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Rudroff T, Fietsam AC, Deters JR, Workman CD, Boles Ponto LL. On the Effects of Transcranial Direct Current Stimulation on Cerebral Glucose Uptake During Walking: A Report of Three Patients With Multiple Sclerosis. Front Hum Neurosci 2022; 16:833619. [PMID: 35145388 PMCID: PMC8824586 DOI: 10.3389/fnhum.2022.833619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 01/04/2022] [Indexed: 11/24/2022] Open
Abstract
Common symptoms of multiple sclerosis (MS) include motor impairments of the lower extremities, particularly gait disturbances. Loss of balance and muscle weakness, representing some peripheral effects, have been shown to influence these symptoms, however, the individual role of cortical and subcortical structures in the central nervous system is still to be understood. Assessing [18F]fluorodeoxyglucose (FDG) uptake in the CNS can assess brain activity and is directly associated with regional neuronal activity. One potential modality to increase cortical excitability and improve motor function in patients with MS (PwMS) is transcranial direct current stimulation (tDCS). However, tDCS group outcomes may not mirror individual subject responses, which impedes our knowledge of the pathophysiology and management of diseases like MS. Three PwMS randomly received both 3 mA tDCS and SHAM targeting the motor cortex (M1) that controls the more-affected leg for 20 min on separate days before walking on a treadmill. The radiotracer, FDG, was injected at minute two of the 20 min walk and the subjects underwent a Positron emission tomography (PET) scan immediately after the task. Differences in relative regional metabolism of areas under the tDCS anode and the basal ganglia were calculated and investigated. The results indicated diverse and individualized responses in regions under the anode and consistent increases in some basal ganglia areas (e.g., caudate nucleus). Thus, anodal tDCS targeting the M1 that controls the more-affected leg of PwMS might be capable of affecting remote subcortical regions and modulating the activity (motor, cognitive, and behavioral functions) of the circuitry connected to these regions.
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Affiliation(s)
- Thorsten Rudroff
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, United States
- Department of Neurology, University of Iowa Health Clinics, Iowa City, IA, United States
- *Correspondence: Thorsten Rudroff,
| | - Alexandra C. Fietsam
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, United States
| | - Justin R. Deters
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, United States
| | - Craig D. Workman
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, United States
| | - Laura L. Boles Ponto
- Department of Radiology, University of Iowa Hospitals and Clinics, Iowa City, IA, United States
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Cerebellar Contributions to Motor Impairments in People with Multiple Sclerosis. THE CEREBELLUM 2021; 21:1052-1060. [PMID: 34657272 DOI: 10.1007/s12311-021-01336-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/10/2021] [Indexed: 12/25/2022]
Abstract
Although Charcot characterized classic cerebellar symptoms in people with multiple sclerosis (PwMS) in 1877, the impact of cerebellar dysfunction on MS symptoms has predominately been evaluated in the last two decades. Recent studies have clearly demonstrated the association between cerebellar pathology, including atrophy and reduced fractional anisotropy in the peduncles, and motor impairments, such as reduced gait velocity and time to complete walking tasks. However, future studies using novel imaging techniques are needed to elucidate all potential pathophysiology that is associated with disability in PwMS. Additionally, future studies are required to determine the most effective treatments for motor impairments in PwMS, including the specific type and duration of exercise interventions, and potential means to amplify their effects, such as transcranial direct current stimulation (tDCS). This mini-review critically discusses the distinct role of cerebellar dysfunction in motor impairments in PwMS, potential treatments, and directions for future studies.
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Fietsam AC, Deters JR, Workman CD, Ponto LLB, Rudroff T. Alterations in Leg Muscle Glucose Uptake and Inter-Limb Asymmetry after a Single Session of tDCS in Four People with Multiple Sclerosis. Brain Sci 2021; 11:brainsci11101363. [PMID: 34679427 PMCID: PMC8533729 DOI: 10.3390/brainsci11101363] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/10/2021] [Accepted: 10/14/2021] [Indexed: 01/11/2023] Open
Abstract
Asymmetrical lower limb weakness is an early symptom and significant contributor to the progressive worsening of walking ability in people with multiple sclerosis (PwMS). Transcranial direct current stimulation (tDCS) may effectively increase neural drive to the more-affected lower limb and, therefore, increase symmetrical activation. Four PwMS (1 female, age range: 27–57) underwent one session each of 3 mA or SHAM tDCS over the motor cortex corresponding to their more-affected limb followed by 20 min of treadmill walking at a self-selected speed. Two min into the treadmill task, the subjects were injected with the glucose analog [18F]fluorodeoxyglucose (FDG). Immediately after treadmill walking, the subjects underwent whole-body positron emission tomography (PET) imaging. Glucose uptake (GU) values were compared between the legs, the spatial distribution of FDG was assessed to estimate glucose uptake heterogeneity (GUh), and GU asymmetry indices (AIs) were calculated. After tDCS, GU was altered, and GUh was decreased in various muscle groups in each subject. Additionally, AIs went from asymmetric to symmetric after tDCS in the subjects that demonstrated asymmetrical glucose uptake during SHAM. These results indicate that tDCS improved GU asymmetries, potentially from an increased neural drive and a more efficient muscle activation strategy of the lower limb in PwMS.
