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

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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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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Modifications in Prefrontal Cortex Oxygenation in Linear and Curvilinear Dual Task Walking: A Combined fNIRS and IMUs Study

Sensors ◽

10.3390/s21186159 ◽

2021 ◽

Vol 21 (18) ◽

pp. 6159

Author(s):

Valeria Belluscio ◽

Gabriele Casti ◽

Marco Ferrari ◽

Valentina Quaresima ◽

Maria Sofia Sappia ◽

...

Keyword(s):

Prefrontal Cortex ◽

Dual Task ◽

Near Infrared ◽

Cognitive Task ◽

Real Life ◽

Motor Task ◽

Hemoglobin Concentration ◽

Cortical Activation ◽

Functional Near Infrared Spectroscopy ◽

Gait Quality

Increased oxygenated hemoglobin concentration of the prefrontal cortex (PFC) has been observed during linear walking, particularly when there is a high attention demand on the task, like in dual-task (DT) paradigms. Despite the knowledge that cognitive and motor demands depend on the complexity of the motor task, most studies have only focused on usual walking, while little is known for more challenging tasks, such as curved paths. To explore the relationship between cortical activation and gait biomechanics, 20 healthy young adults were asked to perform linear and curvilinear walking trajectories in single-task and DT conditions. PFC activation was assessed using functional near-infrared spectroscopy, while gait quality with four inertial measurement units. The Figure-of-8-Walk-Test was adopted as the curvilinear trajectory, with the “Serial 7s” test as concurrent cognitive task. Results show that walking along curvilinear trajectories in DT led to increased PFC activation and decreased motor performance. Under DT walking, the neural correlates of executive function and gait control tend to be modified in response to the cognitive resources imposed by the motor task. Being more representative of real-life situations, this approach to curved walking has the potential to reveal crucial information and to improve people’ s balance, safety, and life’s quality.

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36 Altered Prefrontal Cortex Responses in Older Adults with Subjective Memory Complaints and Dementia During Dual-Task Gait: An Fnirs Study

Age and Ageing ◽

10.1093/ageing/afz164.36 ◽

2019 ◽

Vol 48 (Supplement_4) ◽

pp. iv9-iv12

Author(s):

Wei-Peng Teo ◽

Timo Rantalainen ◽

Helen Macpherson

Keyword(s):

Older Adults ◽

Prefrontal Cortex ◽

Dual Task ◽

Near Infrared ◽

Single Channel ◽

Subjective Memory Complaints ◽

Medical Systems ◽

Subjective Memory ◽

Functional Near Infrared Spectroscopy ◽

Memory Complaints

Abstract In this study, we investigated the effects of walking during single-task and dual-task gait (STG and DTG) conditions, on left prefrontal cortex (LPFC) activation in older adults with subjective memory complaints (SMC) and Dementia. A total of 72 older adults (aged 65-94 yrs; 33 Healthy; 28 SMC; 11 Dementia) were recruited from the community and assisted living facilities. A portable 7m zeno walkway gait analysis mat was used to measure stride, velocity, length and duration during 4 passes of STG and DTG each. A portable single-channel functional near-infrared spectroscopy (fNIRS) device (Portalite, Artinis Medical Systems) was placed over the LPFC to measure changes in oxyhaemoglobin response (O2Hb) during STG and DTG. One-way analysis of variance (ANOVA) with bonferroni post-hoc t-test for multiple comparisons was used to determine differences between groups. Our results showed that stride velocity, duration and length during STG (all p<0.05) and DTG (all p<0.000) were significantly impaired in the Dementia group compared to Healthy and SMC groups, while no significant differences were observed between Healthy and SMC groups. For STG, a greater increase in O2Hb (p<0.05) was observed in the Dementia group compared to the Healthy and SMC groups, while no differences were observed between Healthy and SMC. However, a significant increase and decline in O2Hb was observed during DTG in the SMC and Dementia groups respectively, compared to Healthy. Our findings indicate an altered pattern of cerebral haemodynamic response of the PFC in people with SMC and Dementia that may be indicative of cognitive demands of gait. Our findings may have implications for the use of DTG and fNIRS as a potential early biomarker for cognitive declines in older adults.

