Original Research Article Accepted: June 29, 2010 Published online: August 21, 2010
Dement Geriatr Cogn Disord 2010;30:155–160 DOI: 10.1159/000318755
Awareness of Memory Failures and Motivation for Cognitive Training in Mild Cognitive Impairment Katja Werheid a Matthias Ziegler a Annina Klapper c Klaus-Peter Kühl b
a Department of Psychology, Humboldt-Universität, and b Department of Psychiatry, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, and c Department of Psychology, Justus-Liebig-Universität, Giessen, Germany
Key Words Awareness ⴢ Cognitive training ⴢ Therapy motivation ⴢ Mild cognitive impairment ⴢ Subjective memory complaints ⴢ Cognitive deficits ⴢ Anosognosia
Abstract Background: Awareness of cognitive deficits is considered to be decisive for the effectiveness of cognitive training in mild cognitive impairment (MCI). However, it is unclear in what way awareness influences motivation to participate in cognitive training. Methods: Thirty-two elderly adults with MCI and 72 controls completed the 5-scale Memory Functioning Questionnaire (MFQ) and a motivation questionnaire. The predictive value of the MFQ scales on motivation was analyzed using regression analysis. Results: In the MCI group, but not in controls, higher perceived frequency of memory failures was associated with a lower motivation score. Conclusion: Our findings indicate that, in MCI, greater awareness of cognitive deficits does not necessarily increase motivation to participate in cognitive trainings, and suggest that success expectancy may be a moderating factor. Copyright © 2010 S. Karger AG, Basel
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Awareness of cognitive deficits in mild cognitive impairment (MCI) has attracted increasing attention in recent research. The MCI syndrome is characterized by declined performance in a particular cognitive domain, while everyday life abilities are preserved [1, 2]. MCI has recently become a major topic of research into clinical dementia, as these patients form a subpopulation of elderly adults at high risk of developing dementia [3]. Several studies reported that, in contrast to patients with dementia, individuals with MCI do not overestimate their functional abilities [4, 5] or their cognitive performance [6]. This view is not unequivocal [7, 8], and recent evidence suggests that the level of awareness in MCI does vary [9]. However, awareness was shown to be relatively better preserved in MCI than in dementia, in line with the well-established view that the degree of insight is positively correlated with cognitive ability [5, 10]. The main reason for the broad interest in this topic is that higher awareness of cognitive deficits was found to improve cognitive training outcome [11]. As cognitive training is thought to be most effective when applied as early as possible [12], research in MCI is focused on the early and reliable identification of people who will develop dementia, in order to provide them with preventive Katja Werheid Humboldt University, Department of Psychology, Clinical Gerontopsychology Rudower Chaussee 18 DE–12489 Berlin (Germany) Tel. +49 30 2093 9419, Fax +49 30 2093 9461, E-Mail katja.werheid @ cms.hu-berlin.de
training programs while their cognitive abilities are relatively intact [13]. While participation in cognitive interventions is clearly dependent on therapy motivation [14], the relationship between awareness and therapy motivation may be more complex. Clinicians may find that some individuals with MCI, while clearly aware of their growing cognitive deficits, display only moderate interest in cognitive training programs, while cognitively unimpaired elderly adults would readily participate. The aim of the present study was to revisit the relationship between awareness and therapy motivation in MCI, in comparison to a cognitively unimpaired control group of the same age. The Memory Functioning Questionnaire (MFQ) [15] was chosen as the awareness measure for 3 main reasons. First, it provides highly sensitive self-reports of memory failures through 7-step ratings of concretely described, everyday memory failures. Second, by including several subscales, it considers recent multifactorial concepts of awareness [16, 17]. Finally, as with self-report questionnaires in other domains [18], it distinguishes between the occurrence and subjective significance of a given problem. Thus, with respect to our research question, it casts light on whether therapy motivation is best predicted by the perceived frequency or severity of memory failures. As further possible predictors, it assesses the number of memory aids in use, self-reported retrospective memory ability, and self-referential comparison of actual and former memory ability. Several important factors should be considered when investigating the relationship between awareness and therapy motivation: educational level, the actual level of cognitive performance and depression. While it is still a matter of debate whether subjective memory complaints in MCI are related to cognitive ability [5, 19–21], depression is closely related to subjective memory complaints in MCI [20, 22]. It is valuable, therefore, to obtain a pure measure of the relationship between awareness and therapy motivation without the confounding influence of these variables, and so we decided to statistically control for cognitive test performance, education and depression in our study.
