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Wilkins EW, Young RJ, Houston D, Kawana E, Lopez Mora E, Sunkara MS, Riley ZA, Poston B. Non-Dominant Hemisphere Excitability Is Unaffected during and after Transcranial Direct Current Stimulation of the Dominant Hemisphere. Brain Sci 2024; 14:694. [PMID: 39061434 PMCID: PMC11274959 DOI: 10.3390/brainsci14070694] [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: 06/06/2024] [Revised: 07/05/2024] [Accepted: 07/10/2024] [Indexed: 07/28/2024] Open
Abstract
Transcranial direct current stimulation (tDCS) increases primary motor cortex (M1) excitability and improves motor performance when applied unilaterally to the dominant hemisphere. However, the influence of tDCS on contralateral M1 excitability both during and after application has not been quantified. The purpose was to determine the influence of tDCS applied to the dominant M1 on the excitability of the contralateral non-dominant M1. This study employed a double-blind, randomized, SHAM-controlled, within-subject crossover experimental design. Eighteen young adults performed two experimental sessions (tDCS, SHAM) in counterbalanced order separated by a one-week washout. Transcranial magnetic stimulation (TMS) was used to quantify the excitability of the contralateral M1 to which anodal tDCS was applied for 20 min with a current strength of 1 mA. Motor evoked potential (MEP) amplitudes were assessed in 5 TMS test blocks (Pre, D5, D10, D15, and Post). The Pre and Post TMS test blocks were performed immediately before and after tDCS application, whereas the TMS test blocks performed during tDCS were completed at the 5, 10, and 15 min stimulation timepoints. MEPs were analyzed with a 2 condition (tDCS, SHAM) × 5 test (Pre, D5, D10, D15, Post) within-subject ANOVA. The main effect for condition (p = 0.213), the main effect for test (p = 0.502), and the condition × test interaction (p = 0.860) were all not statistically significant. These results indicate that tDCS does not modulate contralateral M1 excitability during or immediately after application, at least under the current set of common tDCS parameters of stimulation.
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Affiliation(s)
- Erik W. Wilkins
- Department of Kinesiology and Nutrition Sciences, University of Nevada, Las Vegas, NV 89154, USA;
- Interdisciplinary Ph.D. Program in Neuroscience, University of Nevada, Las Vegas, NV 89154, USA;
| | - Richard J. Young
- Interdisciplinary Ph.D. Program in Neuroscience, University of Nevada, Las Vegas, NV 89154, USA;
| | - Daniel Houston
- School of Medicine, University of Nevada, Las Vegas, NV 89154, USA; (D.H.); (E.K.); (E.L.M.)
| | - Eric Kawana
- School of Medicine, University of Nevada, Las Vegas, NV 89154, USA; (D.H.); (E.K.); (E.L.M.)
| | - Edgar Lopez Mora
- School of Medicine, University of Nevada, Las Vegas, NV 89154, USA; (D.H.); (E.K.); (E.L.M.)
| | - Meghana S. Sunkara
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284, USA;
| | - Zachary A. Riley
- Department of Kinesiology, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA;
| | - Brach Poston
- Department of Kinesiology and Nutrition Sciences, University of Nevada, Las Vegas, NV 89154, USA;
- Interdisciplinary Ph.D. Program in Neuroscience, University of Nevada, Las Vegas, NV 89154, USA;
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2
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Santander T, Leslie S, Li LJ, Skinner HE, Simonson JM, Sweeney P, Deen KP, Miller MB, Brunye TT. Towards optimized methodological parameters for maximizing the behavioral effects of transcranial direct current stimulation. Front Hum Neurosci 2024; 18:1305446. [PMID: 39015825 PMCID: PMC11250584 DOI: 10.3389/fnhum.2024.1305446] [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: 10/01/2023] [Accepted: 06/12/2024] [Indexed: 07/18/2024] Open
Abstract
Introduction Transcranial direct current stimulation (tDCS) administers low-intensity direct current electrical stimulation to brain regions via electrodes arranged on the surface of the scalp. The core promise of tDCS is its ability to modulate brain activity and affect performance on diverse cognitive functions (affording causal inferences regarding regional brain activity and behavior), but the optimal methodological parameters for maximizing behavioral effects remain to be elucidated. Here we sought to examine the effects of 10 stimulation and experimental design factors across a series of five cognitive domains: motor performance, visual search, working memory, vigilance, and response inhibition. The objective was to identify a set of optimal parameter settings that consistently and reliably maximized the behavioral effects of tDCS within each cognitive domain. Methods We surveyed tDCS effects on these various cognitive functions in healthy young adults, ultimately resulting in 721 effects across 106 published reports. Hierarchical Bayesian meta-regression models were fit to characterize how (and to what extent) these design parameters differentially predict the likelihood of positive/negative behavioral outcomes. Results Consistent with many previous meta-analyses of tDCS effects, extensive variability was observed across tasks and measured outcomes. Consequently, most design parameters did not confer consistent advantages or disadvantages to behavioral effects-a domain-general model suggested an advantage to using within-subjects designs (versus between-subjects) and the tendency for cathodal stimulation (relative to anodal stimulation) to produce reduced behavioral effects, but these associations were scarcely-evident in domain-specific models. Discussion These findings highlight the urgent need for tDCS studies to more systematically probe the effects of these parameters on behavior to fulfill the promise of identifying causal links between brain function and cognition.
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Affiliation(s)
- Tyler Santander
- Institute for Collaborative Biotechnologies, University of California, Santa Barbara, Santa Barbara, CA, United States
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Sara Leslie
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Luna J. Li
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Henri E. Skinner
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Jessica M. Simonson
- Institute for Collaborative Biotechnologies, University of California, Santa Barbara, Santa Barbara, CA, United States
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Patrick Sweeney
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Kaitlyn P. Deen
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Michael B. Miller
- Institute for Collaborative Biotechnologies, University of California, Santa Barbara, Santa Barbara, CA, United States
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Tad T. Brunye
- U. S. Army DEVCOM Soldier Center, Natick, MA, United States
- Center for Applied Brain and Cognitive Sciences, Tufts University, Medford, MA, United States
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3
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Chen L, Tang C, Wang Z, Zhang L, Gu B, Liu X, Ming D. Enhancing Motor Sequence Learning via Transcutaneous Auricular Vagus Nerve Stimulation (taVNS): An EEG Study. IEEE J Biomed Health Inform 2024; 28:1285-1296. [PMID: 38109248 DOI: 10.1109/jbhi.2023.3344176] [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: 12/20/2023]
Abstract
Motor learning plays a crucial role in human life, and various neuromodulation methods have been utilized to strengthen or improve it. Transcutaneous auricular vagus nerve stimulation (taVNS) has gained increasing attention due to its non-invasive nature, affordability and ease of implementation. Although the potential of taVNS on regulating motor learning has been suggested, its actual regulatory effect has yet been fully explored. Electroencephalogram (EEG) analysis provides an in-depth understanding of cognitive processes involved in motor learning so as to offer methodological support for regulation of motor learning. To investigate the effect of taVNS on motor learning, this study recruited 22 healthy subjects to participate a single-blind, sham-controlled, and within-subject serial reaction time task (SRTT) experiment. Every subject involved in two sessions at least one week apart and received a 20-minute active/sham taVNS in each session. Behavioral indicators as well as EEG characteristics during the task state, were extracted and analyzed. The results revealed that compared to the sham group, the active group showed higher learning performance. Additionally, the EEG results indicated that after taVNS, the motor-related cortical potential amplitudes and alpha-gamma modulation index decreased significantly and functional connectivity based on partial directed coherence towards frontal lobe was enhanced. These findings suggest that taVNS can improve motor learning, mainly through enhancing cognitive and memory functions rather than simple movement learning. This study confirms the positive regulatory effect of taVNS on motor learning, which is particularly promising as it offers a potential avenue for enhancing motor skills and facilitating rehabilitation.
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Pantovic M, de Albuquerque LL, Mastrantonio S, Pomerantz AS, Wilkins EW, Riley ZA, Guadagnoli MA, Poston B. Transcranial Direct Current Stimulation of Primary Motor Cortex over Multiple Days Improves Motor Learning of a Complex Overhand Throwing Task. Brain Sci 2023; 13:1441. [PMID: 37891809 PMCID: PMC10604977 DOI: 10.3390/brainsci13101441] [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: 08/16/2023] [Revised: 10/03/2023] [Accepted: 10/05/2023] [Indexed: 10/29/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) applied to the primary motor cortex (M1) improves motor learning in relatively simple motor tasks performed with the hand and arm. However, it is unknown if tDCS can improve motor learning in complex motor tasks involving whole-body coordination with significant endpoint accuracy requirements. The primary purpose was to determine the influence of tDCS on motor learning over multiple days in a complex over-hand throwing task. This study utilized a double-blind, randomized, SHAM-controlled, between-subjects experimental design. Forty-six young adults were allocated to either a tDCS group or a SHAM group and completed three experimental sessions on three consecutive days at the same time of day. Each experimental session was identical and consisted of overhand throwing trials to a target in a pre-test block, five practice blocks performed simultaneously with 20 min of tDCS, and a post-test block. Overhand throwing performance was quantified as the endpoint error. Transcranial magnetic stimulation was used to obtain motor-evoked potentials (MEPs) from the first dorsal interosseus muscle to quantify changes in M1 excitability due to tDCS. Endpoint error significantly decreased over the three days of practice in the tDCS group but not in the SHAM group. MEP amplitude significantly increased in the tDCS group, but the MEP increases were not associated with increases in motor learning. These findings indicate that tDCS applied over multiple days can improve motor learning in a complex motor tasks in healthy young adults.
