Exploring the challenges of avoiding collisions with virtual pedestrians using a dual-task paradigm in individuals with chronic moderate to severe traumatic brain injury.

BACKGROUND: Individuals with a moderate-to-severe traumatic brain injury (m/sTBI), despite experiencing good locomotor recovery six months post-injury, face challenges in adapting their locomotion to the environment. They also present with altered cognitive functions, which may impact dual-task walking abilities. Whether they present collision avoidance strategies with moving pedestrians that are altered under dual-task conditions, however, remains unclear. This study aimed to compare between individuals with m/sTBI and age-matched control individuals: (1), the locomotor and cognitive costs associated with the concurrent performance of circumventing approaching virtual pedestrians (VRPs) while attending to an auditory-based cognitive task and; (2) gaze behaviour associated with the VRP circumvention task in single and dual-task conditions. METHODOLOGY: Twelve individuals with m/sTBI (age = 43.3 ± 9.5 yrs; >6 mo. post injury) and 12 healthy controls (CTLs) (age = 41.8 ± 8.3 yrs) were assessed while walking in a virtual subway station viewed in a head-mounted display. They performed a collision avoidance task with VRPs, as well as auditory-based cognitive tasks (pitch discrimination and auditory Stroop), both under single and dual-task conditions. Dual-task cost (DTC) for onset distance of trajectory deviation, minimum distance from the VRP, maximum lateral deviation, walking speed, gaze fixations and cognitive task accuracy were contrasted between groups using generalized estimating equations. RESULTS: In contrast to CTLs who showed locomotor DTCs only, individuals with m/sTBI displayed both locomotor and cognitive DTCs. While both groups walked slower under dual-task conditions, only individuals with m/sTBI failed to modify their onset distance of trajectory deviation and maintained smaller minimum distances and smaller maximum lateral deviation compared to single-task walking. Both groups showed shorter gaze fixations on the approaching VRP under dual-task conditions, but this reduction was less pronounced in the individuals with m/sTBI. A reduction in cognitive task accuracy under dual-task conditions was found in the m/sTBI group only. CONCLUSION: Individuals with m/sTBI present altered locomotor and gaze behaviours, as well as altered cognitive performances, when executing a collision avoidance task involving moving pedestrians in dual-task conditions. Potential mechanisms explaining those alterations are discussed. Present findings highlight the compromised complex walking abilities in individuals with m/sTBI who otherwise present a good locomotor recovery.

Gait variability across neurodegenerative and cognitive disorders: Results from the Canadian Consortium of Neurodegeneration in Aging (CCNA) and the Gait and Brain Study.

INTRODUCTION: Gait impairment is common in neurodegenerative disorders. Specifically, gait variability-the stride-to-stride fluctuations in distance and time-has been associated with neurodegeneration and cognitive impairment. However, quantitative comparisons of gait impairments across the cognitive spectrum of dementias have not been systematically investigated. METHODS: Older adults (N = 500) with subjective cognitive impairment, Parkinson disease (PD), mild cognitive impairment (MCI), PD-MCI, Alzheimer's disease (AD), PD-dementia, Lewy body dementia, and frontotemporal dementia, as well cognitive normal controls, who were assessed for their gait and cognitive performance. RESULTS: Factor analyses grouped 11 quantitative gait parameters and identified four independent gait domains: rhythm, pace, variability, and postural control, for group comparisons and classification analysis. Among these domains, only high gait variability was associated with lower cognitive performance and accurately discriminated AD from other neurodegenerative and cognitive conditions. DISCUSSION: Our findings indicate that high gait variability is a marker of cognitive-cortical dysfunction, which can help to identify Alzheimer's disease dementia.

A comparison of the impact of physical exercise, cognitive training and combined intervention on spontaneous walking speed in older adults.

