Journal of Clinical and Experimental Neuropsychology 2003, Vol. 25, No. 3, pp. 382–390
1380-3395/03/2503-382$16.00 # Swets & Zeitlinger
Self-reported Memory Compensation: Similar Patterns in Alzheimer’s Disease and Very Old Adult Samples Roger A. Dixon1, Grace A. Hopp2, Anna-Lisa Cohen3, Cindy M. de Frias3, and Lars Ba¨ckman4 1
Department of Psychology, University of Alberta, Edmonton, Canada, 2Riverview Hospital, Vancouver, BC, Canada, 3 University of Victoria, BC, Canada, and 4Uppsala University, Sweden
ABSTRACT Evidence pertaining to self-reported use of memory compensation techniques was collected using the Memory Compensation Questionnaire (MCQ). Five forms of everyday memory compensation were evaluated: (a) external memory aids, (b) internal mnemonic strategies, (c) investing and managing processing time, (d) applying more effort, and (e) reliance on human memory aids. The sample was derived from the Kungsholmen Project in Stockholm, Sweden, and consisted of (n ¼ 85) healthy older adults (M age ¼ 81.80 years; M MMSE ¼ 28.34) and (n ¼ 21) diagnosed Alzheimer’s Disease (AD) patients (M age ¼ 81.80 years; M MMSE ¼ 23.55). Participants were tested on two occasions, 6 months apart. Results showed that the MCQ was a largely reliable instrument in these two groups. Moreover, we observed substantial sample similarity in frequency of using the five forms of everyday memory compensation techniques. The healthy sample reported using the external techniques more than the AD sample. Over the 6-month interval, however, AD patients differentially increased their use of others to assist them in everyday memory performance. Results are interpreted in terms of insight into changes in memory skills and in the implementation of effective memory support systems.
The term ‘‘compensation’’ has been used widely to represent a cluster of behaviors and processes that are designed to overcome or mitigate cognitive deficits or declines (e.g., Ba¨ckman & Dixon, 1992). Compensatory mechanisms are especially relevant in the fields of aging and neuropsychology, in which late-life cognitive impairments may be produced by processes of normal aging, disease-related neurological losses, or traumatic injuries (see Dixon & Ba¨ckman, 1995). Recent research has investigated compensatory processes in such domains as successful aging and survival (e.g., Freund & Baltes, 1998), personal losses or social decrements (e.g., Brandtsta¨dter & Wentura, 1995), maintenance of everyday or professional
competence (e.g., Abraham & Hanson, 1995), typical cognitive declines in late life (e.g., Salthouse, 1995), and adjustment to neurological diseases or injuries (e.g., Cabeza, in press; Dixon & Ba¨ckman, 1999; Wilson & Watson, 1996). Two related observations are theoretically significant. First, the range of late-life plasticity may be greater than previously believed, both behaviorally (e.g., Baltes, 1987) and neurologically (e.g., Kolb & Whishaw, 1998). Second, a variety of compensatory mechanisms, from both behavioral and neurological sources, are potentially available in late life (Dixon & Ba¨ckman, 1999). In general, at least modest cognitive impairments of selected etiologies may be compensated through a variety
Address correspondence to: Dr. Roger A. Dixon, Department of Psychology, P217 Biological Sciences Building, University of Alberta, Edmonton, AB T6G 2E9, Canada. E-mail:
[email protected] Accepted for publication: August 8, 2002.
