One of the most well-established age-related changes in neural activity disappears after controlling for visual acuity

Effects of aging on neural processing during an active listening task

Factors affecting successful listening in older adults and the corresponding electrophysiological signatures are not well understood. The present study investigated age-related differences in attention and temporal processing, as well as differences in the neural activity related to signal degradation during a number comparison task. Participants listened to digits presented in background babble and were tested at two levels of signal clarity, clear and degraded. Behavioral and electrophysiological measures were examined in 30 older and 20 younger neurologically-healthy adults. Relationships between performance on the number comparison task, behavioral measures, and neural activity were used to determine correlates of listening deficits associated with aging. While older participants showed poorer performance overall on all behavioral measures, their scores on the number comparison task were largely predicted (based on regression analyses) by their sensitivity to temporal fine structure cues. Compared to younger participants, older participants required higher signal-to-noise ratios (SNRs) to achieve equivalent performance on the number comparison task. With increasing listening demands, age-related changes were observed in neural processing represented by the early-N1 and later-P3 time windows. Source localization analyses revealed age differences in source activity for the degraded listening condition that was located in the left prefrontal cortex. In addition, this source activity negatively correlated with task performance in the older group. Together, these results suggest that older adults exhibit reallocation of processing resources to complete a demanding listening task. However, this effect was evident only for poorer performing older adults who showed greater posterior to anterior shift in P3 response amplitudes than older adults who were good performers and younger adults. These findings might reflect less efficient recruitment of neural resources that is associated with aging during effortful listening performance.

A Scoping Review of Audiovisual Integration Methodology: Screening for Auditory and Visual Impairment in Younger and Older Adults

With the rise of the aging population, many scientists studying multisensory integration have turned toward understanding how this process may change with age. This scoping review was conducted to understand and describe the scope and rigor with which researchers studying audiovisual sensory integration screen for hearing and vision impairment. A structured search in three licensed databases (Scopus, PubMed, and PsychInfo) using the key concepts of multisensory integration, audiovisual modality, and aging revealed 2,462 articles, which were screened for inclusion by two reviewers. Articles were included if they (1) tested healthy older adults (minimum mean or median age of 60) with younger adults as a comparison (mean or median age between 18 and 35), (2) measured auditory and visual integration, (3) were written in English, and (4) reported behavioral outcomes. Articles that included the following were excluded: (1) tested taste exclusively, (2) tested olfaction exclusively, (3) tested somatosensation exclusively, (4) tested emotion perception, (5) were not written in English, (6) were clinical commentaries, editorials, interviews, letters, newspaper articles, abstracts only, or non-peer reviewed literature (e.g., theses), and (7) focused on neuroimaging without a behavioral component. Data pertaining to the details of the study (e.g., country of publication, year of publication, etc.) were extracted, however, of higher importance to our research question, data pertaining to screening measures used for hearing and vision impairment (e.g., type of test used, whether hearing- and visual-aids were worn, thresholds used, etc.) were extracted, collated, and summarized. Our search revealed that only 64% of studies screened for age-abnormal hearing impairment, 51% screened for age-abnormal vision impairment, and that consistent definitions of normal or abnormal vision and hearing were not used among the studies that screened for sensory abilities. A total of 1,624 younger adults and 4,778 older participants were included in the scoping review with males composing approximately 44% and females composing 56% of the total sample and most of the data was obtained from only four countries. We recommend that studies investigating the effects of aging on multisensory integration should screen for normal vision and hearing by using the World Health Organization's (WHO) hearing loss and visual impairment cut-off scores in order to maintain consistency among other aging researchers. As mild cognitive impairment (MCI) has been defined as a “transitional” or a “transitory” stage between normal aging and dementia and because approximately 3–5% of the aging population will develop MCI each year, it is therefore important that when researchers aim to study a healthy aging population, that they appropriately screen for MCI. One of our secondary aims was to determine how often researchers were screening for cognitive impairment and the types of tests that were used to do so. Our results revealed that only 55 out of 72 studies tested for neurological and cognitive function, and only a subset used standardized tests. Additionally, among the studies that used standardized tests, the cut-off scores used were not always adequate for screening out mild cognitive impairment. An additional secondary aim of this scoping review was to determine the feasibility of whether a meta-analysis could be conducted in the future to further quantitatively evaluate the results (i.e., are the findings obtained from studies using self-reported vision and hearing impairment screening methods significantly different from those measuring vision and hearing impairment in the lab) and to assess the scope of this problem. We found that it may not be feasible to conduct a meta-analysis with the entire dataset of this scoping review. However, a meta-analysis can be conducted if stricter parameters are used (e.g., focusing on accuracy or response time data only).