BACKGROUND: Spontaneous walking speed (SWS) is one of the most important indicators of health in older adults. Studies have shown benefits of physical trainings on SWS in older adults but the impact of cognitive training and multidomain interventions remains understudied. AIMS: This original study aimed at comparing the impact of aerobic/resistance exercise, computerized cognitive training and the combination of both interventions compared with active control conditions on SWS in healthy older adults. METHODS: Ninety community-dwelling older adults were randomly assigned to four different combinations composed of two active interventions: physical aerobic/resistance and cognitive dual-task trainings, and two active control conditions: stretching exercises and computer lessons. The four combinations were the following: (1) aerobic/resistance and cognitive dual task (n = 28), (2) aerobic/resistance and computer lessons (n = 21), (3) stretching exercises and cognitive dual task and (n = 23), (4) stretching exercises and computer lessons (n = 18). Training sessions were held three times/week for three months. SWS for 30 s was assessed before and after the intervention. RESULTS: Repeated-measures ANOVA showed a main effect of time and a significant three-way interaction suggesting differential improvement in SWS according to training combinations. A clinical meaningful improvement in SWS was observed in groups 1-3 (0.08-0.14 m/s; effect sizes: small to moderate) but not in the active control group 4. DISCUSSION: Results of this study suggest that aerobic/resistance exercise and computerized dual-task training are two non-pharmacological interventions by which SWS, a functional vital sign, can be clinically improved in older adults. CONCLUSION: This original study pointed out different tools to prevent functional decline in older people.

Effects of age and cognitive load on response reprogramming.

A dual-task paradigm was used to examine the effect of cognitive load on motor reprogramming. We propose that in the face of conflict, both executive control and motor control mechanisms become more interconnected in the process of reprogramming motor behaviors. If so, one would expect a concurrent cognitive load to compromise younger adults' (YAs) motor reprogramming ability and further exacerbate the response reprogramming ability of older adults (OAs). Nineteen YAs and 14 OAs overlearned a sequence of key presses. Deviations of the practiced sequence were introduced to assess motor reprogramming ability. A Serial Sevens Test was used as the cognitive load. A 3D motion capture system was used to parse finger movements into planning and motor execution times. Global response time analysis revealed that under single-task conditions, during prepotent transitions, OAs responded as quickly as YAs, but they were disproportionately worse than YAs during conflict transitions. Under dual-task conditions, YAs performance became more similar to that of OAs. Movement data were decomposed into planning and movement time, revealing that under single-task conditions, when responding to conflicting stimuli YAs reduced their movement time in order to compensate for delayed planning time; however, additional cognitive load prevented them from exhibiting this compensatory hastening on conflict transitions. We propose that age-related declines in response reprogramming may be linked to reduced cognitive capacity. Current findings suggest that cognitive capacity, reduced in the case of OAs or YAs under divided attention conditions, influences the ability to flexibly adapt to conflicting conditions.

The association between information and communication technologies, loneliness and social connectedness: A scoping review.

Older adults are at a higher risk of loneliness, compared to other demographics. The use of Internet Communication and Technologies (ICTs) among older adults is steadily increasing and given ICTs provide a means of enhancing social connectedness suggests they may have positive effects on reducing loneliness. Therefore, the aim of this scoping review was to examine the research that explores how ICTs may be implicated in mitigating loneliness and increasing social connectedness among older adults. After the examination of 54 articles, we identified three major themes within the literature: (1) ICTs were associated with a reduction in loneliness and increase in wellbeing. (2) ICTs promoted social connectedness by facilitating conversations. (3) Factors such as training, self-efficacy, self-esteem, autonomy, and the design/features, or affordances, of ICTs contribute toward the associations between ICT use and wellbeing. The heterogeneity of methodologies, statistical reporting, the small sample sizes of interventional and observational studies, and the diversity of the experimental contexts underline the challenges of quantitative research in this field and highlights the necessity of tailoring ICT interventions to the needs and contexts of the older users.

Effects of Exercise Alone or Combined With Cognitive Training and Vitamin D Supplementation to Improve Cognition in Adults With Mild Cognitive Impairment: A Randomized Clinical Trial.

