The impact of the COVID-19 pandemic on nursing home professionals: results of the RESICOVID project

OBJECTIVES

The situation caused by the COVID-19 pandemic has had an impact on the mental, physical, and social health of nursing home staff. The operations and protocols of long-term care facilities had to be adapted to a new, unforeseen, and unknown situation in which a devastating and highly contagious disease was causing large numbers of deaths. The aim of this study was to determine the cumulative impact of the COVID-19 pandemic on care, technical, coordinating-supervisory, and managerial staff working in nursing homes.

METHODS

Correlation analysis and between-group comparisons were carried out to study the relationship between burnout scores, emotional balance, and organic and behavioral symptoms.

RESULTS

The results indicate high levels of burnout and psychological exhaustion. Management professionals displayed higher levels of organic and behavioral symptoms than other professional categories in the same care settings. Despite this negative symptomatology, most professionals showed a positive emotional balance.

CONCLUSION

The need to develop intervention programs to improve the mental, physical, and occupational health of the staff in nursing homes, considering the needs of different professional categories, is emphasized.

Predicting progression of cognitive decline to dementia using dyadic patterns of subjective reporting: evidence from the CompAS longitudinal study

Objective

To analyze the validity of self and informant reports, depressive symptomatology, and some sociodemographic variables to predict the risk of cognitive decline at different follow-up times.

Methods

A total of 337 participants over 50 years of age included in the CompAS and classified as Cognitively Unimpaired (CU), Subjective Cognitive Decline (SCD) and Mild Cognitive Impairment (MCI) groups were assessed at baseline and three follow-ups. A short version of the QAM was administered to assess the severity of subjective cognitive complaints (SCCs), and the GDS-15 was used to evaluate the depressive symptoms. At each follow-up assessment, participants were reclassified according to the stability, regression or progression of their conditions. Logistic regression analysis was used to predict which CU, SCD and MCI participants would remain stable, regress or progress at a 3rd follow-up by using self- and informant-reported complaints, depressive symptomatology, age and education at baseline and 2nd follow-ups as the predictive variables.

Results

Overall, self-reported complaints predicted progression between the asymptomatic and presymptomatic stages. As the objective deterioration increased, i.e., when SCD progressed to MCI or dementia, the SCCs reported by informants proved the best predictors of progression. Depressive symptomatology was also a predictor of progression from CU to SCD and from SCD to MCI.

Conclusion

A late increase in self-reported complaints make valid estimates to predict subjective decline at asymptomatic stages. However, an early increase in complaints reported by informants was more accurate in predicting objective decline from asymptomatic stages. Both, early and late decrease in self-reported complaints successfully predict dementia from prodromic stage. Only late decrease in self-reported complaints predict reversion from prodromic and pre-symptomatic stages.

Normative scores for attentional tests used by the Spanish consortium for ageing normative data (SCAND) study: Trail Making Test, Digit Symbol and Letter Cancellation

Objective: This paper reports normative data for different attentional tests obtained from a sample of middle-aged and older native Spanish adults and considering effects of age, educational level and sex. Method: 2,597 cognitively intact participants, aged from 50 to 98 years old, participated voluntarily in the SCAND consortium studies. The statistical procedure included conversion of percentile ranges into scaled scores. The effects of age, education and sex were taken into account. Linear regressions were used to calculate adjusted scaled scores. Results: Scaled scores and percentiles corresponding to the TMT, Digit Symbol and Letter Cancellation Task are shown. Additional tables show the values to be added to or subtracted from the scaled scores, for age and education in the case of the TMT and Letter Cancellation Task measures, and for education in the case of the Digit Symbol subtest. Conclusions: The current norms provide clinically useful data for evaluating Spanish people aged 50 to 98 years old and contribute to improving detection of initial symptoms of cognitive impairment.

Assessment of validity and comparison of two Spanish versions of the Geriatric Depression Scale

Introduction

The Geriatric Depression Scale is an instrument used to identify depression in people of an older age. The original English version of this scale has been translated into Spanish (GDS-VE); two shorter versions of 5- (GDS-5) and 15-items (GDS-15) have been developed.

Aim of the study

To assess the validity and compare the 5- and 15-item Spanish versions of the GDS among the Spanish population.

Materials and methods

573 Galicia residents aged >50 years participated in this study. The following instruments were applied: the 19-item Control, Autonomy, Self-Realization and Pleasure scale, the Subjective Memory Complaints Questionnaire, the Mini-Mental State Examination test, the GDS-5, and the GDS-15.

