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Jiang P, Gao Y, Zhang L, Jiang L, Li C. Causal associations of fatigue and functional outcome after ischemic stroke: a mediation Mendelian randomization study. Front Neurol 2024; 15:1415553. [PMID: 39119558 PMCID: PMC11306070 DOI: 10.3389/fneur.2024.1415553] [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: 04/10/2024] [Accepted: 07/16/2024] [Indexed: 08/10/2024] Open
Abstract
Background and objectives Fatigue has been associated with adverse effects on recovery from ischemic stroke based on previous observational research. The purpose of our study was to explore the potential causal association of fatigue with poor functional outcome after ischemic stroke by employing Mendelian randomization (MR). Methods A set of instrumental variables, comprising 36 single-nucleotide polymorphisms (SNPs) that are only related to fatigue, were derived from a genome-wide association study (GWAS) that included 449,019 general individuals. The functional outcomes after ischemic stroke were derived from a GWAS (Genetics of Ischemic Stroke Functional Outcome Network) involving 6,021 survivors. Two-sample MR methods were used to assess the causal effect, including inverse variance weighted, MR-Egger, weighted median, simple mode, and weighted mode. In bidirectional MR analysis, the reverse causal association was analyzed using the Wald ratio method. The mediation effects of lipid metabolites were analyzed using two-step MR analysis. Results Genetic liability to fatigue was causally associated with the poor functional outcome (modified Rankin Scale ≥3 at 3 months) after ischemic stroke (OR = 4.20, 95%CI [1.11-15.99], p < 0.05). However, genetic predicted poor functional outcome after ischemic stroke was not associated with fatigue (OR = 1.00, 95%CI [0.99-1.02], p > 0.05). The results of the two-step MR showed that cholesteryl esters to total lipids ratio in large very low-density lipoprotein (VLDL) (ME = -0.13, p < 0.05); concentration of very large VLDL particles (ME = -0.13, p < 0.05); free cholesterol in large VLDL (ME = -0.13, p < 0.05); free cholesterol to total lipids ratio in very large VLDL (ME = -0.22, p < 0.05); phospholipids in large VLDL (ME = -0.15, p < 0.05); phospholipids in very large VLDL (ME = -0.13, p < 0.05); phospholipids to total lipids ratio in large high-density lipoprotein (HDL) (ME = -0.17, p < 0.05); total lipids in very large VLDL (ME = -0.14, p < 0.05); triglycerides in small VLDL (ME = -0.11, p < 0.05); and triglycerides to total lipids ratio in large HDL (ME = -0.10, p < 0.05) assumed a pivotal role in mediating the association between fatigue and poor functional outcome after ischemic stroke. Conclusion Our study provides evidence supporting the causal association between fatigue and the poor functional outcome after ischemic stroke, which emphasizes the importance of implementing interventions aimed at addressing fatigue. This could offer a therapeutic target to improve recovery after ischemic stroke and warrant exploration in a clinical context. One potential mechanism by which fatigue affects functional outcomes after ischemic stroke is through the action of lipid metabolites.
