Combining transcranial direct current stimulation with a motor-cognitive task: the impact on dual-task walking costs in older adults

Abstract Background The performance of a secondary task while walking increases motor-cognitive interference and exacerbates fall risk in older adults. Previous studies have demonstrated that transcranial direct current stimulation (tDCS) may improve certain types of dual-task performance, and, that tDCS delivered during the performance of a task may augment the benefits of stimulation, potentially reducing motor-cognitive interference. However, it is not yet known if combining multi-target tDCS with the simultaneous performance of a task related to the tDCS targets reduces or increases dual-task walking costs among older adults. The objectives of the present work were (1) To examine whether tDCS applied during the performance of a task that putatively utilizes the brain networks targeted by the neuro-stimulation reduces dual-task costs, and (2) to compare the immediate after-effects of tDCS applied during walking, during seated-rest, and during sham stimulation while walking, on dual-task walking costs in older adults. We also explored the impact on postural sway and other measures of cognitive function. Methods A double-blind, ‘within-subject’ cross-over pilot study evaluated the effects of 20 min of anodal tDCS targeting both the primary motor cortex (M1) and the left dorsolateral prefrontal cortex (lDLPFC) in 25 healthy older adults (73.9 ± 5.2 years). Three stimulation conditions were assessed in three separate sessions: (1) tDCS while walking in a complex environment (tDCS + walking), (2) tDCS while seated (tDCS + seated), and (3) walking in a complex environment with sham tDCS (sham + walking). The complex walking condition utilized virtual reality to tax motor and cognitive abilities. During each session, usual-walking, dual-task walking, quiet standing sway, and cognitive function (e.g., Stroop test) were assessed before and immediately after stimulation. Dual-task costs to gait speed and other measures were computed. Results The dual-task cost to gait speed was reduced after tDCS + walking (p = 0.004) as compared to baseline values. Neither tDCS + seated (p = 0.173) nor sham + walking (p = 0.826) influenced this outcome. Similar results were seen for other gait measures and for Stroop performance. Sway was not affected by tDCS. Conclusions tDCS delivered during the performance of challenging walking decreased the dual-task cost to walking in older adults when they were tested just after stimulation. These results support the existence of a state-dependent impact of neuro-modulation that may set the stage for a more optimal neuro-rehabilitation. Trial registration: Clinical Trials Gov Registrations Number: NCT02954328.

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Combining tDCS With a Motor-Cognitive Task to Reduce the Negative Impact of Dual-Tasking on the Gait of Older Adults

Innovation in Aging ◽

10.1093/geroni/igaa057.921 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

pp. 287-288

Author(s):

Jeffrey Hausdorff ◽

Nofar Schneider ◽

Marina Brozgol ◽

Pablo Cornejo Thumm ◽

Nir Giladi ◽

...

Keyword(s):

Older Adults ◽

Virtual Reality ◽

Executive Function ◽

Dual Task ◽

Gait Speed ◽

Negative Impact ◽

Virtual Reality Environment ◽

Dual Tasking ◽

Concurrent Performance ◽

Dual Task Cost

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<0.001) executive function (Stroop interference score). tDCS+seated and sham+walking did not affect the dual-task cost to gait speed (p>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.

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Combining Transcranial Direct Current Stimulation With Tai Chi to Improve Dual-Task Gait Performance in Older Adults With Mild Cognitive Impairment: A Randomized Controlled Trial

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2021.766649 ◽

2021 ◽

Vol 13 ◽

Author(s):

Ying-Yi Liao ◽

Mu-N Liu ◽

Han-Cheng Wang ◽

Vincent Walsh ◽

Chi Ieong Lau

Keyword(s):

Older Adults ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Direct Current ◽

