Cognitive Disorders 685
If you tried our version of the Trail Making Test in Figure 15.1, you probablynoticed that it’s a bit of a mental juggling act. Such mental juggling is typical of
tasks that rely on working memory. Working memory requires keeping information
activated (so that you are aware of it) while operating on it in a specifi c way; for
example, counting backwards by 3 from 100 requires working memory (holding in
mind the number 100, subtracting 3, then holding in mind 97, subtracting 3, and
so on). Working memory relies on the frontal lobes, and the key parts of frontal
lobes don’t operate as effectively in elderly people as they do in younger people—
and hence the elderly typically have problems using working memory (De Beni &
Palladino, 2004; Li, Lindenberger, & Silkström, 2001).
In sum, normal aging typically leads to problems in recall, slower mental process-ing, diffi culty sustaining high levels of attention and in dividing attention, and prob-
lems with working memory. These abilities are necessary for fl uid intelligence, which
usually declines with age but generally not enough to impair daily functioning. In
contrast, crystallized intelligence, which includes recognition memory for vocabulary
and memory for personal events, typically does not decline dramatically with age.
Psychological Disorders and Cognition
Contrary to popular belief, most older adults don’t have a psychological disorder;
in fact, older adults have the lowest prevalence of psychological disorders of any
age group (American Psychological Association, Working Group on Older Adults,
1998). But when an older person does have a psychological disorder, its symptoms
can impair cognitive functioning. Thus, before assuming that an individual’s dete-
riorated cognitive functioning is due to a cognitivedisorder—delirium, amnestic
disorder, or dementia—the clinician must fi rst determine whether the deterioration
could be due to another psychological disorder. For instance, Mrs. B. had a his-
tory of depression and described herself as having a “hot temper” even as a young
adult. Mrs. B.’s daughter described her mother “as always somewhat self-centered
and suspicious of the motives of others, but this had worsened noticeably in recent
years, to the point where she had been isolated within her own home,” which led to
the move to the nursing home (LaRue & Watson, 1998, p. 6).
The neuropsychologist must determine whether Mrs. B.’s memory problemsmight refl ect a psychological disorder such as depression. Let’s briefl y review the
psychological disorders that most commonly diminish cognitive functioning in older
adults: depression, anxiety disorders, and schizophrenia.
Depression
Older adults are less likely than their younger counterparts to be
diagnosed with depression. When they are depressed, however,
the symptoms often differ from those of younger adults: Older
depressed adults have more anxiety, agitation, and memory
problems (Segal, 2003). Thus, cognitive functioning is affected
by depression both directly (memory problems) and indirectly
(anxiety and agitation affect attention, concentration, and other
mental processes; see Table 15.1). When depressed, a particular
group of older adults is at high risk for suicide: Older White men
who live alone have the highest suicide rate of any age group
(WHO, 2002).
A mental health clinician must also determine whether symp-toms of depression in an older person could be causedby a cogni-
tive disorder: Some symptoms of depression, such as fatigue, may
be caused by brain changes associated with a cognitive disorder
(Puente, 2003). Mr. Rosen, in Case 15.1, was being treated for de-
pression and experienced cognitive problems that may or may not
have been related to his depression.
Information processing speed- Slow to respond or initiate behavior; incomplete grasp of complex
information (because of a lag in processing)
Attention and concentration - Absentmindedness for daily activities, events, and appointments;
tasks left incomplete; decreased attentiveness for reading or con-
versation, which can also disrupt memory
Executive function - Diffi culty with calculating, sequencing, multitasking, and other
novel problem solving; infl exible behavior or thinking; persevera-
tive or ruminative thinking; decline in organization and planning;
indecisiveness, decreased initiation of behavior
Memory - Forgetfulness and absentmindedness, but should improve with
prompts, cues, or explicit memory aids
Source: Potter & Steffens, 2007. For more information see the permissions section.
Table 15.1 • Common Cognitive Defi cits
in Late-Life Depression