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Affiliation(s)
- Ping Jiang
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Ying Gao
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
- Institute for Brain Disorders, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Leyi Zhang
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Li Jiang
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Chuanpeng Li
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
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2
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Goh HT, Stewart J, Becker K. Fatigue Is Associated With Perceived Effort and 2-Dimensional Reach Performance After Stroke. J Neurol Phys Ther 2024:01253086-990000000-00071. [PMID: 38934610 DOI: 10.1097/npt.0000000000000483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2024]
Abstract
BACKGROUND AND PURPOSE Poststroke fatigue (PSF) is prevalent and often manifests as high perceived effort during activities. Little is known about how PSF influences goal-directed reaching after stroke. The purpose of this study was 2-fold (1) to evaluate how perceived effort changed when individuals with stroke performed a reaching task with various demands and (2) to determine whether PSF was associated with perceived effort during reaching and reach performance. METHODS Thirty-six individuals with chronic stroke performed 2-dimensional reach actions under varied conditions with the more and less affected arms. Perceived effort during reaching was assessed using rating of perceived exertion (RPE) and Paas Mental Effort Rating Scale (MERS). Derived reach kinematics were used to quantify reach performance. The Fatigue Severity Scale (FSS) was administered to assess fatigue severity. RESULTS Perceived effort was higher when participants reached with the more affected arm, reached toward far and small targets, and performed memory-guided reaching. Both RPE and MERS significantly correlated with the FSS score (r = 0.50 and 0.35, respectively, P < 0.05). Further, FSS correlated with movement time during the more affected arm reaching (ρ = 0.40, p < 0.05) and reach performance discrepancy between the fast and self-selected speed conditions when participants performed with the less affected arm (ρ = 0.36, P < 0.05). Exploratory analysis revealed that the relationship between fatigue and reach control appeared to be modulated by task demand. DISCUSSION AND CONCLUSIONS PSF is associated with perceived effort during reaching and reach performance after stroke. These relationships might offer insights into arm performance in the real world after stroke. VIDEO ABSTRACT for more insights from the authors Supplemental Digital Content available at http://links.lww.com/JNPT/A476.
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Affiliation(s)
- Hui-Ting Goh
- Author Affiliations: School of Physical Therapy, Texas Woman's University, Dallas, Texas (H.-T.G.); Physical Therapy Program, Department of Exercise Science. University of South Carolina, Columbus, South Carolina (J.S.); and Department of Kinesiology, Recreation, and Sport Studies. University of Tennessee, Knoxville, Tennessee (K.B.)
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3
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Wolpe N, Holton R, Fletcher PC. What Is Mental Effort: A Clinical Perspective. Biol Psychiatry 2024:S0006-3223(24)00065-9. [PMID: 38309319 DOI: 10.1016/j.biopsych.2024.01.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 01/21/2024] [Accepted: 01/25/2024] [Indexed: 02/05/2024]
Abstract
Although mental effort is a frequently used term, it is poorly defined and understood. Consequently, its usage is frequently loose and potentially misleading. In neuroscience research, the term is used to mean both the cognitive work that is done to meet task demands and the subjective experience of performing that work. We argue that conflating these two meanings hampers progress in understanding cognitive impairments in neuropsychiatric conditions because cognitive work and the subjective experience of it have distinct underlying mechanisms. We suggest that the most coherent and clinically useful perspective on mental effort is that it is a subjective experience. This makes a clear distinction between cognitive impairments that arise from changes in the cognitive apparatus, as in dementia and brain injury, and those that arise from subjective difficulties in carrying out the cognitive work, as in attention-deficit/hyperactivity disorder, depression, and other motivational disorders. We review recent advances in neuroscience research that suggests that the experience of effort has emerged to control task switches so as to minimize costs relative to benefits. We consider how these advances can contribute to our understanding of the experience of increased effort perception in clinical populations. This more specific framing of mental effort will offer a deeper understanding of the mechanisms of cognitive impairments in differing clinical groups and will ultimately facilitate better therapeutic interventions.
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Affiliation(s)
- Noham Wolpe
- Department of Physical Therapy, The Stanley Steyer School of Health Professions, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel; Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom.