Importance: Exercise, cognitive training, and vitamin D may enhance cognition in older adults with mild cognitive impairment (MCI). Objective: To determine whether aerobic-resistance exercises would improve cognition relative to an active control and if a multidomain intervention including exercises, computerized cognitive training, and vitamin D supplementation would show greater improvements than exercise alone. Design, Setting, and Participants: This randomized clinical trial (the SYNERGIC Study) was a multisite, double-masked, fractional factorial trial that evaluated the effects of aerobic-resistance exercise, computerized cognitive training, and vitamin D on cognition. Eligible participants were between ages 65 and 84 years with MCI enrolled from September 19, 2016, to April 7, 2020. Data were analyzed from February 2021 to December 2022. Interventions: Participants were randomized to 5 study arms and treated for 20 weeks: arm 1 (multidomain intervention with exercise, cognitive training, and vitamin D), arm 2 (exercise, cognitive training, and placebo vitamin D), arm 3 (exercise, sham cognitive training, and vitamin D), arm 4 (exercise, sham cognitive training, and placebo vitamin D), and arm 5 (control group with balance-toning exercise, sham cognitive training, and placebo vitamin D). The vitamin D regimen was a 10 000 IU dose 3 times weekly. Main Outcomes and Measures: Primary outcomes were changes in ADAS-Cog-13 and Plus variant at 6 months. Results: Among 175 randomized participants (mean [SD] age, 73.1 [6.6] years; 86 [49.1%] women), 144 (82%) completed the intervention and 133 (76%) completed the follow-up (month 12). At 6 months, all active arms (ie, arms 1 through 4) with aerobic-resistance exercise regardless of the addition of cognitive training or vitamin D, improved ADAS-Cog-13 when compared with control (mean difference, -1.79 points; 95% CI, -3.27 to -0.31 points; P = .02; d = 0.64). Compared with exercise alone (arms 3 and 4), exercise and cognitive training (arms 1 and 2) improved the ADAS-Cog-13 (mean difference, -1.45 points; 95% CI, -2.70 to -0.21 points; P = .02; d = 0.39). No significant improvement was found with vitamin D. Finally, the multidomain intervention (arm 1) improved the ADAS-Cog-13 score significantly compared with control (mean difference, -2.64 points; 95% CI, -4.42 to -0.80 points; P = .005; d = 0.71). Changes in ADAS-Cog-Plus were not significant. Conclusions and Relevance: In this clinical trial, older adults with MCI receiving aerobic-resistance exercises with sequential computerized cognitive training significantly improved cognition, although some results were inconsistent. Vitamin D supplementation had no effect. Our findings suggest that this multidomain intervention may improve cognition and potentially delay dementia onset in MCI. Trial Registration: ClinicalTrials.gov Identifier: NCT02808676.

Sex-Related Differences in the Associations Between Montreal Cognitive Assessment Scores and Pure-Tone Measures of Hearing.

PURPOSE: Hearing loss (HL) is associated with cognitive performance in older adults, including performance on the Montreal Cognitive Assessment (MoCA), a brief cognitive screening test. Yet, despite well-established sex-related differences in both hearing and cognition, very few studies have tested whether there are sex-related differences in auditory-cognitive associations. METHOD: In the current cross-sectional retrospective analysis, we examined sex-related differences in hearing and cognition in 193 healthy older adults (M = 69 years, 60% women). Hearing was measured using audiometry (pure-tone average [PTA] of thresholds at 500, 1000, 2000, and 4000 Hz in the worse ear). Cognition was assessed using the MoCA. Additionally, we calculated MoCA scores with hearing-dependent subtests excluded from scoring (MoCA-Modified). RESULTS: Men and women did not differ in age, education, or history of depression. Women had better hearing than men. Women with normal hearing were more likely to pass the MoCA compared with their counterparts with HL. In contrast, the likelihood of passing the MoCA did not depend on hearing status in men. Linear regression analysis showed an interaction between sex and PTA in the worse ear. PTAs were significantly correlated with both MoCA and MoCA-Modified scores in women, whereas this was not observed in the men. CONCLUSIONS: This study is one of the first to demonstrate significant sex-related differences in auditory-cognitive associations even when hearing-related cognitive test items are omitted. Potential mechanisms underlying these female-specific effects are discussed. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.19233297.

Multiple routes to help you roam: A comparison of training interventions to improve cognitive-motor dual-tasking in healthy older adults.