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Affiliation(s)
- Milan Pantovic
- Health and Human Performance Department, Utah Tech University, St. George, UT 84770, USA;
| | - Lidio Lima de Albuquerque
- School of Health and Applied Human Sciences, University of North Carolina-Wilmington, Wilmington, NC 28403, USA;
| | - Sierra Mastrantonio
- School of Medicine, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA; (S.M.); (A.S.P.); (M.A.G.)
| | - Austin S. Pomerantz
- School of Medicine, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA; (S.M.); (A.S.P.); (M.A.G.)
| | - Erik W. Wilkins
- Department of Kinesiology and Nutrition Sciences, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA;
| | - Zachary A. Riley
- Department of Kinesiology, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA;
| | - Mark A. Guadagnoli
- School of Medicine, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA; (S.M.); (A.S.P.); (M.A.G.)
| | - Brach Poston
- Department of Kinesiology and Nutrition Sciences, University of Nevada-Las Vegas, Las Vegas, NV 89154, USA;
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Aksu S, Hasırcı Bayır BR, Sayman C, Soyata AZ, Boz G, Karamürsel S. Working memory ımprovement after transcranial direct current stimulation paired with working memory training ın diabetic peripheral neuropathy. APPLIED NEUROPSYCHOLOGY. ADULT 2023:1-14. [PMID: 36630270 DOI: 10.1080/23279095.2022.2164717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Association of cognitive deficits and diabetic peripheral neuropathy (DPN) is frequent. Working memory (WM) deficits result in impairment of daily activities, diminished functionality, and treatment compliance. Mounting evidence suggests that transcranial Direct Current Stimulation (tDCS) with concurrent working memory training (WMT) ameliorates cognitive deficits. Emboldening results of tDCS were shown in DPN. The study aimed to evaluate the efficacy of anodal tDCS over the left dorsolateral prefrontal cortex (DLPFC) coupled with cathodal right DLPFC with concurrent WMT in DPN for the first time. The present randomized triple-blind parallel-group sham-controlled study evaluated the efficacy of 5 sessions of tDCS over the DLPFC concurrent with WMT in 28 individuals with painful DPN on cognitive (primary) and pain-related, psychiatric outcome measures before, immediately after, and 1-month after treatment protocol. tDCS enhanced the efficacy of WMT on working memory and yielded lower anxiety levels than sham tDCS but efficacy was not superior to sham on other cognitive domains, pain severity, quality of life, and depression. tDCS with concurrent WMT enhanced WM and ameliorated anxiety in DPN without affecting other cognitive and pain-related outcomes. Further research scrutinizing the short/long-term efficacy with larger samples is accredited.
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Affiliation(s)
- Serkan Aksu
- Department of Physiology, Faculty of Medicine, Muğla Sıtkı Koçman University, Muğla, Türkiye
- Department of Physiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
| | - Buse Rahime Hasırcı Bayır
- Department of Neurology, Health Sciences University, Haydarpaşa Numune Education and Research Hospital, Istanbul, Türkiye
| | - Ceyhun Sayman
- Translational Neurodevelopmental Neuroscience Phd Programme, Institute of Health Science, Istanbul University, Istanbul, Türkiye
| | - Ahmet Zihni Soyata
- Psychiatry Outpatient Clinic, Başakşehir State Hospital, İstanbul, Turkey
| | - Gökalp Boz
- Department of Psychology, Istanbul University, Istanbul, Türkiye
| | - Sacit Karamürsel
- Department of Physiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Türkiye
- Department of Physiology, School of Medicine, Koc University, Istanbul, Türkiye
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Kern K, Vukelić M, Guggenberger R, Gharabaghi A. Oscillatory neurofeedback networks and poststroke rehabilitative potential in severely impaired stroke patients. Neuroimage Clin 2023; 37:103289. [PMID: 36525745 PMCID: PMC9791174 DOI: 10.1016/j.nicl.2022.103289] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 12/03/2022] [Accepted: 12/12/2022] [Indexed: 12/15/2022]
Abstract
Motor restoration after severe stroke is often limited. However, some of the severely impaired stroke patients may still have a rehabilitative potential. Biomarkers that identify these patients are sparse. Eighteen severely impaired chronic stroke patients with a lack of volitional finger extension participated in an EEG study. During sixty-six trials of kinesthetic motor imagery, a brain-machine interface turned event-related beta-band desynchronization of the ipsilesional sensorimotor cortex into opening of the paralyzed hand by a robotic orthosis. A subgroup of eight patients participated in a subsequent four-week rehabilitation training. Changes of the movement extent were captured with sensors which objectively quantified even discrete improvements of wrist movement. Albeit with the same motor impairment level, patients could be differentiated into two groups, i.e., with and without task-related increase of bilateral cortico-cortical phase synchronization between frontal/premotor and parietal areas. This fronto-parietal integration (FPI) was associated with a significantly higher volitional beta modulation range in the ipsilesional sensorimotor cortex. Following the four-week training, patients with FPI showed significantly higher improvement in wrist movement than those without FPI. Moreover, only the former group improved significantly in the upper extremity Fugl-Meyer-Assessment score. Neurofeedback-related long-range oscillatory coherence may differentiate severely impaired stroke patients with regard to their rehabilitative potential, a finding that needs to be confirmed in larger patient cohorts.
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Affiliation(s)
- Kevin Kern
- Institute for Neuromodulation and Neurotechnology, University of Tübingen, Germany
| | - Mathias Vukelić
- Institute for Neuromodulation and Neurotechnology, University of Tübingen, Germany
| | - Robert Guggenberger
- Institute for Neuromodulation and Neurotechnology, University of Tübingen, Germany
| | - Alireza Gharabaghi
- Institute for Neuromodulation and Neurotechnology, University of Tübingen, Germany.
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7
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da Cunha MJ, Pinto C, Schifino GP, Sant'Anna Py I, Cimolin V, Pagnussat AS. Bicephalic Transcranial Direct-Current Stimulation Does Not Add Benefits to a Footdrop Stimulator for Improving Functional Mobility in People With Chronic Hemiparesis After Stroke: A Double-Blind, Randomized Controlled Trial. Phys Ther 2022; 102:6605113. [PMID: 35689805 DOI: 10.1093/ptj/pzac079] [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: 06/01/2021] [Revised: 12/23/2021] [Accepted: 06/04/2022] [Indexed: 11/14/2022]
Abstract
OBJECTIVE The aim of this study was to assess the effects of applying transcranial direct-current stimulation (tDCS), a footdrop stimulator (FDS), and gait training simultaneously on functional mobility in people with chronic hemiparesis after stroke. METHODS In this double-blind controlled trial, 32 individuals with mild, moderate, and severe chronic hemiparesis after stroke were randomized to tDCS plus FDS or sham tDCS plus FDS groups. Both groups underwent 10 concurrent tDCS and FDS gait training sessions 5 times per week for 2 weeks. Functional mobility was evaluated by the Timed "Up & Go" test (TUG). Secondary outcomes included spasticity of plantarflexors, knee extensors, and hip adductors; quality of life; and walking endurance (distance covered during each treadmill gait training session). Clinical assessments were performed before treatment, after treatment, and at a 1-month follow-up. A generalized estimating equation was used to compare the effects of time, group, and time × group interaction. RESULTS No difference between groups was observed during performance of the TUG or other outcomes. TUG performance was improved in both the tDCS plus FDS group (before treatment = 24.29 [95% CI = 17.72-33.28]; after treatment = 21.75 [95% CI = 15.75-30.08]) and the sham tDCS plus FDS group (before treatment = 19.63 [95% CI = 16.06-23.0]; after treatment = 18.45 [95% CI = 15.26-22.3]). This improvement remained at the follow-up evaluation. Both groups also showed reduced spasticity of plantarflexors and knee extensors, increased quality of life, and increased total distance walked. CONCLUSION This study provided no evidence that bicephalic tDCS improves functional mobility, spasticity, quality of life, or walking endurance in people with chronic hemiparesis after stroke. IMPACT Bicephalic tDCS does not add relevant benefits to FDS and gait training in people who have chronic hemiparesis after stroke. Given that tDCS has few additional effects and given its costs for clinical practice, tDCS for rehabilitation in people with chronic hemiparesis after stroke is discouraged. FDS and gait training improve functional mobility, walking resistance, and quality of life in people with chronic hemiparesis after stroke.
