performance. Although this work is preliminary, it is consistent with afinding of
modest correlations between SMC and objective cognitive function in young and
middle-aged adults (Schaafsma et al. 2010 ; Weber et al. 2013 ; Drogos et al. 2013 ).
Summary
Studies that assess SMC using a single or just a few questions about the presence of
a memory problem demonstrate a relationship between SMC and objective memory
performance across the life span. These associations are also evident in women at
midlife, a time when women experience a small but significant decline in memory
performance. This rather straightforward relationship between subjective perfor-
mance and objective performance is not always evident in studies utilizing vali-
dated questionnaires to measure SMC. For instance, reports of increased frequency
of forgetting have been shown to correlate with working memory and verbal
encoding, but not verbal memory, suggesting that this type of difficulty reflects
attentional issues rather than issues in storing or retrieving successfully encoded
information. Finally, an imaging study demonstrated that compared to women
without SMC, women with SMC showed no difference in cognitive performance
but showed increased activation in brain areas that are critical for working memory.
Such results suggest that individuals with SMC may be working harder to obtain
the same level of performance. Overall, while limited, the literature on SMC in
young and middle-aged adults suggests that SMC do relate to objective cognitive
function and are not just reflective of psychological or personality factors, though
such matters do independently relate to objective function.
Subjective Memory Complaints in Non-demented Older
Adults
SMC Assessed by a Single or Few Questions with Face
Validity
Several studies examining the relationship between SMC and objective cognitive
performance in healthy older adults provide mixed results. In a study of 213
community-dwelling older adults (≥75 years), 37% had SMC assessed by 4
questions about specific memory problems, but their performance on objective
memory tests did not differ from those with no SMC (O’Connor et al. 1990 ). In a
study of 302 community-dwelling individuals, each 75 years of age in the Vienna
Transdanube Aging (VITA) study, only 10% had a memory complaint and only 6%
of those with objective memory problems reported SMC (Jungwirth et al. 2004 ).
There was no difference in objective verbal memory performance between
284 M.T. Weber and P.M. Maki