Results

We found differences in total score between GDS-5 and GDS-15 regarding the variable sex. Internal reliability for GDS-5 and GDS-15 was 0.495 and 0.715, respectively. Sensitivity and specificity for GDS-5 - with a cut-off value of 1 - was 0.517 and 0.650, respectively; for GDS-15 - with a cut-off value of 3 points - sensitivity was 0.755 and specificity 0.668. GDS-5 has a ROC curve of 0.617 and GDS-15 of 0.764.

Conclusion

GDS-15, and to a greater extent GDS-5, should be revised or even reformulated to improve their diagnostic usefulness by choosing higher discriminative ability items or even include new items with greater sensitivity that consider currently prevailing psychosocial factors.

Neuroanatomical and neurocognitive changes associated with subjective cognitive decline

Introduction

Subjective Cognitive Decline (SCD) can progress to mild cognitive impairment (MCI) and Alzheimer's disease (AD) dementia and thus may represent a preclinical stage of the AD continuum. However, evidence about structural changes observed in the brain during SCD remains inconsistent.

Materials and methods

This cross-sectional study aimed to evaluate, in subjects recruited from the CompAS project, neurocognitive and neurostructural differences between a group of forty-nine control subjects and forty-nine individuals who met the diagnostic criteria for SCD and exhibited high levels of subjective cognitive complaints (SCCs). Structural magnetic resonance imaging was used to compare neuroanatomical differences in brain volume and cortical thickness between both groups.

Results

Relative to the control group, the SCD group displayed structural changes involving frontal, parietal, and medial temporal lobe regions of critical importance in AD etiology and functionally related to several cognitive domains, including executive control, attention, memory, and language.

Conclusion

Despite the absence of clinical deficits, SCD may constitute a preclinical entity with a similar (although subtle) pattern of neuroanatomical changes to that observed in individuals with amnestic MCI or AD dementia.

Psychological and functional impacts associated with restrictions in long-term care facilities (LTCF) due to the COVID-19 pandemic: A multicentre study

Objectives: To analyze the impacts of the restrictions implemented in LTCF during the COVID-19 pandemic on the psychological and functional status of older adults. Design: A retrospective multicentre study is designed. We hypothesize that the negative effects of the restrictions will lead to a higher rate of decline between the measures taken immediately before and after the lockdown than between the two measures taken before the lockdown. Setting and participants: 365 participants recruited in four Spanish LTCFs in Galicia and Valencia.Methods: Impacts of restrictions on cognitive (MMSE), affective (GDS) and functional status (Barthel index, Tinetti) were analyzed by Linear Mixed Models with random intercepts, random slopes, and personal and contextual factors as covariates.Results: Social measures covaried significantly with the cognitive and functional status but did not predict longitudinal change. MMSE, Barthel index and Tinetti scores decreased significantly across pre- and post-lockdown measurement times, but only the Tinetti scores showed a specific impact of the restrictions.Conclusions: Only performance-based functional measures showed the real impact of restrictions. The findings highlight the importance of having data from several pre-lockdown measurements to enable identification of changes that can be causally attributed to the restrictions. The findings also support the resilience of older adults in mitigating the effect of the restrictions.

Do informant-reported subjective cognitive complaints predict progression to mild cognitive impairment and dementia better than self-reported complaints in old adults? A meta-analytical study

BACKGROUND

Subjective cognitive complaints (SCCs) are considered a risk factor for objective cognitive decline and conversion to dementia. The aim of this study was to determine whether self-reported or informant-reported SCCs best predict progression to mild cognitive impairment (MCI) and/or dementia.

METHODS

We reviewed prospective longitudinal studies of Cognitively Unimpaired (CU) older adults with self-reported and informant-reported SCCs at baseline, assessed by questions or questionnaires that considered the transition to MCI and/or dementia. A random-effects meta-analysis was performed to obtain pooled estimates and 95% CIs.

RESULTS

Both self-reported and informant-reported SCCs are associated with an elevated risk of transition from CU to MCI and/or dementia. The association appears stronger and more robust for informant-reported data [1.38, with a 95% CI of 1.16 -1.64, p < 0.001] than for self-reported data [1.27 (95% CI 1.06 - 1.534, p = 0.011].

