The Impact of Working Memory Training on Cognitive Abilities in Older Adults: The Role of Cognitive Reserve

Cognition and Cognitive Reserve

Cognition is a mental process that provides the ability to think, know, and learn. Though cognitive skills are necessary to do daily tasks and activities, cognitive aging causes changes in various cognitive functions. Cognitive abilities that are preserved and strengthened by experience can be kept as a reserve and utilized when necessary. The concept of reserving cognition was found when people with Alzheimer's disease had differences in clinical manifestations and cognitive functions. The cognitive reserve builds resilience against cognitive decline and improves the quality of life. Also, several lines of studies have found that the plasticity between neurons has a significant impact on cognitive reserve and acts against cognitive decline. To extend the findings, the present study provides a comprehensive understanding of cognitive reserve and the variables that are involved in maintaining cognition. The study also considers reading as one of the cognitive proxies that develops and maintains cognitive reserve.

Vertigo in the Elderly: A Systematic Literature Review

Background: Dizziness and vertigo are among the most prevalent complaints in the elderly and have a major negative influence on (i) the perception of the quality of life; and (ii) the risk of falling. Due to population aging, particularly in wealthy nations, vertigo represents a growing issue and a serious public health concern. In order to approach the patient correctly and to offer the best treatment options, it is mandatory to identify vertigo’s underlying causes. The aim of this paper was to identify the different etiologies of vertigo and possibly their frequency in the elderly population, by reviewing the scientific literature of the last decade (2012–2022). Methods: A systematic review was performed according to PRISMA guidelines, searching the Medline database from January 2012 through to December 2022. The search identified 1025 candidate papers, but after the application of specific selection criteria, only five were considered for further analysis. Results: A total of 2148 elderly patients (60–90 y old) presenting with vertigo were reported in the selected papers. A total of 3404 conditions were identified as the cause of vertiginous symptoms, (some patients presented multiple etiologies). All major diagnoses were categorized into different subgroups: the most common origin of vertigo was represented by audio-vestibular disorders (28.4%), followed by cardiovascular (20.4%) and neurological diseases (15.1%). Furthermore, 9.1% of patients were diagnosed with psychiatric conditions, whilst ophthalmologic and musculoskeletal disorders accounted for 7.5% and 6.3% of the cases respectively. Medication adverse effects and metabolic-related diseases were also considered among the causes. For 3.4% of cases the etiology remains unclear. Conclusions: Audio-vestibular disorders represent the most frequent cause of vertigo in the elderly. The etiologies affecting the vertigo patient must be defined in order to identify potential life-threatening conditions, such as cardiovascular and neurological disorders, which according to the data of this review constitute the second and third common causes of vertigo. A multidisciplinary strategy, involving different specialists (such as ENTs, Neurologists, Cardiologists, Geriatricians) is recommended for the correct assessment of these disorders.

Encoding specificity instead of online integration of real-world spatial regularities for objects in working memory

Most objects show high degrees of spatial regularity (e.g. beach umbrellas appear above, not under, beach chairs). The spatial regularities of real-world objects benefit visual working memory (VWM), but the mechanisms behind this spatial regularity effect remain unclear. The "encoding specificity" hypothesis suggests that spatial regularity will enhance the visual encoding process but will not facilitate the integration of information online during VWM maintenance. The "perception-alike" hypothesis suggests that spatial regularity will function in both visual encoding and online integration during VWM maintenance. We investigated whether VWM integrates sequentially presented real-world objects by focusing on the existence of the spatial regularity effect. Throughout five experiments, we manipulated the presentation (simultaneous vs. sequential) and regularity (with vs. without regularity) of memory arrays among pairs of real-world objects. The spatial regularity of memory objects presented simultaneously, but not sequentially, improved VWM performance. We also examined whether memory load, verbal suppression and masking, and memory array duration hindered the spatial regularity effect in sequential presentation. We found a stable absence of the spatial regularity effect, suggesting that the participants were unable to integrate real-world objects based on spatial regularities online. Our results support the encoding specificity hypothesis, wherein the spatial regularity of real-world objects can enhance the efficiency of VWM encoding, but VWM cannot exploit spatial regularity to help organize sampled sequential information into meaningful integrations.

Age-Specific Activation Patterns and Inter-Subject Similarity During Verbal Working Memory Maintenance and Cognitive Reserve

Cognitive Reserve (CR), according to a recent consensus definition of the NIH-funded Reserve and Resilience collaboratory, is constituted by any mechanism contributing to cognitive performance beyond, or interacting with, brain structure in the widest sense. To identity multivariate activation patterns fulfilling this postulate, we investigated a verbal Sternberg fMRI task and imaged 181 people with age coverage in the ranges 20-30 (44 participants) and 55-70 (137 participants). Beyond task performance, participants were characterized in terms of demographics, and neuropsychological assessments of vocabulary, episodic memory, perceptual speed, and abstract fluid reasoning. Participants studied an array of either one, three, or six upper-case letters for 3 s (=encoding phase), then a blank fixation screen was presented for 7 s (=maintenance phase), to be probed with a lower-case letter to which they responded with a differential button press whether the letter was part of the studied array or not (=retrieval phase). We focused on identifying maintenance-related activation patterns showing memory load increases in pattern score on an individual participant level for both age groups. We found such a pattern that increased with memory load for all but one person in the young participants (p < 0.001), and such a pattern for all participants in the older group (p < 0.001). Both patterns showed broad topographic similarities; however, relationships to task performance and neuropsychological characteristics were markedly different and point to individual differences in Cognitive Reserve. Beyond the derivation of group-level activation patterns, we also investigated the inter-subject spatial similarity of individual working memory rehearsal patterns in the older participants' group as a function of neuropsychological and task performance, education, and mean cortical thickness. Higher task accuracy and neuropsychological function was reliably associated with higher inter-subject similarity of individual-level activation patterns in older participants.