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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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Effect of Heart Rate Reserve on Prefrontal Cortical Activation While Dual-Task Walking in Older Adults

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph19010047 ◽

2021 ◽

Vol 19 (1) ◽

pp. 47

Author(s):

Alka Bishnoi ◽

Gioella N. Chaparro ◽

Manuel E. Hernandez

Keyword(s):

Older Adults ◽

Heart Rate ◽

Risk Factor ◽

Cognitive Impairment ◽

Dual Task ◽

Cognitive Task ◽

Task Demands ◽

Cortical Activation ◽

Heart Rate Reserve ◽

Prefrontal Cortical

Hypertension is considered a risk factor for cardiovascular health and non-amnestic cognitive impairment in older adults. While heart rate reserve (HRR) has been shown to be a risk factor for hypertension, how impaired HRR in older adults can lead to cognitive impairment is still unclear. The objective of this study was to examine the effects of HRR on prefrontal cortical (PFC) activation under varying dual-task demands in older adults. Twenty-eight older adults (50–82 years of age) were included in this study and divided into higher (n = 14) and lower (n = 14) HRR groups. Participants engaged in the cognitive task which was the Modified Stroop Color Word Test (MSCWT) on a self-paced treadmill while walking. Participants with higher HRR demonstrated increased PFC activation in comparison to lower HRR, even after controlling for covariates in analysis. Furthermore, as cognitive task difficulty increased (from neutral to congruent to incongruent to switching), PFC activation increased. In addition, there was a significant interaction between tasks and HRR group, with older adults with higher HRR demonstrating increases in PFC activation, faster gait speed, and increased accuracy, relative to those with lower HRR, when going from neutral to switching tasks. These results provide evidence of a relationship between HRR and prefrontal cortical activation and cognitive and physical performance, suggesting that HRR may serve as a biomarker for cognitive health of an older adult with or without cardiovascular risk.

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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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Cognitive and Motor Dual Task on Multi-area Brain Activation and Gait Performance in Individuals with Parkinson’s Disease

10.21203/rs.3.rs-258545/v1 ◽

2021 ◽

Author(s):

Yan-Ci Liu ◽

Yea-Ru Yang ◽

Nai-Chen Yeh ◽

Pei-Hsin Ku ◽

Chia-Feng Lu ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Dual Task ◽

Near Infrared ◽

Cognitive Task ◽

Premotor Cortex ◽

Brain Activation ◽

Functional Near Infrared Spectroscopy ◽

Gait Performance ◽

Walking Performance

Abstract Background In people with Parkinson’s disease (PD), gait performance deteriorating during dual task walking compared to single-task walking has been noted in previous studies. However, the effects of different types of dual task on gait performance and brain activation were still unknown. Methods This study investigated the walking performance changes and multi-area brain activities during cognitive and motor dual task walking in people with PD. Twenty-eight participants with PD were recruited and performed single walking (SW), walking while performing a cognitive task (WCT), and walking while performing a motor task (WMT) at their self-selected speed. Gait performance including walking speed, cadence, stride length, stride time, swing cycle, temporal and spatial variability and dual task cost (DTC) were recorded. Brain activation of the prefrontal cortex (PFC), premotor cortex (PMC), and supplementary motor areas (SMA) were measured by functional near-infrared spectroscopy during walking. Results Results showed the walking performance deteriorated upon performing a secondary task, especially the cognitive task. Also, a higher and sustained activation in PMC and SMA during WCT as compared with WMT and SW in the late phase of walking was found. Moreover, gait performance was negatively correlated with PMC and SMA activity during different walking tasks. Conclusions Individuals with PD demonstrated gait deterioration during dual task walking, especially WCT. The SMA and PMC were further activated in people with PD when performing cognitive dual task walking. Trial registrationTCTR20190118010. Registered 18 January 2019, retrospectively registered.

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Cognitive Reserve Moderates the Efficiency of Prefrontal Cortex Activation Patterns of Gait in Older Adults

The Journals of Gerontology Series A ◽

10.1093/gerona/glab288 ◽

2021 ◽

Author(s):

Roee Holtzer ◽

Daliah Ross ◽

Catherine O’Brien ◽

Meltem Izzetoglu ◽

Mark E Wagshul

Keyword(s):

Older Adults ◽

Prefrontal Cortex ◽

Dual Task ◽

Cognitive Functions ◽

Cognitive Reserve ◽

Word Reading ◽

Cognitive Task ◽

Functional Near Infrared Spectroscopy ◽

Activation Patterns ◽

Single Task

Abstract Background Cognitive Reserve (CR) protects against cognitive decline, but whether CR influences the efficiency of cortical control of gait has not been reported. The current study addressed this important gap in the literature. Specifically, we determined the role of CR in moderating the efficiency of functional Near-Infrared-Spectroscopy (fNIRS)-derived HbO2 in the prefrontal cortex (PFC) assessed during active walking. We hypothesized that higher CR would be associated with more efficient brain activation patterns. Methods Participants were 55 (mean age=74.84; %female=49.1) older adults who underwent the combined walking/fNIRS protocol and had MRI data. We used an established dual-task walking paradigm that consisted of three task conditions: Single-Task-Walk (STW), Single-Task-Alpha (STA, cognitive task) and Dual-Task-Walk (DTW). Using the residuals approach, CR was derived from a word-reading test score by removing variance accounted for by socio-demographic variables, tests of current cognitive functions and a measure of structural brain integrity. Results CR moderated the change in fNIRS-derived HbO2 in the PFC across tasks. Higher CR was associated with smaller increases in fNIRS-derived HbO2 from the single tasks to dual task walking (CR x DTW compared to STW: estimate = .183; p < .001; CR x DTW compared to STA: estimate =.257; p < .001). The moderation effect of CR remained significant when adjusting for multiple covariates and concurrent moderation effects of measures of gait performance, current cognitive functions and structural integrity of the brain. Conclusion The current study provided first evidence that higher CR was associated with better neural efficiency of walking in older adults.