Cognitive-motor dual-tasking is a complex activity that predicts falls risk and cognitive impairment in older adults. Cognitive and physical training can both lead to improvements in dual-tasking; however, less is known about what mechanisms underlie these changes. To investigate this, 33 healthy older adults were randomized to one of three training arms: Executive function (EF; n = 10), Aerobic Exercise (AE; n = 10), Gross Motor Abilities (GMA; n = 13) over 12 weeks (1 h, 3×/week). Single and dual-task performance (gait speed, m/s; cognitive accuracy, %) was evaluated before and after training, using the 2-back as concurrent cognitive load. Training arms were designed to improve cognitive and motor functioning, through different mechanisms (i.e., executive functioning - EF, cardiorespiratory fitness - CRF, and energy cost of walking - ECW). Compared to baseline, we observed few changes in dual-task gait speed following training (small effect). However, dual-task cognitive accuracy improved significantly, becoming facilitated by walking (large effect). There were no differences in the magnitude of improvements across training arms. We also found that older adults with lower cognitive ability (i.e., MoCA score < 26; n = 14) improved more on the dual-task cognitive accuracy following training, compared to older adults with higher cognitive ability (i.e., MoCA ≥26; n = 18). Taken together, the results suggest that regardless of the type of intervention, training appears to strengthen cognitive efficiency during dual-tasking, particularly for older adults with lower baseline cognitive status. These gains appear to occur via different mechanisms depending on the form of intervention. Implications of this research are paramount, as we demonstrate multiple routes for improving cognitive-motor dual-tasking in older adults, which may help reduce risk of cognitive impairment.

A Comparison of the Effect of Physical Activity and Cognitive Training on Dual-Task Performance in Older Adults.

OBJECTIVES: Studies suggest that cognitive training and physical activity can improve age-related deficits in dual-task performances. However, both of these interventions have never been compared in the same study. This article investigates the improvement in dual-task performance in 2 types of exercise training groups and a cognitive training group and explores if there are specific dual-task components that are more sensitive or more likely to improve following each type of training. METHODS: Seventy-eight healthy inactive participants older than the age of 60 (M = 69.98, SD = 5.56) were randomized to one of three 12-week training programs: aerobic training (AET) = 26, gross motor abilities (GMA) = 27, and cognition (COG) = 25. Before and after the training program, the participants underwent physical fitness tests, and cognitive evaluations involving a computerized cognitive dual task. The AET consisted of high- and low-intensity aerobic training, the GMA of full-body exercises focusing on agility, balance, coordination, and stretching, and the COG of tablet-based exercises focusing on executive functions. RESULTS: Repeated-measures analysis of variance on reaction time data revealed a group × time interaction (F(2,75) = 11.91, p < .01) with COG having the greatest improvement, followed by a significant improvement in the GMA group. Secondary analysis revealed the COG to also improve the intraindividual variability in reaction time (F(1,24) = 8.62, p < .01), while the GMA improved the dual-task cost (F(1,26) = 12.74, p < .01). DISCUSSION: The results show that physical and cognitive training can help enhance dual-task performance by improving different aspects of the task, suggesting that different mechanisms are in play.

A comparison of physical exercise and cognitive training interventions to improve determinants of functional mobility in healthy older adults.

OBJECTIVES: Mobility is a complex but crucial clinical outcome in older adults. Past observational studies have highlighted that cardiorespiratory fitness (CRF), energy cost of walking (ECW), and cognitive switching abilities are associated with mobility performance, making these key determinants of mobility intervention targets to enhance mobility in older adults. The objective of this study was to compare, in the same design, the impact of three training methods - each known to improve either CRF, ECW, or cognitive switching abilities - on mobility in healthy older adults. METHODS: Seventy-eight participants (69.28 ± 4.85yo) were randomly assigned to one of three twelve-week interventions: Aerobic Exercise (AE; n = 26), Gross Motor Abilities (GMA; n = 27), or Cognitive (COG; n = 25) training. Each intervention was designed to improve one of the three key determinants of mobility (CRF, ECW, and cognitive switching). Primary outcomes (usual gait speed, and TUG performance) and the three mobility determinants were measured before and after the intervention. RESULTS: Repeated-measures ANOVAs showed a time effect for TUG performance (F(1,75) = 14.92, p < .001): all groups equally improved after the intervention (ΔTUGpost-pre, in seconds, with 95% CI: AE = -0.44 [-0.81 to -0.08]; GMA = -0.60 [-1.10 to -0.10]; COG = -0.33 [-0.71 to 0.05]). No significant between group differences were observed. CRF was improved in the AE group only (Hedges' G = 0.27, small effect), ECW and cognitive switching improved the most in the GMA (Hedges' G = -0.78, moderate effect) and COG groups (Hedges' G = -1.93, large effect) respectively. Smaller improvements in ECW were observed following AE and COG trainings (Hedges' G: AE = -0.39, COG = -0.36, both small effects) as well as in cognitive switching following AE and GMA training (Hedges' G: AE = -0.42, GMA = -0.21, both small effects). DISCUSSION: This study provides further support to the notion that multiple interventional approaches (aerobic, gross motor exercise, or cognitive training) can be employed to improve functional mobility in older adults, giving them, and professionals, more options to promote healthy ageing.

