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Palmer JA, Hazen EM, Billinger SA. Dual-task balance control reveals cerebrovascular-behavioral relationships in older adults resistant to cognitive decline. J Am Geriatr Soc 2024; 72:3257-3260. [PMID: 38924057 PMCID: PMC11461119 DOI: 10.1111/jgs.19049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/07/2024] [Accepted: 05/30/2024] [Indexed: 06/28/2024]
Abstract
INTRODUCTION: Age-related decline in cerebrovascular function is linked to cognitive dysfunction.1 Cognitive dual-task interference in balance control is well-known clinically and is emerging as a key risk factor for dementia and falls.2 –4 Links between cerebral blood flow, white matter hyperintensities, and dual-task performance have been found under pathologic conditions (e.g. diabetes, post-stroke).5 ,6 Physically-active older adults show an attenuated decline in cerebral blood flow compared to their sedentary peers, potentially due to exercise effects to reduce vascular stiffness and promote angiogenesis.7 However, whether variance in neurotypical age-related changes in the cerebrovascular system function play a role in the development of cognitive-balance dual-tasking are less clear. Here, we tested the hypothesis that maintaining greater cerebral blood flow velocity (CBFv), measured clinically using transcranial Doppler ultrasound, supports dual-task cognitive and balance function in older adults. We also tested the relationship between CBFv and older adults’ prioritization of balance versus cognitive performance under dual-task conditions, which has been associated with age-related disease.2 ,3 In an exploratory analyses, we tested the effect of advanced age on the relationship between CBFv and cognitive-balance dual-task interference. METHODS: Community-dwelling, cognitively-normal participants (76±4years) (n=30) completed clinical balance/cognitive testing under single-task and dual-task conditions. Balance performance was assessed as the total distance traversed during a challenging beam walking task. Cognitive performance was assessed as response time during a working-memory n-back test. Resting CBFv of the middle cerebral artery was measured using transcranial Doppler ultrasound (Supplementary Text S1 ). We tested whether CBFv was associated with single-task and dual-task interference (DTI) and prioritization of balance and cognitive performance and the effects of using multiple linear regression analyses (detailed in Supplementary Text S1 ). RESULTS: During single-tasking, higher CBFv associated with higher balance function, while no relationship was observed for cognitive performance. During dual-tasking, CBFv associated with DTI across domains of balance and cognition; for cognitive DTI, this effect was driven by individuals ≥75years (Figure 1 ) (Supplementary Text S1 ). Individuals ≥75years exhibited greater cognitive DTI, yet achieved similar balance DTI compared to those <75. Regardless of age, participants with higher CBFv demonstrated greater dual-task prioritization of balance control over cognitive performance (Figure 2 ). Notably, individuals ≥75years tended to ambulate at faster speeds on average during beam walking (25% faster, single-tasking; 13% faster, dual-tasking), but this difference was not statistically significant (Supplementary Text S1 ). DISCUSSION: These results support a link between cerebrovascular system function and cognitive-balance dual-task behavior in cognitively-normal older adults. This cerebrovascular-behavioral link may emerge earlier in brain aging processes affecting balance control compared to cognition. Further, cerebrovascular function may support people’s ability to prioritize balance in the face of competing attentional demands.
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Affiliation(s)
- Jacqueline A. Palmer
- Division of Physical Therapy and Rehabilitation Science, Medical School, University of Minnesota, Minneapolis, MN, United States of America
- Department of Neurology, School of Medicine, University of Kansas Medical Center, Kansas City, KS, United States of America
- University of Kansas Alzheimer’s Disease Research Center, Fairway, KS, United States of America
| | - Emily M. Hazen
- Department of Neurology, School of Medicine, University of Kansas Medical Center, Kansas City, KS, United States of America
| | - Sandra A. Billinger
- Department of Neurology, School of Medicine, University of Kansas Medical Center, Kansas City, KS, United States of America
- University of Kansas Alzheimer’s Disease Research Center, Fairway, KS, United States of America
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
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Palmer JA, Payne AM, Mirdamadi JL, Ting LH, Borich MR. Delayed Cortical Responses During Reactive Balance After Stroke Associated With Slower Kinetics and Clinical Balance Dysfunction. Neurorehabil Neural Repair 2024:15459683241282786. [PMID: 39328051 DOI: 10.1177/15459683241282786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2024]
Abstract
BACKGROUND Slowed balance and mobility after stroke have been well-characterized. Yet the effects of unilateral cortical lesions on whole-body neuromechanical control is poorly understood, despite increased reliance on cortical resources for balance and mobility with aging. Objective. We tested whether individuals post stroke show impaired cortical responses evoked during reactive balance, and the effect of asymmetrical interlimb contributions to balance recovery and the evoked cortical response. METHODS Using electroencephalography, we assessed cortical N1 responses evoked over fronto-midline regions (Cz) during backward support-surface perturbations loading both legs and posterior-lateral directions that preferentially load the paretic or nonparetic leg in individuals' post-stroke and age-matched controls. We tested relationships between cortical responses and clinical balance/mobility function, as well as to center of pressure (CoP) rate of rise (RoR) during balance recovery. RESULTS Cortical N1 responses were smaller and delayed after stroke (P < .047), regardless of perturbation condition. In contrast to controls, slower cortical response latencies associated with lower clinical function in stroke (Mini Balance Evaluation Systems Test: r = -.61, P = .007; Timed-Up-and-Go: r = .53, P = .024; walking speed: r = -.46, P = .055). Paretic-loaded balance recovery revealed slower CoP RoR (P = .012) that was associated with delayed cortical response latencies (r = -.70, P = .003); these relationships were not present during bilateral and nonparetic-loaded conditions, nor in the older adults control group. CONCLUSIONS Individuals after stroke may be limited in their balance ability by the slowed speed of their cortical responses to destabilization. In particular, paretic leg loading may reveal cortical response impairments that reflect reduced paretic motor capacity.
