Combining frontal tDCS with walking rehabilitation to enhance mobility and cognition: a pilot clinical trial

Abstract Walking function is compromised with older age, particularly for cognitively demanding complex walking tasks. Frontal lobe brain networks are important to both complex walking and cognitive function. There is a need for interventions that target this brain region. This pilot study assessed a novel intervention to enhance both walking and executive function in older adults. The primary hypothesis was that eighteen sessions of frontal lobe tDCS combined with complex walking rehabilitation would be feasible, safe, and show preliminary efficacy for improvements in walking and cognition. Eighteen participants were randomized to one of three intervention groups: active tDCS and rehabilitation with complex walking tasks (Active/Complex); sham tDCS and rehabilitation with complex walking tasks (Sham/Complex); or sham tDCS and rehabilitation with typical walking (Sham/Typical). Outcome measures included multiple tests of walking function, executive function, and prefrontal activity during walking measured by functional near infrared spectroscopy. For the walking tests, effect sizes for Active/Complex were generally higher than for Sham/Complex. The Sham/Typical group exhibited walking test effect sizes that were often larger than either of the complex walking groups, possibly due to higher intervention step count. For the executive function tests, effect sizes were largest for the Active/Complex group. Improvements in prefrontal activity during walking were observed, as conceptualized by the Compensation Related Utilization of Neural Circuits Hypothesis. These preliminary findings support that tDCS combined with complex walking rehabilitation in older adults is feasible and may enhance both walking function and executive function.

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fNIRS Outcomes for a Pilot Clinical Trial Combining Frontal tDCS With Walking Rehabilitation in Older Adults

Innovation in Aging ◽

10.1093/geroni/igaa057.2872 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

pp. 792-793

Author(s):

David Clark ◽

Sudeshna Chatterjee ◽

Jared Skinner ◽

Paige Lysne ◽

Samuel Wu ◽

...

Keyword(s):

Older Adults ◽

Executive Function ◽

Outcome Measures ◽

Near Infrared ◽

Neural Circuits ◽

Functional Near Infrared Spectroscopy ◽

Active Complex ◽

Multiple Tests ◽

Walking Rehabilitation ◽

Primary Hypothesis

Abstract This pilot study assessed a novel intervention to enhance both walking and executive function in older adults. The primary hypothesis was that eighteen sessions of frontal lobe tDCS combined with walking rehabilitation would be feasible, safe, and show preliminary efficacy. Eighteen participants were randomized to one of three intervention groups: active tDCS and rehabilitation with complex walking tasks (Active/Complex); sham tDCS and rehabilitation with complex walking tasks (Sham/Complex); or sham tDCS and rehabilitation with typical walking (Sham/Typical). Outcome measures included multiple tests of walking function, executive function, and prefrontal activity during walking as measured by functional near infrared spectroscopy (fNIRS). Of the three groups, the Active/Complex group demonstrated the broadest improvements across outcome measures including for prefrontal activity. The functional range of prefrontal activity in this group was increased considerably, as conceptualized by the Compensation Related Utilization of Neural Circuits Hypothesis. Frontal tDCS is a promising adjuvant to walking rehabilitation.

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Effects of fNIRS Processing Methods on Prefrontal Hemodynamics During Single and Dual Task Walking in Older Adults

Innovation in Aging ◽

10.1093/geroni/igaa057.922 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

pp. 288-288

Author(s):

Meltem Izzetoglu ◽

Roee Holtzer

Keyword(s):

Older Adults ◽

Dual Task ◽

Gold Standard ◽

Near Infrared ◽

Strong Support ◽

Effect Sizes ◽

Linear Mixed Effect Model ◽

Artifact Removal ◽

Functional Near Infrared Spectroscopy ◽

Mixed Effect

Abstract functional near infrared spectroscopy (fNIRS) has been increasingly used to assess changes in the hemodynamic response during active walking in aging and disease populations. Key findings revealed that HbO2 in the prefrontal cortex (PFC) increased from single-task-walk (STW) to dual-task-walk (DTW) due to the greater cognitive demands inherent in the latter condition. However, previous studies utilized a limited and inconsistent number of algorithms and filters to remove artifacts from fNIRS-derived brain activation data. Critically, there is no gold standard for artifact removal at the present time, which reduces replicability and generalizability. To address this critical limitation, we have reanalyzed a large dataset of older adults (n=83) who underwent our walking protocol by using different hemodynamic conversion parameters (molar extinction coefficients and age and wavelength dependent differential pathlength factors) and applying different filters having various cut-off frequencies for artifact removal. On the extracted hemodynamic responses, namely oxygenated-hemoglobin (HbO2) and deoxygenated-hemoglobin (Hb), linear mixed effect model results indicated that task effects showed similar significant increases in HbO2 from STW to DTW (range of effect sizes was 0.59 to 0.64) and as well as the expected decline in Hb from STW to DTW (range of effect sizes was 0.18 to 0.32) irrespective of the methods used. In addition, the intraclass correlations suggested excellent reliability across methods (HbO2 range = 0.982 to 0.996; Hb range = 0.883 to 0.984). In conclusion, these findings provide strong support to previously published articles but also highlight the need to establish a gold standard for fNIRS processing.