| | - Richard Holton
- Faculty of Philosophy, University of Cambridge, Cambridge, United Kingdom
| | - Paul C Fletcher
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Cambridgeshire and Peterborough National Health Service Foundation Trust, Elizabeth House, Fulbourn, Cambridge, United Kingdom; Wellcome Trust Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
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4
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Goh HT, Stewart J, Becker K. Validating the Fatigue Scale for Motor and Cognitive Function (FSMC) in chronic stroke. NeuroRehabilitation 2024; 54:275-285. [PMID: 38143385 DOI: 10.3233/nre-230189] [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] [Indexed: 12/26/2023]
Abstract
BACKGROUND Post-stroke fatigue can manifest as both physical and mental fatigue. The Fatigue Scale for Motor and Cognitive Functions (FSMC) evaluates fatigue on the motor and cognitive domains separately, however, the psychometric properties of this measure in stroke have not been reported. OBJECTIVE To determine the internal consistency, test-retest reliability, and concurrent validity of the FSMC in chronic stroke. METHODS Thirty-four participants with chronic stroke (55.26±12.27 years of age; 59.53±89.21 months post-stroke) completed the FSMC on two separate visits. Internal consistency and reliability of the FSMC were examined using Cronbach's alpha and two-way mixed effects intraclass correlation coefficients (ICC), respectively. Correlation between the FSMC and the Fatigue Severity Scale and Visual Analog Scale-Fatigue was used to assess concurrent validity. RESULTS Internal consistency was excellent (Cronbach's alpha > 0.9) and reliability was moderate to good (ICC = 0.72-0.81) for all FSMC scores. The FSMC demonstrated moderate to good concurrent validity with the Fatigue Severity Scale (ρ= 0.66-0.72) but only fair concurrent validity with the Visual Analog Scale-Fatigue (ρ= 0.37-0.44). CONCLUSION The FSMC is a valid and reliable measure of post-stroke fatigue and may be a useful tool to examine physical fatigue and cognitive fatigue in chronic stroke.
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Affiliation(s)
- Hui-Ting Goh
- School of Physical Therapy, Texas Woman's University, Dallas, TX, USA
| | - Jill Stewart
- Department of Exercise Science, Physical Therapy Program, University of South Carolina, Columbus, SC, USA
| | - Kevin Becker
- Department of Kinesiology, Recreation, and Sport Studies, University of Tennessee, Knoxville, TN, USA
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5
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Tankisi H, Versace V, Kuppuswamy A, Cole J. The role of clinical neurophysiology in the definition and assessment of fatigue and fatigability. Clin Neurophysiol Pract 2023; 9:39-50. [PMID: 38274859 PMCID: PMC10808861 DOI: 10.1016/j.cnp.2023.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 11/24/2023] [Accepted: 12/07/2023] [Indexed: 01/27/2024] Open
Abstract
Though a common symptom, fatigue is difficult to define and investigate, occurs in a wide variety of neurological and systemic disorders, with differing pathological causes. It is also often accompanied by a psychological component. As a symptom of long-term COVID-19 it has gained more attention. In this review, we begin by differentiating fatigue, a perception, from fatigability, quantifiable through biomarkers. Central and peripheral nervous system and muscle disorders associated with these are summarised. We provide a comprehensive and objective framework to help identify potential causes of fatigue and fatigability in a given disease condition. It also considers the effectiveness of neurophysiological tests as objective biomarkers for its assessment. Among these, twitch interpolation, motor cortex stimulation, electroencephalography and magnetencephalography, and readiness potentials will be described for the assessment of central fatigability, and surface and needle electromyography (EMG), single fibre EMG and nerve conduction studies for the assessment of peripheral fatigability. The purpose of this review is to guide clinicians in how to approach fatigue, and fatigability, and to suggest that neurophysiological tests may allow an understanding of their origin and interactions. In this way, their differing types and origins, and hence their possible differing treatments, may also be defined more clearly.