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Affiliation(s)
- Jacqueline A Palmer
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA
| | - Aiden M Payne
- Department of Psychology, College of Arts and Sciences, Florida State University, Tallahassee, FL, USA
| | - Jasmine L Mirdamadi
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA
| | - Lena H Ting
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA
- Department of Biomedical Engineering, Emory and Georgia Tech, Atlanta, GA, USA
| | - Michael R Borich
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA
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Handiru VS, Suviseshamuthu ES, Saleh S, Su H, Yue G, Allexandre D. Identifying neural correlates of balance impairment in traumatic brain injury using partial least squares correlation analysis. J Neural Eng 2024; 21:056012. [PMID: 39178907 DOI: 10.1088/1741-2552/ad7320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Accepted: 08/23/2024] [Indexed: 08/26/2024]
Abstract
Objective.Balance impairment is one of the most debilitating consequences of traumatic brain injury (TBI). To study the neurophysiological underpinnings of balance impairment, the brain functional connectivity during perturbation tasks can provide new insights. To better characterize the association between the task-relevant functional connectivity and the degree of balance deficits in TBI, the analysis needs to be performed on the data stratified based on the balance impairment. However, such stratification is not straightforward, and it warrants a data-driven approach.Approach.We conducted a study to assess the balance control using a computerized posturography platform in 17 individuals with TBI and 15 age-matched healthy controls. We stratified the TBI participants into balance-impaired and non-impaired TBI usingk-means clustering of either center of pressure (COP) displacement during a balance perturbation task or Berg Balance Scale score as a functional outcome measure. We analyzed brain functional connectivity using the imaginary part of coherence across different cortical regions in various frequency bands. These connectivity features are then studied using the mean-centered partial least squares correlation analysis, which is a multivariate statistical framework with the advantage of handling more features than the number of samples, thus making it suitable for a small-sample study.Main results.Based on the nonparametric significance testing using permutation and bootstrap procedure, we noticed that the weakened theta-band connectivity strength in the following regions of interest significantly contributed to distinguishing balance impaired from non-impaired population, regardless of the type of stratification:left middle frontal gyrus, right paracentral lobule, precuneus, andbilateral middle occipital gyri. Significance.Identifying neural regions linked to balance impairment enhances our understanding of TBI-related balance dysfunction and could inform new treatment strategies. Future work will explore the impact of balance platform training on sensorimotor and visuomotor connectivity.
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Affiliation(s)
- Vikram Shenoy Handiru
- Center for Mobility and Rehabilitation Engineering Research, Kessler Foundation, West Orange, NJ, United States of America
- Department of Physical Medicine and Rehabilitation, Rutgers University-New Jersey Medical School, Newark, NJ, United States of America
| | - Easter Selvan Suviseshamuthu
- Center for Mobility and Rehabilitation Engineering Research, Kessler Foundation, West Orange, NJ, United States of America
- Department of Physical Medicine and Rehabilitation, Rutgers University-New Jersey Medical School, Newark, NJ, United States of America
| | - Soha Saleh
- Department of Physical Medicine and Rehabilitation, Rutgers University-New Jersey Medical School, Newark, NJ, United States of America
- Department of Rehabilitation and Movement Sciences, School of Health Professions, Rutgers University, Newark, NJ 07107, United States of America
- Department of Neurology, Rutgers University, Newark, NJ 07101, United States of America
- Brain Health Institute, Rutgers University, Piscataway, NJ 08854, United States of America
| | - Haiyan Su
- School of Computing, Montclair State University, Montclair, NJ, United States of America
| | - Guang Yue
- Center for Mobility and Rehabilitation Engineering Research, Kessler Foundation, West Orange, NJ, United States of America
- Department of Physical Medicine and Rehabilitation, Rutgers University-New Jersey Medical School, Newark, NJ, United States of America
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Chen YC, Tsai YY, Huang WM, Zhao CG, Hwang IS. Age-Related Topological Organization of Phase-Amplitude Coupling Between Postural Fluctuations and Scalp EEG During Unsteady Stance. IEEE Trans Neural Syst Rehabil Eng 2024; 32:3231-3239. [PMID: 39196741 DOI: 10.1109/tnsre.2024.3451023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2024]
Abstract
Through phase-amplitude analysis, this study investigated how low-frequency postural fluctuations interact with high-frequency scalp electroencephalography (EEG) amplitudes, shedding light on age-related mechanic differences in balance control during uneven surface navigation. Twenty young ( 24.1 ± 1.9 years) and twenty older adults ( 66.2 ± 2.7 years) stood on a training stabilometer with visual guidance, while their scalp EEG and stabilometer plate movements were monitored. In addition to analyzing the dynamics of the postural fluctuation phase, phase-amplitude coupling (PAC) for postural fluctuations below 2 Hz and within EEG sub-bands (theta: 4-7 Hz, alpha: 8-12 Hz, beta: 13-35 Hz) was calculated. The results indicated that older adults exhibited significantly larger postural fluctuation amplitudes(p <0.001) and lower mean frequencies of the postural fluctuation phase ( p = 0.005 ) than young adults. The PAC between postural fluctuation and theta EEG (FCz and bilateral temporal-parietal-occipital area), as well as that between postural fluctuation and alpha EEG oscillation, was lower in older adults than in young adults (p <0.05). In contrast, the PAC between the phase of postural fluctuation and beta EEG oscillation, particularly in C3 ( p=0.006 ), was higher in older adults than in young adults. In summary, the postural fluctuation phase and phase-amplitude coupling between postural fluctuation and EEG are sensitive indicators of the age-related decline in postural adjustments, reflecting less flexible motor state transitions and adaptive changes in error monitoring and visuospatial attention.