CONCLUSIONS

Our results suggest that corroborated information from one informant could provide important details for distinguishing between normal aging and clinical states.

The role of dyadic cognitive report and subjective cognitive decline in early ADRD clinical research and trials: Current knowledge, gaps, and recommendations

Efficient identification of cognitive decline and Alzheimer's disease (AD) risk in early stages of the AD disease continuum is a critical unmet need. Subjective cognitive decline is increasingly recognized as an early symptomatic stage of AD. Dyadic cognitive report, including subjective cognitive complaints (SCC) from a participant and an informant/study partner who knows the participant well, represents an accurate, reliable, and efficient source of data for assessing risk. However, the separate and combined contributions of self- and study partner report, and the dynamic relationship between the two, remains unclear. The Subjective Cognitive Decline Professional Interest Area within the Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment convened a working group focused on dyadic patterns of subjective report. Group members identified aspects of dyadic-report information important to the AD research field, gaps in knowledge, and recommendations. By reviewing existing data on this topic, we found evidence that dyadic measures are associated with objective measures of cognition and provide unique information in preclinical and prodromal AD about disease stage and progression and AD biomarker status. External factors including dyad (participant-study partner pair) relationship and sociocultural factors contribute to these associations. We recommend greater dyad report use in research settings to identify AD risk. Priority areas for future research include (1) elucidation of the contributions of demographic and sociocultural factors, dyad type, and dyad relationship to dyad report; (2) exploration of agreement and discordance between self- and study partner report across the AD syndromic and disease continuum; (3) identification of domains (e.g., memory, executive function, neuropsychiatric) that predict AD risk outcomes and differentiate cognitive impairment due to AD from other impairment; (4) development of best practices for study partner engagement; (5) exploration of study partner report as AD clinical trial endpoints; (6) continued development, validation, and optimization, of study partner report instruments tailored to the goals of the research and population.

Cognitive reserve and mental health in cognitive frailty phenotypes: Insights from a study with a Portuguese sample

Background

Research on prevalence of cognitive frailty phenotypes in community-dwelling older adults in different countries is important to estimate their prevalence and to determine the influence of cognitive reserve and mental health in order to prevent frailty. The aims of this study were to estimate the prevalence of reversible and potentially reversible cognitive frailty (R-CF, PR-CF) in a Portuguese sample of old adults and explore the associations between these phenotypes and demographic, comorbidity, social support, cognitive reserve and mental health factors.

Methods

We assessed frailty (Fried criteria) in 250 community-dwelling older adults (179 women) aged 60 years or over (mean 71.04 years) without dementia, neurological or psychiatric disorders. Subjective cognitive decline and Mild cognitive impairment were diagnosed according to standard criteria. The questionnaires Charlson Index, Medical Outcomes Study Social Support, Cognitive Reserve Index and General Health were used for assessing comorbidity, social support, cognitive reserve and mental health, respectively.

Results

Prevalence of R-CF was 14%, and that of PR-CF, 15.2%. Cognitive frailty profiles differed significantly in relation to education, comorbidity, mental health, and cognitive reserve, but not in age or sex. Multivariate logistic regression showed that age, sex, comorbidity, social support, mental health, and cognitive reserve together predicted R-CF and PR-CF (90% specificity 75% sensitivity) with significant OR for mental health and cognitive reserve.

Discussion

Cognitive reserve and mental health are important factors predicting R-CF and PR-CF. We recommend assessing these factors for early detection of cognitive frailty and promoting psychological well-being and lifestyles that increase cognitive reserve in adults.

Psychosis as a Treatment Target in Dementia: A Roadmap for Designing Interventions

Psychotic phenomena are among the most severe and disruptive symptoms of dementias and appear in 30% to 50% of patients. They are associated with a worse evolution and great suffering to patients and caregivers. Their current treatments obtain limited results and are not free of adverse effects, which are sometimes serious. It is therefore crucial to develop new treatments that can improve this situation. We review available data that could enlighten the future design of clinical trials with psychosis in dementia as main target. Along with an explanation of its prevalence in the common diseases that cause dementia, we present proposals aimed at improving the definition of symptoms and what should be included and excluded in clinical trials. A review of the available information regarding the neurobiological basis of symptoms, in terms of pathology, neuroimaging, and genomics, is provided as a guide towards new therapeutic targets. The correct evaluation of symptoms is transcendental in any therapeutic trial and these aspects are extensively addressed. Finally, a critical overview of existing pharmacological and non-pharmacological treatments is made, revealing the unmet needs, in terms of efficacy and safety. Our work emphasizes the need for better definition and measurement of psychotic symptoms in dementias in order to highlight their differences with symptoms that appear in non-dementing diseases such as schizophrenia. Advances in neurobiology should illuminate the development of new, more effective and safer molecules for which this review can serve as a roadmap in the design of future clinical trials.