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Affiliation(s)
- Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
- Institute of Clinical Medicine, Aarhus University, Denmark
| | - Viviana Versace
- Department of Neurorehabilitation, Hospital of Vipiteno (SABES-ASDAA), Teaching Hospital of the Paracelsus Medical Private University (PMU), Vipiteno-Sterzing, Italy
| | - Annapoorna Kuppuswamy
- Department of Clinical and Movement Neuroscience, Institute of Neurology, University College London, WC1N 3BG London, UK
- Department of Biomedical Sciences, University of Leeds, UK
| | - Jonathan Cole
- Clinical Neurophysiology, University Hospitals Dorset (Poole), UK
- University of Bournemouth, Poole, UK
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6
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Raizen DM, Mullington J, Anaclet C, Clarke G, Critchley H, Dantzer R, Davis R, Drew KL, Fessel J, Fuller PM, Gibson EM, Harrington M, Ian Lipkin W, Klerman EB, Klimas N, Komaroff AL, Koroshetz W, Krupp L, Kuppuswamy A, Lasselin J, Lewis LD, Magistretti PJ, Matos HY, Miaskowski C, Miller AH, Nath A, Nedergaard M, Opp MR, Ritchie MD, Rogulja D, Rolls A, Salamone JD, Saper C, Whittemore V, Wylie G, Younger J, Zee PC, Craig Heller H. Beyond the symptom: the biology of fatigue. Sleep 2023; 46:zsad069. [PMID: 37224457 PMCID: PMC10485572 DOI: 10.1093/sleep/zsad069] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 05/24/2023] [Indexed: 05/26/2023] Open
Abstract
A workshop titled "Beyond the Symptom: The Biology of Fatigue" was held virtually September 27-28, 2021. It was jointly organized by the Sleep Research Society and the Neurobiology of Fatigue Working Group of the NIH Blueprint Neuroscience Research Program. For access to the presentations and video recordings, see: https://neuroscienceblueprint.nih.gov/about/event/beyond-symptom-biology-fatigue. The goals of this workshop were to bring together clinicians and scientists who use a variety of research approaches to understand fatigue in multiple conditions and to identify key gaps in our understanding of the biology of fatigue. This workshop summary distills key issues discussed in this workshop and provides a list of promising directions for future research on this topic. We do not attempt to provide a comprehensive review of the state of our understanding of fatigue, nor to provide a comprehensive reprise of the many excellent presentations. Rather, our goal is to highlight key advances and to focus on questions and future approaches to answering them.
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Affiliation(s)
- David M Raizen
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Janet Mullington
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Christelle Anaclet
- Department of Neurological Surgery, University of California, Davis School of Medicine, Sacramento, CA, USA
| | - Gerard Clarke
- Department of Psychiatry and Neurobehavioural Science, and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Hugo Critchley
- Brighton and Sussex Medical School Department of Neuroscience, University of Sussex, Brighton, UK
| | - Robert Dantzer
- Department of Symptom Research, Division of Internal Medicine, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Ronald Davis
- Department of Biochemistry and Genetics, Stanford University, Palo Alto, CA, USA
| | - Kelly L Drew
- Department of Chemistry and Biochemistry, Institute of Arctic Biology, Center for Transformative Research in Metabolism, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Josh Fessel
- Division of Clinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Patrick M Fuller
- Department of Neurological Surgery, University of California, Davis School of Medicine, Sacramento, CA, USA
| | - Erin M Gibson
- Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, CA, USA
| | - Mary Harrington
- Department of Psychology, Neuroscience Program, Smith College, Northampton, MA, USA
| | - W Ian Lipkin
- Center for Infection and Immunity, and Departments of Neurology and Pathology, Columbia University, New York City, NY, USA
| | - Elizabeth B Klerman
- Division of Sleep Medicine, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Nancy Klimas
- Department of Clinical Immunology, College of Osteopathic Medicine, Nova Southeastern University, Ft. Lauderdale, FL, USA
| | - Anthony L Komaroff
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Walter Koroshetz
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Lauren Krupp
- Department of Neurology, NYU Grossman School of Medicine, NYC, NY, USA
| | - Anna Kuppuswamy
- University College London, Queen Square Institute of Neurology, London, England
| | - Julie Lasselin
- Department of Psychology, Stockholm University, Stockholm, Sweden
| | - Laura D Lewis
- Center for Systems Neuroscience, Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Pierre J Magistretti
- Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | - Heidi Y Matos
