a diagnostic feature in one condition (MCI) that is often a precursor to another
condition (Alzheimer’s disease), in which the absence of SMC is a descriptive
feature.
In this chapter, we review the literature examining the relationship between
SMC and objective cognitive performance in healthy middle-aged and older adults,
as well as the link between SMC in older adults and later cognitive decline or
dementia. We examine the differing methods for measuring SMC in relation to
objective memory performance and explore possible reasons for discrepantfind-
ings. Further, we examine factors that bear upon the relationship between SMC and
objective memory performance. We ask whether the relationship between SMC and
memory performance differs by age, types of questions asked about memory per-
formance, and domains of cognitive function objectively assessed. The aim here is
not to determine whether SMC are indicative of impairment. In many instances,
relationships may be modest and masked by stronger relationships with psycho-
logical function. For some, this is evident that SMC are unreliable and invalid (Jorm
et al. 1997 ; Schofield et al.1997b). Our perspective is that subtle perceived changes
in memory function may be important, particularly in healthy populations, and we
offer an examination of how a subjectively reported experience of memory concerns
may, or may not, reflect cognition and brain function assessed objectively.
How SMC are Assessed
In published studies, SMC have been assessed in a variety of ways, ranging from a
single question to lengthier validated questionnaires. Single questions may ask
individuals about their current memory function (i.e.,“Do you have problems with
your memory?”and“How do you rate your memory?”), or ask individuals to rate
their memory according to some comparison, (i.e.,“How would you rate your
memory now, compared to 5 years ago?”and“Do you have more problems with
your memory than most?”). From a methodological perspective, measuring SMC
with a single question lacks precision, but this approach has face validity in its
relevance to real-world concerns about memory function. Other studies have
attempted to assess SMC with non-validated, but informative sets of questions
about memory difficulties in everyday life (such as misplacing objects), across
specific situations (forgetting information read in a newspaper), or across categories
(such as short-term memory, perceptual memory, etc.). Standardized question-
naires, which have demonstrated reliability, internal consistency, and validity,
typically involve many questions and often provide subscale scores on different
memory constructs. In these questionnaires, individuals may be asked to rate the
frequency of memory difficulties separate from how serious they view these lapses
to be.
278 M.T. Weber and P.M. Maki