Changes in visual memory in mild cognitive impairment: a longitudinal study with CANTAB

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.

Impact of the COVID-19 Lockdown on a Long-Term Care Facility: The Role of Social Contact

(1) Background: Long-term care facilities (LTCFs) have been harmed by the coronavirus, and older adults have remained isolated for a long time with many restrictions. The aim of this study was to measure the decline in cognitive, functional, and affective status in a care facility after the lockdown in the first wave of the COVID-19 pandemic and to compare it with previous measures in order to determine if this decline was accelerated. (2) Methods: Ninety-eight participants were recruited. Data from three retrospective pre-lockdown assessments and an additional post-lockdown assessment were analyzed. Mixed ANOVA analyses were performed according to the Clinical Dementia Rating levels, considering social-contact frequency during the lockdown as a covariate. (3) Results: The cognitive and functional scores were lower and depression scores were higher after the strict lockdown, accelerating a general pattern of decline that was already present in LTCF residents. The frequency of social contact eliminated the measurement differences in the cognitive and functional scores and the group differences in depression scores. (4) Conclusions: The effects of the SARS-CoV-2 lockdown in an LTCF were mediated by the frequency of contact. Clinical implications: Preventive measures must be taken to ensure social contact with relatives and friends and reduce the negative consequences of social isolation in LTCFs.

Prevalence of Cognitive Frailty, Do Psychosocial-Related Factors Matter?

Cognitive frailty (CF) is a topic of growing interest with implications for the study of preventive interventions in aging. Nevertheless, little research has been done to assess the influence of psychosocial variables on the risk of CF. Our objectives were to estimate the prevalence of CF in a Spanish sample and to explore the influence of psychosocial variables in this prevalence. Physical frailty and cognitive, functional, psychosocial, and socio-demographic aspects were assessed in a sample of 285 participants over 60 years. Univariate and multivariate logistic regression models were carried out. A prevalence of 21.8% (95% CI 17.4-26.9) was established when both frail and pre-frail conditions were included, and a prevalence of 3.2% (95% CI 1.7-5.9) if only frail individuals were considered. Age, educational level, profession and psychological well-being variables significantly predicted CF. Frailty and pre-frailty are high-prevalence health conditions in older adults influenced by socio-demographic, socio-educative and affective factors.

Dual and triple tasks performance in institutionalized prefrail and frail older adults

OBJECTIVE

The aim of this pilot study was to investigate differences on dual- and triple-task performance in institutionalized prefrail and frail older adults. Performance on these tasks is relevant since many activities of daily living involve simultaneous motor and cognitive tasks.

METHODS

We used a phenotypic description of frailty based on the presence or absence of five criteria related to physical fitness and metabolism (unintentional weight loss, self-reported exhaustion, muscle weakness, low gait speed, and low physical activity). Thirty-three institutionalized older adults (≥ 65 years, 78.8% females) were divided according to their frailty status. Participants completed cognitive tasks (a phonemic verbal fluency task and a visuospatial tracking task) while cycling on a stationary cycle (upper- and lower-extremity function was assessed). Cycling (number of arm and foot cycles) and cognitive (number of correct answers) performances were measured during single-, dual-, and triple-task conditions. Performances and costs of dual -and triple- tasking on cycling and cognitive performances were compared between prefrail and frail groups.

RESULTS

Prefrail and frail older adults did not differ in their performance in dual-tasks; however, frail older adults showed a poorer performance in the triple-task.

CONCLUSIONS

Although future studies need to confirm our observations in larger samples, this pilot study suggests that developing new tools based on triple tasking could be useful for the comprehensive assessment of frailty.

Longitudinal Patterns of the Tip-of-the-Tongue Phenomenon in People With Subjective Cognitive Complaints and Mild Cognitive Impairment

Background

The Tip-of-the-Tongue (ToTs) state is considered a universal phenomenon and is a frequent cognitive complaint in old age. Previous cross-sectional studies have found that ToT measures successfully discriminate between cognitively unimpaired adults and adults with Mild Cognitive Impairment (MCI). The aim of this study was to identify longitudinal patterns of ToTs in individuals with subjective complaints and with MCI regarding progress of their cognitive status.