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Affiliation(s)
- Maira Jaqueline da Cunha
- Rehabilitation Sciences Graduate Program, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil.,Movement Analysis and Rehabilitation Laboratory, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Camila Pinto
- Health Sciences Graduate Program, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil.,Movement Analysis and Rehabilitation Laboratory, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Giulia Palermo Schifino
- Rehabilitation Sciences Graduate Program, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil.,Movement Analysis and Rehabilitation Laboratory, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Isabela Sant'Anna Py
- Movement Analysis and Rehabilitation Laboratory, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Veronica Cimolin
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Aline Souza Pagnussat
- Rehabilitation Sciences Graduate Program, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil.,Health Sciences Graduate Program, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil.,Movement Analysis and Rehabilitation Laboratory, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil
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8
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Matsuo H, Kubota M, Hori Y, Izubuchi Y, Takahashi A, Watanabe S, Nakajima H, Matsumine A. Combining transcranial direct current stimulation and peripheral electrical stimulation to improve upper limb function in a patient with acute central cord syndrome: a case report. J Int Med Res 2022; 50:3000605221083248. [PMID: 35352598 PMCID: PMC8973073 DOI: 10.1177/03000605221083248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We report the immediate improvement of weakened muscles after combined treatment with transcranial direct current stimulation (tDCS) and peripheral electrical stimulation (PES) in a patient with acute central cord syndrome (CCS) who presented with severe upper limb motor dysfunction. A 70-year-old man sustained CCS with severe motor deficits in the left upper limb, which did not improve with conventional training until 6 days after injury. On the seventh day after the injury, the left upper limb was targeted with combined tDCS (1 mA for 20 minutes/day, anode on the right, cathode on the left) and PES (deltoid and wrist extensors, 20 minutes/day at the motor threshold), and his performance score immediately improved from 0 to 6 on the Box and Block test. After four sessions, the left upper limb function improved to 32 on the Box and Block test, and manual muscle test scores of the stimulated deltoid and wrist extensors improved from 1 to 2. This improvement of the left upper limb led to improved self-care activities such as eating and changing clothes. Exercise combined with tDCS and PES may be a novel treatment for upper limb movement deficits after acute CCS.
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Affiliation(s)
- Hideaki Matsuo
- Division of Physical Therapy and Rehabilitation Medicine, University of Fukui Hospital, Fukui, Japan
| | - Masafumi Kubota
- Division of Physical Therapy and Rehabilitation Medicine, University of Fukui Hospital, Fukui, Japan.,Department of Physical Therapy, Graduate Course of Rehabilitation Science, School of Health Sciences, College of Medical, Pharmaceutical, and Health Sciences, Kanazawa University, Kanazawa, Japan
| | - Yasue Hori
- Division of Physical Therapy and Rehabilitation Medicine, University of Fukui Hospital, Fukui, Japan
| | - Yuya Izubuchi
- Department of Orthopaedics and Rehabilitation Medicine, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Ai Takahashi
- Division of Physical Therapy and Rehabilitation Medicine, University of Fukui Hospital, Fukui, Japan.,Department of Orthopaedics and Rehabilitation Medicine, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Shuji Watanabe
- Department of Orthopaedics and Rehabilitation Medicine, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Hideaki Nakajima
- Department of Orthopaedics and Rehabilitation Medicine, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Akihiko Matsumine
- Department of Orthopaedics and Rehabilitation Medicine, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
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Lee JH, Jeun YJ, Park HY, Jung YJ. Effect of Transcranial Direct Current Stimulation Combined with Rehabilitation on Arm and Hand Function in Stroke Patients: A Systematic Review and Meta-Analysis. Healthcare (Basel) 2021; 9:healthcare9121705. [PMID: 34946431 PMCID: PMC8701815 DOI: 10.3390/healthcare9121705] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/03/2021] [Accepted: 12/03/2021] [Indexed: 11/16/2022] Open
Abstract
Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that may enhance motor recovery after stroke. We performed a systematic review and meta-analysis to assess the efficacy of tDCS combined with rehabilitation on arm and hand function after stroke. Electronic databases were searched from their inception to September 2021. We performed a systematic review of selected randomized controlled trials, and methodological qualities were measured using the PEDro (Physiotherapy Evidence Database) scale. We calculated the standardized mean difference for effect size using the Comprehensive Meta-Analysis 3.0 software. We selected 28 studies for the systematic review and 20 studies for the meta-analysis. The overall effect size was 0.480 (95% CI [0.307; 0.653], p < 0.05), indicating a moderate effect size of tDCS combined with rehabilitation for upper extremity function in stroke survivors. The tDCS with occupational therapy/physical therapy (0.696; 95% CI [0.390; 1.003], p < 0.05) or virtual reality therapy (0.510; 95% CI [0.111; 0.909], p < 0.05) was also significantly more effective than other treatments. This meta-analysis of 20 randomized controlled trials provides further evidence that tDCS combined with rehabilitation, especially occupational therapy/physical therapy and virtual reality therapy, may benefit upper extremity function of the paretic upper limb in stroke patients.
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Affiliation(s)
- Joo-Hyun Lee
- Department of Occupational Therapy, Baekseok University, Cheonan 31065, Korea;
| | - Yu-Jin Jeun
- Department of ICT Convergence, The Graduate School, Soonchunhyang University, Asan 31538, Korea;
| | - Hae Yean Park
- Department of Occupational Therapy, College of Software and Digital Healthcare Convergence, Yonsei University, Wonju 26493, Korea;
| | - Young-Jin Jung
- School of Healthcare and Biomedical Engineering, Chonnam National University, Yeosu 59626, Korea
- Correspondence:
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Flix-Díez L, Delicado-Miralles M, Gurdiel-Álvarez F, Velasco E, Galán-Calle M, Lerma Lara S. Reversed Polarity bi-tDCS over M1 during a Five Days Motor Task Training Did Not Influence Motor Learning. A Triple-Blind Clinical Trial. Brain Sci 2021; 11:brainsci11060691. [PMID: 34070256 PMCID: PMC8225177 DOI: 10.3390/brainsci11060691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/18/2021] [Accepted: 05/22/2021] [Indexed: 12/04/2022] Open
Abstract
Transcranial direct current stimulation (tDCS) has been investigated as a way of improving motor learning. Our purpose was to explore the reversal bilateral tDCS effects on manual dexterity training, during five days, with the retention component measured after 5 days to determine whether somatosensory effects were produced. In this randomized, triple-blind clinical trial, 28 healthy subjects (14 women) were recruited and randomized into tDCS and placebo groups, although only 23 participants (13 women) finished the complete protocol. Participants received the real or placebo treatment during five consecutive days, while performing a motor dexterity training program of 20 min. The motor dexterity and the sensitivity of the hand were assessed pre- and post-day 1, post 5 days of training, and 5 days after training concluded. Training improved motor dexterity, but tDCS only produced a tendency to improve retention. The intervention did not produce changes in the somatosensory variables assessed. Thus, reversal bi-tDCS had no effects during motor learning on healthy subjects, but it could favor the retention of the motor skills acquired. These results do not support the cooperative inter-hemispheric model.
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Affiliation(s)
- Laura Flix-Díez
- Department of Physical Therapy, University of Valencia (UV), 46003 Valencia, Spain;
| | - Miguel Delicado-Miralles
- Instituto de Neurociencias de Alicante (UMH-CSIC), 03550 Sant Joant d’Alacant, Spain; (M.D.-M.); (E.V.)
| | - Francisco Gurdiel-Álvarez
- Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine University of Rey Juan Carlos, 28922 Alcorcón, Spain;
| | - Enrique Velasco
- Instituto de Neurociencias de Alicante (UMH-CSIC), 03550 Sant Joant d’Alacant, Spain; (M.D.-M.); (E.V.)
| | - María Galán-Calle
- Health Sciences Faculty, Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, 28023 Madrid, Spain;
| | - Sergio Lerma Lara
- Health Sciences Faculty, Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, 28023 Madrid, Spain;
- Motion in Brains Research Group, Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, 28023 Madrid, Spain
- Correspondence: ; Tel.: +34-91-5035900 (ext. 255)
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11
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Wang B, Xiao S, Yu C, Zhou J, Fu W. Effects of Transcranial Direct Current Stimulation Combined With Physical Training on the Excitability of the Motor Cortex, Physical Performance, and Motor Learning: A Systematic Review. Front Neurosci 2021; 15:648354. [PMID: 33897361 PMCID: PMC8062775 DOI: 10.3389/fnins.2021.648354] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 03/08/2021] [Indexed: 01/28/2023] Open
Abstract
Purpose: This systematic review aims to examine the efficacy of transcranial direct current stimulation (tDCS) combined with physical training on the excitability of the motor cortex, physical performance, and motor learning. Methods: A systematic search was performed on PubMed, Web of Science, and EBSCO databases for relevant research published from inception to August 2020. Eligible studies included those that used a randomized controlled design and reported the effects of tDCS combined with physical training to improve motor-evoked potential (MEP), dynamic posture stability index (DPSI), reaction time, and error rate on participants without nervous system diseases. The risk of bias was assessed by the Cochrane risk of bias assessment tool. Results: Twenty-four of an initial yield of 768 studies met the eligibility criteria. The risk of bias was considered low. Results showed that anodal tDCS combined with physical training can significantly increase MEP amplitude, decrease DPSI, increase muscle strength, and decrease reaction time and error rate in motor learning tasks. Moreover, the gain effect is significantly greater than sham tDCS combined with physical training. Conclusion: tDCS combined with physical training can effectively improve the excitability of the motor cortex, physical performance, and motor learning. The reported results encourage further research to understand further the synergistic effects of tDCS combined with physical training.