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Christine Miaskowski
- Department of Physiological Nursing, School of Nursing, University of California, San Francisco, CA, USA
| | - Andrew H Miller
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA
| | - Avindra Nath
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Maiken Nedergaard
- Departments of Neurology and Neurosurgery, University of Rochester Medical Center, Rochester, NY, USA
| | - Mark R Opp
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Marylyn D Ritchie
- Department of Genetics, Institute for Biomedical Informatics, Penn Center for Precision Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Dragana Rogulja
- Department of Neurobiology, Harvard University, Boston, MA, USA
| | - Asya Rolls
- Rappaport Institute for Medical Research, Technion, Israel Institute of Technology, Haifa, Israel
| | - John D Salamone
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, USA
| | - Clifford Saper
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Vicky Whittemore
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Glenn Wylie
- Rocco Ortenzio Neuroimaging Center at Kessler Foundation, East Hanover, NJ, USA
| | - Jarred Younger
- Department of Psychology, University of Alabama, Birmingham, Birmingham, AL, USA
| | - Phyllis C Zee
- Center for Circadian and Sleep Medicine, Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - H Craig Heller
- Department of Biology, Stanford University and Sleep Research Society, Stanford, CA, USA
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7
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Wu CH, De Doncker W, Kuppuswamy A. Electroencephalography-Derived Functional Connectivity in Sensorimotor Networks in Post Stroke Fatigue. Brain Topogr 2023; 36:727-735. [PMID: 37328707 PMCID: PMC10415526 DOI: 10.1007/s10548-023-00975-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 06/04/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND Poor suppression of anticipated sensory information from muscle contractions is thought to underlie high fatigue. Such diminished task-related sensory attenuation is reflected in resting state connectivity. Here we test the hypothesis 'altered electroencephalography (EEG)-derived functional connectivity in somatosensory network in the beta band, is a signature of fatigue in post-stroke fatigue'. METHODS In non-depressed, minimally impaired stroke survivors (n = 29), with median disease duration of 5 years, resting state neuronal activity was measured using 64-channel EEG. Graph theory-based network analysis measure of functional connectivity via small-world index (SW) was calculated focusing on right and left motor (Brodmann areas 4, 6, 8, 9, 24 and 32) and sensory (Brodmann areas 1, 2, 3, 5, 7, 40 and 43) networks, in the beta (13-30 Hz) frequency range. Fatigue was measured using Fatigue Severity Scale - FSS (Stroke), with scores of > 4, defined as high fatigue. RESULTS Results confirmed the working hypothesis, with high fatigue stroke survivors showing higher small-worldness in the somatosensory networks when compared to low fatigue. CONCLUSION High levels of small-worldness in somatosensory networks indicates altered processing of somesthetic input. Such altered processing would explain high effort perception within the sensory attenuation model of fatigue.
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Affiliation(s)
- Chi-Hsu Wu
- Institute of Neurology, University College London, Box 146, 33 Queen Square, London, WC1N 3BG, England
| | - William De Doncker
- Institute of Neurology, University College London, Box 146, 33 Queen Square, London, WC1N 3BG, England
| | - Annapoorna Kuppuswamy
- Institute of Neurology, University College London, Box 146, 33 Queen Square, London, WC1N 3BG, England.
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8
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Husain S, Wrightson JG, Johnson E, Brunton LK, Condliffe E. Walking and Fatigue in People with Cerebral Palsy: Brief Report. Dev Neurorehabil 2022; 25:501-504. [PMID: 35289718 DOI: 10.1080/17518423.2022.2053222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The aim of this study was to examine the relationship between perceived fatigue and perceptions of walking abilities and difficulty in people with cerebral palsy (CP). Twenty individuals with CP (range 10-21y; mean age 14.8y) who usually walk in the community were recruited. Community mobility was assessed using the Functional Mobility Scale. Participants were asked about their walking ability and frequency, perceived effort during walking (using the Children's Effort Rating Table), and perceived fatigue (using the Fatigue Impact and Severity Self-Assessment). Community mobility, frequency, and perceived effort during walking were significantly related to fatigue. No relationship was found between time spent walking (maximum walking time) and fatigue. Here we demonstrate that perceived fatigue is related to walking in people with CP.