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of mechanisms and techniques, some of which may be administered or maintained by rehabilitation clinicians (e.g., Robertson & Murre, 1999; Wilson, 1995), intervention researchers (e.g., Fasotti, Kovacs, Eling, & Brouwer, 2000), or caregivers and family members (e.g., Cavanaugh et al., 1989). Compensatory processes for everyday cognition may involve multiple levels of analysis and are rarely available in all their aspects to simple observation. Therefore, researchers may wish to collect basic information pertaining to multiple facets of compensatory behavior (Ba¨ ckman & Dixon, 1992). Self-reports about everyday memory compensation are particularly promising forms of data in this respect (e.g., Dixon, de Frias, & Ba¨ ckman, 2001; Zanetti et al., 1999). However, as is well-known in awareness, insight, and metacognition literatures (e.g., Hertzog & Hultsch, 2000; Markova & Berrios, 2000; Schacter, 1990), self-reports have both advantages and disadvantages. Two pertinent advantages are that: (a) well-constructed self-report instruments can represent a wide range of everyday compensatory behaviors, and (b) simple questionnaires may be administered to, and understood easily by, a wide range of participants in a variety of settings. Two disadvantages are that: (a) they represent self-reports about actual behaviors and they may vary in veridicality, and (b) the specific neurological populations to which they may be applied have largely not yet been determined. Nevertheless, carefully constructed self-report instruments presenting specific examples of everyday memory behaviors have been effectively used for several purposes in numerous populations (Hertzog & Hultsch, 2000; Markova & Berrios, 2000). Among the scales used in compensation research are a successful aging questionnaire (Freund & Baltes, 1998), an awareness of deficit rating scale (Verhey, Rozentaal, Ponds, & Jolles, 1995), and clinically-informed verbal supplements to rehabilitation for memory loss research (e.g., Wilson & Watson, 1996). To our knowledge, however, only one procedure has been implemented that systematically investigates the everyday use of memory compensation techniques. Known as the Memory Compensation
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Questionnaire (MCQ; Dixon et al., 2001), it collects information on the extent of everyday use of techniques of memory compensation. More specifically, five forms of everyday memory compensation are represented in separate subscales, each with multiple exemplar items. These include the following strategies: (a) investing more time in everyday memory tasks, (b) expending more effort on rehearsing, retaining, or retrieving information, (c) using external storage or reminder devices for supporting everyday remembering, (d) using human mnemonic aids (other people) to assist in typical memory tasks, and (e) using relatively internal mnemonic techniques to enhance memory performance. Two other MCQ subscales are used for different purposes: (f) one reflects the extent to which an individual is committed to success in everyday remembering, and (b) the other reflects the awareness of changes in the need to compensate for memory losses over the recent past. In a recent study with a large sample of older adults (aged 54–85 years old), Dixon et al. (2001) observed high levels of psychometric reliability for all MCQ subscales, as well as good preliminary information supporting measurement validity, across two 3-year longitudinal assessments. Interestingly, the most frequently reported compensatory category was the use of external memory aids, such as calendars and notes. Previous research has suggested that this form of memory support is perhaps the most effective and generalizable one (e.g., Cavanaugh & Poon, 1989; Dixon & Hultsch, 1983; Wilson, JC, & Hughes, 1997). Some qualifications were noted, such as the fact that in this sample the frequency of use of external techniques were uniformly high for all women but related to age for the men. Specifically, older men tended to use these techniques more than younger men. Similarly, older men tended to use other humans (e.g., spouses) as memory aids more than did either younger men and all women. This volunteer sample from the Victoria Longitudinal Study (VLS; see Hultsch, Hertzog, Dixon, & Small, 1998) is a generally healthy and educated one. As the sample is free of known neurological disease, it is unsurprising that no 3-year changes in frequency of compensatory behaviors were observed.
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What characteristics of everyday memory compensation would be observed for a lessprivileged group of older adults, including those with (a) more advanced age, (b) fewer years of formal education, and (c) diagnosed mild-tomoderate Alzheimer’s disease (AD)? We examined the extent to which the MCQ is a reliable instrument for healthy older adults and AD patients drawn from a population-based study of aging in Stockholm, Sweden. This study, known as the Kungsholmen Project (see Fratiglioni, Viitanen, Ba¨ ckman, Sandman, & Winblad, 1992), is similar to the VLS, in that it follows older adults over multiple occasions. The present design included two occasions of measurement (6 months apart) of MCQ responses. Systematic self-report memory compensation data have not been previously available for such samples. The 6-month interval was designed to detect initial or early changes in reported compensatory behavior. The first research question was whether people with AD could generate codable and psychometrically meaningful responses to such Likert-type items regarding everyday memory behaviors. The second research question concerned which forms of compensation were used most frequently by the two groups. The third research question was whether there were differential changes in reported frequency over the 6-month period. Certainly, impaired memory functioning is among the hallmarks of AD (e.g., Morris, 1996) and techniques for compensating for memory loss are among the crucial challenges for the clinical neuropsychology of aging (e.g., Wilson & Watson, 1996). Overall, this article reflects the general interest in understanding further a selected aspect of older adults’ and AD patients’ awareness of their own everyday memory functioning – as well as what they believe they do to compensate for memory decrements.