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Jakubowski KL, Martino G, Beck ON, Sawicki GS, Ting LH. Center of mass states render multi-joint torques throughout standing balance recovery. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.14.607976. [PMID: 39229207 PMCID: PMC11370471 DOI: 10.1101/2024.08.14.607976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Successful reactive balance control requires coordinated modulation of hip, knee, and ankle torques. Stabilizing joint torques arise from feedforward neural signals that modulate the musculoskeletal system's intrinsic mechanical properties, namely muscle short-range stiffness, and neural feedback pathways that activate muscles in response to sensory input. Although feedforward and feedback pathways are known to modulate the torque at each joint, the role of each pathway to the balance-correcting response across joints is poorly understood. Since the feedforward and feedback torque responses act at different delays following perturbations to balance, we modified the sensorimotor response model (SRM), previously used to analyze the muscle activation response to perturbations, to consist of parallel feedback loops with different delays. Each loop within the model is driven by the same information, center of mass (CoM) kinematics, but each loop has an independent delay. We evaluated if a parallel loop SRM could decompose the reactive torques into the feedforward and feedback contributions during balance-correcting responses to backward support surface translations at four magnitudes. The SRM accurately reconstructed reactive joint torques at the hip, knee, and ankle, across all perturbation magnitudes (R 2 >0.84 & VAF>0.83). Moreover, the hip and knee exhibited feedforward and feedback components, while the ankle only exhibited feedback components. The lack of a feedforward component at the ankle may occur because the compliance of the Achilles tendon attenuates muscle short-range stiffness. Our model may provide a framework for evaluating changes in the feedforward and feedback contributions to balance that occur due to aging, injury, or disease. NEWS AND NOTEWORTHY Reactive balance control requires coordination of neurally-mediated feedforward and feedback pathways to generate stabilizing joint torques at the hip, knee, and ankle. Using a sensorimotor response model, we decomposed reactive joint torques into feedforward and feedback contributions based on delays relative to center of mass kinematics. Responses across joints were driven by the same signals, but contributions from feedforward versus feedback pathways differed, likely due to differences in musculotendon properties between proximal and distal muscles.
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Chen YC, Lo IP, Tsai YY, Zhao CG, Hwang IS. Dual-task improvement of older adults after treadmill walking combined with blood flow restriction of low occlusion pressure: the effect on the heart-brain axis. J Neuroeng Rehabil 2024; 21:116. [PMID: 38997727 PMCID: PMC11241870 DOI: 10.1186/s12984-024-01412-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 06/23/2024] [Indexed: 07/14/2024] Open
Abstract
OBJECTIVE This study explored the impact of one session of low-pressure leg blood flow restriction (BFR) during treadmill walking on dual-task performance in older adults using the neurovisceral integration model framework. METHODS Twenty-seven older adults participated in 20-min treadmill sessions, either with BFR (100 mmHg cuff pressure on both thighs) or without it (NBFR). Dual-task performance, measured through light-pod tapping while standing on foam, and heart rate variability during treadmill walking were compared. RESULTS Following BFR treadmill walking, the reaction time (p = 0.002) and sway area (p = 0.012) of the posture dual-task were significantly reduced. Participants exhibited a lower mean heart rate (p < 0.001) and higher heart rate variability (p = 0.038) during BFR treadmill walking. Notably, BFR also led to band-specific reductions in regional brain activities (theta, alpha, and beta bands, p < 0.05). The topology of the EEG network in the theta and alpha bands became more star-like in the post-test after BFR treadmill walking (p < 0.005). CONCLUSION BFR treadmill walking improves dual-task performance in older adults via vagally-mediated network integration with superior neural economy. This approach has the potential to prevent age-related falls by promoting cognitive reserves.
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Affiliation(s)
- Yi-Ching Chen
- Department of Physical Therapy, College of Medical Science and Technology, Chung Shan Medical University, Taichung City, Taiwan
- Physical Therapy Room, Chung Shan Medical University Hospital, Taichung City, Taiwan
| | - I-Ping Lo
- Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan City, 701, Taiwan
| | - Yi-Ying Tsai
- Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan City, 701, Taiwan
| | - Chen-Guang Zhao
- Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan City, 701, Taiwan
| | - Ing-Shiou Hwang
- Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan City, 701, Taiwan.
- Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan City, Taiwan.