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Affiliation(s)
- Sarrah Husain
- University of Calgary Cumming School of Medicine, Department of Community Health Sciences, Calgary, AB, Canada
| | - James G Wrightson
- University of Calgary Cumming School of Medicine, Calgary, AB, Canada
| | - Erika Johnson
- University of Calgary Cumming School of Medicine, Clinical Neurosciences, Calgary, AB, Canada
| | - Laura Kristine Brunton
- School of Physical Therapy, Health Sciences Building, Western University, London, ON, Canada
| | - Elizabeth Condliffe
- Department of Clinical Neurosciences, University of Calgary Cumming School of Medicine, Calgary, AB, Canada
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9
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Memory-Guided Reaching: Is It Effortful? Motor Control 2022; 27:194-216. [PMID: 36170972 DOI: 10.1123/mc.2021-0136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 08/05/2022] [Accepted: 08/10/2022] [Indexed: 11/18/2022]
Abstract
We previously showed that perceived effort during visually guided reaching was altered as task demand varied. Further, self-reported subjective fatigue correlated with perceived effort and reach performance under visually guided conditions. Memory-guided reaching often leads to performance deterioration and can provide insights about the planning and control of reach actions. It is unclear how perceived effort changes during memory-guided reaching and whether self-reported subjective fatigue is associated with perceived effort of memory-guided reaching. Twenty-three young adults performed reach actions under visually- and memory-guided conditions. Perceived effort, reaction time, and endpoint error increased significantly from the visually- to the memory-guided condition. Self-reported subjective fatigue was associated with perceived effort and reach distance error during memory-guided reaching; those with higher levels of fatigue reported greater perceived effort and tended to reach farther when visual information was not available. These findings establish a foundation to examine relationships between subjective fatigue, perceived effort, and reach control.
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10
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Abstract
The last decade has seen the emergence of new theoretical frameworks to explain pathological fatigue, a much neglected, yet highly significant symptom across a wide range of diseases. While the new models of fatigue provide new hypotheses to test, they also raise a number of questions. The primary purpose of this essay is to examine the predictions of three recently proposed models of fatigue, the overlap and differences between them, and the evidence from diseases that may lend support to the models of fatigue. I also present expansions for the sensory attenuation model of fatigue. Further questions examined here are the following: What are the neural substrates of fatigue? How can sensory attenuation, which underpins agency also explain fatigue? Are fatigue and agency related?
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Affiliation(s)
- Annapoorna Kuppuswamy
- Department of Clinical and Movement Neuroscience, Institute of Neurology, University College London, London, UK
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11
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Forman CR, Jacobsen KJ, Karabanov AN, Nielsen JB, Lorentzen J. Corticomuscular coherence is reduced in relation to dorsiflexion fatigability to the same extent in adults with cerebral palsy as in neurologically intact adults. Eur J Appl Physiol 2022; 122:1459-1471. [PMID: 35366090 DOI: 10.1007/s00421-022-04938-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 03/18/2022] [Indexed: 11/28/2022]
Abstract
PURPOSE Fatigue is frequent in adults with cerebral palsy (CP) and it is unclear whether this is due to altered corticospinal drive. We aimed to compare changes in corticospinal drive following sustained muscle contractions in adults with CP and neurologically intact (NI) adults. METHODS Fourteen adults with CP [age 37.6 (10.1), seven females, GMFCS levels I-II] and ten NI adults [age 35.4 (10.3), 6 females] performed 1-min static dorsiflexion at 30% of maximal voluntary contraction (MVC) before and after a submaximal contraction at 60% MVC. Electroencephalography (EEG) and electromyography (EMG) from the anterior tibial muscle were analyzed to quantify the coupling, expressed by corticomuscular coherence (CMC). RESULTS Adults with CP had lower MVCs but similar time to exhaustion during the relative load of the fatigability trial. Both groups exhibited fatigability-related changes in EMG median frequency and EMG amplitude. The CP group showed lower beta band (16-35 Hz) CMC before fatigability, but both groups decreased beta band CMC following fatigability. There was a linear correlation between decrease of beta band CMC and fatigability-related increase in EMG. CONCLUSION Fatigability following static contraction until failure was related to decreased beta band CMC in both NI adults and adults with CP. Our findings indicate that compensatory mechanisms to fatigability are present in both groups, and that fatigability affects the corticospinal drive in the same way. We suggest that the perceived physical fatigue in CP is related to the high relative load of activities of daily living rather than any particular physiological mechanism.