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Mean and variability in functional brain activations differentially predict executive function in older adults: an investigation employing functional near-infrared spectroscopy

Neurophotonics ◽

10.1117/1.nph.5.1.011013 ◽

2017 ◽

Vol 5 (01) ◽

pp. 1 ◽

Cited By ~ 5

Author(s):

Drew W. R. Halliday ◽

Bryce P. Mulligan ◽

Douglas D. Garrett ◽

Stefan Schmidt ◽

Sandra R. Hundza ◽

...

Keyword(s):

Older Adults ◽

Executive Function ◽

Infrared Spectroscopy ◽

Near Infrared Spectroscopy ◽

Near Infrared ◽

Functional Near Infrared Spectroscopy ◽

Functional Brain

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Obstacle Negotiation in Older Adults: Prefrontal Activation Interpreted Through Conceptual Models of Brain Aging

Innovation in Aging ◽

10.1093/geroni/igaa034 ◽

2020 ◽

Vol 4 (4) ◽

Author(s):

Sudeshna A Chatterjee ◽

Rachael D Seidler ◽

Jared W Skinner ◽

Paige E Lysne ◽

Chanoan Sumonthee ◽

...

Keyword(s):

Older Adults ◽

Executive Function ◽

Task Performance ◽

Near Infrared ◽

Brain Aging ◽

Hemoglobin Concentration ◽

Brain Activation ◽

Functional Near Infrared Spectroscopy ◽

Walking Performance ◽

Design And Methods

Abstract Background and Objectives The influence of interindividual differences on brain activation during obstacle negotiation and the implications for walking performance are poorly understood in older adults. This study investigated the extent to which prefrontal recruitment during obstacle negotiation is explained by differences in age, executive function, and sex. These data were interpreted according to the Compensation-Related Utilization of Neural Circuits Hypothesis (CRUNCH) framework of brain aging. We also tested the association between prefrontal recruitment and walking performance. Research Design and Methods Prefrontal oxygenated hemoglobin concentration (O2Hb) was measured during typical walking (Typical) and obstacle negotiation (Obstacles) tasks in 50 adults aged 65 years and older using functional near-infrared spectroscopy. The primary outcome was the change in prefrontal recruitment (∆PFR), measured as Obstacles ∆O2Hb minus Typical ∆O2Hb. Multiple regression was used to test the relationship between ∆PFR and age, executive function measured by the Trail Making Test, and sex. Pearson’s correlation coefficient was used to investigate the association between ∆PFR and the cost of Obstacles walking speed relative to Typical walking. Results Age, executive function, and their interaction significantly predicted greater ∆PFR (R2 = 0.34, p = .01). Participants were subgrouped according to age and executive function to examine the interaction effects. Adults of lower age and with lower executive function exhibited greater ∆PFR during Obstacles compared to their peers with higher executive function (p = .03). Adults of advanced age exhibited a ceiling of prefrontal recruitment during obstacle negotiation, regardless of executive function level (p = .87). Greater ∆PFR was significantly associated with a smaller cost of Obstacles (r = 0.3, p = .03). Discussion and Implications These findings are consistent with the CRUNCH framework: neural inefficiency where a greater amount of brain activation is needed for task performance at a similar level, compensatory overactivation to prevent a steeper decline in task performance, and capacity limitation with a recruitment ceiling effect.

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Obstacle negotiation in older adults: prefrontal activation interpreted through conceptual models of brain aging

Innovation in Aging ◽

10.1093/geroni/igaa057.1584 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

pp. 490-490

Author(s):

David Clark ◽

Sudeshna Chatterjee ◽

Rachael Seidler ◽

Jared Skinner ◽

Dorian Rose ◽

...