Method

The study included 193 participants with subjective cognitive complaints (SCC) and 56 participants with MCI who completed a baseline and two follow-up assessments, with an interval of about 18 months between each assessment. Participants were classified into three groups by considering cognitive stability or deterioration from the baseline diagnosis: SCC-stable, MCI-stable and MCI-worsened. Participants performed a ToT task involving recognition and naming of famous people depicted in 50 photographs. Generalized Linear Mixed Models (GLMM) were used to model longitudinal changes in familiarity, feeling of knowing, semantic access, phonological access and verbal fluency.

Results

Phonological access differentiated MCI patients, stable and worsened, from adults with SCCs at all evaluation times. Phonological access declined over time in the three groups, without significant interactions between groups and time.

Discussion

This study provides the first longitudinal evidence of differences in ToT measures for adults with MCI. The findings indicate that phonological access measures successfully differentiated between the diagnostic groups. However, slopes remain irrespective of the diagnostic group and progression toward more advance stages of cognitive impairment.

Does the neuropsychiatric inventory predict progression from mild cognitive impairment to dementia? A systematic review and meta-analysis

BACKGROUND

Neuropsychiatric Symptoms (NPS) are common in Mild Cognitive Impairment (MCI). The Neuropsychiatric Inventory (NPI) and its shorter version, the Neuropsychiatric Inventory Questionnaire (NPI-Q), are the most common measures to assess NPS. Our objective was to determine if NPI/NPI-Q ratings predict conversion from MCI to dementia.

METHODS

Empirical longitudinal studies published in English or Spanish, concerned with the role of NPS as a risk factor for conversion from MCI to dementia, with a diagnosis of MCI following clinical criteria, that reported NPI/NPI-Q total score in converters versus non-converters, were included. Random effects models were used, and heterogeneity was explored with stratification and a random-effects meta-regression. The overall conversion rate and the standardized mean difference (SMD) for evolution, as a function of NPI/NPI-Q scores, were calculated.

RESULTS

The overall conversion rate was 35 %. Mean NPI/NPI-Q ratings were higher in converters versus in non-converters, with the overall SMD approaching significance. Heterogeneity was observed in studies of more than two years of follow-up and in a study with a mean age of more than 80 years. This heterogeneity concerned the size, not the direction of the difference.

CONCLUSIONS

Our results suggest that NPI/NPI-Q ratings are associated with conversion from MCI to dementia.

Does Empirically Derived Classification of Individuals with Subjective Cognitive Complaints Predict Dementia?

(1) Background: Early identification of mild cognitive impairment (MCI) in people reporting subjective cognitive complaints (SCC) and the study of progression of cognitive decline are important issues in dementia research. This paper examines whether empirically derived procedures predict progression from MCI to dementia. (2) Methods: At baseline, 192 participants with SCC were diagnosed according to clinical criteria as cognitively unimpaired (70), single-domain amnestic MCI (65), multiple-domain amnestic MCI (33) and multiple-domain non-amnestic MCI (24). A two-stage hierarchical cluster analysis was performed for empirical classification. Categorical regression analysis was then used to assess the predictive value of the clusters obtained. Participants were re-assessed after 36 months. (3) Results: Participants were grouped into four empirically derived clusters: Cluster 1, similar to multiple-domain amnestic MCI; Cluster 2, characterized by subjective cognitive decline (SCD) but with low scores in language and working memory; Cluster 3, with specific deterioration in episodic memory, similar to single-domain amnestic MCI; and Cluster 4, with SCD but with scores above the mean in all domains. The majority of participants who progressed to dementia were included in Cluster 1. (4) Conclusions: Cluster analysis differentiated between MCI and SCD in a sample of people with SCC and empirical criteria were more closely associated with progression to dementia than standard criteria.

Assessing Everyday Activities Across the Dementia Spectrum with the Amsterdam IADL Questionnaire

BACKGROUND

Instrumental activities of daily living (IADL) are complex activities which involve multiple cognitive processes, and which are expected to be susceptible to the early effects of cognitive impairment. Informant-based questionnaires are the most common tools used to assess IADL performance in dementia, but must be adjusted for use in early stages of impairment.