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Affiliation(s)
- Christian Riis Forman
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark. .,Elsass Foundation, Charlottenlund, Denmark.
| | - Kim Jennifer Jacobsen
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark.,Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Anke Ninija Karabanov
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Jens Bo Nielsen
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark.,Elsass Foundation, Charlottenlund, Denmark
| | - Jakob Lorentzen
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark.,Elsass Foundation, Charlottenlund, Denmark
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12
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Ondobaka S, De Doncker W, Ward N, Kuppuswamy A. Neural effective connectivity explains subjective fatigue in stroke. Brain 2021; 145:285-294. [PMID: 34791073 PMCID: PMC8967104 DOI: 10.1093/brain/awab287] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 05/20/2021] [Accepted: 06/21/2021] [Indexed: 11/20/2022] Open
Abstract
Persistent fatigue is a major debilitating symptom in many psychiatric and neurological conditions, including stroke. Post-stroke fatigue has been linked to low corticomotor excitability. Yet, it remains elusive as to what the neuronal mechanisms are that underlie motor cortex excitability and chronic persistence of fatigue. In this cross-sectional observational study, in two experiments we examined a total of 59 non-depressed stroke survivors with minimal motoric and cognitive impairments using ‘resting-state’ MRI and single- and paired-pulse transcranial magnetic stimulation. In the first session of Experiment 1, we assessed resting motor thresholds—a typical measure of cortical excitability—by applying transcranial magnetic stimulation to the primary motor cortex (M1) and measuring motor-evoked potentials in the hand affected by stroke. In the second session, we measured their brain activity with resting-state MRI to assess effective connectivity interactions at rest. In Experiment 2 we examined effective inter-hemispheric connectivity in an independent sample of patients using paired-pulse transcranial magnetic stimulation. We also assessed the levels of non-exercise induced, persistent fatigue using Fatigue Severity Scale (FSS-7), a self-report questionnaire that has been widely applied and validated across different conditions. We used spectral dynamic causal modelling in Experiment 1 and paired-pulse transcranial magnetic stimulation in Experiment 2 to characterize how neuronal effective connectivity relates to self-reported post-stroke fatigue. In a multiple regression analysis, we used the balance in inhibitory connectivity between homologue regions in M1 as the main predictor, and have included lesioned hemisphere, resting motor threshold and levels of depression as additional predictors. Our novel index of inter-hemispheric inhibition balance was a significant predictor of post-stroke fatigue in Experiment 1 (β = 1.524, P = 7.56 × 10−5, confidence interval: 0.921 to 2.127) and in Experiment 2 (β = 0.541, P = 0.049, confidence interval: 0.002 to 1.080). In Experiment 2, depression scores and corticospinal excitability, a measure associated with subjective fatigue, also significantly accounted for variability in fatigue. We suggest that the balance in inter-hemispheric inhibitory effects between primary motor regions can explain subjective post-stroke fatigue. Findings provide novel insights into neural mechanisms that underlie persistent fatigue.
