scholarly journals The Cortical Dynamics of Dual-Task Standing in Older Adults

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. 72-73
Author(s):  
Melike Kahya ◽  
On-Yee Lo ◽  
Junhong Zhou ◽  
Alvaro Pascual-Leone ◽  
Lewis Lipsitz ◽  
...  

Abstract In older adults, the extent to which performing a cognitive task when standing diminishes postural control is predictive of future falls and cognitive decline. The cortical control of such “dual-tasking,” however, remains poorly understood. Electroencephalogram (EEG) studies have demonstrated that the level of attention and cognitive inhibitory activity during cognitive task performance can be quantified by changes in brain activity in specific frequency bands; namely, an increase in theta/beta ratio and a decrease in alpha-band power, respectively. We hypothesized that in older adults, dual-tasking would increase theta/beta ratio and decrease alpha-band power, and, that greater alpha-band power during quiet standing would predict worse dual-task performance. To test this hypothesis, we recorded postural sway and EEG (32-channels) in 30 older adults without overt disease as they completed trials of standing, with and without verbalized serial subtractions, on four separate visits. Postural sway speed, as well as absolute theta/beta power ratio and alpha-band power, were calculated. The theta/beta power ratio and alpha-band power demonstrated high test-retest reliability during quiet and dual-task standing across visits (intra-class correlation coefficients >0.70). Compared with quiet standing, dual-tasking increased theta/beta power ratio (p<0.0001) and decreased alpha-band power (p=0.002). Participants who exhibited greater alpha-band power during quiet standing demonstrated a greater dual-task cost (i.e., percent increase, indicative of worse performance) to postural sway speed (r=0.3, p=0.01). These results suggest that in older adults, dual-tasking while standing increases EEG-derived metrics related to attention, and, that greater cognitive inhibitory activity during quiet standing is associated with worse dual-task standing performance.

2016 ◽  
Vol 32 (6) ◽  
pp. 541-547 ◽  
Author(s):  
Renee Beach Sample ◽  
Kurt Jackson ◽  
Allison L. Kinney ◽  
Wiebke S. Diestelkamp ◽  
Senia Smoot Reinert ◽  
...  

Falls occur in 33% of older adults each year, some leading to moderate to severe injuries. To reduce falls and fall-related injuries, it is important to identify individuals with subtle risk factors elevating their likelihood of falling. The objective of this study was to determine how postural sway measures differed between fallers and nonfallers under standard and dual-task conditions. Quietstanding posturography measures were collected from 150 older adults during standard, cognitive, manual, and cognitive+manual tasks, and analyzed through traditional and nonlinear analyses. Of the traditional measures, M/L sway range and 95% confidence ellipse sway area showed statistically significant differences in all 4 test conditions between fallers and nonfallers. Although the manual dual task showed the most stable balance, effect sizes demonstrated larger differences between fallers and nonfallers. Nonlinear analysis revealed M/L sample entropy and M/L α-scaling exponent differentiating between fallers and nonfallers, with the cognitive task demonstrating larger differences. Based on the results, it is recommended to: (1) apply M/L sway range and 95% confidence ellipse area, (2) use the manual task to differentiate between fallers and nonfallers when using traditional analyses, and (3) use the cognitive task and M/L alpha and M/L sample entropy when using nonlinear analyses.


2016 ◽  
Vol 28 (2) ◽  
pp. 275-281 ◽  
Author(s):  
Brad Manor ◽  
Junhong Zhou ◽  
Azizah Jor'dan ◽  
Jue Zhang ◽  
Jing Fang ◽  
...  

