How cognitive reserve influences older adults' cognitive state, executive functions and language comprehension: A structural equation model

Pragmatic Skills in Late Adulthood

Research investigating pragmatic abilities in healthy aging suggests that both production and comprehension might be compromised; however, it is not clear how pragmatic abilities evolve in late adulthood, as well as when difficulties are more likely to arise. The aim of this study is to investigate the decline of pragmatic skills in aging, and to explore what cognitive and demographic factors support pragmatic competence. We assessed pragmatic production skills, including discourse abilities such as speech, informativeness, information flow, paralinguistic aspects, as well as the ability to produce informative descriptions of pictures, and pragmatic comprehension skills, which encompassed the ability to understand discourse and the main aspects of a narrative text, to infer non-literal meanings and to comprehend verbal humor in a group of elderly individuals and in a sample of younger participants. Moreover, specific cognitive functions (short-term memory, verbal and visuospatial working memory, inhibition Theory of Mind, and Cognitive Reserve) were assessed in both groups. Pragmatic difficulties seem to occur in late adulthood, likely around 70 years, and emerge more prominently when participants are asked to understand verbal humor. Age was the only predictor of general pragmatic performance in a sample of cognitively unimpaired older adults; conversely, when elderly individuals with less intact inhibitory control are considered, a general role of inhibition emerged, in addition to working memory and ToM in specific tasks.

Tele-Global Examination of Mental State (Tele-GEMS): an open tool for the remote neuropsychological screening

Tele-neuropsychology, i.e., the application of remote audio-visual technologies to neuropsychological evaluation or rehabilitation, has become increasingly popular and widespread during and after the COVID-19 pandemic. New tools with updated normative data and appropriate methodological developments are necessary. We present Tele-GEMS, a telephone-based cognitive screening developed on N = 601 Italian participants. It yields a global score tapping on orientation, memory, spatial representation, language, and pragmatic abilities. Its administration lasts about 10 min. Clinical cut-offs are provided, accounting for demographic variables (age, education, and sex) and also for a comprehensive index taking into account cognitively stimulating life experiences that can build up a cognitive reserve. Tele-GEMS shows good internal consistency and a good inter-rater agreement. The test includes the thresholds for estimating a significant change after repeated measurements. Tele-GEMS has a good construct validity as assessed with MoCA and a suitable criterion validity assessed with its in-person version (GEMS). All the materials and the instructions, including scripts and an online Application for the automatic calculation of cut-offs, are accessible on OSF at https://osf.io/t3bma/ under a Creative Commons license.

Moderating effects of cognitive reserve on the relationship between brain structure and cognitive abilities in middle-aged and older adults

The cognitive reserve (CR) hypothesis is reinforced by negative moderating effects, suggesting that those with higher CR are less reliant on brain structure for cognitive function. Previous research on CR's moderating effects yielded inconsistent results, motivating our 3 studies using UK Biobank data. Study I examined five CR proxies' moderating effects on global, lobar, and regional brain-cognition models; study II extended study I by using a larger sample size; and study III investigated age-related moderating effects on the hippocampal regions. In study I, most moderating effects were negative and none survived the multiple comparison correction, but study II identified 13 global-level models with significant negative moderating effects that survived correction. Study III showed age influenced CR proxies' moderating effects in hippocampal regions. Our findings suggest that the effects of CR proxies on brain integrity and cognition varied depending on the proxy used, brain integrity indicators, cognitive domain, and age group. This study offers significant insights regarding the importance of CR for brain integrity and cognitive outcomes.

Factors associated with cognitive impairment in Latin American older adults: A cross-sectional observational study of COVID-19 confinement

INTRODUCTION

The effects of COVID-19 confinement have been severe, especially in older adults. Therefore, we analyzed the factors associated with cognitive impairment (CI) in Latin America (LA).

METHODS

We conducted a cross-sectional observational study with a total of 5245 older adults from 10 countries in LA.

Measurement

We used the Telephone Montreal Cognitive Assessment (T-MoCA) and the Eight-item Informant Interview to Differentiate Aging and Dementia (AD8) scale.

RESULTS

We found that age, depressive symptomatology, bone fractures, being widowed, having a family member with dementia, and unemployment were associated with an increased risk of CI. In contrast, higher education, hypertension with continuous treatment, quarantine, and keeping stimulating cognitive and physical activities were associated with a lower probability of CI. No significant association was found between suffering from diabetes or being retired and CI.

DISCUSSION

It is essential to conduct follow-up studies on these factors, considering their relationship with CI and the duration of confinement.