Keyword(s):

Older Adults ◽

Executive Function ◽

Near Infrared ◽

Brain Aging ◽

Hemoglobin Concentration ◽

Cognitive Models ◽

Functional Near Infrared Spectroscopy ◽

Age Related ◽

Walking Performance ◽

The Relationship

Abstract Age-related decline in executive function is associated with walking deficits in older adults. The main objective of this study was to better understand the cognitive control of obstacle negotiation in older adults by identifying predictors of prefrontal recruitment during the task. The study also examined the association between prefrontal recruitment and walking performance as well as interpretation of prefrontal activity relative to cognitive models of brain aging. Prefrontal oxygenated hemoglobin concentration (O2Hb) was measured by functional near-infrared spectroscopy during typical walking (Typical) and obstacle negotiation (Obstacles) tasks in older adults. The primary outcome was change in prefrontal recruitment (∆PFR), measured as Obstacles ∆O2Hb minus Typical ∆O2Hb. Stepwise regression was used to identify potential predictors of ∆PFR. Additional analyses were conducted to further examine the relationship between ΔPFR and the identified predictors. Greater ∆PFR was predicted by lower age, worse executive function, and their interaction (R2=0.19 , p=0.02). Particularly, the effect of executive function on ∆PFR was more pronounced for “early aging” than for “late aging” older adults (p<0.001). Greater ∆PFR was significantly associated with a smaller reduction in walking speed during Obstacles compared to Typical. In conclusion, age, executive function, and their interaction predict prefrontal recruitment during obstacle negotiation in older adults. These findings are generally consistent with existing cognitive models of brain aging including neural inefficiency, compensatory overactivation, and capacity-limitation with a recruitment ceiling effect.

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A-9 Examining Neural Variability during Dual-Task Walking and Cortical Thickness in Older Adults

Archives of Clinical Neuropsychology ◽

10.1093/arclin/acab062.27 ◽

2021 ◽

Vol 36 (6) ◽

pp. 1048-1048

Author(s):

Daliah Ross ◽

Mark E Wagshul ◽

Meltem Izzetoglu ◽

Roee Holtzer

Keyword(s):

Older Adults ◽

Prefrontal Cortex ◽

Cortical Thickness ◽

Dual Task ◽

Near Infrared ◽

Adverse Outcomes ◽

Functional Near Infrared Spectroscopy ◽

Single Task ◽

Mobility Impairments ◽

Neural Variability

Abstract Objective Greater intraindividual variability (IIV) in behavioral and cognitive performance is a risk factor for adverse outcomes but research concerning IIV in neural signal is scarce. Using functional near-infrared spectroscopy (fNIRS), we showed that IIV in oxygenated hemoglobin (HbO2) levels in the prefrontal cortex increased from single task (Single-Task-Walk–STW; Single-Task-Alpha–STA) to Dual-Task-Walk (DTW) conditions in older adults. Herein, we predicted that, consistent with the neural inefficiency hypothesis, reduced cortical thickness would be associated with greater increases in IIV in fNIRS-derived HbO2 from single tasks to DTW when adjusting for behavioral performance. Method Participants were right-handed older adults without dementia recruited from the community (N = 55; M(SD) age = 74.84(4.97); %female = 49.1). Neuroimaging included fNIRS for HbO2 levels in the prefrontal cortex during tasks and MRI for cortical thickness. IIV was operationalized using the SD of fNIRS-derived HbO2 observations assessed during a 30-s interval in each experimental condition. Results Moderation analyses, assessed through linear mixed effects models, revealed that in several frontal (p < 0.02), parietal (p < 0.02), temporal (p < 0.01), and occipital (p < 0.01) regions, thinner cortex was associated with greater increases in HbO2 IIV from the single tasks to DTW. Conclusion Reduced cortical thickness was associated with inefficient increases in IIV in fNIRS-derived HbO2 from single tasks to dual-task walking. Worse IIV in gait performance under DTW predicts adverse mobility outcomes. Reduced cortical thickness and worse IIV of fNIRS-derived HbO2 during DTW are possible brain mechanisms that explain the risk of developing mobility impairments in aging and disease populations.

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The association between media multitasking and executive function in Chinese adolescents: Evidence from self-reported, behavioral and fNIRS data

Cyberpsychology Journal of Psychosocial Research on Cyberspace ◽

10.5817/cp2021-2-8 ◽

2021 ◽

Vol 15 (2) ◽

Author(s):

Jiutong Luo ◽

Hui Li ◽

Pui-sze Yeung ◽

Chunqi Chang

Keyword(s):