OBJECTIVE

To investigate the differences in IADL on the continuum of cognitive decline (i.e. no cognitive decline - subjective cognitive decline - mild cognitive impairment- mild dementia - moderate dementia) using the Spanish version of the Amsterdam IADL Questionnaire (A-IADL-Q).

METHODS

A total of 500 volunteer participants were included: 88 participants with no signs of cognitive decline, 109 participants with subjective cognitive complaints, 114 participants with mild cognitive impairment (MCI), 81 participants with mild dementia and 108 participants with moderate dementia. IADL was assessed with the A-IADL-Q, a computerized and adaptive questionnaire that calculates scores according to the specific pattern of responses of each participant. The data were examined by ANOVAs and regression analysis. Multinomial logistic regression analysis was used to evaluate the capacity of the A-IADL-Q to distinguish between diagnostic groups.

RESULTS

Participants with no cognitive decline and those with subjective cognitive decline obtained higher A-IADL-Q scores than MCI participants, and participants with MCI obtained higher scores than patients with dementia. The A-IADL-Q showed excellent discrimination between non-cognitive impairment and dementia, and significant but low discrimination between non-cognitive impairment and MCI.

CONCLUSION

A-IADL-Q can discriminate IADL functioning between groups across the dementia spectrum.

Using an Overlapping Time Interval Strategy to Study Diagnostic Instability in Mild Cognitive Impairment Subtypes

(1) Background: Mild cognitive impairment (MCI) is a diagnostic label in which stability is typically low. The aim of this study was to examine temporal changes in the diagnosis of MCI subtypes by using an overlapping-time strategy; (2) Methods: The study included 435 participants aged over 50 years with subjective cognitive complaints and who completed at least one follow-up evaluation. The probability of transition was estimated using Bayesian odds ratios; (3) Results: Within the different time intervals, the controls with subjective cognitive complaints represented the largest proportion of participants, followed by sda-MCI at baseline and in the first five intervals of the follow-up, but not in the last eight intervals. The odds ratios indicated higher odds of conversion to dementia in sda-MCI and mda-MCI groups relative to na-MCI (e.g., interval 9–15 months—sda-MCI OR = 9 and mda-MCI OR = 3.36; interval 27–33—sda-MCI OR = 16 and mda-MCI = 5.06; interval 42–48—sda-MCI OR = 8.16 and mda-MCI = 3.45; interval 45–51—sda-MCI OR = 3.31 and mda-MCI = 1); (4) Conclusions: Notable patterns of instability consistent with the current literature were observed. The limitations of a prospective approach in the study of MCI transitions are discussed.

Machine learning approaches to studying the role of cognitive reserve in conversion from mild cognitive impairment to dementia

OBJECTIVES

The overall aim of the present study was to explore the role of cognitive reserve (CR) in the conversion from mild cognitive impairment (MCI) to dementia. We used traditional and machine learning (ML) techniques to compare converter and nonconverter participants. We also discuss the predictive value of CR proxies in relation to the ML model performance.

METHODS

In total, 169 participants completed the longitudinal study. Participants were divided into a control group and three MCI subgroups, according to the Petersen criteria for diagnosis. Information about the participants was compared using nine ML classification techniques. Seven relevant performance metrics were computed in order to evaluate the accuracy of prediction regarding converter and nonconverter participants.

RESULTS

ML algorithms applied to socio-demographic, basic health, and CR proxy data enabled prediction of conversion to dementia. The best performing models were the gradient boosting classifier (accuracy (ACC) = 0.93; F1 = 0.86, and Cohen κ = 0.82) and random forest classifier (ACC = 0.92; F1 = 0.79, and Cohen κ = 0.71). Use of ML techniques corroborated the protective role of CR as a mediator of conversion to dementia, whereby participants with more years of education and higher vocabulary scores survived longer without developing dementia.

CONCLUSIONS

We used ML approaches to explore the role of CR in conversion from MCI to dementia. The findings indicate the potential value of ML algorithms for detecting risk of conversion to dementia in cognitive aging and CR studies. Further research is required to develop an ML-based procedure that can be used to make robust predictions.

Cognitive frailty: A conceptual systematic review and an operational proposal for future research

OBJECTIVE

To analyze the definition of "cognitive frailty" and to study the conceptual and operational definitions used and their implications for empirical research. The relationships between this concept and cognitive reserve, the role of neuropathology and brain reserve, motor signs of aging and the reversibility of cognitive frailty are also discussed.