Dual tasking (e.g., walking or standing while performing a cognitive task) disrupts performance in one or both tasks, and such dual-task costs increase with aging into senescence. Dual tasking activates a network of brain regions including pFC. We therefore hypothesized that facilitation of prefrontal cortical activity via transcranial direct current stimulation (tDCS) would reduce dual-task costs in older adults. Thirty-seven healthy older adults completed two visits during which dual tasking was assessed before and after 20 min of real or sham tDCS targeting the left pFC. Trials of single-task standing, walking, and verbalized serial subtractions were completed, along with dual-task trials of standing or walking while performing serial subtractions. Dual-task costs were calculated as the percent change in markers of gait and postural control and serial subtraction performance, from single to dual tasking. Significant dual-task costs to standing, walking, and serial subtraction performance were observed before tDCS (p < .01). These dual-task costs were less after real tDCS as compared with sham tDCS as well as compared with either pre-tDCS condition (p < .03). Further analyses indicated that tDCS did not alter single task performance but instead improved performance solely within dual-task conditions (p < .02). These results demonstrate that dual tasking can be improved by modulating prefrontal activity, thus indicating that dual-task decrements are modifiable and may not necessarily reflect an obligatory consequence of aging. Moreover, tDCS may ultimately serve as a novel approach to preserving dual-task capacity into senescence.


2021 ◽  
Vol 11 (9) ◽  
pp. 933
Author(s):  
Graça Monteiro de Barros ◽  
Filipe Melo ◽  
Josefa Domingos ◽  
Raul Oliveira ◽  
Luís Silva ◽  
...  

Numerous of our daily activities are performed within multitask or dual task conditions. These conditions involve the interaction of perceptual and motor processes involved in postural control. Age-related changes may negatively impact cognition and balance control. Studies identifying changes related to dual-task actions in older people are need. This study aimed to determine the effects of different types of dual-tasking on the balance control of healthy older adults. The sample included 36 community-living older adults, performing two tests—a sway test and a timed up-and-go test—in three conditions: (a) single motor task; (b) dual motor task; and (c) dual motor task with cognitive demands. Cognitive processes (dual-task and cognition) affected static balance, increasing amplitude (p < 0.001) and frequency (p < 0.001) of the center of mass displacements. Dynamic balance revealed significant differences between the single motor condition and the other two conditions during gait phases (p < 0.001). The effect of dual-tasking in older adults suggests that cognitive processes are a main cause of increased variability in balance and gait when under an automatic control. During sit-to-stand, turning, and turn-to-sit movements under dual-tasking, the perceptive information becomes the most important focus of attention, while any cognitive task becomes secondary.


2020 ◽  
Vol 14 (01) ◽  
pp. 14-23
Author(s):  
Ana Carolina de Mello Alves Rodrigues ◽  
Rodolpho Cesar dos Reis Tinini ◽  
Valeska Gatica-Rojas ◽  
Alfredo Mauricio Batista De Paula ◽  
Andre Luis Sena Guimarães ◽  
...  

BACKGROUND: Older adults require special attention during cognitive-motor tasks since automatic postural control is reduced. AIM: To analyze the effect of physical exercise on dual-task processing of healthy older women performing standing balance. METHOD: Sixteen healthy older women were assessed in a quiet standing position with eyes open/closed (single-task, EO, and EC) and with a cognitive task (dual-task, DT) using a Wii Balance Board. All individuals performed training (aerobic, strength, and virtual reality exercises) at moderate effort. Center of pressure (CoP) anteroposterior and mediolateral displacement were analyzed over time pre- and post-training. The Wilcoxon test was used to compare pre- and post-training. RESULTS: Greater variability in CoP was observed pre- compared to post-training. In the DT, there was a significance decrease in post-training variability compared to pre-training (p<0.01). CONCLUSION: Physical exercise programs for older adults may contribute to simultaneously improving motor-cognitive performances, associated with improvement in the divided attention.