Synergistic Effects of Cognitive Training and Physical Exercise on Dual-Task Performance in Older Adults.

BACKGROUND: Studies report benefits of physical exercise and cognitive training to enhance cognition in older adults. However, most studies did not compare these interventions to appropriate active controls. Moreover, physical exercise and cognitive training seem to involve different mechanisms of brain plasticity, suggesting a potential synergistic effect on cognition. OBJECTIVE: This study investigated the synergistic effect of cognitive training and aerobic/resistance physical exercise on dual-task performance in older adults. Intervention effects were compared to active controls for both the cognitive and the exercise domain. METHOD: Eighty-seven older adults completed one of 4 different combinations of interventions, in which computer lessons was active control for cognitive training and stretching/toning exercise control for aerobic/resistance training: (a) cognitive dual-task training and aerobic/resistance training (COG+/AER+), (b) computer lessons and aerobic/resistance training (COG-/AER+), (c) cognitive dual-task training and stretching/toning exercises (COG+/AER-), and (d) computer lessons and stretching/toning exercises (COG-/AER-). The primary outcome was performance in an untrained transfer dual task. Stepwise backward removal regression analyses were used to predict pre- versus post-test changes in groups that have completed the dual-task training, aerobic/resistance or both interventions. RESULTS: Participation in AER+ did not predict improvement in any dual-task outcomes. Participation in COG+ predicted reduction in dual-task cost and participation in COG+/AER+ predicted reduction in task-set cost. DISCUSSION: Results suggest that the combination of cognitive and physical training protocols exerted a synergistic effect on task-set cost which reflects the cost of maintaining multiple response alternatives, whereas cognitive training specifically improved dual-task cost, which reflects the ability of synchronizing concurrent tasks.

Effects of age on listening and postural control during realistic multi-tasking conditions.

Successful performance of balance-related activities requires the effective integration of sensory, cognitive, and motor processes that can be affected by age-related changes. Of these age-related sensory changes, the effects of declines in hearing on balance have not been well-studied despite the fact that hearing loss has now been acknowledged as a significant risk factor for falls. The goal of this study was to evaluate age-related differences in a "standing while listening" task within increasingly challenging conditions resembling those that are often encountered in realistic, everyday situations. This study used a dual-task paradigm in an immersive Virtual Reality street scene setting in which postural load (firm, compliant), listening load (number of talkers), and visual load (eyes open/closed) were manipulated. A multi-talker divided attention listening task was used. Postural performance was assessed using center of pressure (COP) path length, while listening performance was assessed using spoken word recognition accuracy. Results demonstrated that age-related differences were observed in postural performance when postural demands were the highest and in listening performance when listening demands were the highest. Proportional dual-task costs were more pronounced for postural task performance compared to listening task performance and were more pronounced for older compared to younger adults. Postural dual-task costs increased as a function of increasing listening loads. Removal of visual information improved listening task performance across both groups and reduced the dual-task costs to listening in older adults when listening demands were highest (resulting in dual-task benefits). Taken together, the findings support previously documented age-related declines in postural control and auditory processing, demonstrate that increasing listening demands may result in poorer balance, particularly in older adults, and provide additional insights into the interactive effects of age-related declines when sensory, motor, and cognitive challenges are incremented factorially.

A comparison of motor skill learning and retention in younger and older adults.

The goal of the current study was to explore learning and short-term retention using a modified serial reaction time task. The multi-finger sequence task was designed to present repeated and random sequences in a completely interleaved fashion, giving participants within block, variable practice, on the two types of sequences. Eighteen younger adults (M(age) = 24 years) and 15 older adults (M(age) = 65 years) participated in the experiment. Participants were asked to respond on a piano keyboard to a visual stimulus that appeared in one of four squares on the computer screen. They were not informed that one of the sequences presented would repeat. Sequence-specific learning, within-day and across-days, was inferred from differences in accuracy and reaction time between repeated and random sequences. Age equivalence was observed in sequence-specific learning and retention across days, and suggests that older adults may benefit from variable practice.