Systematic Review Registration:https://doi.org/10.17605/OSF.IO/GTUHD.

Development of Visual Acuity in Children: Assessing the Contributions of Cognition and Age in LEA Chart Acuity Readings

SIGNIFICANCE

The development of visual acuity has often been looked upon as a function of age. This study considers whether cognition might also be a predictor of acuity in children. The results indicate that cognition is a predictor of acuity and therefore should play a role in vision evaluations and developmental research.

PURPOSE

Prior studies have shown that changes in visual acuity in typically developing children occur beyond primary school age. However, these studies almost exclusively use chronological age as the sole predictor for visual development. Because many of the tasks used to measure acuity have a cognitive demand, it is possible that age is not the best predictor for changes in this function. The aims of this study were to explore the effect of cognition on the development of visual acuity and to compare this predictor with age.

METHODS

The predictive ability of chronological age and cognition on acuity was assessed in a group of 81 typical children between 5 and 11 years old.

RESULTS

Analysis of resulting trajectories showed that, although age indeed was a good predictor, development of visual acuity was equally well predicted by cognition. Moreover, partial correlations showed a strong correlation between cognition and acuity when controlling for age but no significant correlation between age and acuity when controlling for cognition.

CONCLUSIONS

These results suggest that age alone is not the optimal determinant for the development of visual acuity in typical school-aged children, as cognition was also found to be an important predictor.

Inhibition of emotions in healthy aging: age-related differences in brain network connectivity

INTRODUCTION

Successful inhibition of distracting emotions is important for preserving well-being and daily functioning. There is conflicting evidence regarding the impact of healthy aging on emotional inhibition, and possible age-related alterations in the neuronal underpinnings of emotional interference processing are unexplored.

METHODS

Thirty younger (mean age 26 years; 15 women) and 30 older (mean age 71 years; 13 women) healthy adults performed a face-word emotional Stroop task while undergoing functional magnetic resonance imaging of the brain. A resting-state scan was acquired for calculating the amplitude of low-frequency fluctuations as an estimate of vascular reactivity. Comparisons of brain activation during the task were assessed in a whole-brain, voxel-wise analysis, contrasting congruent, and incongruent conditions. The canonical regions of the frontoparietal, salience, dorsal attention, and default mode networks were used as seed regions for assessing functional connectivity within and between large-scale brain networks. Task performance was evaluated using response accuracy and response time.

RESULTS

The older adults had longer response times and lower task accuracy than the younger adults, but the emotional interference effect was not significantly different between the groups. Whole-brain analysis revealed no significant age-related differences in brain activation patterns. Rescaling the data for estimated variability in vascular reactivity did not affect the results. In older adults, there was relatively stronger functional connectivity with the default mode network, the sensorimotor network, and the dorsal attention network for the frontoparietal and salience network seeds during the task. Conversely, younger adults had relatively stronger connections within and between the frontoparietal and salience networks.

CONCLUSION

In this first fMRI study of emotional Stroop interference in older and younger adults, we found that the emotional interference effect was unchanged in healthy aging and replicated the finding from non-emotional task studies that older adults have greater between-network and less within-network connectivity compared to younger adults.

Age Differences in the Subcomponents of Executive Functioning

OBJECTIVES

Across the life span, deficits in executive functioning (EF) are associated with poor behavioral control and failure to achieve goals. Though EF is often discussed as one broad construct, a prominent model of EF suggests that it is composed of three subdomains: inhibition, set shifting, and updating. These subdomains are seen in both younger (YA) and older adults (OA), with performance deficits across subdomains in OA. Therefore, our goal was to investigate whether subdomains of EF might be differentially affected by age, and how these differences may relate to broader global age differences in EF.

METHODS

To assess these age differences, we conducted a meta-analysis at multiple levels, including task level, subdomain level, and of global EF. Based on previous work, we hypothesized that there would be overall differences in EF in OA.

RESULTS

Using 1,268 effect sizes from 401 articles, we found overall differences in EF with age. Results suggested that differences in performance are not uniform, such that variability in age effects emerged at the task level, and updating was not as affected by age as other subdomains.

DISCUSSION

These findings advance our understanding of age differences in EF, and stand to inform early detection of EF decline.

Does dance counteract age-related cognitive and brain declines in middle-aged and older adults? A systematic review

BACKGROUND

Dance is a multidomain activity that combines aerobic, coordination and cognitive exercise. This music-associated physical and cognitive exercise is a leisure activity that motivates people, elicits emotions, and avoids boredom, promoting adherence to practice. Continuing physical activity is of paramount importance, since cognitive benefits tend to disappear or even reverse when training ceases.