2010 ◽  
Vol 104 (6) ◽  
pp. 3510-3517 ◽  
Author(s):  
Hyun Gu Kang ◽  
Lewis A. Lipsitz

Distractions affect postural control, but this mechanism is not well understood. Diversion of resources during cognitive stress may lead to decreased motor drive and postural muscle tone. This may appear as decreased postural stiffness and increased postural sway amplitude. We hypothesized that dual tasking leads to decreased stiffness and increased sway amplitude. Postural sway (center of pressure; COP) data were used from 724 participants aged 77.9 ± 5.3 yr, a representative sample of community-dwelling older adults, the MOBILIZE Boston Study cohort. Subjects stood barefoot with eyes open for 30 s per trial on a force plate. Five trials were performed each with and without a serial subtractions-by-3 task. Sway data were fit to a damped oscillator inverted pendulum model. Amplitudes (COP and center of mass), mechanical stiffness, and damping of the sway behavior were determined. Sway amplitudes and damping increased with the dual task ( P < 0.001); stiffness decreased only mediolaterally ( P < 0.001). Those with difficulty doing the dual task exhibited larger sway and less damping mediolaterally ( P ≤ 0.001) and an increased stiffness with dual task anteroposteriorly (interaction P = 0.004). Dual task could still independently explain increases in sway ( P < 0.001) after accounting for stiffness changes. Thus the hypothesis was supported only in mediolateral sway. The simple model helped to explain the dual task related increase of sway only mediolaterally. It also elucidated the differential influence of cognitive function on the mechanics of anteroposterior and mediolateral sway behaviors. Dual task may divert the resources necessary for mediolateral postural control, thus leading to falls.


Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8428
Author(s):  
Kayla Bohlke ◽  
Xiaonan Zhu ◽  
Patrick J. Sparto ◽  
Mark S. Redfern ◽  
Caterina Rosano ◽  
...  

Dual-task balance studies explore interference between balance and cognitive tasks. This study is a descriptive analysis of accelerometry balance metrics to determine if a verbal cognitive task influences postural control after the task ends. Fifty-two healthy older adults (75 ± 6 years old, 30 female) performed standing balance and cognitive dual-tasks. An accelerometer recorded movement from before, during, and after the task (reciting every other letter of the alphabet). Thirty-six balance metrics were calculated for each task condition. The effect of the cognitive task on postural control was determined by a generalized linear model. Twelve variables, including anterior–posterior centroid frequency, peak frequency and entropy rate, medial-later entropy rate and wavelet entropy, and bandwidth in all directions, exhibited significant differences between baseline and cognitive task periods, but not between baseline and post-task periods. These results indicate that the verbal cognitive task did alter balance, but did not bring about persistent effects after the task had ended. Traditional balance measurements, i.e., root mean square and normalized path length, notably lacked significance, highlighting the potential to use other accelerometer metrics for the early detection of balance problems. These novel insights into the temporal dynamics of dual-task balance support current dual-task paradigms to reduce fall risk in older adults.


2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 287-288
Author(s):  
Jeffrey Hausdorff ◽  
Nofar Schneider ◽  
Marina Brozgol ◽  
Pablo Cornejo Thumm ◽  
Nir Giladi ◽  
...  

Abstract The simultaneous performance of a secondary task while walking (i.e., dual tasking) increases motor-cognitive interference and fall risk in older adults. Combining transcranial direct current stimulation (tDCS) with the concurrent performance of a task that putatively involves the same brain networks targeted by the tDCS may reduce the negative impact of dual-tasking on walking. We examined whether tDCS applied while walking reduces the dual-task costs to gait and whether this combination is better than tDCS alone or walking alone (with sham stimulation). In 25 healthy older adults (aged 75.7±10.5yrs), a double-blind, within-subject, cross-over pilot study evaluated the acute after-effects of 20 minutes of tDCS targeting the primary motor cortex and the dorsal lateral pre frontal cortex during three separate sessions:1) tDCS while walking on a treadmill in a virtual-reality environment (tDCS+walking), 2) tDCS while seated (tDCS+seated), and 3) walking in the virtual-reality environment with sham tDCS (sham+walking). The complex walking condition taxed motor and cognitive abilities. During each session, single- and dual-task walking and cognitive function were assessed before and immediately after stimulation. Compared to pre-tDCS performance, tDCS+walking reduced the dual-task cost to gait speed (p=0.004) and other gait features (e.g., variability p=0.02), and improved (p&lt;0.001) executive function (Stroop interference score). tDCS+seated and sham+walking did not affect the dual-task cost to gait speed (p&gt;0.17). These initial findings demonstrate that tDCS delivered during challenging walking ameliorates dual-task gait and executive function in older adults, suggesting that the concurrent performance of related tasks enhances the efficacy of the neural stimulation and mobility.