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Affiliation(s)
- Alexandra C. Fietsam
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA; (A.C.F.); (J.R.D.); (C.D.W.)
| | - Justin R. Deters
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA; (A.C.F.); (J.R.D.); (C.D.W.)
| | - Craig D. Workman
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA; (A.C.F.); (J.R.D.); (C.D.W.)
| | - Laura L. Boles Ponto
- Department of Radiology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA;
| | - Thorsten Rudroff
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA; (A.C.F.); (J.R.D.); (C.D.W.)
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA
- Correspondence: ; Tel.: +1-319-467-0363
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Fietsam AC, Deters JR, Workman CD, Rudroff T. Personal Protective Equipment Alters Leg Muscle Fatigability Independent of Transcranial Direct Current Stimulation: A Comparison with Pre-COVID-19 Pandemic Results. Brain Sci 2021; 11:brainsci11080962. [PMID: 34439581 PMCID: PMC8392507 DOI: 10.3390/brainsci11080962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/02/2021] [Accepted: 07/19/2021] [Indexed: 01/12/2023] Open
Abstract
In response to the COVID-19 pandemic, the use of personal protective equipment (PPE; e.g., face mask) has increased. Mandating subjects to wear PPE during vigorous exercise might affect the fatigue outcomes of transcranial direct current stimulation (tDCS) studies. The purpose of this study was to investigate whether the use of PPE affected the performance of a tDCS-influenced fatigue task in healthy adults. A total of 16 young and healthy subjects were recruited and wore PPE during an isokinetic fatigue task in conjunction with sham, 2 mA, and 4 mA tDCS conditions. Subjects were matched to subjects who did not wear PPE during our previous pre-pandemic study in which right knee extensor fatigability increased under these same conditions. The results show that right knee extensor fatigability, derived from torque and work (FI-T and FI-W, respectively), was higher in the PPE study compared to the No PPE study in the sham condition. Additionally, there were no differences in knee extensor fatigability or muscle activity between sham, 2 mA, and 4 mA tDCS in the present study, which contrasts with our previous results. Thus, PPE worn by subjects and researchers might have a detrimental effect on fatigue outcomes in tDCS studies irrespective of the stimulation intervention.
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Affiliation(s)
- Alexandra C. Fietsam
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA; (A.C.F.); (J.R.D.); (C.D.W.)
| | - Justin R. Deters
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA; (A.C.F.); (J.R.D.); (C.D.W.)
| | - Craig D. Workman
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA; (A.C.F.); (J.R.D.); (C.D.W.)
| | - Thorsten Rudroff
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA; (A.C.F.); (J.R.D.); (C.D.W.)
- Department of Neurology, University of Iowa Health Clinics, Iowa City, IA 52242, USA
- Correspondence: ; Tel.: +1-319-467-0363
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Rudroff T, Fietsam AC, Deters JR, Bryant AD, Kamholz J. Post-COVID-19 Fatigue: Potential Contributing Factors. Brain Sci 2020; 10:E1012. [PMID: 33352638 PMCID: PMC7766297 DOI: 10.3390/brainsci10121012] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 01/08/2023] Open
Abstract
Much of the spotlight for coronavirus disease 2019 (COVID-19) is on the acute symptoms and recovery. However, many recovered patients face persistent physical, cognitive, and psychological symptoms well past the acute phase. Of these symptoms, fatigue is one of the most persistent and debilitating. In this "perspective article," we define fatigue as the decrease in physical and/or mental performance that results from changes in central, psychological, and/or peripheral factors due to the COVID-19 disease and propose a model to explain potential factors contributing to post-COVID-19 fatigue. According to our model, fatigue is dependent on conditional and physiological factors. Conditional dependency comprises the task, environment, and physical and mental capacity of individuals, while physiological factors include central, psychological, and peripheral aspects. This model provides a framework for clinicians and researchers. However, future research is needed to validate our proposed model and elucidate all mechanisms of fatigue due to COVID-19.
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Affiliation(s)
- Thorsten Rudroff
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA; (A.C.F.); (J.R.D.)
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA;
| | - Alexandra C. Fietsam
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA; (A.C.F.); (J.R.D.)
| | - Justin R. Deters
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA 52242, USA; (A.C.F.); (J.R.D.)
| | - Andrew D. Bryant
- Department of Internal Medicine, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA;
| | - John Kamholz
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA;
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