitive defi cits signifi cantly impair social or occupational functioning and refl ect a

signifi cant decline from a previous level of higher functioning.

C. The cognitive defi cits are not exclusively present during delirium.

D. The cognitive defi cits cannot be better attributed to another Axis I disorder, such as

depression [Chapter 6] or schizophrenia [Chapter 12].

Source: Rabin et al., 2006, p. 211, Exhibit 10.1; based on American Psychiatric Association, 2000.

Dementia

A set of cognitive disorders characterized

by defi cits in learning new information or

recalling information already learned plus at

least one other type of cognitive impairment.