tions, psychiatric evaluations, neurological testing, cognitive testing, and social and family interviews (see Fratiglioni et al., 1992). The present sample is a subset of the larger KP sample. Several selection criteria were exercised. For inclusion in the normal, healthy older adult group, participants were required to have been free of severe cardiovascular disease, lung dysfunction, and neurological or psychiatric disorders (e.g., depression). All participants in the healthy group (n ¼ 85) participated in two sequential occasions of measurement, and remained undiagnosed for AD for 2 years beyond the first occasion. Specific characteristics for this group include, M age ¼ 81.80 years, at first testing (SD ¼ 3.14), M Mini Mental State Exam (MMSE; Folstein, Folstein, & McHugh, 1975) score ¼ 28.34 (SD ¼ 1.89), and M years of schooling ¼ 9.94 years (SD ¼ 3.81). There were 66 women and 19 men in this group. The AD group (n ¼ 21) was comprised of individuals who were diagnosed with probable AD according to current NINCDS/ADRDA criteria (McKhann et al., 1984) on the basis of the first occasion of measurement, but who returned 6 months later for the second wave of testing. Corresponding characteristics of this group include, M age ¼ 81.81 years, at first testing (SD ¼ 2.82), M MMSE score ¼ 23.55 (SD ¼ 3.49), and M years of schooling ¼ 8.81 (SD ¼ 3.92). There were 13 women and 8 men in this group.
Measures MMSE The Swedish version of the MMSE (Folstein, Folstein, & McHugh, 1975) was used in this study (see Hopp, Dixon, Grut, & Ba¨ ckman, 1997).
Memory Compensation Questionnaire (MCQ)
METHOD
The MCQ is a self-report instrument addressing the variety and extent of means for compensating for memory losses and deficits. Respondents report the frequency with which they engage in functional, adaptive, or strategic memory-related behaviors. Only the five scales representing forms of compensatory behavior relevant to everyday memory were used in this study. These scales, all of which use Likert-type response formats, are described below (see Dixon et al., 2001, for further information). In all cases, higher scores represent more frequent use of a given strategy.
Participants
External (Eight Items)
The Kungsholmen Project (KP) conducted a population-based recruitment of all adults over age 75 living in the Kungsholmen community of Stockholm, Sweden. The assessment included complete medical examina-
All items concern the use of external memory aids (such as notes, calendars, and bookmarks) for enhancing memory performance. A sample item reads: ‘‘Do you post notes on a board or other prominent place to
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help you remember things for the future (e.g., meetings or dates)?’’
Table 1. Psychometric Characteristics for the MCQ Scales for Healthy and AD Patients.
Internal (Ten Items)
MCQ scale
These items concern the use of internal mnemonic strategies (such as imagery and rehearsal) for promoting effective memory performance. A sample item reads: ‘‘Do you repeat telephone numbers to yourself in order to remember them well?’’
Time (Five Items) These items reflect the extent to which the respondent invests more time in performing a valued everyday memory task. Examples include reading passages more slowly and asking people to speak more slowly when a goal is to remember the information. A sample item is: ‘‘When you want to remember a story do you read it more than once?’’
Effort (Six Items) These items are similar to the Time items, in that they focus on the investment or application of more effort in performing memory tasks. Examples include concentrating more or trying harder when the goal is to remember an event. A sample item reads: ‘‘Do you concentrate a lot to learn something you really want to remember?’’
Reliance (Five Items) Items in this scale concern the extent to which the respondent relies on other people as memory aids, such as asking a friend or spouse to help remember to do something. A sample item reads: ‘‘When you want to remember an important appointment do you ask somebody else (e.g., spouse or friend) to remind you?’’
Procedure All participants were tested in Stockholm. Although the original design for this aspect of the KP included five assessment occasions at 6-month intervals, the AD patients rarely returned for more than two occasions. Thus, the present data represent a two-occasion longitudinal study.