Influence of cognitive reserve on neuropsychological performance in subjective cognitive decline and mild cognitive impairment older adults

The analysis of the relationships between cognitive reserve and different cognitive domains has become a matter of interest since it can help us detect deviations from the typical ageing process. The main objective of our study was to analyse a structural equation model representing cognitive reserve’s relationships with three cognitive domains (episodic memory, working memory, and sentence comprehension) in older adults with subjective cognitive decline and mild cognitive impairment patients, in a cross-sectional study. A total of 266 Spanish-speaking older adults, from 65 to 80 years old, voluntarily participated in the study. The assessment protocol includes questionnaires as well as screening and domain-specific tests, providing relevant information for the classification of participants in the two groups previously mentioned (n1 = 150 and n2 = 116). The proposed model presented metric and configural invariance as well as stability across groups, since the indices reflecting goodness-of-fit reach acceptable values. Our hypotheses are partially confirmed since cognitive reserve strongly influences working memory and it does moderately in sentence comprehension in both groups, but it hardly influences episodic memory in the subjective cognitive decline group, while both are inversely associated in the patients’ group. Working memory could be considered as a mechanism through which cognitive reserve exerts its protector role on other cognitive domains: on sentence comprehension in both groups, and on episodic memory in the subjective cognitive decline group. However, in mild cognitive impairments patients, cognitive reserve does no longer influence episodic memory via working memory in a significant manner.

Task Demands and Sentence Reading Comprehension among Healthy Older Adults: The Complementary Roles of Cognitive Reserve and Working Memory

Ageing entails different functional brain changes. Education, reading experience, and leisure activities, among others, might contribute to the maintenance of cognitive performance among older adults and are conceptualised as proxies for cognitive reserve. However, ageing also conveys a depletion of working memory capacity, which adversely impacts language comprehension. This study investigated how cognitive reserve proxies and working memory jointly predict the performance of healthy older adults in a sentence reading comprehension task, and how their predictive value changes depending on sentence structure and task demands. Cognitively healthy older adults (n = 120) completed a sentence–picture verification task under two conditions: concurrent viewing of the sentence and picture or their sequential presentation, thereby imposing greater demands on working memory. They also completed a questionnaire on cognitive reserve proxies as well as a verbal working memory test. The sentence structure was manipulated by altering the canonical word order and modifying the amount of propositional information. While the cognitive reserve was the main predictor in the concurrent condition, the predictive role of working memory increased under the sequential presentation, particularly for complex sentences. These findings highlight the complementary roles played by cognitive reserve and working memory in the reading comprehension of older adults.

Trajectory Pattern of Cognitive Decline in Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy

BACKGROUND AND OBJECTIVES

The course and pattern of cognitive decline in ischemic cerebral small vessel disease remain poorly characterized. We analyzed the trajectory pattern of cognitive decline from age 25 to 75 years in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

METHODS

We applied latent process mixed models to data obtained from patients with CADASIL who were repeatedly scored during their follow-up using 16 selected clinical scales or cognitive tests.

RESULTS

The modeled evolutions of these scores obtained from 1,243 observations in 265 patients recruited at the French National Referral Centre (50.1 years on average and 45.3% men) showed wide and heterogeneous variations in amplitude along the age-related progression of the disease. Although the Backward Digit Span remained essentially stable, a linear deterioration of scores obtained using the Symbol Digit Numbers or Number of Errors of Trail Making Test B was detected from 25 to 75 years. By contrast, the largest score changes were observed at midlife using the Digit Cancellation Task. All other tests related to executive functions, memory performances, or global cognitive efficiency showed a rate of change accelerating especially at the advanced stage of the disease. Male gender and the presence of gait disorders or of some disability at baseline were found to predict earlier or large changes of 4 scores (Index of Sensitivity to Cueing, Delayed Total Recall, Initiation/Perseveration, and Barthel Index) in a subgroup of individuals distinct from the rest of the sample.

DISCUSSION

Cognitive alterations develop heterogeneously during the progression of CADASIL and vary largely according to the stage of the disease. These results suggest that not only the target population and study duration but also the stage of disease progression should be considered in preparing future clinical trials aimed at reducing cognitive decline in any such condition.

Higher levels of neuroticism in older adults predict lower executive functioning across time: the mediating role of perceived stress

Neuroticism has been associated with individual differences across multiple cognitive functions. Yet, the literature on its specific association with executive functions (EF) in older adults is scarce, especially using longitudinal designs. To disentangle the specific influence of neuroticism on EF and on coarse cognitive functioning in old adulthood, respectively, we examined the relationship between neuroticism, the Trail Making Test (TMT) and the Mini-Mental State Examination (MMSE) in a 6-year longitudinal study using Bayesian analyses. Data of 768 older adults (M age = 73.51 years at Wave 1) were included in a cross-lagged analysis. Results showed no cross-sectional link between neuroticism and TMT performance at Wave 1 and no longitudinal link between neuroticism at Wave 1 and MMSE at Wave 2. However, neuroticism at Wave 1 predicted TMT performance at Wave 2, indicating that the more neurotic participants were, the lower they performed on the TMT six years later. Additional analyses showed that this relation was fully mediated by participants' perceived stress. Our results suggest that the more neurotic older adults are the more stress they may perceive six years later, which in turn negatively relates to their EF. In sum, this study demonstrates that neuroticism may lead to lower EF in older age across six years. It further suggests older adults' perceived stress as mediator, thereby providing novel insights into the mechanisms underlying this relation. Possible intervention approaches to counter these effects are discussed.