Gerontology ◽  
2018 ◽  
Vol 65 (2) ◽  
pp. 164-173 ◽  
Author(s):  
Frederico Pieruccini-Faria ◽  
Yanina Sarquis-Adamson ◽  
Manuel Montero-Odasso

Background: Older adults with Mild Cognitive Impairment (MCI) are at higher risk of falls and injuries, but the underlying mechanism is poorly understood. Inappropriate anticipatory postural adjustments to overcome balance perturbations are affected by cognitive decline. However, it is unknown whether anticipatory gait control to avoid an obstacle is affected in MCI. Objective: Using the dual-task paradigm, we aim to assess whether gait control is affected during obstacle negotiation challenges in older adults with MCI. Methods: Seventy-nine participants (mean age = 72.0 ± 2.7 years; women = 30.3%) from the “Gait and Brain Study” were included in this study (controls = 27; MCI = 52). In order to assess the anticipatory control behaviour for obstacle negotiation, a 6-m electronic walkway embedded with sensors recorded foot prints to measure gait speed and step length variability, during early (3 steps before the late phase) and late (3 steps before the obstacle) pre-crossing phases of an ad hoc obstacle, set at 15% of participant’s height. Participants walked under single- and dual-task gait (counting backwards by 1’s from 100 while walking) conditions. Three-way mixed repeated-measures analysis of variance models examined differences in gait performance between groups when transitioning between pre-crossing phases towards an obstacle during single- and dual-task conditions. Analyses were adjusted for age, sex, years of education, lower limb function, fear of falling, medical status, depressive symptoms, baseline gait speed and executive function. Results: A significant three-way interaction among groups, pre-crossing phases and task showed that participants with MCI attenuated the gait deceleration (p = 0.02) and performed fewer step length adjustments (p = 0.03) when approaching the obstacle compared with controls while dual-tasking. These interactions were attenuated when executive function performance was added as a covariate in the adjusted statistical model. Conclusion: Older adults with MCI attenuate the anticipatory gait adjustments needed to avoid an obstacle when dual-tasking. Deficits in higher-order cognitive processing may limit obstacle negotiation capabilities in MCI populations, being a potential falls risk factor.


2019 ◽  
Author(s):  
Hamid Allahverdipour ◽  
Iman Dianat ◽  
Galavizh Mameh ◽  
mohammad Asghari Jafarabadi

Abstract Background: The aim of this study was to evaluate the effects of cognitive and physical loads on dynamic and static balance of older adults under single, dual and multi-task conditions. Methods: The effects of single versus combined (dual-task and multi-task) cognitive (to speak out the name of the weekdays in a reverse order) and physical (with three levels including handling weights of 1kg, 2kg and 3kg in each hand) loads on dynamic and static balance of 42 older adults (21 males and 21 females), aged ≥ 60 years were studied. Dynamic and static balance measures were evaluated using the Timed Up and Go (TUG) and stabilometer (sway index) tests, respectively. Results: The TUG speed of female participants was generally slower than that of male participants. Cognitive task influenced the participants’ dynamic balance during the dual-task conditions, while the static balance was not affected in this phase. The dynamic and static balance measures were more influenced when performing the multi-tasks than when doing the dual-tasks. The effects of various levels of physical demand on the dynamic balance varied greatly under dual- and multi-task conditions. Conclusions: The findings add to the understanding of the factors influencing the elderly balance and control under cognitive and physical functioning.


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