To examine the prevalence and correlates of cognitive impairment (CI) in adults over 50 years old attending primary care centres with complaints of memory failure. A sample of 580 individuals aged 50+ years with no previous diagnosis of dementia was assessed by use of the Mini Mental State Examination, the Cambridge Cognitive Assessment-Revised and the California Verbal Learning Test - to evaluate CI-dependent variables - and administration of a questionnaire on memory complaints and other instruments - to measure correlates. The prevalence of CI was 46.20% and positive associations were found for age, gender, level of education, subjective memory complaints, instrumental activities of daily living, reading habits and frequency of leisure activities. In the logistic regression, modelled CI was associated with older age, gender (49.12% women, 39.66% men), instrumental activities of daily living, and reading habits. Almost half of the adults aged 50+ years attending primary care centres with subjective memory complaints were affected by CI. Early evaluation of cognitive functioning is essential to establish adequate preventive and intervention strategies.

Objectives:To use a Machine Learning (ML) approach to compare Neuropsychiatric Symptoms (NPS) in participants of a longitudinal study who developed dementia and those who did not.Design:Mann-Whitney U and ML analysis. Nine ML algorithms were evaluated using a 10-fold stratified validation procedure. Performance metrics (accuracy, recall, F-1 score, and Cohen’s kappa) were computed for each algorithm, and graphic metrics (ROC and precision-recall curves) and features analysis were computed for the best-performing algorithm.Setting:Primary care health centers.Participants:128 participants: 78 cognitively unimpaired and 50 with MCI.Measurements:Diagnosis at baseline, months from the baseline assessment until the 3rd follow-up or development of dementia, gender, age, Charlson Comorbidity Index, Neuropsychiatric Inventory-Questionnaire (NPI-Q) individual items, NPI-Q total severity, and total stress score and Geriatric Depression Scale-15 items (GDS-15) total score.Results:30 participants developed dementia, while 98 did not. Most of the participants who developed dementia were diagnosed at baseline with amnestic multidomain MCI. The Random Forest Plot model provided the metrics that best predicted conversion to dementia (e.g. accuracy=.88, F1=.67, and Cohen’s kappa=.63). The algorithm indicated the importance of the metrics, in the following (decreasing) order: months from first assessment, age, the diagnostic group at baseline, total NPI-Q severity score, total NPI-Q stress score, and GDS-15 total score.Conclusions:ML is a valuable technique for detecting the risk of conversion to dementia in MCI patients. Some NPS proxies, including NPI-Q total severity score, NPI-Q total stress score, and GDS-15 total score, were deemed as the most important variables for predicting conversion, adding further support to the hypothesis that some NPS are associated with a higher risk of dementia in MCI.

Objective: Analyze the effects of CR on cognitive performance in adults with subjective cognitive complaints at follow-up. Method: We analyzed the factorial structure of the three constructs defined in cognitive performance (Episodic memory, Working memory, and General cognitive performance) separately to search for evidence of the invariance of the measurement model. We then developed four structural nested models to analyze the relationship between CR and cognitive performance, measured at baseline and after approximately 18 months, in 266 participants older than 50 years with subjective cognitive complaints. Results: The nested models revealed the following main results: direct effects of CR on all cognitive constructs at baseline and also indirect effects on the same constructs at follow-up, and indirect effects of CR on other cognitive constructs at follow-up via working memory at follow-up. Conclusion: The findings show that the proposed model is useful for measuring the influence of CR on cognitive performance in follow-up studies and that CR has a positive influence on cognitive performance at follow-up via working memory. CR may enhance mechanisms of information processing, favoring performance of tasks involving other cognitive constructs in older adults with subjective cognitive complaints.

Background: Mild cognitive impairment (MCI), as a stage in the cognitive continuum between normal ageing and dementia, is mainly characterized by memory impairment. The aims of this study were to examine CANTAB measures of temporal changes of visual memory in MCI and to evaluate the usefulness of the baseline scores for predicting changes in cognitive status.Methods: The study included 201 participants aged over 50 years with subjective cognitive complaints. Visual memory was assessed with four CANTAB tests [paired associates learning (PAL), delayed matching to sample (DMS), pattern recognition memory (PRM) and spatial span (SSP)] administered at baseline and on two further occasions, with a follow-up interval of 18–24 months. Participants were divided into three groups according to the change in their cognitive status: participants with subjective cognitive complaints who remained stable, MCI participants who remained stable (MCI-Stable) and MCI participants whose cognitive deterioration continued (MCI-Worsened). Linear mixed models were used to model longitudinal changes, with evaluation time as a fixed variable, and multinomial regression models were used to predict changes in cognitive status.Results: Isolated significant effects were obtained for age and group with all CANTAB tests used. Interactions between evaluation time and group were identified in the PAL and DMS tests, indicating different temporal patterns depending on the changes in cognitive status. Regression models also indicated that CANTAB scores were good predictors of changes in cognitive status.Conclusions: Decline in visual memory measured by PAL and DMS tests can successfully distinguish different types of MCI, and considered together PAL, DMS, PRM and SSP can predict changes in cognitive status.

Cognitive reserve (CR) is often operationally defined as a complex structure of latent variables. Here, we present a structural model that analyzes the effect of CR on three cognitive domains: episodic memory, working memory, and general cognitive performance. We developed and analyzed a structural equation model (SEM) to study CR and cognitive performance in 326 participants over 50 years old with subjective memory complaints. The CR construct was found to consist of two factors: (a) educational level and (b) lifestyle. The model revealed that CR had significant direct effects on episodic memory, working memory, and general cognitive performance, and indirect effects on episodic memory via working memory. As a latent construct, CR is related to cognitive performance in participants over 50 years with subjective memory complaints, and it should therefore be considered in the evaluation and diagnosis of such people.