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Affiliation(s)
- Baofeng Wang
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Songlin Xiao
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Changxiao Yu
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Junhong Zhou
- The Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife, Boston, MA, United States.,Harvard Medical School, Boston, MA, United States
| | - Weijie Fu
- School of Kinesiology, Shanghai University of Sport, Shanghai, China.,Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China
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12
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TDCS effects on pointing task learning in young and old adults. Sci Rep 2021; 11:3421. [PMID: 33564052 PMCID: PMC7873227 DOI: 10.1038/s41598-021-82275-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 01/14/2021] [Indexed: 01/19/2023] Open
Abstract
Skill increase in motor performance can be defined as explicitly measuring task success but also via more implicit measures of movement kinematics. Even though these measures are often related, there is evidence that they represent distinct concepts of learning. In the present study, the effect of multiple tDCS-sessions on both explicit and implicit measures of learning are investigated in a pointing task in 30 young adults (YA) between 27.07 ± 3.8 years and 30 old adults (OA) between 67.97 years ± 5.3 years. We hypothesized, that OA would show slower explicit skill learning indicated by higher movement times/lower accuracy and slower implicit learning indicated by higher spatial variability but profit more from anodal tDCS compared with YA. We found age-related differences in movement time but not in accuracy or spatial variability. TDCS did not skill learning facilitate learning neither in explicit nor implicit parameters. However, contrary to our hypotheses, we found tDCS-associated higher accuracy only in YA but not in spatial variability. Taken together, our data shows limited overlapping of tDCS effects in explicit and implicit skill parameters. Furthermore, it supports the assumption that tDCS is capable of producing a performance-enhancing brain state at least for explicit skill acquisition.
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13
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Kim T, Kim H, Wright DL. Improving consolidation by applying anodal transcranial direct current stimulation at primary motor cortex during repetitive practice. Neurobiol Learn Mem 2020; 178:107365. [PMID: 33348047 DOI: 10.1016/j.nlm.2020.107365] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 11/22/2020] [Accepted: 12/15/2020] [Indexed: 11/19/2022]
Abstract
Engagement of primary motor cortex (M1) is important for successful consolidation of motor skills. Recruitment of M1 has been reported to be more extensive during interleaved compared to repetitive practice and this differential recruitment has been proposed to contribute to the long-term retention benefit associated with interleaved practice. The present study administered anodal direct current stimulation (tDCS) during repetitive practice in an attempt to increase M1 activity throughout repetitive practice with the goal to improve the retention performance of individuals exposed to this training format. Fifty-four participants were assigned to one of three experimental groups that included: interleaved-sham, repetitive-sham, and repetitive-anodal tDCS. Real or sham stimulation at M1 was administered during practice of three motor sequences for approximately 20-min. Performance in the absence of any stimulation was evaluated prior to practice, immediately after practice as well as at 6-hr, and 24-h after practice was complete. As expected, for the sham conditions, interleaved as opposed repetitive practice resulted in superior offline gain. This was manifest as more rapid stabilization of performance after 6-h as well as an enhancement in performance with a period of overnight sleep. Administration of anodal stimulation at M1 during repetitive practice improved offline gains assessed at both 6-h and 24-h tests compared to the repetitive practice sham group. These data are consistent with the claims that reduced activation at M1 during repetitive practice impedes offline gain relative to interleaved practice and that M1 plays an important role in early consolidation of novel motor skills even in the context of the simultaneous acquisition of multiple new skills. Moreover, these findings highlight a possible role for M1 during sleep-related consolidation, possibly as part of a network including the dorsal premotor region, which supports delayed performance enhancement.
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Affiliation(s)
- Taewon Kim
- Division of Stroke and Vascular Neurology, Department of Neurology, Duke University Medical Center, Durham, NC, USA.
| | - Hakjoo Kim
- Non-Invasive Brain Stimulation Laboratory, Department of Health and Kinesiology, Texas A&M University, College Station, TX, USA.
| | - David L Wright
- Non-Invasive Brain Stimulation Laboratory, Department of Health and Kinesiology, Texas A&M University, College Station, TX, USA.
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14
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Marquardt L, Kusztrits I, Craven AR, Hugdahl K, Specht K, Hirnstein M. A multimodal study of the effects of tDCS on dorsolateral prefrontal and temporo-parietal areas during dichotic listening. Eur J Neurosci 2020; 53:449-459. [PMID: 32746504 DOI: 10.1111/ejn.14932] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 07/24/2020] [Indexed: 01/06/2023]
Abstract
The underlying neural mechanisms of transcranial direct current stimulation (tDCS), especially beyond the primary motor cortex, remain unclear. Several studies examined tDCS effects on either functional activity, neurotransmitters or behavior but few investigated those aspects together to reveal how the brain responds to tDCS. The objective is to elucidate the underlying mechanisms of tDCS using a multimodal approach that extends from behavioral to neurotransmitter levels of explanation. Thirty-two healthy participants performed an auditory dichotic listening task at two visits, one session with sham and one session with real tDCS (2 mA) while simultaneously undergoing functional magnetic resonance imaging (fMRI). The anode and cathode were placed over the left temporo-parietal cortex (TPC) and dorsolateral prefrontal cortex, respectively. Before and after simultaneous dichotic listening/fMRI/tDCS, combined glutamate and glutamine (Glx) and myo-inositol levels were assessed in the stimulated areas. While fMRI and dichotic listening showed expected functional activity and behavioral effects, neither method demonstrated differences between real and sham stimulation. Glx only showed a statistical trend towards higher levels after real tDCS in both stimulated brain areas. There were no significant correlations between behavior and Glx. Despite a reasonable sample size, electrical field strength, and replication of behavioral and functional activity results, tDCS had little to no effect on dichotic listening, Glx, and functional activity. The study emphasizes that findings about the underlying neural mechanisms of the primary motor cortex cannot simply be generalized to other brain areas. Particularly, the TPC might be less sensitive to tDCS. Moreover, the study demonstrates the general feasibility of multimodal approaches.
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Affiliation(s)
- Lynn Marquardt
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway.,NORMENT Center of Excellence, University of Bergen, Haukeland University Hospital, Bergen, Norway
| | - Isabella Kusztrits
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway.,NORMENT Center of Excellence, University of Bergen, Haukeland University Hospital, Bergen, Norway
| | - Alexander R Craven
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway.,NORMENT Center of Excellence, University of Bergen, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Engineering, Haukeland University Hospital, Bergen, Norway
| | - Kenneth Hugdahl
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway.,NORMENT Center of Excellence, University of Bergen, Haukeland University Hospital, Bergen, Norway.,Department of Radiology, Haukeland University Hospital, Bergen, Norway.,Division of Psychiatry, Haukeland University Hospital, Bergen, Norway
| | - Karsten Specht
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway.,Mohn Medical and Imaging Visualization Centre, Haukeland University Hospital, Bergen, Norway.,Department of Education, UiT/The Arctic University of Norway, Tromsø, Norway
| | - Marco Hirnstein
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway.,NORMENT Center of Excellence, University of Bergen, Haukeland University Hospital, Bergen, Norway
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15
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Guggenberger R, Heringhaus M, Gharabaghi A. Brain-Machine Neurofeedback: Robotics or Electrical Stimulation? Front Bioeng Biotechnol 2020; 8:639. [PMID: 32733860 PMCID: PMC7358603 DOI: 10.3389/fbioe.2020.00639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 05/26/2020] [Indexed: 12/19/2022] Open
Abstract
Neurotechnology such as brain-machine interfaces (BMI) are currently being investigated as training devices for neurorehabilitation, when active movements are no longer possible. When the hand is paralyzed following a stroke for example, a robotic orthosis, functional electrical stimulation (FES) or their combination may provide movement assistance; i.e., the corresponding sensory and proprioceptive neurofeedback is given contingent to the movement intention or imagination, thereby closing the sensorimotor loop. Controlling these devices may be challenging or even frustrating. Direct comparisons between these two feedback modalities (robotics vs. FES) with regard to the workload they pose for the user are, however, missing. Twenty healthy subjects controlled a BMI by kinesthetic motor imagery of finger extension. Motor imagery-related sensorimotor desynchronization in the EEG beta frequency-band (17–21 Hz) was turned into passive opening of the contralateral hand by a robotic orthosis or FES in a randomized, cross-over block design. Mental demand, physical demand, temporal demand, performance, effort, and frustration level were captured with the NASA Task Load Index (NASA-TLX) questionnaire by comparing these workload components to each other (weights), evaluating them individually (ratings), and estimating the respective combinations (adjusted workload ratings). The findings were compared to the task-related aspects of active hand movement with EMG feedback. Furthermore, both feedback modalities were compared with regard to their BMI performance. Robotic and FES feedback had similar workloads when weighting and rating the different components. For both robotics and FES, mental demand was the most relevant component, and higher than during active movement with EMG feedback. The FES task led to significantly more physical (p = 0.0368) and less temporal demand (p = 0.0403) than the robotic task in the adjusted workload ratings. Notably, the FES task showed a physical demand 2.67 times closer to the EMG task, but a mental demand 6.79 times closer to the robotic task. On average, significantly more onsets were reached during the robotic as compared to the FES task (17.22 onsets, SD = 3.02 vs. 16.46, SD = 2.94 out of 20 opportunities; p = 0.016), even though there were no significant differences between the BMI classification accuracies of the conditions (p = 0.806; CI = −0.027 to −0.034). These findings may inform the design of neurorehabilitation interfaces toward human-centered hardware for a more natural bidirectional interaction and acceptance by the user.