Methods Sample and Procedure The sample consisted of 32 individuals with MCI and 72 control participants. The patients were recruited from the memory clinic of the Department of Psychiatry, Campus Benjamin Franklin, Charité. The diagnosis of MCI was based on the revised Pe-
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tersen criteria [2]: patients scored at least 1 SD below the age norm in one or more of the following domains in the CERAD+ test battery (http://www.memoryclinic.ch), i.e. verbal learning and memory, nonverbal learning and memory, verbal fluency, naming, information processing speed, executive and visuoconstructive functions. Twenty-five patients were diagnosed as having the mnestic subtype, the others ‘multidomain’ MCI. Based on an interview with a close family member, recent cognitive deterioration and preserved basic daily activities were confirmed, although more complex activities of daily living might be slightly impaired. Control participants were contacted by panels of healthy volunteers at Humboldt University, Berlin, and Charité, Department of Psychiatry. Subjects with a major neurological disorder other than the primary diagnosis of MCI or with a current diagnosis of psychiatric disorders according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition [23], were excluded. None of the participants had previously participated in a cognitive training intervention. All participants reported normal or corrected-to-normal vision, and provided written, informed consent to volunteer in the study, which was approved by the ethical committee at Charité Berlin. Materials and Procedure All subjects performed a neuropsychological test battery designed to assess different aspects of memory. Verbal and visual episodic memory was measured by the delayed recall score of the California Verbal Learning Test [24] and the delayed recall score of the visual reproduction subtest of the Revised Wechsler Memory Scale [25]. Working memory was assessed by the digit span forward and backward scores of the Revised Wechsler Memory Scale [25]. Semantic memory was assessed by standard German vocabulary and semantic word fluency tests [26, 27]. These test scores served as predictors in subsequent analyses. To control for general cognitive ability and current depressive symptoms, participants performed the Mini Mental State Examination [28], and the 15-item version of the Geriatric Depression Scale [29]. First, awareness was measured by the MFQ [15, 30], containing 5 subscales: frequency (18 items) and subjective severity (18 items) of different memory failures in everyday life, self-reported retrospective memory ability (4 items), self-referential comparison of actual and former memory ability (5 items) and the number of memory aids in use (8 items). In total, 64 items were rated on 7-point Likert scales. Therapy motivation was measured by a written questionnaire administered immediately after the MFQ. The motivation questionnaire started with a brief introduction of the topic: ‘We would now like you to answer some additional questions about your motivation to participate in a cognitive training program’, followed by 4 questions: (i) Would you like to participate in a cognitive training program? (ii) How much time per week would you spend for cognitive training each week? (iii) How much money would you be willing to pay for a cognitive training? (iv) Cognitive trainings are often administered to groups – what group size would you prefer? The questions of the motivation questionnaire were thought to access different aspects of motivation, as we considered motivation to be a heterogeneous construct. To avoid biased responding in the MCI group, the two questionnaires were administered by a research assistant who was not involved in clinical assessment or treatment of the patients.