RESULTS In the first phase of analyses, we examined the reliability of the MCQ scales, beginning with the internal consistency estimates (Cronbach’s ) for each of 5 scales on each of two occasions separately by group (healthy old and AD). Overall, the results indicated a pattern of internally consistent
Coefficient Alpha at Time 1
Coefficient Alpha at Time 2
Correlation between Times 1 and 2
External Healthy AD
.64 .71
.54 .70
.74 .67
Internal Healthy AD
.82 .80
.75 .76
.79 .46
Time Healthy AD
.60 .51
.66 .05
.64 .29
Reliance Healthy AD
.70 .88
.77 .83
.56 .65
Effort Healthy AD
.74 .79
.69 .60
.41 .71
MCQ scales for both groups. Considering the 20 observed alphas (see Table 1), there were only three exceptions to the range of ¼ .60 to ¼ .88. No group differences in magnitude of Cronbach’s were noted; in fact, the AD patients had slightly higher values on the majority of subscales. Two of the exceptions to the abovenoted acceptable range of consistency estimates were for the two occasions of the Time scale for the AD participants. At the first wave, the AD group produced ¼ .51, a value not exceptionally different from the others. At the second wave, however, the magnitude ( ¼ .05) indicated that their responses at this point in the disease progression were not internally consistent. In contrast, the healthy group produced more internally consistent responses on both occasions. Retest Pearson product-moment correlations were computed across the 6-month interval. The magnitudes of these retest reliability correlations were substantial and similar for both the healthy (range r ¼ .41–.79) and the AD (range r ¼ .29– .74) groups. The r ¼ .29 reliability was observed for the Time scale; the correlation of the next lowest magnitude was r ¼ .46. Overall, evidence suggests that, with one exception, the MCQ scales
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Table 2. Means of the MCQ Scales for Healthy and AD Patients Across Two Occasions. MCQ scale
Time 1
Time 2
External Healthy AD
3.91 (.66) 3.50 (.83)
3.95 (.61) 3.39 (.93)
Internal Healthy AD
2.50 (.73) 2.42 (.68)
2.53 (.71) 2.38 (.70)
Time Healthy AD
2.56 (.78) 2.41 (.63)
2.62 (.92) 2.58 (.56)
Reliancea Healthy AD
1.72 (.64) 1.77 (.82)
1.58 (.66) 2.10 (1.15)
Effort Healthy AD
2.58 (.86) 2.23 (.85)
2.58 (.81) 2.39 (.72)
a
Significant GroupTime interaction.
behave similarly and acceptably for normal old and AD persons. Regarding the second and third research questions, we conducted separate 2 (Group)2 (Occasion) repeated measures analyses of variance (ANOVA) for each scale. Overall, the groups reported similar frequency of use of compensatory strategies; the means are presented in Table 2. Two statistically significant effects were observed. The ANOVA for the External scale revealed a significant main effect for Group, F (1, 81) ¼ 7.36, p < .009, with the healthy adults (M ¼ 3.93, SD ¼ .64) reporting greater use of external aids than did the AD patients (M ¼ 3.45, SD ¼ .88). The ANOVA for the Reliance scale produced a significant GroupOccasion interaction, F (1, 79) ¼ 5.82, p < .02. As can be seen in Table 2, this interaction was due to the AD patients reporting an increase in reliance on others over the 6-month period, whereas the healthy group reported a slight decline in the use of this memory strategy. DISCUSSION A variety of familiar and effective means of compensating for memory declines have been
identified. These mechanisms of memory compensation are of practical utility, in that their implementation could enhance everyday cognitive performance (Dixon & Ba¨ ckman, 1995). To what extent are they known and used by vulnerable populations such as very old healthy adults, AD patients, and older adults with other memory impairments? To answer this important question (Ba¨ ckman, Small, Wahlin, & Larsson, 2000; Wilson et al., 1997; Wilson & Watson, 1996) we used the MCQ, which had been previously administered only to healthy and well-educated volunteer samples, with two groups matched on (low) education and age, one of which had been diagnosed with AD. Regarding the first research question – that is, whether the MCQ would be reliable for these new populations – the psychometric evidence clearly supports the inference that it may be used to collect reliable information regarding reported use of everyday memory compensation techniques. Both the internal consistency estimates and the retest correlations were generally substantial and quite similar for both groups. In addition, the alpha estimates for both groups were similar in magnitude to those obtained with the recent large samples of more privileged older adults (Dixon et al., 2001; Table 1). Other researchers have had similar success in implementing alternative memory monitoring assessments (e.g., Moulin, Perfect, & Jones, 2000) and insight evaluations (e.g., Zanetti et al., 1999) with AD patients in a similar MMSE range. There was, however, one exception to this general trend. The items in the MCQ Time scale, which represents the extent to which the respondent spends more time (e.g., slows down) processing of to-be-remembered materials, did not cohere as a scale for the AD group, at least on the second occasion. The 6-month retest reliability estimate (r ¼ .29) was the lowest one observed for all MCQ scales across the two groups, and was lower than the values for the 3year interval in the earlier study (Dixon et al., 2001). The low reliability estimate could be interpreted in two complementary ways. On the one hand, a measurement interpretation would focus on whether these 5 items have the same meaning at the second wave for AD patients as