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Affiliation(s)
- Robert Guggenberger
- Institute for Neuromodulation and Neurotechnology, Department of Neurosurgery and Neurotechnology, University of Tübingen, Tübingen, Germany
| | - Monika Heringhaus
- Institute for Neuromodulation and Neurotechnology, Department of Neurosurgery and Neurotechnology, University of Tübingen, Tübingen, Germany
| | - Alireza Gharabaghi
- Institute for Neuromodulation and Neurotechnology, Department of Neurosurgery and Neurotechnology, University of Tübingen, Tübingen, Germany
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16
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Wiltshire CEE, Watkins KE. Failure of tDCS to modulate motor excitability and speech motor learning. Neuropsychologia 2020; 146:107568. [PMID: 32687836 PMCID: PMC7534039 DOI: 10.1016/j.neuropsychologia.2020.107568] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/25/2020] [Accepted: 07/15/2020] [Indexed: 12/25/2022]
Abstract
Transcranial direct current stimulation (tDCS) modulates cortical excitability in a polarity-specific way and, when used in combination with a behavioural task, it can alter performance. TDCS has the potential, therefore, for use as an adjunct to therapies designed to treat disorders affecting speech, including, but not limited to acquired aphasias and developmental stuttering. For this reason, it is important to conduct studies evaluating its effectiveness and the parameters optimal for stimulation. Here, we aimed to evaluate the effects of bi-hemispheric tDCS over speech motor cortex on performance of a complex speech motor learning task, namely the repetition of tongue twisters. A previous study in older participants showed that tDCS could modulate performance on a similar task. To further understand the effects of tDCS, we also measured the excitability of the speech motor cortex before and after stimulation. Three groups of 20 healthy young controls received: (i) anodal tDCS to the left IFG/LipM1 and cathodal tDCS to the right hemisphere homologue; or (ii) cathodal tDCS over the left and anodal over the right; or (iii) sham stimulation. Participants heard and repeated novel tongue twisters and matched simple sentences before, during and 10 min after the stimulation. One mA tDCS was delivered concurrent with task performance for 13 min. Motor excitability was measured using transcranial magnetic stimulation to elicit motor-evoked potentials in the lip before and immediately after tDCS. The study was double-blind, randomized, and sham-controlled; the design and analysis were pre-registered. Performance on the task improved from baseline to after stimulation but was not significantly modulated by tDCS. Similarly, a small decrease in motor excitability was seen in all three stimulation groups but did not differ among them and was unrelated to task performance. Bayesian analyses provide substantial evidence in support of the null hypotheses in both cases, namely that tongue twister performance and motor excitability were not affected by tDCS. We discuss our findings in the context of the previous positive results for a similar task. We conclude that tDCS may be most effective when brain function is sub-optimal due to age-related declines or pathology. Further study is required to determine why tDCS failed to modulate excitability in the speech motor cortex in the expected ways.
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Affiliation(s)
- Charlotte E E Wiltshire
- Wellcome Centre for Integrative Neuroimaging, Department of Experimental Psychology, Radcliffe Observatory Quarter, University of Oxford, OX2 6GG, UK.
| | - Kate E Watkins
- Wellcome Centre for Integrative Neuroimaging, Department of Experimental Psychology, Radcliffe Observatory Quarter, University of Oxford, OX2 6GG, UK.
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17
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Asín-Prieto G, Martínez-Expósito A, Barroso FO, Urendes EJ, Gonzalez-Vargas J, Alnajjar FS, González-Alted C, Shimoda S, Pons JL, Moreno JC. Haptic Adaptive Feedback to Promote Motor Learning With a Robotic Ankle Exoskeleton Integrated With a Video Game. Front Bioeng Biotechnol 2020; 8:113. [PMID: 32154239 PMCID: PMC7047324 DOI: 10.3389/fbioe.2020.00113] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 02/04/2020] [Indexed: 12/18/2022] Open
Abstract
Background: Robotic devices have been used to rehabilitate walking function after stroke. Although results suggest that post-stroke patients benefit from this non-conventional therapy, there is no agreement on the optimal robot-assisted approaches to promote neurorecovery. Here we present a new robotic therapy protocol using a grounded exoskeleton perturbing the ankle joint based on tacit learning control. Method: Ten healthy individuals and a post-stroke patient participated in the study and were enrolled in a pilot intervention protocol that involved performance of ankle movements following different trajectories via video game visual feedback. The system autonomously modulated task difficulty according to the performance to increase the challenge. We hypothesized that motor learning throughout training sessions would lead to increased corticospinal excitability of dorsi-plantarflexor muscles. Transcranial Magnetic Stimulation was used to assess the effects on corticospinal excitability. Results: Improvements have been observed on task performance and motor outcomes in both healthy individuals and post-stroke patient case study. Tibialis Anterior corticospinal excitability increased significantly after the training; however no significant changes were observed on Soleus corticospinal excitability. Clinical scales showed functional improvements in the stroke patient. Discussion and Significance: Our findings both in neurophysiological and performance assessment suggest improved motor learning. Some limitations of the study include treatment duration and intensity, as well as the non-significant changes in corticospinal excitability obtained for Soleus. Nonetheless, results suggest that this robotic training framework is a potentially interesting approach that can be explored for gait rehabilitation in post-stroke patients.
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Affiliation(s)
- Guillermo Asín-Prieto
- Neural Rehabilitation Group, Cajal Institute, CSIC-Spanish National Research Council, Madrid, Spain
| | - Aitor Martínez-Expósito
- Neural Rehabilitation Group, Cajal Institute, CSIC-Spanish National Research Council, Madrid, Spain
| | - Filipe O Barroso
- Neural Rehabilitation Group, Cajal Institute, CSIC-Spanish National Research Council, Madrid, Spain
| | - Eloy J Urendes
- Department of Information Systems Engineering, University San Pablo CEU, Boadilla del Monte, Spain
| | - Jose Gonzalez-Vargas
- Department of Translations Research and Knowledge Management, OttoBock Healthcare GmbH, Duderstadt, Germany
| | - Fady S Alnajjar
- College of Information Technology, The United Arab Emirates University, Al-Ain, United Arab Emirates
| | | | - Shingo Shimoda
- Intelligent Behaviour Control Unit, RIKEN, Nagoya, Japan
| | - Jose L Pons
- Neural Rehabilitation Group, Cajal Institute, CSIC-Spanish National Research Council, Madrid, Spain.,Legs & Walking AbilityLab, Shirley Ryan AbilityLab, Chicago, IL, United States.,Department of Biomedical Engineering and Mechanical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL, United States.,Department of PM&R, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Juan C Moreno
- Neural Rehabilitation Group, Cajal Institute, CSIC-Spanish National Research Council, Madrid, Spain
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18
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Halakoo S, Ehsani F, Hosnian M, Zoghi M, Jaberzadeh S. The comparative effects of unilateral and bilateral transcranial direct current stimulation on motor learning and motor performance: A systematic review of literature and meta-analysis. J Clin Neurosci 2020; 72:8-14. [PMID: 31973922 DOI: 10.1016/j.jocn.2019.12.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/01/2019] [Indexed: 11/17/2022]
Abstract
Application of unilateral tDCS (Uni-tDCS) vs. bilateral tDCS (Bi-tDCS) is another important factor that can affect the physiological results of tDCS intervention on motor learning and motor performance. According to the evidence, some studies indicated that motor performance or motor learning are facilitated in healthy individuals by application of the Bi-tDCS more than the Uni-tDCS. On the other hand, some studies showed that there was no significant differences between Uni-tDCS and Bi-tDCS; and both techniques were more effective than sham stimulation. In contrast, the other studies have shown more significant effectiveness of Uni-tDCS than Bi-tDCS on motor performance and motor learning. The aim of this study was to systematically review the studies which investigated the effectiveness of Uni-tDCS and Bi-tDCS intervention on the motor learning and motor performance. The search was performed from databases in the Google Scholar, PubMed, Elsevier, Medline, Ovid and Science Direct with the keywords of motor behavior, motor performance, motor learning, Bi-tDCS or bilateral tDCS, dual tDCS, Uni-tDCS or unilateral tDCS, anodal tDCS and cathodal tDCS from 2000 to 2019. The results indicated that the study population was a key factor in determining study's findings. Data meta-analysis showed that Uni-tDCS was more effective than Bi-tDCS in patients with stroke, while, Bi-tDCS was more effective than Uni-tDCS to improve motor learning and motor performance in healthy individuals.