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Table 1. Demographic data and indices of cognitive performance of elderly adults with MCI and controls
Number Gender, % female
Age, years MMSE GDS-15 CVLT delayed recall CVLT learning score VM delayed recall DS backward DS forward Vocabulary test Semantic fluency
MCI
Controls
2
p
w
32 53
72 61
0.58
0.45
0.07
Mean 8 SD
Mean 8 SD
t
p
ES
66.9089.4 26.9082.2 1.2581.9 13.1582.3 38.44812.2 19.88811.5 5.4482.0 6.8482.2 35.1883.2 19.9487.4
66.085.3 29.1081.0 3.6083.2 7.8484.3 56.3588.3 31.7185.9 6.6381.8 7.5481.5 31.4785.5 24.4385.8
0.49 6.74 3.84 8.18 8.74 6.91 2.97 1.89 4.35 3.34
0.630 0.001 0.002 0.001 0.001 0.001 0.004 0.062 0.001 0.001
0.13 1.44 0.98 1.75 1.87 1.48 0.63 0.40 0.93 0.71
Effect sizes: w = 2 test for frequencies; ES = effect size; for all t tests, Hedge’s g (difference in means/pooled standard deviation); MMST = Mini Mental State Examination; GDS-15 = Geriatric Depression Scale, 15-item version; CVLT = California Verbal Learning Test; VM = visual memory subtest of the Wechsler Memory Scale; DS = digit spans backward and forward.
Statistical Analyses Our analyses aimed at determining the predictive value of awareness indicators derived from the MFQ for therapy motivation, while controlling for education, depression and cognitive ability. To obtain indicators for the 5 awareness types, answers on the scales of the MFQ were averaged for each participant. Missing values were substituted by the individual scale means. To optimize reliability of the criterion, answers to the motivation questionnaire were combined to a single score through linear combination. To achieve the optimal weighting of the items in terms of their contribution to the common factor ‘motivation’ underlying the items, we conducted a principal-component analysis with 1 extracted factor (eigenvalues: 2.366, 0.991, 0.345). Based on the item loadings, a factor score was computed. In this way we attempted to achieve an optimal weighting of each item according to how prototypical it was for motivation. Using regression analyses conducted separately for both groups, the influence of education, depression and cognitive performance was residualized from this score. Prior to this analysis, cognitive test parameters (table 1) had been combined using principal-component analysis, in order to avoid multicollinearity in subsequent regression analyses [31]. Based on a minimum average partial test [32], 3 correlated factors were extracted: episodic memory (California Verbal Learning Test learning score and delayed recall; visual memory delayed recall), working memory (spans forward and backward) and semantic memory (vocabulary test, semantic fluency). In the next step, education, depression and the cognitive ability factors were residualized from motivation by linear-regression analyses conducted separately for patients and control group. The residual scores then served as dependent variables in the main regression analysis involving the MFQ variables as predictors.
Again, this procedure was conducted separately for patients and controls. Significance levels within the analyses were computed, based on bias-corrected confidence intervals, with n = 10,000 bootstrap samples (one-tailed). Answers on the 5 scales of the MFQ were averaged for each participant and served as predictors for the main regression analysis. In this way, we could control for any differences between the groups due to educational level, depression and cognitive ability.
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Results
Demographic data, indices of cognitive performance, and group comparisons for the variables used in the following analyses are reported in table 1. Regression analysis revealed a moderate but significant impact of the predictors on motivation, which differed between the two groups (fig. 1). In the control group, therapy motivation was best predicted by higher scores on the retrospective memory scale, and lower scores on the self-referential comparison scale. In MCI, by contrast, increased motivation for patients went along with lower frequency of memory failures and, as a tendency, with more frequent use of external memory aids. The predictors explained approximately 19% of the criterion variance in the patient group and 11% of the criterion variance in the control group. Multicollinearity could be excluded, as no conditioning index larger than 30 occurred in either group [33]. 157
MFQ subscales
Fig. 1. Regression model predicting motivation to participate in cognitive therapy based on subscales of the MFQ for both groups. MF frequency = Frequency of occurrence of memory failures; MF severity = subjective assessment of the memory failure gravity; MA retrospective = assessment of the subjective difficulty to recall past events; MA self-referential comparison = subjective assessment of the functionality of memory in comparison to the past; external aids = frequency of use of different memory hooks; e = error of measurement. * p ! 0.05; a p ! 0.10 (one-tailed).