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Executive Control of Walking in People With Parkinson’s Disease With Freezing of Gait

Neurorehabilitation and Neural Repair ◽

10.1177/1545968320969940 ◽

2020 ◽

Vol 34 (12) ◽

pp. 1138-1149

Author(s):

Rodrigo Vitorio ◽

Samuel Stuart ◽

Martina Mancini

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Executive Control ◽

Dual Task ◽

Near Infrared ◽

Inertial Sensors ◽

Cognitive Task ◽

Freezing Of Gait ◽

Functional Near Infrared Spectroscopy ◽

Indirect Measures

Background Walking abnormalities in people with Parkinson’s disease (PD) are characterized by a shift in locomotor control from healthy automaticity to compensatory prefrontal executive control. Indirect measures of automaticity of walking (eg, step-to-step variability and dual-task cost) suggest that freezing of gait (FoG) may be associated with reduced automaticity of walking. However, the influence of FoG status on actual prefrontal cortex (PFC) activity during walking remains unclear. Objective To investigate the influence of FoG status on automaticity of walking in people with PD. Methods Forty-seven people with PD were distributed into 2 groups based on FoG status, which was assessed by the New Freezing of Gait Questionnaire: PD−FoG (n = 23; UPDRS-III = 35) and PD+FoG (n = 24; UPDRS-III = 43.1). Participants walked over a 9-m straight path (with a 180° turn at each end) for 80 seconds. Two conditions were tested off medication: single- and dual-task walking (ie, with a concomitant cognitive task). A portable functional near-infrared spectroscopy system recorded PFC activity while walking (including turns). Wearable inertial sensors were used to calculate spatiotemporal gait parameters. Results PD+FoG had greater PFC activation during both single and dual-task walking than PD−FoG ( P = .031). There were no differences in gait between PD−FoG and PD+FoG. Both groups decreased gait speed ( P = .029) and stride length ( P < .001) during dual-task walking compared with single-task walking. Conclusions These findings suggest that PD+FoG have reduced automaticity of walking, even in absence of FoG episodes. PFC activity while walking seems to be more sensitive than gait measures in identifying reduction in automaticity of walking in PD+FoG.

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The Effects of Perceived Pain in the Past Month on Prefrontal Cortex Activation Patterns Assessed During Cognitive and Motor Performances in Older Adults

Pain Medicine ◽

10.1093/pm/pnaa404 ◽

2020 ◽

Author(s):

Hannah Pakray ◽

Elizabeth Seng ◽

Meltem Izzetoglu ◽

Roee Holtzer

Keyword(s):

Older Adults ◽

Prefrontal Cortex ◽

Dual Task ◽

Near Infrared ◽

Pain Severity ◽

Gait Velocity ◽

Functional Near Infrared Spectroscopy ◽

Healthy Older Adults ◽

Perceived Pain ◽

Subjective Pain

Abstract Objective Pain is prevalent and functionally impactful in older adults. The prefrontal cortex is involved in pain perception, attentional control, and cortical control of locomotion. Although pain is a known moderator of attentional capacity, its moderating effect on cortical control of locomotion has not been assessed. This study aimed to examine the effects of subjective pain on changes in functional near-infrared spectroscopy–derived measurements of oxygenated hemoglobin (HbO2), gait velocity, and cognitive accuracy from single- to dual-task walking conditions among older adults. Subjects The sample consisted of 383 healthy older adults (55% female). Methods Participants completed two single tasks (Single-Task-Walk [STW] and Cognitive Interference [Alpha]) and the Dual-Task-Walk (DTW), during which participants performed the two single tasks simultaneously. The Medical Outcomes Study Pain Severity Scale and Pain Effects Scale were used to assess pain severity and interference. ProtoKinetics Movement Analysis Software was used to assess gait velocity and rate of correct letter generation to assess cognitive accuracy. Functional Near-Infrared Spectroscopy (fNIRS) was used to assess HbO2 during active walking. Results Linear mixed-effects models revealed that HbO2 increased from single- to dual-task conditions. Perceived pain presence was associated with an attenuated increase in HbO2 from Alpha to DTW. Among those with pain, worse pain severity was associated with an attenuated increase in HbO2 from STW to DTW. Pain interference did not moderate the increase in HbO2 from single to dual tasks. Pain did not have a moderating effect on behavioral outcomes. Conclusions Task-related changes in the hemodynamic response in the prefrontal cortex during walking may be a sensitive marker of the effects of subjective pain on brain function in healthy older adults.

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