Cognitive reserve may outperform age, mood and psychiatric comorbidities as a predictor of executive functioning in bipolar disorder and healthy adults

INTRODUCTION

Cognitive reserve plays a protective role against executive dysfunction in healthy adults and individuals with psychiatric illnesses such as bipolar disorder. However, the magnitude of the influence of cognitive reserve on specific executive functions (EFs), and its impact relative to variables such as depressive symptoms, age and psychiatric comorbidities, is unexplored. This study aimed to quantify the influence of cognitive reserve on specific EFs, and compare its impact with that of depressive symptoms, age and psychiatric comorbidities, in separate models for patients with bipolar disorder and healthy adults.

METHOD

This was a cross-sectional study of 121 adults with no mood disorders and 109 with bipolar disorder, all of whom underwent a comprehensive psychiatric assessment and evaluation of the EFs. Cognitive reserve was measured using years of education, IQ and reading and writing habits. The association between EFs and predictors (cognitive reserve, depressive symptoms, age and psychiatric comorbidities) was evaluated through structural equation modeling. Four models were constructed for each group independently (bipolar disorder and control), one each for working memory, verbal fluency, inhibition and flexibility, due to group differences in age and cognitive reserve.

RESULTS

Working memory, inhibition and flexibility were most significantly predicted by cognitive reserve and age. Verbal fluency was only predicted by cognitive reserve. Comorbidities and depressive symptoms were not significant in any of the models. Cognitive reserve had a positive influence on all EFs in models for patients with bipolar disorder and models for control participants. Age had a negative impact on three of the four EFs tested.

CONCLUSION

Fostering cognitive reserve through continued education and cognitively stimulating leisure activities may be an effective intervention for executive dysfunction in patients and non-patients alike. In some cases, the effects of these interventions may outweigh the negative cognitive impact of aging, depressive symptoms and psychiatric conditions.

Spanish Validation for Olfactory Function Testing Using the Sniffin' Sticks Olfactory Test: Threshold, Discrimination, and Identification

The assessment of olfactory function is becoming increasingly relevant, especially in cases of cognitive decline (i.e., neurodegenerative diseases), where olfactory alterations may be relevant as potential early biomarkers. The Sniffin' Sticks Olfactory Test, developed in Germany and validated in several countries, is an objective measure of olfactory performance. This study aims to validate this test in a Spanish sample. This study included 209 healthy normosmic volunteers (154 females and 55 males) aged between 20 to 79 years (mean age = 50.11 ± 15.18 years) as the normative sample. From this group, 22 participants were retested in order to obtain test-retest reliability evidence. Odor familiarity for descriptors in the olfactory identification test was also studied on an independent healthy sample (n = 69), and required cultural modifications were applied. Results indicate that men and women, as well as smokers and non-smokers, performed equally in every test. However, significant differences were found between age groups in every score. The general trend is that olfactory function progressively decreases as a function of age, the elderly group (+60 years) being the one with the lowest scores. In conclusion, this normative data, in addition to the test's cultural modifications, allows the Sniffin' Sticks Olfactory Test to be administered on a Spanish population.

Propiedades psicométricas y datos normativos de la prueba ECCO_Senior: un instrumento para evaluar la comprensión gramatical en adultos mayores

El test ECCO_Senior se diseñó para evaluar la comprensión de oraciones en adultos mayores. Es una prueba corta y de fácil aplicación, que se ha empleado en distintos estudios previos. En el estudio participaron 670 personas, de 50 a 85 años de edad, que cumplían criterios de inclusión relativos al estatus cognitivo general, el estado de ánimo y porcentaje mínimo de aciertos en el test. Además de los test de cribado (MEC y GDS-15) y un cuestionario socio-demográfico, se aplicó a todos los participantes el test ECCO_Senior con el que se pueden obtener distintos índices (generales y específicos). Además de comprobar si existen diferencias entre los grupos según la edad y el nivel educativo, se evaluaron las propiedades psicométricas del test, incluyendo evidencias de validez en las que se probó la bondad de ajuste de tres modelos estructurales que sirven para identificar los índices que explican un mayor porcentaje de la varianza del constructo (comprensión de oraciones). Se ofrecen normas interpretativas del test por edad y nivel de estudios en los Apéndices. Los resultados indican que el test permite evaluar la comprensión de oraciones con una fiabilidad adecuada y es sensible a las dificultades que puede experimentar un adulto al realizar esta tarea. Los tres modelos muestran un buen ajuste y permiten concluir que las oraciones no ajustadas al orden sintáctico canónico y los distractores léxicos (si se considera el tipo de ítem) serían los mejores indicadores en términos del porcentaje de la varianza del constructo que explican.