Investigating age-related changes in anterior and posterior neural activity throughout the information processing stream

Relationship between Sensory Processing and Quality of Life: A Systematic Review

Background: Sensory processing has been described as the ability to register, modulate, and organize sensory information to respond to environmental demands. Different theoretical approaches have studied the differential characteristics of sensory processing, such as Dunn’s model. From this framework, high sensitivity in sensory processing has been described as responses to stimuli from environment quite often due to a rapid activation of the central nervous system. It should be noted that the association between high sensitivity in sensory processing and health outcomes obtained in different studies are not homogeneous, so it is necessary to develop a review of this research in order to clarify the relationship between sensory processing and quality of life. Methods: We conducted a systematic review of the relevant studies using the PubMed, ScienceDirect, Scopus, and ProQuest databases to assess how sensory processing patterns are related to quality of life. Results: Fourteen studies concerning sensory processing and quality of life were included in the review. Some studies indicate negative, moderate, and significant correlations between these variables in which high sensitivity is related to a poor quality of life in the population studied. Conclusions: High sensitivity in sensory processing could have a negative impact on quality of life, thereby facilitating a fluctuation in well-being, daily functioning, and health.

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.

Age Effects on Distraction in a Visual Task Requiring Fast Reactions: An Event-Related Potential Study

We investigated the effects of distractors in older and younger participants in choice and simple reaction time tasks with concurrent registration of event-related potentials. In the task the participants had to prevent a disk from falling into a bin after a color or luminosity change (target stimuli). Infrequently, task-irrelevant stimuli (schematic faces or threatening objects) were superimposed on the target stimuli (distractors), or the bin disappeared which required no response (Nogo trials). Reaction time was delayed to the distractors, but this effect was similar in the two age groups. As a robust age-related difference, in the older group a large anterior positivity and posterior negativity emerged to the distractors within the 100-200 ms post-stimulus range, and these components were larger for schematic faces than for threatening objects. sLORETA localized the age-specific effect to the ventral stream of the visual system and to anterior structures considered as parts of the executive system. The Nogo stimuli elicited a late positivity (Nogo P3) with longer latency in the older group. We interpreted the age-related differences as decreased but compensated resistance to task-irrelevant change of the target stimuli.

Differential effects of mind-wandering and visual distraction on age-related changes in neuro-electric brain activity and variability

Optimal performance in many tasks requires minimizing the impact of both visual distractors in the environment and distracting internal thoughts (i.e., mind-wandering). Prior research has indicated that older adults are disproportionately affected by the presence of visual distractors compared to young adults, but are not excessively affected by distracting thoughts. Yet an explanation for these dissociable effects remains elusive. In the current study, we assessed age-related differences in event-related potentials and neural variability associated with internal distraction and visual distractors in a go/no-go task. Compared to young adults, older adults showed an increased visual distraction cost in mean reaction time (RT) and RT variability but a reduction in internal distraction frequency and a reduced internal distraction cost on go accuracy and RT variability. Visual distraction and internal distraction were associated with opposite patterns of behavioral and neural effects. Behaviorally, across age groups, internal distraction was associated with more no-go errors whereas visual distraction was associated with reduced no-go errors. Across groups, internal distraction was associated with decreased P3 amplitude, whereas visual distraction was associated with increased P3 amplitude. In addition, internal distraction was associated with an increase in neural variability (more so in young versus older adults), while visual distraction was associated with a reduction in variability in young adults only. We suggest that the opposing effects of the two distractor types on behavioral and neural measures occur because visual distraction is associated with increased attentional resources devoted to the task to overcome visual interference whereas internal distraction is associated with decreased attentional resources devoted to the task. Moreover, older adults exhibited reduced flexibility of neural variability as a function of both distractor types, which may correspond to a diminished ability to up-regulate attention in the face of visual distraction and a diminished shift in attention away from the task during internal distraction.

The role of sensory processing difficulties, cognitive impairment, and disease severity in predicting functional behavior among patients with multiple sclerosis

PURPOSE

To compare sensory processing and functional behavior abilities between participants with multiple sclerosis (MS), with and without cognitive impairments, and healthy controls, and to examine the role disease severity, cognitive impairment, and sensory processing have in predicting the functional behavior of persons with MS.

METHODS

Sixty-one participants with MS were enrolled in this study, 43 with cognitive impairments and 18 without (based on the Brief International Cognitive Assessment for MS composite z-score), and 36 healthy controls. Participants were between the ages 23 and 63 and asked to complete the Adolescent/Adult Sensory Profile, Functional Behavior Profile, and MS Functional Composite.