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Affiliation(s)
- Sasha Ondobaka
- CoreMind ltd, NW1 8NP, London, UK.,Department of Clinical and Movement Neuroscience, Institute of Neurology, University College London, WC1N 3BG London, UK
| | - William De Doncker
- Department of Clinical and Movement Neuroscience, Institute of Neurology, University College London, WC1N 3BG London, UK
| | - Nick Ward
- Department of Clinical and Movement Neuroscience, Institute of Neurology, University College London, WC1N 3BG London, UK.,NHNN, University College London, WC1N 3BG London, UK
| | - Annapoorna Kuppuswamy
- Department of Clinical and Movement Neuroscience, Institute of Neurology, University College London, WC1N 3BG London, UK
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Toward the unity of pathological and exertional fatigue: A predictive processing model. COGNITIVE AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2021; 22:215-228. [PMID: 34668170 PMCID: PMC8983507 DOI: 10.3758/s13415-021-00958-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Accepted: 09/21/2021] [Indexed: 01/23/2023]
Abstract
Fatigue is a common experience in both health and disease. Yet, pathological (i.e., prolonged or chronic) and transient (i.e., exertional) fatigue symptoms are traditionally considered distinct, compounding a separation between interested research fields within the study of fatigue. Within the clinical neurosciences, nascent frameworks position pathological fatigue as a product of inference derived through hierarchical predictive processing. The metacognitive theory of dyshomeostasis (Stephan et al., 2016) states that pathological fatigue emerges from the metacognitive mechanism in which the detection of persistent mismatches between prior interoceptive predictions and ascending sensory evidence (i.e., prediction error) signals low evidence for internal generative models, which undermine an agent’s feeling of mastery over the body and is thus experienced phenomenologically as fatigue. Although acute, transient subjective symptoms of exertional fatigue have also been associated with increasing interoceptive prediction error, the dynamic computations that underlie its development have not been clearly defined. Here, drawing on the metacognitive theory of dyshomeostasis, we extend this account to offer an explicit description of the development of fatigue during extended periods of (physical) exertion. Accordingly, it is proposed that a loss of certainty or confidence in control predictions in response to persistent detection of prediction error features as a common foundation for the conscious experience of both pathological and nonpathological fatigue.
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14
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Effect of transcranial direct current stimulation on post-stroke fatigue. J Neurol 2021; 268:2831-2842. [PMID: 33598767 PMCID: PMC8289762 DOI: 10.1007/s00415-021-10442-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 01/03/2023]
Abstract
Background Fatigue is one of the most commonly reported symptoms post-stroke, which has a severe impact on the quality of life. Post-stroke fatigue is associated with reduced motor cortical excitability, specifically of the affected hemisphere. Objective The aim of this exploratory study was to assess whether fatigue symptoms can be reduced by increasing cortical excitability using anodal transcranial direct current stimulation (tDCS). Methods In this sham-controlled, double-blind intervention study, tDCS was applied bilaterally over the primary motor cortex in a single session in thirty stroke survivors with high severity of fatigue. A questionnaire-based measure of trait fatigue (primary outcome) was obtained before, after a week and 5 weeks post stimulation. Secondary outcome measures of state fatigue, motor cortex neurophysiology and perceived effort were also assessed pre, immediately post, a week and 5 weeks post stimulation. Results Anodal tDCS significantly improved fatigue symptoms a week after real stimulation when compared to sham stimulation. There was also a significant change in motor cortex neurophysiology of the affected hemisphere and perceived effort, a week after stimulation. The degree of improvement in fatigue was associated with baseline anxiety levels. Conclusion A single session of anodal tDCS improves fatigue symptoms with the effect lasting up to a week post stimulation. tDCS may therefore be a useful tool for managing fatigue symptoms post-stroke. Trial registration NCT04634864 Date of registration 17/11/2020–“retrospectively registered”.
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