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Pan J, Zhang S. Dual-Task Effect on Center of Pressure Oscillations and Prefrontal Cortex Activation Between Young and Older Adults. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2024:1-11. [PMID: 38986156 DOI: 10.1080/02701367.2024.2365940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 05/31/2024] [Indexed: 07/12/2024]
Abstract
Purpose: This study aimed to investigate the dual-task effect on conventional center of pressure (CoP) outcomes, CoP oscillations, and prefrontal cortex (PFC) activation between young and older adults. Methods: Fourteen healthy older adults (age: 66.25 ± 3.43 years) and another fourteen gender-matched young adults (age: 19.80 ± 0.75 years) participated in this study. Participants completed single-task and dual-task standing trials in a fixed order. The displacement of CoP and PFC activation were recorded using a Force plate and a functional near-infrared spectroscopy system, respectively. Two-way MANOVAs were used to examine the group and task effects. Additionally, the Pearson correlation analyses were used to investigate the relationship between CoP oscillations and PFC activation. Results: Our results showed a worse balance performance, greater CoP oscillations of 0-0.1 (11.03 ± 8.24 vs. 23.20 ± 12.54 cm2) and 0.1-0.5 (13.62 ± 9.30 vs. 30.00 ± 23.12 cm2) Hz in the medial-lateral direction and higher right (dorsomedial: -0.0003 ± 0.021 vs. 0.021 ± 0.021 & ventrolateral: 0.0087 ± 0.047 vs. 0.025 ± 0.045 mol/ml) and left (dorsomedial: 0.0033 ± 0.024 vs. 0.020 ± 0.025 & ventrolateral: 0.0060 ± 0.037 vs. 0.034 ± 0.037 mol/ml) PFC activation in response to a secondary cognitive task in older adults (p < .05). Older adults also showed significant positive correlations between CoP oscillations in the anterior-posterior direction and PFC activation under the single-task standing. Conclusion: These results suggest that older adults presented a loss of postural automaticity contributing to cognitive dysfunction. Moreover, heightened CoP oscillations at 0-0.5 Hz in response to a secondary cognitive task could provide evidence of a loss of automaticity, which might be associated with a greater reliance on the sensory inputs.
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Mirdamadi JL, Ting LH, Borich MR. Distinct Cortical Correlates of Perception and Motor Function in Balance Control. J Neurosci 2024; 44:e1520232024. [PMID: 38413231 PMCID: PMC11007305 DOI: 10.1523/jneurosci.1520-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 02/07/2024] [Accepted: 02/14/2024] [Indexed: 02/29/2024] Open
Abstract
Fluctuations in brain activity alter how we perceive our body and generate movements but have not been investigated in functional whole-body behaviors. During reactive balance, we recently showed that evoked brain activity is associated with the balance ability in young individuals. Furthermore, in PD, impaired whole-body motion perception in reactive balance is associated with impaired balance. Here, we investigated the brain activity during the whole-body motion perception in reactive balance in young adults (9 female, 10 male). We hypothesized that both ongoing and evoked cortical activity influences the efficiency of information processing for successful perception and movement during whole-body behaviors. We characterized two cortical signals using electroencephalography localized to the SMA: (1) the "N1," a perturbation-evoked potential that decreases in amplitude with expectancy and is larger in individuals with lower balance function, and (2) preperturbation β power, a transient rhythm that favors maintenance of the current sensorimotor state and is inversely associated with tactile perception. In a two-alternative forced choice task, participants judged whether pairs of backward support surface perturbations during standing were in the "same" or "different" direction. As expected, lower whole-body perception was associated with lower balance ability. Within a perturbation pair, N1 attenuation was larger on correctly perceived trials and associated with better balance, but not perception. In contrast, preperturbation β power was higher on incorrectly perceived trials and associated with poorer perception, but not balance. Together, ongoing and evoked cortical activity have unique roles in information processing that give rise to distinct associations with perceptual and balance ability.
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Affiliation(s)
- Jasmine L Mirdamadi
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Lena H Ting
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, Georgia 30322
- The Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, Georgia 30322
| | - Michael R Borich
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, Georgia 30322
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Huang HJ, Ferris DP. Non-invasive brain imaging to advance the understanding of human balance. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2023; 28:100505. [PMID: 38250696 PMCID: PMC10795750 DOI: 10.1016/j.cobme.2023.100505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Affiliation(s)
- Helen J. Huang
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, FL, USA
- Disability, Aging, and Technology Cluster, University of Central Florida, Orlando, FL, USA
- Biionix (Bionic Materials, Implants & Interfaces) Cluster, University of Central Florida, Orlando, FL, USA
| | - Daniel P. Ferris
- J. Crayton Pruitt Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA
- Department of Neurology, University of Florida, Gainesville, FL, USA
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Palmer JA, Payne AM, Mirdamadi JL, Ting LH, Borich MR. Delayed cortical engagement associated with balance dysfunction after stroke. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.11.28.23299035. [PMID: 38076827 PMCID: PMC10705625 DOI: 10.1101/2023.11.28.23299035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Cortical resources are typically engaged for balance and mobility in older adults, but these resources are impaired post-stroke. Although slowed balance and mobility after stroke have been well-characterized, the effects of unilateral cortical lesions due to stroke on neuromechanical control of balance is poorly understood. Our central hypothesis is that stroke impairs the ability to rapidly and effectively engage the cerebral cortex during balance and mobility behaviors, resulting in asymmetrical contributions of each limb to balance control. Using electroencephalography (EEG), we assessed cortical N1 responses evoked over fronto-midline regions (Cz) during balance recovery in response to backward support-surface perturbations loading both legs, as well as posterior-lateral directions that preferentially load the paretic or nonparetic leg. Cortical N1 responses were smaller and delayed in the stroke group. While older adults exhibited weak or absent relationships between cortical responses and clinical function, stroke survivors exhibited strong associations between slower N1 latencies and slower walking, lower clinical mobility, and lower balance function. We further assessed kinetics of balance recovery during perturbations using center of pressure rate of rise. During backward support-surface perturbations that loaded the legs bilaterally, balance recovery kinetics were not different between stroke and control groups and were not associated with cortical response latency. However, lateralized perturbations revealed slower kinetic reactions during paretic loading compared to controls, and to non-paretic loading within stroke participants. Individuals post stroke had similar nonparetic-loaded kinetic reactions to controls implicating that they effectively compensate for impaired paretic leg kinetics when relying on the non-paretic leg. In contrast, paretic-loaded balance recovery revealed time-synchronized associations between slower cortical responses and slower kinetic reactions only in the stroke group, potentially reflecting the limits of cortical engagement for balance recovery revealed within the behavioral context of paretic motor capacity. Overall, our results implicate individuals after stroke may be uniquely limited in their balance ability by the slowed speed of their cortical engagement, particularly under challenging balance conditions that rely on the paretic leg. We expect this neuromechanical insight will enable progress toward an individualized framework for the assessment and treatment of balance impairments based on the interaction between neuropathology and behavioral context.