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they did 6 months earlier (an issue of measurement equivalence). With the progression of the disease, it may be increasingly more difficult to understand items concerning an indirect and complex means of compensating for memory losses. For example, asking a conversation partner to slow down so that one may comprehend and remember better what the partner is saying requires memory self-awareness, insight into the particular memory-demanding situation, and a plan to implement a multi-step compensatory strategy. Such a strategy may be less spontaneously accessible and initiated by AD patients. If so, their responses to such items will appear as somewhat random. It would be interesting to examine whether training in time pressure management (e.g., Fasotti et al., 2000) would be successful in a similar AD sample. On the other hand, a substantive interpretation of the relatively low psychometric characteristics of the MCQ Time scale for AD patients, would focus on the notion that there may be substantial individual differences in the use of this sort of strategy, especially for AD patients. That is, given individuals may respond quite differently to specific Time items, but as a group produce fairly regular overall means. The latter condition is apparent in Table 2. It is clear that the group means for Time were virtually identical on the two occasions, indicating perhaps a stable overall system, but possible shifting of intraindividual change patterns within this domain. Other researchers have observed meaningful intraindividual variability (in more compressed occasions) on cognitive measures for similar AD patients (see Hultsch & MacDonald, in press). In general, for individuals affected by central nervous system slowing – as are all older adults and AD patients – controlling the speed of information input may be an effective means of moderating the deleterious cognitive effects of rapid presentation. Perhaps only selected forms of investing more time would be useful to AD patients. Toward this end, it is interesting to note that normal older adults routinely show improved performance when study time is increased in memory tasks (e.g., Craik & Rabinowitz, 1985; Kinsbourne & Berryhill, 1972). By contrast, research indicates that AD patients typically fail to benefit from more study
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time during memory tasks (Almkvist, Fratiglioni, Agu¨ ero-Torres, Viitanen, & Ba¨ ckman, 1999). However, some interventions (e.g., increasing insight and training in time-related strategies) appear to improve implementation of this compensatory strategy (e.g., in closed head injury patients; Fasotti et al., 2000). Overall, we observed strong evidence of similar psychometric characteristics for these two groups of adults on MCQ scales. The general result of the group and occasion comparisons is that the healthy older adults and the AD participants report quite similar frequencies of everyday memory compensation behavior. Prior to interpreting two important patterns of results, we comment briefly on the reliability data for the External scale. As can be seen in the table, the External scale produced consistent estimates, but at a magnitude slightly lower than those of most of the other scales – and somewhat lower than those produced by the larger normative sample (Dixon et al., 2001). As the present healthy group varied from the original sample in at least two potentially important respects – education (lower) and average age (higher) – the influence of these potential influences could be investigated in the future. For example, in re-examining the original normative data, it appears that a trend toward lower coefficient alphas with advancing age may be present. We suggest, therefore, that future research sample explicitly along a wide range of older adult ages. Perhaps, much like memory phenomena per se (Ba¨ ckman et al., 2000), memory compensation may be age-related even in older adult samples. Continuing with the External scale, the use of such memory aids are the most frequently reported means of memory compensation, although the healthy adults reported more frequent use than did the AD participants. In the larger normative sample (Dixon et al., 2001) this compensatory mechanism was also most frequently nominated. As using various memory aids is one of the most effective and generalizable means of improving everyday memory performance, this result is encouraging. Because it is also one of the easiest compensatory techniques to establish with memory impaired individuals (e.g., Wilson, Emslie, Quirk, & Evans, 2001; Wilson &