Dual Task ◽

Transcranial Direct Current Stimulation ◽

Tai Chi ◽

Controlled Trial ◽

Gait Performance ◽

Direct Current Stimulation

Introduction: Engaging in a secondary task while walking increases motor-cognitive interference and exacerbates fall risk in older adults with mild cognitive impairment (MCI). Previous studies have demonstrated that Tai Chi (TC) may improve cognitive function and dual-task gait performance. Intriguingly, with emerging studies also indicating the potential of transcranial direct current stimulation (tDCS) in enhancing such motor-cognitive performance, whether combining tDCS with TC might be superior to TC alone is still unclear. The purpose of this study was to investigate the effects of combining tDCS with TC on dual-task gait in patients with MCI.Materials and Methods: Twenty patients with MCI were randomly assigned to receive either anodal or sham tDCS, both combined with TC, for 36 sessions over 12 weeks. Subjects received 40 min of TC training in each session. During the first 20 min, they simultaneously received either anodal or sham tDCS over the left dorsolateral prefrontal cortex. Outcome measures included dual-task gait performance and other cognitive functions.Results: There were significant interaction effects between groups on the cognitive dual task walking. Compared to sham, the anodal tDCS group demonstrated a greater improvement on cadence and dual task cost of speed.Conclusion: Combining tDCS with TC may offer additional benefits over TC alone in enhancing dual-task gait performance in patients with MCI.Clinical Trial Registration: [www.ClinicalTrials.gov], identifier [TCTR20201201007].

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Walking While Talking and Prefrontal Oxygenation in Motoric Cognitive Risk Syndrome: Clinical and Pathophysiological Aspects

Journal of Alzheimer s Disease ◽

10.3233/jad-210239 ◽

2021 ◽

pp. 1-12

Author(s):

Cristina Udina ◽

Emmeline Ayers ◽

Marco Inzitari ◽

Joe Verghese

Keyword(s):

Older Adults ◽

Cognitive Function ◽

Task Performance ◽

Dual Task ◽

Near Infrared ◽

Community Dwelling ◽

Functional Near Infrared Spectroscopy ◽

Cognitive Risk ◽

Dual Task Cost ◽

Dual Task Performance

Background: Motoric cognitive risk syndrome (MCR) combines slow gait and cognitive complaints and has been proposed as a predementia syndrome. The nature of dual-task performance in MCR has not been established. Objective: To assess differences in dual-task performance between participants with and without MCR and to study the prefrontal cortex (PFC)-based brain activity during dual-task using functional near-infrared spectroscopy. Methods: Cohort study of community-dwelling non-demented older adults included in the “Central Control of Mobility in Aging” study. Comprehensive assessment included global cognition and executive function tests along with clinical variables. Dual-task paradigm consisted in walking while reciting alternate letters of the alphabet (WWT) on an electronic walkway. We compared dual-task performance between MCR (n = 60) and No MCR (n = 478) participants and assessed the relationship of dual-task performance with cognitive function. In a subsample, we compared PFC oxygenation during WWT between MCR (n = 32) and No MCR (n = 293). Results: In our sample of 538 high-functioning older adults (76.6±6.5 years), with 11.2% prevalence of MCR, dual-task cost was not significantly different, compared to No MCR participants. Among MCR participants, no significant relationship was found between WWT velocity and cognitive function, whereas No MCR participants with better cognitive function showed faster WWT velocities. PFC oxygenation during WWT was higher in MCR compared to No MCR (1.02±1.25 versus 0.66±0.83, p = 0.03). Conclusion: MCR participants showed no significant differences in the dual-task cost while exhibiting higher PFC oxygenation during dual-task walking. The dual-task performance (WWT velocity) in MCR participants was not related to cognition.

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Transcranial Direct Current Stimulation May Improve Cognitive-Motor Function in Functionally Limited Older Adults

Neurorehabilitation and Neural Repair ◽

10.1177/1545968318792616 ◽

2018 ◽

Vol 32 (9) ◽

pp. 788-798 ◽

Cited By ~ 15

Author(s):

Brad Manor ◽

Junhong Zhou ◽

Rachel Harrison ◽

On-Yee Lo ◽

Thomas G. Travison ◽

...

Keyword(s):