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Affiliation(s)
- Jacqueline A Palmer
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, 1441 Clifton Road NE, Atlanta, GA 30322 USA
| | - Aiden M Payne
- Department of Psychology, College of Arts and Sciences, Florida State University, Tallahassee, FL, USA
| | - Jasmine L Mirdamadi
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, 1441 Clifton Road NE, Atlanta, GA 30322 USA
| | - Lena H Ting
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, 1441 Clifton Road NE, Atlanta, GA 30322 USA
- Department of Biomedical Engineering, Emory and Georgia Tech, 1760 Haygood Road, Atlanta, GA, 30322, USA
| | - Michael R Borich
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, 1441 Clifton Road NE, Atlanta, GA 30322 USA
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Martino G, Beck ON, Ting LH. Voluntary muscle coactivation in quiet standing elicits reciprocal rather than coactive agonist-antagonist control of reactive balance. J Neurophysiol 2023; 129:1378-1388. [PMID: 37162064 PMCID: PMC10259861 DOI: 10.1152/jn.00458.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 04/04/2023] [Accepted: 05/06/2023] [Indexed: 05/11/2023] Open
Abstract
Muscle coactivation increases in challenging balance conditions as well as with advanced age and mobility impairments. Increased muscle coactivation can occur both in anticipation of (feedforward) and in reaction to (feedback) perturbations, however, the causal relationship between feedforward and feedback muscle coactivation remains elusive. Here, we hypothesized that feedforward muscle coactivation would increase both the body's initial mechanical resistance due to muscle intrinsic properties and the later feedback-mediated muscle coactivation in response to postural perturbations. Young adults voluntarily increased leg muscle coactivation using visual biofeedback before support-surface perturbations. In contrast to our hypothesis, feedforward muscle coactivation did not increase the body's initial intrinsic resistance to perturbations, nor did it increase feedback muscle coactivation. Rather, perturbations with feedforward muscle coactivation elicited a medium- to long-latency increase of feedback-mediated agonist activity but a decrease of feedback-mediated antagonist activity. This reciprocal rather than coactivation effect on ankle agonist and antagonist muscles enabled faster reactive ankle torque generation, reduced ankle dorsiflexion, and reduced center of mass (CoM) motion. We conclude that in young adults, voluntary feedforward muscle coactivation can be independently modulated with respect to feedback-mediated muscle coactivation. Furthermore, our findings suggest feedforward muscle coactivation may be useful for enabling quicker joint torque generation through reciprocal, rather than coactivated, agonist-antagonist feedback muscle activity. As such our results suggest that behavioral context is critical to whether muscle coactivation functions to increase agility versus stability.NEW & NOTEWORTHY Feedforward and feedback muscle coactivation are commonly observed in older and mobility impaired adults and are considered strategies to improve stability by increasing body stiffness prior to and in response to perturbations. In young adults, voluntary feedforward coactivation does not necessarily increase feedback coactivation in response to perturbations. Instead, feedforward coactivation enabled faster ankle torques through reciprocal agonist-antagonist muscle activity. As such, coactivation may promote either agility or stability depending on the behavioral context.
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Affiliation(s)
- Giovanni Martino
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Tech, Atlanta, Georgia, United States
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Owen N Beck
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Tech, Atlanta, Georgia, United States
- Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas, United States
| | - Lena H Ting
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Tech, Atlanta, Georgia, United States
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, Georgia, United States
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12
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Beck ON, Shepherd MK, Rastogi R, Martino G, Ting LH, Sawicki GS. Exoskeletons need to react faster than physiological responses to improve standing balance. Sci Robot 2023; 8:eadf1080. [PMID: 36791215 PMCID: PMC10169237 DOI: 10.1126/scirobotics.adf1080] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Maintaining balance throughout daily activities is challenging because of the unstable nature of the human body. For instance, a person's delayed reaction times limit their ability to restore balance after disturbances. Wearable exoskeletons have the potential to enhance user balance after a disturbance by reacting faster than physiologically possible. However, "artificially fast" balance-correcting exoskeleton torque may interfere with the user's ensuing physiological responses, consequently hindering the overall reactive balance response. Here, we show that exoskeletons need to react faster than physiological responses to improve standing balance after postural perturbations. Delivering ankle exoskeleton torque before the onset of physiological reactive joint moments improved standing balance by 9%, whereas delaying torque onset to coincide with that of physiological reactive ankle moments did not. In addition, artificially fast exoskeleton torque disrupted the ankle mechanics that generate initial local sensory feedback, but the initial reactive soleus muscle activity was only reduced by 18% versus baseline. More variance of the initial reactive soleus muscle activity was accounted for using delayed and scaled whole-body mechanics [specifically center of mass (CoM) velocity] versus local ankle-or soleus fascicle-mechanics, supporting the notion that reactive muscle activity is commanded to achieve task-level goals, such as maintaining balance. Together, to elicit symbiotic human-exoskeleton balance control, device torque may need to be informed by mechanical estimates of global sensory feedback, such as CoM kinematics, that precede physiological responses.