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Watson, 1996), it may be possible to train AD patients to use such techniques even further. That is, although the relatively high frequency of use is encouraging for the AD persons, the control group results indicate that such techniques could be used even more. Indeed, cognitive training research suggests that, although AD patients fail to benefit from most intervention procedures, they may benefit from the provision of external aids for remembering (Bird, Alexopoulos, & Adamowicz, 1995; Woods & Bird, 1999). The least frequently used compensatory technique could also be available for future training for AD adults. This technique, reliance on others, refers to the use of individuals in one’s social space (e.g., colleagues, caregivers, partners) to enhance one’s cognitive performance. With healthy older adults, such use of well-acquainted partners in episodic memory has been demonstrated experimentally (Dixon & Gould, 1998). In a recent larger normative study, we observed that this technique was also the least frequently reported mechanism of everyday memory compensation (Dixon et al., 2001). However, using other humans as memory aids is conceptually similar to using external nonliving memory aids. Therefore, this form of memory compensation may be linked conceptually to that represented by the MCQ External scale. Taken together, these results indicate that a large swath of older adults (notably, including AD patients) report a substantial degree of use of a demonstrably effective means of compensating for everyday memory failures. In this regard, the significant interaction obtained in the ANOVA on Reliance is especially important. Although both groups initially report relatively low levels of reliance on others, the AD group reported an increase in such behaviors over a 6-month period, whereas the control adults reported a slight decrease. This differential increase could reflect the related possibilities that (a) there is an increasing awareness on the part of the AD participants that others in their social world may be helping them accommodate to the cognitive demands of their everyday lives, and (b) the AD participants are in an early phase of decline in which the actual extent of assistance in everyday memory performance is increasing gradually. Such insight for AD patients has been
previously observed (Zanetti et al., 1999). Whether this potential increase in insight would continue beyond this 6-month follow-up period, or precisely when anosognosia might be in evidence, is not known. One may expect, however, that a well-functioning support system would include ample opportunities in the early phases of AD for caregivers to assist them in memory functioning. The overall means for both groups on the remaining three MCQ scales – Internal, Time, and Effort – are notably similar both to one another and to the larger normative sample (Dixon et al., 2001). This result suggests that, at this point, the early AD patients and the lower-education older adults attempt to manage memory changes in about the same ways as do their more educationally privileged (in terms of years of schooling) coevals. The greatest effort is placed on external strategies, while the less generalizable internal strategies and arguably more difficult remediation strategies (i.e., Time and Effort), are spontaneously invoked less frequently. In sum, it appears that the MCQ provides a generally reliable representation of a broad set of self-reported memory compensation behaviors. As such, it may be useful to researchers in gathering information pertaining to beliefs about everyday memory activities, and how these reports may vary over time and conditions. The MCQ should also be useful to clinicians who may want relatively quick, but systematic and theoretically informed, assessments of the varieties of compensatory procedures selected individuals are enacting in everyday life. Regarding practical implications, further validity work on the correlates of compensatory reports will shed light on the everyday aspects of the phenomenon. For example, recent work (De Frias, Dixon, & Ba¨ ckman, 2003) has indicated that personality characteristics are correlated with memory compensation use in healthy adults. Of considerable additional interest is the corollary question: Would memory compensation reports also be correlated with laboratory or everyday memory behaviors for healthy adults and AD patients? Also of future interest would be information concerning the extent to which AD patients and others are actually (and appropriately)
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implementing external strategies, the increasingly useful reliance techniques, a variety of internal mnemonics, or time and effort management procedures. Overall, the frequency of use and the commitment to memory success may be indicative of the individual’s insight into and the dilemma of memory loss and their present motivation for doing something about it. ACKNOWLEDGMENTS These data were collected in the context of the Kungsholmen Project, which is supported by grants from the Swedish Council of Research in the Humanities and the Social Sciences and the Swedish Council for Social Research to Lars Ba¨ ckman. We appreciate the data collection and diagnostic assistance of Vanja Blomqvist, Michaela Grut, Tarja-Brita Robins ˚ ke Wahlin. The present analyses and the Wahlin, and A development of the MCQ instrument was supported by a grant from the National Institute on Aging (AG08235) to Roger Dixon.
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