OBJECTIVE

The question we addressed in this systematic review is what influence dance has on the brain and cognition of healthy middle-aged and older adults.

LITERATURE SURVEY

We systematically reviewed the effects of dance on brain and cognition in older adults using MEDLINE, Psyc-Info, PubMed and Scopus databases.

METHODOLOGY

After screening 1051 studies, thirty-five met the eligibility inclusion criteria. These studies showed that dance improves brain structure and function as well as physical and cognitive functions.

CONCLUSIONS

The protective effect of dance training on cognition in older adults, together with the possibility of adapting intensity and style to suit possible physical limitations makes this activity very suitable for older adults.

Peripheral visual perception during natural overground dual-task walking in older and younger adults

Little is known about the neurophysiological processes underlying visual processing during active behavior and how these change over the life span. This study investigated early (P1) and later (P3) event-related potentials of the electroencephalogram associated with visual perception in older and younger adults while sitting, standing, and walking. While sitting and standing, accurate performance in both groups was not associated with event-related potential characteristics. During walking, in contrast, prolonged latencies and reduced amplitudes of the P1 were related to slower responses and increased misses, respectively. No covariations of behavior and P3 characteristics were observed. However, prolonged P3 latencies with increasing motor task complexity were present for both age groups, and reduced amplitudes while walking were replicated in younger participants. Older participants were more affected by walking in general as reflected in slower walking speeds as well as reduced accuracy and relative P1 amplitudes. These results provide further insights into cognitive-motor interference during natural walking in younger and older adults on early attentional-perceptual processing stages, even for simple additional visual tasks.

Capacity-limited resources are used for managing sensory degradation and cognitive demands: Implications for age-related cognitive decline and dementia

Older adults with sensory deficits are at higher risk for developing cognitive impairment and dementia. It remains uncertain if the link between sensory and cognitive functioning reflects a common underlying factor or whether sensory deficits directly undermine cognitive processing. This issue was addressed by comparing behavioral and event-related potential responses of 16 older and 16 young adults during a working memory paradigm that parametrically varied visual contrast level (100%, 69%, 22%) and cognitive task load (1-4 face pairs to remember). The groups were well-matched on demographic and neuropsychological variables; however, older adults had worse corrected visual acuity and contrast sensitivity. The study's major finding was an interaction between visual contrast level and task load on performance accuracy (percent of correct responses) and the allocation of resources for decision making/updating (as indexed by the P3b amplitude). The negative impact of degraded visual processing was greater at higher levels of task demand. This result suggests that a shared pool of processing resources is used to mediate cognitive operations and manage the processing of degraded images. The study also demonstrated that older adults reach the limits of their processing capacity at lower levels of task load. The interaction between visual degradation and task demand, accompanied by the age-related reduction in available processing resources highlight the increased vulnerability of older adults. Specifically, an age-associated decline in visual acuity and contrast sensitivity puts older adults at risk for depleting their limited resources in the service of processing degraded visual images. The results of this study underscore the potential importance of optimizing vision in older adults to help mitigate age-associated cognitive decline.

Visual Performance and Occupational Safety Among Aging Workers

With the rapid growth of the aging workforce, age-related conditions may negatively influence overall workplace safety and health among these workers and their employers. In this summary, we have outlined details about visual acuity, glare sensitivity, and contrast sensitivity, which are common age-related vision changes that can potentially affect their occupational safety. The occupational health nurse is well positioned to address these concerns by instructing aging workers about potential development of vision change and ensuring they receive the appropriate vision screening. By assisting employers to modify work environments to accommodate this population, the occupational health nurse can reduce the risk of injury, as well as positively impact the health of their aging workforce.

Resolving Age-Related Differences in Working Memory: Equating Perception and Attention Makes Older Adults Remember as Well as Younger Adults

OBJECTIVES

Older adults show clear deficits in working memory functioning. Here, we investigate the often-reported decline in focus switching, that is, the ability to shift items from the focus of attention into working memory, and back. Specifically, we examined whether equating subjects on early processing (perception and attention) might ameliorate the deficit.

METHOD

We examined 1-Back and 2-Back performance in younger and older adults, with line segments of different orientation as the stimuli. Stimuli were calibrated depending on each individual's 75% threshold for 1-Back performance. Subjects made match/mismatch judgments.