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Affiliation(s)
- Owen N Beck
- Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, USA.,Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, USA
| | - Max K Shepherd
- Department of Physical Therapy and Rehabilitation Science, Northeastern University, Boston, MA, USA.,Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, USA
| | - Rish Rastogi
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, USA
| | - Giovanni Martino
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, USA
| | - Lena H Ting
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, USA.,Department of Rehabilitation Medicine, Division of Physical Therapy, Emory University, Atlanta, GA, USA
| | - Gregory S Sawicki
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
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13
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Rogan S, Taeymans J. Effects of stochastic resonance whole-body vibration on sensorimotor function in elderly individuals-A systematic review. Front Sports Act Living 2023; 5:1083617. [PMID: 37139302 PMCID: PMC10149870 DOI: 10.3389/fspor.2023.1083617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 03/27/2023] [Indexed: 05/05/2023] Open
Abstract
Introduction Due to demographic changes, falls are increasingly becoming a focus of health care. It is known that within six months after a fall, two thirds of fallers will fall again. Therefore, therapeutic procedures to improve balance that are simple and can be performed in a short time are needed. Stochastic resonance whole-body vibration (SR-WBV) may be such a procedure. Method An electronic search to assess the effectiveness of SR-WBV on balance in the elderly was conducted using databases that included CINAHL Cochrane, PEDro, and PubMed. Included studies were assessed using the Collaboration Risk of Bias Tool by two independent reviewers. Results Nine studies showing moderate methodological quality were included. Treatment parameters were heterogeneous. Vibration frequency ranged from 1 to 12 Hz. Six studies found statistically significant improvements of balance from baseline to post measurement after SR-WBV interventions. One article found clinical relevance of the improvement in total time of the "Expanded Time to Get Up and Go Test". Discussion Physiological adaptations after balance training are specific and may explain some of the observed heterogeneity. Two out of nine studies assessed reactive balance and both indicated statistically significant improvements after SR-WBV. Therefore, SR-WBV represents a reactive balance training.
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Affiliation(s)
- Slavko Rogan
- Department of Health, Discipline of Physiotherapy, Bern University of Applied Sciences, Bern, Switzerland
- Correspondence: Slavko Rogan
| | - Jan Taeymans
- Department of Health, Discipline of Physiotherapy, Bern University of Applied Sciences, Bern, Switzerland
- Faculty of Physical Education and Physiotherapy, Free University of Brussels, Brussels, Belgium
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14
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Purohit R, Bhatt T. Mobile Brain Imaging to Examine Task-Related Cortical Correlates of Reactive Balance: A Systematic Review. Brain Sci 2022; 12:1487. [PMID: 36358413 PMCID: PMC9688648 DOI: 10.3390/brainsci12111487] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/23/2022] [Accepted: 10/25/2022] [Indexed: 02/18/2024] Open
Abstract
This systematic review examined available findings on spatial and temporal characteristics of cortical activity in response to unpredicted mechanical perturbations. Secondly, this review investigated associations between cortical activity and behavioral/biomechanical measures. Databases were searched from 1980-2021 and a total of 35 cross-sectional studies (31 EEG and 4 fNIRS) were included. Majority of EEG studies assessed perturbation-evoked potentials (PEPs), whereas other studies assessed changes in cortical frequencies. Further, fNIRS studies assessed hemodynamic changes. The PEP-N1, commonly identified at sensorimotor areas, was most examined and was influenced by context prediction, perturbation magnitude, motor adaptation and age. Other PEPs were identified at frontal, parietal and sensorimotor areas and were influenced by task position. Further, changes in cortical frequencies were observed at prefrontal, sensorimotor and parietal areas and were influenced by task difficulty. Lastly, hemodynamic changes were observed at prefrontal and frontal areas and were influenced by task prediction. Limited studies reported associations between cortical and behavioral outcomes. This review provided evidence regarding the involvement of cerebral cortex for sensory processing of unpredicted perturbations, error-detection of expected versus actual postural state, and planning and execution of compensatory stepping responses. There is still limited evidence examining cortical activity during reactive balance tasks in populations with high fall-risk.
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Affiliation(s)
- Rudri Purohit
- Department of Physical Therapy, University of Illinois at Chicago, Chicago, IL 60612, USA
- Ph.D. Program in Rehabilitation Sciences, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Tanvi Bhatt
- Department of Physical Therapy, University of Illinois at Chicago, Chicago, IL 60612, USA
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15
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Payne AM, McKay JL, Ting LH. The cortical N1 response to balance perturbation is associated with balance and cognitive function in different ways between older adults with and without Parkinson's disease. Cereb Cortex Commun 2022; 3:tgac030. [PMID: 36043162 PMCID: PMC9415190 DOI: 10.1093/texcom/tgac030] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 06/28/2022] [Accepted: 07/05/2022] [Indexed: 12/02/2022] Open
Abstract
Mechanisms underlying associations between balance and cognitive impairments in older adults with and without Parkinson's disease are poorly understood. Balance disturbances evoke a cortical N1 response that is associated with both balance and cognitive abilities in unimpaired populations. We hypothesized that the N1 response reflects neural mechanisms that are shared between balance and cognitive function, and would therefore be associated with both balance and cognitive impairments in Parkinson's disease. Although N1 responses did not differ at the group level, they showed different associations with balance and cognitive function in the Parkinson's disease vs. control groups. In the control group, higher N1 amplitudes were correlated with lower cognitive set shifting ability and lower balance confidence. However, in Parkinson's disease, narrower N1 widths (i.e., shorter durations) were associated with greater parkinsonian motor symptom severity, lower balance ability and confidence, lower mobility, and lower overall cognitive function. Despite different relationships across populations, the present results suggest the N1 response reflects neural processes related to both balance and cognitive function. A better understanding of neural mechanisms linking balance and cognitive function could provide insight into associations between balance and cognitive decline in aging populations.