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Affiliation(s)
- Sara Halakoo
- Neuromuscular Rehabilitation Research Center, Semnan University of Medical Sciences, Semnan, Iran
| | - Fatemeh Ehsani
- Neuromuscular Rehabilitation Research Center, Semnan University of Medical Sciences, Semnan, Iran.
| | - Motahareh Hosnian
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Zoghi
- Discipline of Physiotherapy, Department of Rehabilitation, Nutrition and Sport, School of Allied Health, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Shapour Jaberzadeh
- Department of Physiotherapy, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
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19
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Acquisition of chopstick-operation skills with the non-dominant hand and concomitant changes in brain activity. Sci Rep 2019; 9:20397. [PMID: 31892724 PMCID: PMC6938489 DOI: 10.1038/s41598-019-56956-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 12/18/2019] [Indexed: 01/07/2023] Open
Abstract
Despite their common use as eating utensils in East Asia, chopsticks require complex fine motor-skills for adequate operation and are thus most frequently used with the dominant hand; however, the effect of training time on the proficiency of using chopsticks with the non-dominant hand, as well as the brain activity underlying changes in skill, remain unclear. This study characterised the effect of time spent training in chopstick operation with the non-dominant hand on chopstick-use proficiency and the related brain activity to obtain data that may help individuals who are obliged to change handedness due to neurological disease to learn to use their non-dominant hand in performing daily activities. Thirty-two healthy right-handed students were randomly allocated to training (n = 16) or control (n = 16) groups; the former received 6 weeks of training in chopstick use with their non-dominant (left) hand, and the latter received none. After training, significant improvements in the execution speed and smoothness of upper extremity joints were observed in the training group. Moreover, left dorsolateral prefrontal cortex activity significantly decreased, and bilateral premotor cortex activity significantly increased across training. These results indicated that 6 weeks of chopstick training with the non-dominant hand effectively improved chopstick operation.
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20
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The Tolerability and Efficacy of 4 mA Transcranial Direct Current Stimulation on Leg Muscle Fatigability. Brain Sci 2019; 10:brainsci10010012. [PMID: 31878058 PMCID: PMC7017217 DOI: 10.3390/brainsci10010012] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 12/19/2019] [Accepted: 12/20/2019] [Indexed: 12/12/2022] Open
Abstract
Transcranial direct current stimulation (tDCS) modulates cortical excitability and affects a variety of outcomes. tDCS at intensities ≤2 mA is well-tolerated, but the tolerability and efficacy of tDCS at intensities >2 mA merits systematic investigation. The study objective was to determine the tolerability and effects of 4 mA tDCS on leg muscle fatigability. Thirty-one young, healthy adults underwent two randomly ordered tDCS conditions (sham, 4 mA) applied before and during an isokinetic fatigue test of the knee extensors and flexors. Subjects reported the severity of the sensations felt from tDCS. Primary outcomes were sensation tolerability and the fatigue index of the knee extensors and flexors. A repeated-measures ANOVA determined statistical significance (p < 0.05). Sensation severity at 4 mA tDCS was not substantially different than sham. However, two subjects reported a moderate–severe headache, which dissipated soon after the stimulation ended. The left knee flexors had significantly greater fatigability with 4 mA tDCS compared with sham (p = 0.018). tDCS at 4 mA was well-tolerated by young, healthy subjects and increased left knee flexor fatigability. Exploration of higher intensity tDCS (>2 mA) to determine the potential benefits of increasing intensity, especially in clinical populations with decreased brain activity/excitability, is warranted.
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21
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Workman CD, Kamholz J, Rudroff T. Transcranial Direct Current Stimulation (tDCS) to Improve Gait in Multiple Sclerosis: A Timing Window Comparison. Front Hum Neurosci 2019; 13:420. [PMID: 31849628 PMCID: PMC6893177 DOI: 10.3389/fnhum.2019.00420] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 11/13/2019] [Indexed: 12/18/2022] Open
Abstract
Unilateral weakness of the lower limb is a hallmark of multiple sclerosis (MS) and a significant contributor to the progressive worsening of walking ability. There are currently no effective rehabilitation strategies targeting strength asymmetries and/or gait impairments in people with MS (PwMS). Transcranial direct current stimulation (tDCS) has improved motor outcomes in various populations, but the effect of tDCS on gait in PwMS and the ideal timing window of tDCS application are still unknown. This study investigated the effects of tDCS, either before or during a 6 min walk test (6MWT), on the distance walked and gait characteristics in PwMS. Twelve participants were recruited and randomly assigned into BEFORE or DURING groups (both n = 6). The BEFORE group received stimulation before performing a 6MWT (sham/2 mA, 13 min). The DURING group received stimulation only during a 6MWT (sham/2 mA, 6 min). Stimulation was over the more MS-affected primary motor cortex (M1). Distance walked and gait characteristics of the walk were the primary and secondary outcomes. The results indicated a significant decrease in distance walked in the DURING group (p = 0.026) and a significant increase in gait velocity in the BEFORE group (p = 0.04). These changes were accompanied by trends (p < 0.1) in distance walked, gait velocity, and stride length. Overall, the results of this study suggest that tDCS performed before a 6MWT might be more effective than tDCS during a 6MWT and that a single session of tDCS may not be sufficient to influence gait. Clinical Trial Registration: www.ClinicalTrials.gov, identifier #NCT03757819.
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Affiliation(s)
- Craig D Workman
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, United States
| | - John Kamholz
- Department of Neurology, Carver College of Medicine, University of Iowa Hospitals and Clinics, Iowa City, IA, United States
| | - Thorsten Rudroff
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, United States.,Department of Neurology, Carver College of Medicine, University of Iowa Hospitals and Clinics, Iowa City, IA, United States
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22
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Application of anodal tDCS at primary motor cortex immediately after practice of a motor sequence does not improve offline gain. Exp Brain Res 2019; 238:29-37. [PMID: 31758203 DOI: 10.1007/s00221-019-05697-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 11/17/2019] [Indexed: 10/25/2022]
Abstract
Tecchio et al. (J Neurophysiology 104: 1134-1140, 2010) reported that the application of anodal tDCS at primary motor cortex (M1) immediately after practice of a procedural motor skill enhanced consolidation, which in turn improved offline gain. Tecchio et al. noted, however, that this study did not account for known after-effects associated with this form of non-invasive stimulation. The present study was designed to explicitly reevaluate Tecchio et al.'s claim. As in the original study, individuals experienced either anodal or sham stimulation at M1 after practice of a serial reaction time task (SRTT) followed by test trials 15-min later. Two additional novel conditions experienced the test trials after 120-min rather than 15-min thus allowing potential stimulation after-effects to dissipate. The expectation was that if anodal stimulation influences post-practice consolidation leading to offline gain, this effect would be present not only at 15-min but also after 120-min. In agreement with the working hypothesis, findings revealed offline gain at both 15-min and the longer 2-h time period. Unexpectedly, we found no interaction between real and sham conditions. The lack of difference between Real and Sham effects weakens confidence in the potential of post-practice tDCS for consolidation enhancement, while it is more consistent with other claims that decoupling practice and anodal tDCS stimulation in time can reduce the effectiveness of exogenous stimulation for procedural skill gain.
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Patel R, Ashcroft J, Patel A, Ashrafian H, Woods AJ, Singh H, Darzi A, Leff DR. The Impact of Transcranial Direct Current Stimulation on Upper-Limb Motor Performance in Healthy Adults: A Systematic Review and Meta-Analysis. Front Neurosci 2019; 13:1213. [PMID: 31803003 PMCID: PMC6873898 DOI: 10.3389/fnins.2019.01213] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 10/28/2019] [Indexed: 11/25/2022] Open
Abstract
Background: Transcranial direct current stimulation (tDCS) has previously been reported to improve facets of upper limb motor performance such as accuracy and strength. However, the magnitude of motor performance improvement has not been reviewed by contemporaneous systematic review or meta-analysis of sham vs. active tDCS. Objective: To systematically review and meta-analyse the existing evidence regarding the benefits of tDCS on upper limb motor performance in healthy adults. Methods: A systematic search was conducted to obtain relevant articles from three databases (MEDLINE, EMBASE, and PsycINFO) yielding 3,200 abstracts. Following independent assessment by two reviewers, a total of 86 articles were included for review, of which 37 were deemed suitable for meta-analysis. Results: Meta-analyses were performed for four outcome measures, namely: reaction time (RT), execution time (ET), time to task failure (TTF), and force. Further qualitative review was performed for accuracy and error. Statistically significant improvements in RT (effect size −0.01; 95% CI −0.02 to 0.001, p = 0.03) and ET (effect size −0.03; 95% CI −0.05 to −0.01, p = 0.017) were demonstrated compared to sham. In exercise tasks, increased force (effect size 0.10; 95% CI 0.08 to 0.13, p < 0.001) and a trend towards improved TTF was also observed. Conclusions: This meta-analysis provides evidence attesting to the impact of tDCS on upper limb motor performance in healthy adults. Improved performance is demonstrable in reaction time, task completion time, elbow flexion tasks and accuracy. Considerable heterogeneity exists amongst the literature, further confirming the need for a standardised approach to reporting tDCS studies.