RESULTS

After the calibration on 1-Back performance, no age-related differences were found on either accuracy or sensitivity in the 2-Back task. Additionally, when investigating focus-switch trials versus non-focus-switch trials in a random-order 2-Back task, older adults were more efficient at switching the focus of attention than younger adults.

DISCUSSION

These results provide evidence for the view that age-related limitations in focus switching in working memory are caused (at least in part) by changes in early processing (perception and attention), suggesting that (at least some of the) age-related differences in working memory functioning may be due to shifts in trade-off between early processing and memory-related processing.

Automatic Conflict Monitoring by Event-Related Potentials Could be used to Estimate Visual Acuity Levels

Numerous studies have explored the physical attribute features or face perceptions in conflict processing, while complicate gradient conflicts were rarely discussed. The aim of the study was to discuss the relationship between the event-related potential (ERP) component features and different visual acuity levels by using the modified S1-S2 task under non-attention status. Three visual acuity levels were applied, each with four orientations of "E" optotype stimuli randomly presented in the center of the visual field while participants were required to concentrate on listening to stories. The results showed that the amplitudes of P1 and P3 as well as difference P3 were larger in supra-threshold condition. In threshold condition, larger amplitudes for both N2 and difference N2 exhibited in frontal and central areas. In sub-threshold condition, there was no endogenous component elicited by mismatch stimuli except smaller anterior N1. Meanwhile, the specific distributions of N1 and N2 were presented and compared with previous face processing. The findings showed that visual conflict processing took place not only at an early stage but also at the late period, which might be as the consequences of interaction between conflict strength and involuntary attention. We concluded that automatic conflict detecting of visual icons by the serial ERP components could distinguish different visual acuity levels. The involvement of endogenous components could reveal the specific mechanism of more precise and fine conflict identification of complex physical attributes under non-attention status, furthermore could be used as valid markers to estimate the magnitude of visual acuity objectively.

Increased Early Processing of Task-Irrelevant Auditory Stimuli in Older Adults

The inhibitory deficit hypothesis of cognitive aging posits that older adults' inability to adequately suppress processing of irrelevant information is a major source of cognitive decline. Prior research has demonstrated that in response to task-irrelevant auditory stimuli there is an age-associated increase in the amplitude of the N1 wave, an ERP marker of early perceptual processing. Here, we tested predictions derived from the inhibitory deficit hypothesis that the age-related increase in N1 would be 1) observed under an auditory-ignore, but not auditory-attend condition, 2) attenuated in individuals with high executive capacity (EC), and 3) augmented by increasing cognitive load of the primary visual task. ERPs were measured in 114 well-matched young, middle-aged, young-old, and old-old adults, designated as having high or average EC based on neuropsychological testing. Under the auditory-ignore (visual-attend) task, participants ignored auditory stimuli and responded to rare target letters under low and high load. Under the auditory-attend task, participants ignored visual stimuli and responded to rare target tones. Results confirmed an age-associated increase in N1 amplitude to auditory stimuli under the auditory-ignore but not auditory-attend task. Contrary to predictions, EC did not modulate the N1 response. The load effect was the opposite of expectation: the N1 to task-irrelevant auditory events was smaller under high load. Finally, older adults did not simply fail to suppress the N1 to auditory stimuli in the task-irrelevant modality; they generated a larger response than to identical stimuli in the task-relevant modality. In summary, several of the study's findings do not fit the inhibitory-deficit hypothesis of cognitive aging, which may need to be refined or supplemented by alternative accounts.

Linking cognitive and visual perceptual decline in healthy aging: The information degradation hypothesis

Several hypotheses attempt to explain the relation between cognitive and perceptual decline in aging (e.g., common-cause, sensory deprivation, cognitive load on perception, information degradation). Unfortunately, the majority of past studies examining this association have used correlational analyses, not allowing for these hypotheses to be tested sufficiently. This correlational issue is especially relevant for the information degradation hypothesis, which states that degraded perceptual signal inputs, resulting from either age-related neurobiological processes (e.g., retinal degeneration) or experimental manipulations (e.g., reduced visual contrast), lead to errors in perceptual processing, which in turn may affect non-perceptual, higher-order cognitive processes. Even though the majority of studies examining the relation between age-related cognitive and perceptual decline have been correlational, we reviewed several studies demonstrating that visual manipulations affect both younger and older adults' cognitive performance, supporting the information degradation hypothesis and contradicting implications of other hypotheses (e.g., common-cause, sensory deprivation, cognitive load on perception). The reviewed evidence indicates the necessity to further examine the information degradation hypothesis in order to identify mechanisms underlying age-related cognitive decline.