Older Adults ◽

Prefrontal Cortex ◽

Executive Function ◽

Direct Current ◽

Dual Task ◽

Transcranial Direct Current Stimulation ◽

Dorsolateral Prefrontal Cortex ◽

Dual Tasking ◽

Direct Current Stimulation ◽

Dorsolateral Prefrontal

Objective. To determine the effects of a transcranial direct current stimulation (tDCS) intervention with the anode placed over the left dorsolateral prefrontal cortex (dlPFC) and cathode over the right supraorbital region, on cognition, mobility, and “dual-task” standing and walking in older adults with mild-to-moderate motor and cognitive impairments. Methods. A double-blinded, block-randomized, sham-controlled trial was conducted in 18 nondemented, ambulatory adults aged ⩾65 years with slow walking speed (⩽1.0 m/s) and “executive” dysfunction (Trail Making Test B score ⩽25th percentile of age- and education-matched norms). Interventions included ten 20-minute sessions of tDCS or sham stimulation. Cognition, mobility, and dual-task standing and walking were assessed at baseline, postintervention, and 2 weeks thereafter. Dual tasking was also assessed immediately before and after the first tDCS session. Results. Intervention compliance was high (mean ± SD = 9.5 ± 1.1 sessions) and no unexpected or serious side effects were reported. tDCS, compared with sham, induced improvements in the Montreal Cognitive Assessment total score ( P = .03) and specifically within the executive function subscore of this test ( P = .002), and in several metrics of dual-task standing and walking ( P < .05). Each of these effects persisted for 2 weeks. tDCS had no effect on the Timed Up-and-Go test of mobility or the Geriatric Depression Scale. Those participants who exhibited larger improvements in dual-task standing posture following the first tDCS session exhibited larger cognitive-motor improvements following 2 weeks of tDCS ( P < .04). Interpretation. tDCS intervention designed to stimulate the left dorsolateral prefrontal cortex may improve executive function and dual tasking in older adults with functional limitations.

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Effects of transcranial direct current stimulation (tDCS) on multiscale complexity of dual-task postural control in older adults

Experimental Brain Research ◽

10.1007/s00221-015-4310-0 ◽

2015 ◽

Vol 233 (8) ◽

pp. 2401-2409 ◽

Cited By ~ 28

Author(s):

Diange Zhou ◽

Junhong Zhou ◽

Hu Chen ◽

Brad Manor ◽

Jianhao Lin ◽

...

Keyword(s):

Older Adults ◽

Postural Control ◽

Direct Current ◽

Dual Task ◽

Transcranial Direct Current Stimulation ◽

Direct Current Stimulation

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TARGETED TRANSCRANIAL DIRECT CURRENT STIMULATION IMPROVES DUAL-TASK WALKING PERFORMANCE IN OLDER ADULTS

Innovation in Aging ◽

10.1093/geroni/igz038.2923 ◽

2019 ◽

Vol 3 (Supplement_1) ◽

pp. S794-S794

Author(s):

Brad Manor ◽

Junhong Zhou ◽

On-Yee Lo ◽

Racheli Katz ◽

Marina Brozgol ◽

...

Keyword(s):

Older Adults ◽

Direct Current ◽

Dual Task ◽

Transcranial Direct Current Stimulation ◽

Repeated Measures ◽

Primary Motor Cortex ◽

Cognitive Task ◽

Brain Network ◽

Direct Current Stimulation ◽

Left Dlpfc

Abstract In older adults, the ability to walk while engaged in an unrelated cognitive task (i.e., dual tasking) depends upon activation of both motor and cognitive brain networks. Noninvasive transcranial direct current stimulation (tDCS) can facilitate the excitability of specific brain regions and their connected neural networks. In this multi-site, randomized controlled within-subject cross-over study, we tested the effects of single, 20-minute sessions of tDCS targeting 1) the primary motor cortex (M1), 2) the left dorsolateral prefrontal cortex (dlPFC, a primary region subserving cognitive function), 3) both M1 and left dlPFC, or 4) neither region (sham). Forty-eight older adults free of overt illness or disease (mean±SD age=75±6 years, 35 women) completed four study visits at least 72 hours apart, during which dual task gait was assessed before and after tDCS administration. Stimulation was delivered using the Starstim™ system (Neuroelectrics Corp) and the same array of six gel electrodes to ensure double-blinding. Participants were successfully blinded to tDCS condition and reported no unexpected tDCS side effects. Repeated-measures ANOVAs adjusted for age and sex revealed that the dual task cost to gait speed was smaller (i.e., better and closer to zero) following tDCS that targeted both M1 and the left dlPFC, as well as the left dlPFC alone, compared to all other time points (condition-time interaction: F=3.0, p=0.04). The dual task costs following these two types of stimulation were similar. These results suggest that noninvasive facilitation of cognitive-motor brain network excitability leads to acute improvement in dual task performance in older adults.

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