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Affiliation(s)
- Aiden M Payne
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Tech, Atlanta, GA 30332, USA
| | - J Lucas McKay
- Department of Biomedical Informatics, Emory University School of Medicine, Atlanta, GA 30322, USA,Jean & Paul Amos Parkinson’s Disease & Movement Disorders Program, Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Lena H Ting
- Corresponding author: Lena H. Ting, Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, 1441 Clifton Rd, Rm R225, Atlanta, GA 30322, USA.
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16
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Palmer JA, Kaufman CS, Vidoni ED, Honea RA, Burns JM, Billinger SA. Cerebrovascular response to exercise interacts with individual genotype and amyloid-beta deposition to influence response inhibition with aging. Neurobiol Aging 2022; 114:15-26. [DOI: 10.1016/j.neurobiolaging.2022.02.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 02/23/2022] [Accepted: 02/24/2022] [Indexed: 12/23/2022]
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17
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Monaghan AS, Johansson H, Torres A, Brewer GA, Peterson DS. The impact of divided attention on automatic postural responses: A systematic review and meta-analysis. Exp Gerontol 2022; 162:111759. [PMID: 35245641 DOI: 10.1016/j.exger.2022.111759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/23/2022] [Accepted: 02/25/2022] [Indexed: 11/28/2022]
Abstract
Quick responses to a loss of balance or "automatic postural responses" (APRs) are critical for fall prevention. The addition of a distracting task- dual-tasking (DT), typically worsens performance on mobility tasks. However, the effect of DT on APRs is unclear. We conducted a systematic review and meta-analyses to examine the effects of DT on spatial, temporal, and neuromuscular components of APRs and the effect of DT on cognitive performance. A Meta-analysis of 19 cohorts (n = 329) showed significant worsening in spatial kinematic features of APRs under DT conditions (P = 0.01), and a meta-analysis of 9 cohorts (n = 123) demonstrated later muscle onset during DT (P = 0.003). No significant DT effect was observed for temporal kinematic outcomes in 18 cohorts (n = 328; P = 0.47). Finally, significant declines in cognitive performance were evident in 20 cohorts (n = 400; P = 0.002). These results indicate that, despite the somewhat reactive nature of APRs, the addition of a secondary task negatively impacts some aspects of the response. These findings underscore the importance of cortical structures in APR generation. Given the importance of APRs for falls, identifying aspects of APRs that are altered under DT may inform fall-prevention treatment approaches.
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Affiliation(s)
- Andrew S Monaghan
- College of Health Solutions, Arizona State University, N 5th St. Phoenix, AZ 85282, USA.
| | - Hanna Johansson
- Department of Neurobiology, Care Sciences and Society, Division of Physiotherapy, Karolinska Institutet, Alfred Nobels Allé 23, 141 83 Huddinge, Stockholm, Sweden.
| | - Alexis Torres
- Department of Psychology, Arizona State University, 950 S McAllister Ave, Tempe, AZ, USA.
| | - Gene A Brewer
- Department of Psychology, Arizona State University, 950 S McAllister Ave, Tempe, AZ, USA.
| | - Daniel S Peterson
- College of Health Solutions, Arizona State University, N 5th St. Phoenix, AZ 85282, USA; Phoenix VA Health Care Center, 650 E Indian School Rd, Phoenix, AZ, USA.
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18
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Cortical reorganization to improve dynamic balance control with error amplification feedback. J Neuroeng Rehabil 2022; 19:3. [PMID: 35034661 PMCID: PMC8762892 DOI: 10.1186/s12984-022-00980-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 12/29/2021] [Indexed: 11/21/2022] Open
Abstract
Background Error amplification (EA), virtually magnify task errors in visual feedback, is a potential neurocognitive approach to facilitate motor performance. With regional activities and inter-regional connectivity of electroencephalography (EEG), this study investigated underlying cortical mechanisms associated with improvement of postural balance using EA. Methods Eighteen healthy young participants maintained postural stability on a stabilometer, guided by two visual feedbacks (error amplification (EA) vs. real error (RE)), while stabilometer plate movement and scalp EEG were recorded. Plate dynamics, including root mean square (RMS), sample entropy (SampEn), and mean frequency (MF) were used to characterize behavioral strategies. Regional cortical activity and inter-regional connectivity of EEG sub-bands were characterized to infer neural control with relative power and phase-lag index (PLI), respectively. Results In contrast to RE, EA magnified the errors in the visual feedback to twice its size during stabilometer stance. The results showed that EA led to smaller RMS of postural fluctuations with greater SampEn and MF than RE did. Compared with RE, EA altered cortical organizations with greater regional powers in the mid-frontal cluster (theta, 4–7 Hz), occipital cluster (alpha, 8–12 Hz), and left temporal cluster (beta, 13–35 Hz). In terms of the phase-lag index of EEG between electrode pairs, EA significantly reduced long-range prefrontal-parietal and prefrontal-occipital connectivity of the alpha/beta bands, and the right tempo-parietal connectivity of the theta/alpha bands. Alternatively, EA augmented the fronto-centro-parietal connectivity of the theta/alpha bands, along with the right temporo-frontal and temporo-parietal connectivity of the beta band. Conclusion EA alters postural strategies to improve stance stability on a stabilometer with visual feedback, attributable to enhanced error processing and attentional release for target localization. This study provides supporting neural correlates for the use of virtual reality with EA during balance training.