STUDY DESIGN

Systematic review of empirical studies identified from Medline Advanced 1966, CINAHL, Web of Science, PsycINFO, and Scopus until August 2017.

MAIN - OUTCOME MEASURES

Effect sizes. The quality of the articles was assessed by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Statement. Three independent reviewers participated in the study selection and data extraction.

RESULTS

Nineteen studies involving 31,707 participants met the inclusion criteria. Significant associations were reported between cognitive frailty and physical frailty or gait speed. Screening instruments were usually used to determine objective cognitive decline rather than extensive neuropsychological assessments. Educational level was the only indicator of cognitive reserve that was systematically included in the evaluation of cognitive frailty. Motor decline and gait variables were not systematically included in protocols for the assessment of cognitive frailty.

CONCLUSIONS

A strong operational definition would benefit both the development of treatments to counter cognitive frailty and the assessment of treatment effectiveness. Nevertheless, since there is clear agreement regarding the importance of interventions for and the prevention of cognitive frailty, randomized controlled trials investigating the efficacy of preventive interventions are necessary.

Can the post-error effect mask age-related differences in congruency conditions when education and overall accuracy are controlled for?

OBJECTIVE

Age-related differences in stimulus-response congruency tasks have been attributed to older adults' greater difficulties in handling the irrelevant spatial-dimensional overlap between stimulus and response. However, performance on congruency tasks may also be influenced by the previous trial accuracy (i.e. post-error effect), which may affect young and older adults differently. The main objective of this study was to analyse age-related differences in the post-error effect as a function of congruency. In addition, we examined the meditational role of the Gratton effect on the age-related differences in the post-error slowing (PES) and post-error increased accuracy (PIA) as a function of congruency.

METHOD

The sample comprised 165 healthy adult participants with diverse educational attainment, divided into five age groups. Participants performed a spatial stimulus-response congruency task. Age-related differences in the post-error effect were analysed for each congruency condition taking into account educational attainment and overall accuracy. Statistical procedures were used to neutralize age-related processing speed effects on the PES.

RESULTS

PES was observed across all age groups, except the Very old group (aged 85-98 years), and it was not related to congruency condition. PIA was observed across age groups in all congruency conditions and was slightly higher in incongruent trials. Evidence of simultaneous PES and PIA was found for young participants and older participants under 85 years. The Very old group did not need to significantly slow down their responses after errors to improve accuracy. No age- related difference was found in the influence of the Gratton effect on PES or PIA as a function of congruency.

CONCLUSIONS

PES and PIA were observed in young adults and older adults under 85 years old. Evidence of simultaneous PES and PIA in the young and older age group (except for the Very old) indicates that the post-error effect can be interpreted in terms of recruitment of additional resources to prevent subsequent errors. Slightly higher accuracy was observed in the incongruent condition in post-error trials relative to pre-error correct trials across age groups.

Effects of Cognitive Reserve on Cognitive Performance in a Follow-Up Study in Older Adults With Subjective Cognitive Complaints. The Role of Working Memory

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.

[Cognitive neuroscience of aging. Contributions and challenges]

The cognitive neuroscience of aging is a young discipline that has emerged as a result of the combination of: A) the theoretical and explanatory frameworks proposed by the cognitive psychology perspective throughout the second half of the twentieth century; B) the designs and methodological procedures arising from experimental psychology and the need to test the hypotheses proposed from the cognitive psychology perspective; C) the contributions of the computer sciences to the explanation of brain functions; and D) the development and use of neuroimaging techniques that have enabled the recording of brain activity in humans while tasks that test some cognitive process or function are performed. An analysis on the impact of research conducted from this perspective over the last 3decades has been carried out, including its shortcomings, as well as the potential directions and usefulness that will advantageously continue to drive this discipline in its description and explanation of the process es of cerebral and cognitive aging.

Longitudinal Assessment of Verbal Learning and Memory in Amnestic Mild Cognitive Impairment: Practice Effects and Meaningful Changes

Objectives: To identify learning effects and meaningful changes in amnestic mild cognitive impairment (aMCI) at a follow-up assessment.

Method: The Spanish version of the California Verbal Learning Test (CVLT) was administered to a sample of 274 adults of age over 50 years with subjective memory complains (SMC), including single and multiple domain aMCI groups and participants with SMC but without cognitive impairment (SMC group). The Wilcoxon test was used to compare results at baseline and after 18 months in short and long recall, and standardized regression-based (SRB) methods were used to study meaningful changes.