RESULTS

Both MS groups showed sensory processing difficulties with lower ability to register sensory input and greater sensory sensitivity and avoidance versus healthy controls. Among both MS groups, sensory processing difficulties correlated with greater disease severity and poor functional behavior in daily life. The significant predictors of functional behavior in daily life were a lower ability to register sensory input and greater sensory avoidance.

CONCLUSIONS

Persons with MS have sensory processing difficulties regardless of their cognitive abilities, which negatively affect their functional behavior. Research and practice should further explore the role of sensory processing as expressed in daily scenarios for persons with MS and consider the functional impacts of this study in order to optimize daily life experiences for patients.Implications for rehabilitationSensory processing difficulties in multiple sclerosis (MS) are mainly expressed in poor ability to register and modulate sensory input from daily environment, regardless of patients' cognitive status.Sensory processing difficulties in MS may affect patients' ability to perform activities of daily living.Sensory processing difficulties in MS should be evaluated using objective measures (electrophysiology tools) as well as self-reports that reflect patients' difficulties in real life context.Intervention programs in MS should refer to sensory processing difficulties, to their correlation with disease severity, cognitive status and to their impacts on people's daily function.

Markers of Novelty Processing in Older Adults Are Stable and Reliable

Exploratory behavior and responsiveness to novelty play an important role in maintaining cognitive function in older adults. Inferences about age- or disease-related differences in neural and behavioral responses to novelty are most often based on results from single experimental testing sessions. There has been very limited research on whether such findings represent stable characteristics of populations studied, which is essential if investigators are to determine the result of interventions aimed at promoting exploratory behaviors or draw appropriate conclusions about differences in the processing of novelty across diverse clinical groups. The goal of the current study was to investigate the short-term test-retest reliability of event-related potential (ERP) and behavioral responses to novel stimuli in cognitively normal older adults. ERPs and viewing durations were recorded in 70 healthy older adults participating in a subject-controlled visual novelty oddball task during two sessions occurring 7 weeks apart. Mean midline P3 amplitude and latency, mean midline amplitude during successive 50 ms intervals, temporospatial factors derived from principal component analysis (PCA), and viewing duration in response to novel stimuli were measured during each session. Analysis of variance (ANOVA) revealed no reliable differences in the value of any measurements between Time 1 and 2. Intraclass correlation coefficients (ICCs) between Time 1 and 2 were excellent for mean P3 amplitude (ICC = 0.86), the two temporospatial factors consistent with the P3 components (ICC of 0.88 and 0.76) and viewing duration of novel stimuli (ICC = 0.81). Reliability was only fair for P3 peak latency (ICC = 0.56). Successive 50 ms mean amplitude measures from 100 to 1,000 ms yielded fair to excellent reliabilities, and all but one of the 12 temporospatial factors identified demonstrated ICCs in the good to excellent range. We conclude that older adults demonstrate substantial stability in ERP and behavioral responses to novel visual stimuli over a 7-week period. These results suggest that older adults may have a characteristic way of processing novelty that appears resistant to transient changes in their environment or internal states, which can be indexed during a single testing session. The establishment of reliable measures of novelty processing will allow investigators to determine whether proposed interventions have an impact on this important aspect of behavior.

A posterior-to-anterior shift of brain functional dynamics in aging

Convergent evidence from task-based functional magnetic resonance imaging (fMRI) studies suggests a posterior-to-anterior shift as an adaptive compensatory scaffolding mechanism for aging. This study aimed to investigate whether brain functional dynamics at rest follow the same scaffolding mechanism for aging using a large Chinese sample aged from 22 to 79 years (n = 277). We defined a probability of brain regions being hubs over a period of time to characterize functional hub dynamic, and defined variability of the functional connectivity to characterize dynamic functional connectivity using resting-state fMRI. Our results revealed that both functional hub dynamics and dynamic functional connectivity posited an age-related posterior-to-anterior shift. Specifically, the posterior brain region showed attenuated dynamics, while the anterior brain regions showed augmented dynamics in aging. Interestingly, our analysis further indicated that the age-related episodic memory decline was associated with the age-related decrease in the brain functional dynamics of the posterior regions. Hence, these findings provided a new dimension to view the scaffolding mechanism for aging based on the brain functional dynamics.