Discussion
The objective of our study was to explore how awareness of cognitive deficits may relate to motivation for cognitive therapy in MCI. We found initial evidence that this relationship may differ from that in cognitively unimpaired adults of the same age. Cognitively unimpaired older adults reported higher motivation for cognitive therapy the more they viewed the comparison of actual and earlier memory ability as unfavorable, and the more they were aware of the temporal gradient of their autobiographical memory. Notably, even in the absence of objective memory deficits, they considered participation in cognitive training to be a preventive measure. Thus, our findings in the control group were in accordance with previous research [34]. The pattern found in the MCI group differed markedly. The main result was that the more frequently memory failures were perceived by elderly adults with MCI, the less motivated they were to participate in a cognitive training intervention. This pattern may point to the view that motivation in this group is mediated by factors other than awareness. For example, expectation of success for a proposed intervention may be an important factor, as predicted by psychological motivation theory [35, 36]. As those participants in the MCI group who were in the memory clinic setting of our study were informed about their increased risk to develop dementia, those who frequently observed memory failures may have considered themselves as being among those actually converting. Without any further information on the effectiveness, 158
Dement Geriatr Cogn Disord 2010;30:155–160
MF frequency MF severity MA retrospective MA self-referential
MCI
Controls
e
–0.55*
0.09
R2 = 0.19 (control 0.11)
0.03
0.10
0.07
0.27*
–0.09
–0.22*
0.37a
–0.18
Therapy motivation
External aids
the potential and the limits of cognitive training, their expectancy of success might have been low. While speculative at this point, this explanation is supported by the second strongest predictor found in the MCI group. Although failing to reach statistical significance, the use of external memory aids was also negatively related to motivation. Thus, the more memory aids that participants with MCI used already, the lower was their motivation for cognitive training. The importance of success expectancy in addition to awareness may be especially relevant in the field of neurodegenerative disease, as no cure is currently available, and evidence on the relative benefit of cognitive training may be difficult to communicate. In this respect, elderly adults with MCI might differ from other groups for whom cognitive training is a treatment option. For example, in patients with traumatic brain injury, greater awareness of cognitive deficits was found to be positively related with enhanced motivation for cognitive interventions [37]. Clearly, the findings of this study are limited in several respects, which should be considered in future research. The investigated samples were comparatively small, and although all MCI participants complained of memory deficits, not all of them had a diagnosis of the mnestic MCI subtype. Further, the results may have been influenced by idiosyncratic factors, such as the availability of other interventions for the investigated sample, their having high educational level, or the specific instructions used in the motivation questionnaire. For example, participants did not receive a detailed description Werheid /Ziegler /Klapper /Kühl
of what the intervention would be like, and the person administering the questionnaire was not the future therapist. This rather impersonal setting was chosen in order to avoid influencing people and in order to keep the instructions standardized. Despite these limitations, it should be noted that the results found in the control group were perfectly in line with previous research, thereby validating the preliminary findings of our study. They confirm the view that coping strategies [38] and perceived self-efficacy are crucial for participation in cognitive training [39]. Further research investigating larger samples would allow to investigate nonlinear relationships of awareness and motivation, and to focus on specific MCI subtypes. To verify the speculative hypoth-
eses drawn from the current data set, future research should directly access success expectancy, the amount of given information or other factors likely influencing the specific decision. Also, the number of memory strategies and memory aids already in use might be indicative at this point. Finally, it has to be said that, on the basis of our study, no conclusions can be drawn with respect to the effectiveness or appropriateness of cognitive training in MCI. Our findings, however, do suggest that when offering cognitive training interventions to persons with MCI, awareness of cognitive deficits should be considered a necessary, but not sufficient, condition for participant motivation.
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