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Barollo F, Hassan M, Petersen H, Rigoni I, Ramon C, Gargiulo P, Fratini A. Cortical pathways during Postural Control: new insights from functional EEG source connectivity. IEEE Trans Neural Syst Rehabil Eng 2022; 30:72-84. [PMID: 34990367 DOI: 10.1109/tnsre.2022.3140888] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Postural control is a complex feedback system that relies on vast array of sensory inputs in order to maintain a stable upright stance. The brain cortex plays a crucial role in the processing of this information and in the elaboration of a successful adaptive strategy to external stimulation preventing loss of balance and falls. In the present work, the participants postural control system was challenged by disrupting the upright stance via a mechanical skeletal muscle vibration applied to the calves. The EEG source connectivity method was used to investigate the cortical response to the external stimulation and highlight the brain network primarily involved in high-level coordination of the postural control system. The cortical network reconfiguration was assessed during two experimental conditions of eyes open and eyes closed and the network flexibility (i.e. its dynamic reconfiguration over time) was correlated with the sample entropy of the stabilogram sway. The results highlight two different cortical strategies in the alpha band: the predominance of frontal lobe connections during open eyes and the strengthening of temporal-parietal network connections in the absence of visual cues. Furthermore, a high correlation emerges between the flexibility in the regions surrounding the right temporo-parietal junction and the sample entropy of the CoP sway, suggesting their centrality in the postural control system. These results open the possibility to employ network-based flexibility metrics as markers of a healthy postural control system, with implications in the diagnosis and treatment of postural impairing diseases.
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20
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Payne AM, Palmer JA, McKay JL, Ting LH. Lower Cognitive Set Shifting Ability Is Associated With Stiffer Balance Recovery Behavior and Larger Perturbation-Evoked Cortical Responses in Older Adults. Front Aging Neurosci 2021; 13:742243. [PMID: 34938171 PMCID: PMC8685437 DOI: 10.3389/fnagi.2021.742243] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 11/16/2021] [Indexed: 11/25/2022] Open
Abstract
The mechanisms underlying associations between cognitive set shifting impairments and balance dysfunction are unclear. Cognitive set shifting refers to the ability to flexibly adjust behavior to changes in task rules or contexts, which could be involved in flexibly adjusting balance recovery behavior to different contexts, such as the direction the body is falling. Prior studies found associations between cognitive set shifting impairments and severe balance dysfunction in populations experiencing frequent falls. The objective of this study was to test whether cognitive set shifting ability is expressed in successful balance recovery behavior in older adults with high clinical balance ability (N = 19, 71 ± 7 years, 6 female). We measured cognitive set shifting ability using the Trail Making Test and clinical balance ability using the miniBESTest. For most participants, cognitive set shifting performance (Trail Making Test B-A = 37 ± 20 s) was faster than normative averages (46 s for comparable age and education levels), and balance ability scores (miniBESTest = 25 ± 2/28) were above the threshold for fall risk (23 for people between 70 and 80 years). Reactive balance recovery in response to support-surface translations in anterior and posterior directions was assessed in terms of body motion, muscle activity, and brain activity. Across participants, lower cognitive set shifting ability was associated with smaller peak center of mass displacement during balance recovery, lower directional specificity of late phase balance-correcting muscle activity (i.e., greater antagonist muscle activity 200-300 ms after perturbation onset), and larger cortical N1 responses (100-200 ms). None of these measures were associated with clinical balance ability. Our results suggest that cognitive set shifting ability is expressed in balance recovery behavior even in the absence of profound clinical balance disability. Specifically, our results suggest that lower flexibility in cognitive task performance is associated with lower ability to incorporate the directional context into the cortically mediated later phase of the motor response. The resulting antagonist activity and stiffer balance behavior may help explain associations between cognitive set shifting impairments and frequent falls.
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Affiliation(s)
- Aiden M. Payne
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Tech, Atlanta, GA, United States
| | - Jacqueline A. Palmer
- Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, United States
| | - J. Lucas McKay
- Department of Biomedical Informatics, Emory University School of Medicine, Atlanta, GA, United States,Jean and Paul Amos PD and Movement Disorders Program, Department of Neurology, Emory University School of Medicine, Atlanta, GA, United States
| | - Lena H. Ting
- Wallace H. Coulter Department of Biomedical Engineering, Emory University and Georgia Tech, Atlanta, GA, United States,Division of Physical Therapy, Department of Rehabilitation Medicine, Emory University, Atlanta, GA, United States,*Correspondence: Lena H. Ting,
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21
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Obstacle avoidance movement-related motor cortical activity with cognitive task. Exp Brain Res 2021; 240:421-428. [PMID: 34775531 DOI: 10.1007/s00221-021-06268-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 11/02/2021] [Indexed: 10/19/2022]
Abstract
Lack of attention to obstacles on the floor or walking path may cause trip and fall accidents. The preparatory activity in the motor cortex to the perturbation associated with obstacle avoidance movements with cognitive task is still unclear. The purpose of this study was to investigate the motor cortical activity involved in the preparation and execution of concurrent obstacle avoidance movement and cognitive task. Twenty young adults were required to step over obstacles that were projected on the floor while performing a cognitive task. The electroencephalogram was recorded, and the movement-related cortical potentials (MRCP) aligned by foot dorsiflexion were evaluated. There was no significant difference in the number of contacts between the toe and the obstacle between the obstacle avoidance task and obstacle avoidance with cognitive task; however, the distance between the toe and the obstacle just before obstacle avoidance movement was significantly extended in the latter task. The amplitude and the onset of MRCP during the dual task were decreased and delayed, respectively, compared with the simple obstacle avoidance movement task. These results suggest that the young participants changed their clearance strategy to stepping over the obstacle during the concurrent motor and cognitive dual task to reduce motor cortical activity.
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