Results: Scores were significantly higher at follow-up for short and long-delayed recall in all groups indicating generalized practice effect. SRB scores indicated a significant decline in recall in a higher proportion of participants with aMCI than in SMC group.

Discussion: Patients with multiple and single domain aMCI benefit from practice in a verbal learning memory test. The SRB approach revealed a higher incidence of meaningful decline in short and long-delay recall and recognition in the aMCI groups than in the SMC group. Specifically, compared to SMC participants, single-domain aMCI individuals declined in a higher proportion in all measures, and multiple-domain aMCI individuals in long delay free recall.

Normative scores of the Cambridge Cognitive Examination-Revised in healthy Spanish population

BACKGROUND

The Cambridge Cognitive Examination-Revised (CAMCOG) is widely used in clinical, epidemiological and research studies, but normative scores for age and educational level have not yet been established in the Spanish population.

METHOD

The CAMCOG-R was administered to 730 adult members ofthe community, aged between 50-97 years, living throughout the region of Galicia. Initial screening yielded provisional identification of cognitive impairment and depressive symptoms. The final sample consisted of 643 cognitively healthy adults. The following instruments were administered: a questionnaire concerning socio-demographic and clinical data, the Charlson's Comorbidity Index, the Mini-Mental State Examination, the Montreal Cognitive Assessment (MoCA), the Lawton and Brody Index, a short version of the Geriatric Depression Scale, and the CASP-19 quality of life scale.

RESULTS

Internal consistency values of the CAMCOG-R were similar to those obtained for the original scale. The convergent validity between MoCA and CAMCOG-R was good, and the divergent validity between CASP-19 and CAMCOG-R was higher than the recommended value. Percentiles and inter-quartile range for age and educational level were calculated.

CONCLUSIONS

Psychometric indexes showed that the CAMCOG-R is a reliable and valid instrument, which can generally avoid a ceiling effect. The study findings confirm the importance of specifying the normative data by age and educational level.

Temporal changes in semantic and lexical access related to mild cognitive impairment

BACKGROUND

It has been hypothesized that the deterioration in the ability to name famous people in normal aging and cognitive impairment is a continuum in which meaning-based representations and form-based representations are differentially impaired, with early impairments in lexical access but not in semantic access.

AIMS

This hypothesis is tested in a follow-up study comparing the performance of fifty-six participants with amnestic mild cognitive impairment and forty-one control participants were assessed.

METHOD

A lexical task was conducted involving recognition and naming of famous people from photographs. Proportional semantic and phonological access measures were calculated.

RESULTS

Comparisons revealed significant differences between baseline and follow-up, with improvements in semantic access in the control group and decrements in phonological access in the group with amnestic mild cognitive impairment. Phonological access and reaction time measures were significantly and positively correlated, and semantic access and reaction time were significantly and negatively correlated.

CONCLUSIONS

These results add evidence to the hypothesis that the decrease of processing resources is related to the increase of difficulties in lexical access throughout aging. Patterns of change must be replicated over longer periods of time.

Characterizing Magnitude and Selectivity of Attrition in a Study of Mild Cognitive Impairment

OBJECTIVES

Attrition is one of the greatest difficulties in longitudinal studies on cognitive ageing because of the associated risk of underestimating declines. The aims of this paper were to characterize the magnitude and selectivity of attrition in a study of mild cognitive impairment.

DESIGN

Forty two patients with multiple-domain amnestic MCI, 71 with single-domain amnestic MCI, 35 with non-amnestic MCI and 318 healthy controls were recruited from primary care centers and assessed at baseline.

MEASUREMENTS

All participants underwent extensive neuropsychological evaluation, including the Mini-Mental State Examination, the Californian Verbal Learning Test, the CAMCOG-R battery, the Counting Span task and Listening Span task, and the Subjective Memory Complaints Questionnaire.

RESULTS

21.5% of the participants at baseline did not participate in the follow-up assessment. Comparison between respondents and non-returners did not reveal differences in cognitive performance in the MCI group. Data obtained at the initial assessment regarding comorbidity, social activities and attention given to memory training enabled prediction of the status of the participants in the follow-up assessment.

CONCLUSION

Identification of potential non- returners is relevant, especially in MCI studies, in order to develop retention strategies to minimize attrition.