Executive Function ◽

Near Infrared ◽

Negative Relationship ◽

Chinese Adolescents ◽

Cognitive Tasks ◽

Media Multitasking ◽

Behavioral Measures ◽

Functional Near Infrared Spectroscopy ◽

Multiple Assessment ◽

Stroop Tasks

This study examined the association between media multitasking and executive function in Chinese adolescents by comparing heavy/high and light/low media multitaskers, i.e., HMMs and LMMs, with self-reports, behavioral measures and functional near-infrared spectroscopy (fNIRS). The participants were 12 HMMs (media multitasking scores above the 75th percentile) and 10 LMMs (media multitasking scores below the 25th percentile) chosen from a sample of 61 adolescents. Each participant completed a self-reported questionnaire on executive function and three executive function cognitive tasks: 2-back, Color Stroop, and Number-letter Determination) while wearing the fNIRS. The results indicated that: (1) the HMMs showed more impairment in executive function than the LMMs based on questionnaire data analysis; (2) there were no significant differences between the HMMs and LMMs in their performance on the cognitive tasks; and (3) the HMMs showed greater prefrontal activation than the LMMs during the 2-back and Color Stroop tasks. These findings implied that media multitasking might be associated with the reduced effectiveness in the brain areas responsible for executive function. These findings provide evidence of the negative relationship between media multitasking and executive function; and indicated the benefits of using multiple assessment methods in studying this topic.

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PREFRONTAL CORTICAL ACTIVITY DIFFERENCES WHILE DUAL-TASK WALKING IN OLDER ADULTS WITH IMPAIRED MOBILITY

Innovation in Aging ◽

10.1093/geroni/igz038.2922 ◽

2019 ◽

Vol 3 (Supplement_1) ◽

pp. S793-S794

Author(s):

Manuel E Hernandez

Keyword(s):

Older Adults ◽

Dual Task ◽

Near Infrared ◽

Local Community ◽

Cognitive Task ◽

Mobility Impairment ◽

Functional Near Infrared Spectroscopy ◽

Mobility Impairments ◽

Prefrontal Cortical ◽

Walking Difficulty

Abstract Mobility impairments are prevalent in older adults. Whereas walking had traditionally been viewed as an autonomous process, evidence over the last decade has shown that cognitive processes such as attention and executive function have a significant impact on gait function in older adults. However, the exact neural mechanisms underlying difficulties in the control of mobility in older adults remains an open question. We examine the changes in the executive control of mobility in older adults with mobility impairments using functional near-infrared spectroscopy, as operationalized by performance in the community balance and mobility scale (CB&M). We hypothesized that prefrontal cortical (PFC) activity increases would be higher in older adults with mobility impairments, compared with older adults without mobility impairment, as dual-task walking difficulty increased. Older adults with (n=10, mean±SD age: 77±8 years, 8 females, CB&M= 58±12) and without mobility impairment (n=14, mean±SD age: 63±9 years, 11 females, CB&M= 87±6) were recruited from the local community. Dual-task walking was performed at a comfortable pace, while the difficulty of the concurrent cognitive task was increased using the modified Stroop test. PFC activity was measured using measures of oxygenated hemoglobin across the PFC. Older adults with mobility impairments demonstrated disproportionate increases in PFC activity, in comparison to those without mobility impairments, as the difficulty of the concurrent cognitive task increased (P<.001), even after controlling for age. In conclusion, these data suggest that older adults with mobility impairments may require greater attentional resources than those without mobility impairments when concurrently performing thinking and walking tasks.

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Bilingual effects on cognitive shifting and prefrontal activations in young children

International Journal of Bilingualism ◽

10.1177/1367006919880274 ◽

2019 ◽

Vol 24 (4) ◽

pp. 729-739 ◽

Cited By ~ 1

Author(s):

Yusuke Moriguchi ◽

Kanda Lertladaluck

Keyword(s):

Second Language ◽

Executive Function ◽

Young Children ◽

Near Infrared ◽

Nursery School ◽

Bilingual Children ◽

Neural Processing ◽

Language Experience ◽

Functional Near Infrared Spectroscopy ◽

Cognitive Shifting

Aims and objectives: Bilingual children constantly experience spontaneous switching between languages in everyday settings, and some researchers suggest that this experience leads to an advantage in task performance during executive function tasks. Neural processing during executive function tasks remains largely unknown, especially in young bilingual children. Methodology: Using functional near-infrared spectroscopy, this study examined whether young children who attended an immersion second-language program demonstrated enhanced cognitive shifting and lateral prefrontal activation. Data and analysis: We recruited children ( N = 24) who attended an international nursery school, and examined whether their performance on cognitive shifting, and whether the oxygenated hemoglobin changes in the prefrontal regions during the task, were correlated with the children’s second-language verbal age and the length of time the children had been speaking the second language. Findings: Results revealed that the verbal age of the second language and the length of time speaking it were significantly correlated with behavioral performances of cognitive shifting tasks. However, they were not correlated with the activations in the lateral prefrontal regions. Originality: We examined the neural correlates of bilingual effects on cognitive shifting and prefrontal activations in young children. Implications: The results suggest that second-language experience may not be directly related to neural processing in the lateral prefrontal cortex, at least in young children.

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