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Affiliation(s)
- Ronak Patel
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - James Ashcroft
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Ashish Patel
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Hutan Ashrafian
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Adam J Woods
- Department of Clinical and Health Psychology, Center for Cognitive Aging and Memory, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Harsimrat Singh
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Ara Darzi
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
| | - Daniel Richard Leff
- Department of Surgery & Cancer, Imperial College London, London, United Kingdom
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Hanenberg C, Getzmann S, Lewald J. Transcranial direct current stimulation of posterior temporal cortex modulates electrophysiological correlates of auditory selective spatial attention in posterior parietal cortex. Neuropsychologia 2019; 131:160-170. [PMID: 31145907 DOI: 10.1016/j.neuropsychologia.2019.05.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 05/03/2019] [Accepted: 05/25/2019] [Indexed: 01/12/2023]
Abstract
Speech perception in "cocktail-party" situations, in which a sound source of interest has to be extracted out of multiple irrelevant sounds, poses a remarkable challenge to the human auditory system. Studies on structural and electrophysiological correlates of auditory selective spatial attention revealed critical roles of the posterior temporal cortex and the N2 event-related potential (ERP) component in the underlying processes. Here, we explored effects of transcranial direct current stimulation (tDCS) to posterior temporal cortex on neurophysiological correlates of auditory selective spatial attention, with a specific focus on the N2. In a single-blind, sham-controlled crossover design with baseline and follow-up measurements, monopolar anodal and cathodal tDCS was applied for 16 min to the right posterior superior temporal cortex. Two age groups of human subjects, a younger (n = 20; age 18-30 yrs) and an older group (n = 19; age 66-77 yrs), completed an auditory free-field multiple-speakers localization task while ERPs were recorded. The ERP data showed an offline effect of anodal, but not cathodal, tDCS immediately after DC offset for targets contralateral, but not ipsilateral, to the hemisphere of tDCS, without differences between groups. This effect mainly consisted in a substantial increase of the N2 amplitude by 0.9 μV (SE 0.4 μV; d = 0.40) compared with sham tDCS. At the same point in time, cortical source localization revealed a reduction of activity in ipsilateral (right) posterior parietal cortex. Also, localization error was improved after anodal, but not cathodal, tDCS. Given that both the N2 and the posterior parietal cortex are involved in processes of auditory selective spatial attention, these results suggest that anodal tDCS specifically enhanced inhibitory attentional brain processes underlying the focusing onto a target sound source, possibly by improved suppression of irrelevant distracters.
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Affiliation(s)
- Christina Hanenberg
- Ruhr University Bochum, Faculty of Psychology, D-44780, Bochum, Germany; Leibniz Research Centre for Working Environment and Human Factors, D-44139, Dortmund, Germany
| | - Stephan Getzmann
- Leibniz Research Centre for Working Environment and Human Factors, D-44139, Dortmund, Germany
| | - Jörg Lewald
- Ruhr University Bochum, Faculty of Psychology, D-44780, Bochum, Germany.
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Bihemispheric anodal transcranial direct-current stimulation over temporal cortex enhances auditory selective spatial attention. Exp Brain Res 2019; 237:1539-1549. [PMID: 30927041 DOI: 10.1007/s00221-019-05525-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 03/20/2019] [Indexed: 10/27/2022]
Abstract
The capacity to selectively focus on a particular speaker of interest in a complex acoustic environment with multiple persons speaking simultaneously-a so-called "cocktail-party" situation-is of decisive importance for human verbal communication. Here, the efficacy of single-dose transcranial direct-current stimulation (tDCS) in improving this ability was tested in young healthy adults (n = 24), using a spatial task that required the localization of a target word in a simulated "cocktail-party" situation. In a sham-controlled crossover design, offline bihemispheric double-monopolar anodal tDCS was applied for 30 min at 1 mA over auditory regions of temporal lobe, and the participant's performance was assessed prior to tDCS, immediately after tDCS, and 1 h after tDCS. A significant increase in the amount of correct localizations by on average 3.7 percentage points (d = 1.04) was found after active, relative to sham, tDCS, with only insignificant reduction of the effect within 1 h after tDCS offset. Thus, the method of bihemispheric tDCS could be a promising tool for enhancement of human auditory attentional functions that are relevant for spatial orientation and communication in everyday life.
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Lopez-Alonso V, Liew SL, Fernández Del Olmo M, Cheeran B, Sandrini M, Abe M, Cohen LG. A Preliminary Comparison of Motor Learning Across Different Non-invasive Brain Stimulation Paradigms Shows No Consistent Modulations. Front Neurosci 2018; 12:253. [PMID: 29740271 PMCID: PMC5924807 DOI: 10.3389/fnins.2018.00253] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 04/03/2018] [Indexed: 12/13/2022] Open
Abstract
Non-invasive brain stimulation (NIBS) has been widely explored as a way to safely modulate brain activity and alter human performance for nearly three decades. Research using NIBS has grown exponentially within the last decade with promising results across a variety of clinical and healthy populations. However, recent work has shown high inter-individual variability and a lack of reproducibility of previous results. Here, we conducted a small preliminary study to explore the effects of three of the most commonly used excitatory NIBS paradigms over the primary motor cortex (M1) on motor learning (Sequential Visuomotor Isometric Pinch Force Tracking Task) and secondarily relate changes in motor learning to changes in cortical excitability (MEP amplitude and SICI). We compared anodal transcranial direct current stimulation (tDCS), paired associative stimulation (PAS25), and intermittent theta burst stimulation (iTBS), along with a sham tDCS control condition. Stimulation was applied prior to motor learning. Participants (n = 28) were randomized into one of the four groups and were trained on a skilled motor task. Motor learning was measured immediately after training (online), 1 day after training (consolidation), and 1 week after training (retention). We did not find consistent differential effects on motor learning or cortical excitability across groups. Within the boundaries of our small sample sizes, we then assessed effect sizes across the NIBS groups that could help power future studies. These results, which require replication with larger samples, are consistent with previous reports of small and variable effect sizes of these interventions on motor learning.
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Affiliation(s)
- Virginia Lopez-Alonso
- Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, MD, United States.,Department of Physical Activity and Sport Sciences, "Center of Higher Education Alberta Giménez (CESAG)" Comillas Pontifical University, Palma, Spain.,Department of Physical Education, Faculty of Sciences of Sport and Physical Education, University of A Coruña, A Coruña, Spain
| | - Sook-Lei Liew
- Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, MD, United States.,Departments of Occupational Therapy, Biokinesiology, and Neurology, Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, United States
| | - Miguel Fernández Del Olmo
- Department of Physical Education, Faculty of Sciences of Sport and Physical Education, University of A Coruña, A Coruña, Spain
| | - Binith Cheeran
- Molecular and Clinical Sciences Institute, St. George's, University of London, London, United Kingdom.,The London Clinic, London, United Kingdom
| | - Marco Sandrini
- Department of Psychology, University of Roehampton, London, United Kingdom
| | - Mitsunari Abe
- Faculty of Medicine, Center for Neurological Disorders, Fukushima Medical University, Fukushima, Japan
| | - Leonardo G Cohen
- Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, MD, United States
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Pixa NH, Pollok B. Effects of tDCS on Bimanual Motor Skills: A Brief Review. Front Behav Neurosci 2018; 12:63. [PMID: 29670514 PMCID: PMC5893856 DOI: 10.3389/fnbeh.2018.00063] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/16/2018] [Indexed: 01/07/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that allows the modulation of cortical excitability as well as neuroplastic reorganization using a weak constant current applied through the skull on the cerebral cortex. TDCS has been found to improve motor performance in general and motor learning in particular. However, these effects have been reported almost exclusively for unimanual motor tasks such as serial reaction time tasks, adaptation tasks, or visuo-motor tracking. Despite the importance of bimanual actions in most activities of daily living, only few studies have investigated the effects of tDCS on bimanual motor skills. The objectives of this review article are: (i) to provide a concise overview of the few existing studies in this area; and (ii) to discuss the effects of tDCS on bimanual motor skills in healthy volunteers and patients suffering from neurological diseases. Despite considerable variations in stimulation protocols, the bimanual tasks employed, and study designs, the data suggest that tDCS has the potential to enhance bimanual motor skills. The findings imply that the effects of tDCS vary with task demands, such as complexity and the level of expertise of the participating volunteers. Nevertheless, optimized stimulation protocols tailored to bimanual tasks and individual performance considering the underlying neural substrates of task execution are required in order to probe the effectiveness of tDCS in greater detail, thus creating an opportunity to support motor recovery in neuro-rehabilitation.