Examining prepotent response suppression in aging: a kinematic analysis.

Two experiments were designed to explore how age differences in conflict detection may contribute to poorer motor performance. In each experiment, 12 young adults (YAs) and 12 older adults (OAs) performed a finger sequencing task in which the frequency of specific critical transitions was varied. These critical transitions were contrasted with violation transitions to assess the ability to detect a conflict in response requirements. In addition to accuracy and reaction time, the authors used kinematic data to parse movements into planning and motor execution phases. OAs were differentially slower to respond to violations than YAs, in line with other research on executive control, prepotent response suppression, and aging. Kinematic analyses revealed that YAs executed movements more rapidly on violation than critical transitions, whereas OAs executed movements at the same speed regardless of response predictability and increased planning time. The authors argue that OAs are unable to reprogram prepotent movement plans to overcome slowed movement planning in cognitively challenging situations. The results are discussed in terms of the influence of age-related cognitive inefficiency on motor control.

The effect of simultaneously and sequentially delivered cognitive and aerobic training on mobility among older adults with hearing loss.

BACKGROUND: Older adults exhibit declines in auditory and motor functioning, which are compensated for through the recruitment of cognitive resources. Cognitive or physical training alone has been shown to improve cognitive functioning and transfer to motor tasks, but results are mixed when these are combined in studies of healthy older adults, and few studies have included those with age-related hearing loss (ARHL), who are at a higher risk of falls. RESEARCH QUESTION: To examine format effects in mixed training, we used a repeated measures intervention design to compare the efficacy of Simultaneous and Sequential multimodal training formats. METHODS: 42 older adults (Mage = 68.05, SDage = 4.65, females = 26) with (ARHL) and without hearing loss (OAH) completed an intervention study consisting of 12 sessions of multimodal training (computerized cognitive dual-task and recumbent aerobic cycling). Participants were randomly assigned to either the Simultaneous (concurrent cognitive and aerobic) or Sequential training group (cognitive followed by aerobic) and completed assessments of single- and dual-task mobility concurrent with an auditory working memory task. Training gains were assessed with repeated measures ANOVAs using magnitude of improvement from pre- to post-training on primary outcome measures as the dependent variable. RESULTS: Gains in auditory working memory were greater in the Sequential group than Simultaneous particularly among OAH. ARHL participants were unaffected by format. While all participants improved on a measure of chair rises, there was no benefit to standing balance. The results demonstrate an advantage to Sequential training, suggesting a benefit to focusing on each task in isolation. SIGNIFICANCE: The gains noted in the ARHL indicate the potential benefit of incorporating cognitive remediation into traditional audiological rehabilitation. Moreover, it is important to consider the cost of dividing attention when combining training.

Effects of Age on Dual-Task Walking While Listening.

This study examined the effects of age on single- and dual-task listening and walking during virtual street crossing. Seventeen younger and 12 older adults participated. In each listening trial, three sentences were presented simultaneously from separate locations. Participants were instructed to report the target sentence. Predictability of the target sentence location was varied. Treadmill walking was measured using motion analysis. Measures included word recognition accuracy, head and trunk angles, and spatiotemporal gait parameters. Older adults exhibited a more upright head alignment and less variability in stride time during dual-tasking, particularly under less certain target sentence location conditions. Younger adults' walking was unaffected by dual-task demands. Together, the results indicate greater postural prioritization in older adults than young.

The Effects of Age and Hearing Loss on Dual-Task Balance and Listening.

Objectives: Among older adults (OA), hearing loss is associated with an increased risk for falls. The aim of the present study was to experimentally investigate the cognitive compensation hypothesis, wherein decreased auditory and motor functioning are compensated by the recruitment of cognitive resources. Method: Twenty-nine younger adults (YA), 26 OA, and 32 OA with age-related hearing loss (ARHL) completed a dual-task paradigm consisting of cognitive and balance recovery tasks performed singly and concurrently. The auditory stimuli were presented with or without background noise. Results: Both older adult groups performed significantly worse than YA on the cognitive task in noisy conditions and ARHL also demonstrated disproportionate negative effects of dual-tasking and noise. The kinematic data indicated that OA and ARHL demonstrated greater plantarflexion when compared with YA. Conversely, YA showed greater hip extension in response to dual-tasking. Discussion: The cognitive and balance results suggest that YA were able to flexibly allocate their attention between tasks, whereas ARHL exhibited prioritization of posture over cognitive performance.

