The fuzzy frontier between subjective memory complaints and early dementia. A survey of patient management in German memory clinics

Self-reported cognitive concerns and abilities: two sides of one coin?

OBJECTIVE

Patient-reported cognitive function can be measured using negatively worded items (concerns) and positively worded (abilities) items. It is possible that reporting abilities is less subject to the influence of emotional states. This study evaluated the relationship between cognitive concerns and cognitive abilities.

METHODS

Cancer patients (N = 509; mean age = 61 years; 50% men; 86% White) completed concerns and abilities items developed by the National Institutes of Health Patient-Reported Outcomes Information System (PROMIS). Confirmatory factor analysis was used to evaluate the extent to which items were loaded on one single factor (unidimensionality). Multidimensionality was evaluated using bi-factor analysis (local factors: concerns and abilities). Slope parameters from multidimensional item response theory (IRT) and unidimensional IRT were compared to evaluate which factor solution fits best.

RESULTS

Acceptable fit indices were found in both one-factor confirmatory factor analysis (comparative fit index (CFI) = 0.96; root mean squared error of approximation (RMSEA) = 0.062) and bi-factor analysis (CFI = 0.98; RMSEA = 0.043). Thus, abilities and concerns could be considered as a single dimension. Yet, high loadings on the local factor in bi-factor analysis and slope discrepancies between unidimensional IRT and multidimensional IRT indicate that abilities should be considered as a separate factor from concerns.

CONCLUSIONS

Concerns and abilities could be measured using one-unidimensional item bank. Results also support measuring each construct separately. We recommend a conservative approach by measuring and reporting concerns and abilities separately. We therefore recommend two separate but co-calibrated item banks in the PROMIS network: cognitive function item bank-concerns and cognitive function item bank-abilities. Both item banks showed good psychometric properties and are available for research and clinical purposes.

Memory clinics

Memory clinics were first described in the 1980s. They have become accepted worldwide as useful vehicles for improving practice in the identification, investigation, and treatment of memory disorders, including dementia. They are provided in various settings, the setting determining clientele and practice. All aim to facilitate referral from GPs, other specialists, or by self referral, in the early stages of impairment, and to avoid the stigma associated with psychiatric services. They bring together professionals with a range of skills for the benefit of patients, carers, and colleagues, and contribute to health promotion, health education, audit, and research, as well as service to patients.

Subjective memory complaints in Chinese subjects with mild cognitive impairment and early Alzheimer's disease

BACKGROUND

Mild cognitive impairment (MCI) represents a transitional state between normal aging and dementia. However, there is inconsistent opinion as to the validity of subjective memory complaints as a criterion for diagnosis.

OBJECTIVE

This study aimed to examine the potential significance of applying a short memory questionnaire in the assessment of Chinese subjects with MCI and early dementia.

METHODS

Three hundred and six ambulatory Chinese subjects were recruited. Each participant completed a short memory questionnaire. They were also assessed with the Chinese versions of the mini-mental state examination (CMMSE), Alzheimer's disease assessment scale-cognitive subscale (ADAS-Cog), category verbal fluency test (CVFT) and span tests. Severity of cognitive impairment was evaluated using the Clinical Dementia Rating (CDR); subjects with CDR 0.5 were further classified into MCI not demented (MCIND) and MCI possible incipient dementia (MCIID) depending on the subscale scores of CDR.

RESULTS

An increasing frequency of memory complaints with increasing CDR was observed (Kruskal Wallis test, chi square = 21.29, df 3, p < 0.001). With a cutoff of 3 or more memory complaints, the memory questionnaire demonstrated a sensitivity of 65.3% and 70.4% in identifying subjects with incipient and early dementia respectively. Significant associations between memory complaints and most cognitive test performance were found (Spearman's correlations, p < 0.01). Logistic regression analysis revealed that educational level, the memory questionnaire, ADAS-Cog total and delayed recall scores were significant predictors of MCIID status.

CONCLUSIONS

The findings suggested that a short memory questionnaire is useful in the screening of MCI, particularly in subjects who already present with subtle functioning disturbances. Subjective memory complaints were significant correlated with objective performance of memory functions, reflecting the usefulness of memory complaints in the assessment of MCI.