Multisensory, Multi-Tasking Performance of Older Adults With and Without Subjective Cognitive Decline.

As the population ages, it is increasingly important to detect non-normative cognitive declines as early as possible. Measures of combined sensory-motor-cognitive functioning may be early markers for identifying individuals who are at increased risk of developing dementia. Further, older adults experiencing subjective cognitive decline (SCD) may have elevated risk of dementia compared to those without SCD. Tasks involving complex, multisensory interactions reflective of everyday challenges may be particularly sensitive to subjectively perceived, pre-clinical declines. In the current study, older adults with and without SCD were asked to simultaneously perform a standing balance task and a listening task under increasingly challenging sensory/cognitive/motor conditions using a dual-task paradigm in a realistic, immersive virtual environment. It was hypothesized that, compared to older adults without SCD, those with SCD would exhibit greater decrements in postural control and listening response accuracy as sensory/motor/cognitive loads increased. However, counter to predictions, older adults with SCD demonstrated greater reductions in postural sway under more challenging dual-task conditions than those without SCD. Across both groups, poorer postural task performance was associated with poorer cognitive function and speech-in-noise thresholds measured with standard baseline tests. Poorer listening task performance was associated with poorer global cognitive function, poorer mobility, and poorer speech-in-noise detection. Overall, the results provide additional support for the growing evidence demonstrating associations between sensory, motor, and cognitive functioning and contribute to an evolving consideration of how best to categorize and characterize SCD in a way that guides strategies for screening, assessment, and intervention.

Consensus on Shared Measures of Mobility and Cognition: From the Canadian Consortium on Neurodegeneration in Aging (CCNA).

BACKGROUND: A new paradigm is emerging in which mobility and cognitive impairments, previously studied, diagnosed, and managed separately in older adults, are in fact regulated by shared brain resources. Deterioration in these shared brain mechanisms by normal aging and neurodegeneration increases the risk of developing dementia, falls, and fractures. This new paradigm requires an integrated approach to measuring both domains. We aim to identify a complementary battery of existing tests of mobility and cognition in community-dwelling older adults that enable assessment of motor-cognitive interactions. METHODS: Experts on mobility and cognition in aging participated in a semistructured consensus based on the Delphi process. After performing a scoping review to select candidate tests, multiple rounds of consultations provided structured feedback on tests that captured shared characteristics of mobility and cognition. These tests needed to be sensitive to changes in both mobility and cognition, applicable across research studies and clinics, sensitive to interventions, feasible to perform in older adults, been previously validated, and have minimal ceiling/floor effects. RESULTS: From 17 tests appraised, 10 tests fulfilled prespecified criteria and were selected as part of the "Core-battery" of tests. The expert panel also recommended a "Minimum-battery" of tests that included gait speed, dual-task gait speed, the Montreal Cognitive Assessment and Trail Making Test A&B. CONCLUSIONS: A standardized assessment battery that captures shared characteristics of mobility and cognition seen in aging and neurodegeneration may increase comparability across research studies, detection of subtle or common reversible factors, and accelerate research progress in dementia, falls, and aging-related disabilities.

Attentional switching in the sequential flanker task: age, location, and time course effects.

The sequential flanker task was developed to study sequential performance using methodology borrowed from studies of task switching. We investigated age differences in backward inhibition [BI: Mayr, U., & Keele, S. W. (2000). Changing internal constraints on action: The role of backward inhibition. Journal of Experimental Psychology: General, 129, 4-26] during a sequential category search task. Participants learned four animal categories in a fixed order, and then searched for exemplars from those categories in runs of mis-ordered exemplars. Across three experiments, we observed robust BI facilitation effects. However, the magnitude of BI effects did not differ across age groups. This age-invariance held despite manipulations of distractibility (Experiment 2), and interstimulus interval (Experiment 3), suggesting that BI processes may be relatively automatic and obligatory in the context of sequential tasks. The findings are discussed in terms of the attentional mechanisms that underlie task set switching and sequential performance.