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Affiliation(s)
- Nils H Pixa
- Department of Sport Psychology, Institute of Sports Science, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Bettina Pollok
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
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van Steenburgh JJ, Varvaris M, Schretlen DJ, Vannorsdall TD, Gordon B. Balanced bifrontal transcranial direct current stimulation enhances working memory in adults with high-functioning autism: a sham-controlled crossover study. Mol Autism 2017; 8:40. [PMID: 28775825 PMCID: PMC5534041 DOI: 10.1186/s13229-017-0152-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 06/16/2017] [Indexed: 11/20/2022] Open
Abstract
Background Working memory (WM) often is impaired in autism spectrum disorder (ASD). Such impairment may underlie core deficits in cognition and social functioning. Transcranial direct current stimulation (tDCS) has been shown to enhance WM in both healthy adults and clinical populations, but its efficacy in ASD is unknown. We predicted that bifrontal tDCS would improve WM performances of adults with high-functioning autism during active stimulation compared to sham stimulation and that such enhancement would generalize to an untrained task. Methods Twelve adults with high-functioning ASD engaged in a battery of WM tasks that included backward spatial span, backward digit span, spatial n-back and letter n-back. While engaged, 40 min of 1.5 mA bifrontal stimulation was applied over the left and the right dorsolateral prefrontal cortices (DLPFC). Using a single-blind crossover design, each participant received left anodal/right cathodal stimulation, right anodal/left cathodal stimulation, or sham stimulation, in randomized counterbalanced order on three separate days. Following tDCS, participants again engaged in letter and spatial n-back tasks before taking the Brief Test of Attention (BTA). We used repeated-measures ANOVA to compare overall performance on the WM battery as measured by a composite of z-scores for all five measures. Post hoc ANOVAs, t tests, Friedman’s tests, and Wilcoxon signed-rank tests were used to measure the online and offline effects of tDCS and to assess performances on individual measures. Results Compared to sham stimulation, both left DLPFC anodal stimulation (t11 = 5.4, p = 0.0002) and right DLPFC anodal stimulation (t11 = 3.57, p = 0.004) improved overall WM performance. Left anodal stimulation (t11 = 3.9, p = 0.003) and right anodal stimulation (t11 = 2.7, p = 0.019) enhanced performances during stimulation. Enhancement transferred to an untrained task 50 min after right anodal stimulation (z11 = 2.263, p = 0.024). The tasks that showed the largest effects of active stimulation were spatial span backward (z11 = 2.39, p = 0.017) and BTA (z11 = 2.263, p = 0.024). Conclusions In adults with high-functioning ASD, active bifrontal tDCS given during WM tasks appears to improve performance. TDCS benefits also transferred to an untrained task completed shortly after stimulation. These results suggest that tDCS can improve WM task performance and could reduce some core deficits of autism. Trial registration NCT01602263
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Affiliation(s)
- J Jason van Steenburgh
- Department of Neurology, The Johns Hopkins University School of Medicine, 1629 Thames Street, Suite 350, Baltimore, MD 21231 USA
| | - Mark Varvaris
- Department of Neurology, The Johns Hopkins University School of Medicine, 1629 Thames Street, Suite 350, Baltimore, MD 21231 USA
| | - David J Schretlen
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287 USA.,Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Science, 600 N. Wolfe Street, Baltimore, MD 21287 USA
| | - Tracy D Vannorsdall
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287 USA.,Department of Neurology, The Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore, MD 21287 USA
| | - Barry Gordon
- Department of Neurology, The Johns Hopkins University School of Medicine, 1629 Thames Street, Suite 350, Baltimore, MD 21231 USA
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Cooperation Not Competition: Bihemispheric tDCS and fMRI Show Role for Ipsilateral Hemisphere in Motor Learning. J Neurosci 2017; 37:7500-7512. [PMID: 28674174 PMCID: PMC5546115 DOI: 10.1523/jneurosci.3414-16.2017] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 04/01/2017] [Accepted: 04/17/2017] [Indexed: 11/21/2022] Open
Abstract
What is the role of ipsilateral motor and premotor areas in motor learning? One view is that ipsilateral activity suppresses contralateral motor cortex and, accordingly, that inhibiting ipsilateral regions can improve motor learning. Alternatively, the ipsilateral motor cortex may play an active role in the control and/or learning of unilateral hand movements. We approached this question by applying double-blind bihemispheric transcranial direct current stimulation (tDCS) over both contralateral and ipsilateral motor cortex in a between-group design during 4 d of unimanual explicit sequence training in human participants. Independently of whether the anode was placed over contralateral or ipsilateral motor cortex, bihemispheric stimulation yielded substantial performance gains relative to unihemispheric or sham stimulation. This performance advantage appeared to be supported by plastic changes in both hemispheres. First, we found that behavioral advantages generalized strongly to the untrained hand, suggesting that tDCS strengthened effector-independent representations. Second, functional imaging during speed-matched execution of trained sequences conducted 48 h after training revealed sustained, polarity-independent increases in activity in both motor cortices relative to the sham group. These results suggest a cooperative rather than competitive interaction of the two motor cortices during skill learning and suggest that bihemispheric brain stimulation during unimanual skill learning may be beneficial because it harnesses plasticity in the ipsilateral hemisphere.SIGNIFICANCE STATEMENT Many neurorehabilitation approaches are based on the idea that is beneficial to boost excitability in the contralateral hemisphere while attenuating that of the ipsilateral cortex to reduce interhemispheric inhibition. We observed that bihemispheric transcranial direct current stimulation (tDCS) with the excitatory anode either over contralateral or ipsilateral motor cortex facilitated motor learning nearly twice as strongly as unihemispheric tDCS. These increases in motor learning were accompanied by increases in fMRI activation in both motor cortices that outlasted the stimulation period, as well as increased generalization to the untrained hand. Collectively, our findings suggest a cooperative rather than a competitive role of the hemispheres and imply that it is most beneficial to harness plasticity in both hemispheres in neurorehabilitation of motor deficits.
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The effect of transcranial direct current stimulation on motor sequence learning and upper limb function after stroke. Clin Neurophysiol 2017; 128:1389-1398. [PMID: 28410884 DOI: 10.1016/j.clinph.2017.03.036] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 03/19/2017] [Accepted: 03/24/2017] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To assess the impact of electrode arrangement on the efficacy of tDCS in stroke survivors and determine whether changes in transcallosal inhibition (TCI) underlie improvements. METHODS 24 stroke survivors (3-124months post-stroke) with upper limb impairment participated. They received blinded tDCS during a motor sequence learning task, requiring the paretic arm to direct a cursor to illuminating targets on a monitor. Four tDCS conditions were studied (crossover); anodal to ipsilesional M1, cathodal to contralesional M1, bihemispheric, sham. The Jebsen Taylor hand function test (JTT) was assessed pre- and post-stimulation and TCI assessed as the ipsilateral silent period (iSP) duration using transcranial magnetic stimulation. RESULTS The time to react to target illumination reduced with learning of the movement sequence, irrespective of tDCS condition (p>0.1). JTT performance improved after unilateral tDCS (anodal or cathodal) compared with sham (p<0.05), but not after bihemispheric (p>0.1). There was no effect of tDCS on change in iSP duration (p>0.1). CONCLUSIONS Unilateral tDCS is effective for improving JTT performance, but not motor sequence learning. SIGNIFICANCE This has implications for the design of future clinical trials.
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Fiori V, Nitsche M, Iasevoli L, Cucuzza G, Caltagirone C, Marangolo P. Differential effects of bihemispheric and unihemispheric transcranial direct current stimulation in young and elderly adults in verbal learning. Behav Brain Res 2017; 321:170-175. [DOI: 10.1016/j.bbr.2016.12.044] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 12/29/2016] [Accepted: 12/31/2016] [Indexed: 12/19/2022]
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Buch ER, Santarnecchi E, Antal A, Born J, Celnik PA, Classen J, Gerloff C, Hallett M, Hummel FC, Nitsche MA, Pascual-Leone A, Paulus WJ, Reis J, Robertson EM, Rothwell JC, Sandrini M, Schambra HM, Wassermann EM, Ziemann U, Cohen LG. Effects of tDCS on motor learning and memory formation: A consensus and critical position paper. Clin Neurophysiol 2017; 128:589-603. [PMID: 28231477 DOI: 10.1016/j.clinph.2017.01.004] [Citation(s) in RCA: 215] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 01/05/2017] [Accepted: 01/11/2017] [Indexed: 01/05/2023]
Abstract
Motor skills are required for activities of daily living. Transcranial direct current stimulation (tDCS) applied in association with motor skill learning has been investigated as a tool for enhancing training effects in health and disease. Here, we review the published literature investigating whether tDCS can facilitate the acquisition, retention or adaptation of motor skills. Work in multiple laboratories is underway to develop a mechanistic understanding of tDCS effects on different forms of learning and to optimize stimulation protocols. Efforts are required to improve reproducibility and standardization. Overall, reproducibility remains to be fully tested, effect sizes with present techniques vary over a wide range, and the basis of observed inter-individual variability in tDCS effects is incompletely understood. It is recommended that future studies explicitly state in the Methods the exploratory (hypothesis-generating) or hypothesis-driven (confirmatory) nature of the experimental designs. General research practices could be improved with prospective pre-registration of hypothesis-based investigations, more emphasis on the detailed description of methods (including all pertinent details to enable future modeling of induced current and experimental replication), and use of post-publication open data repositories. A checklist is proposed for reporting tDCS investigations in a way that can improve efforts to assess reproducibility.
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Affiliation(s)
- Ethan R Buch
- Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Emiliano Santarnecchi
- Berenson-Allen Center for Non-Invasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Medical Center, Harvard Medical School, Boston, MA, USA
| | - Andrea Antal
- Department of Clinical Neurophysiology, University Medical Center, Georg-August University, Göttingen, Germany
| | - Jan Born
- Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany; Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Pablo A Celnik
- Department of Physical Medicine and Rehabilitation, Johns Hopkins Medical Institution, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins Medical Institution, Baltimore, MD, USA
| | - Joseph Classen
- Department of Neurology, University of Leipzig, Leipzig, Germany
| | - Christian Gerloff
- Brain Imaging and NeuroStimulation (BINS) Laboratory, Department of Neurology University Medical Center Hamburg-Eppendorf Martinistr, Hamburg, Germany
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Friedhelm C Hummel
- Brain Imaging and NeuroStimulation (BINS) Laboratory, Department of Neurology University Medical Center Hamburg-Eppendorf Martinistr, Hamburg, Germany
| | - Michael A Nitsche
- Department of Psychology and Neuroscience, Leibniz Research Center for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | - Alvaro Pascual-Leone
- Berenson-Allen Center for Non-Invasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Medical Center, Harvard Medical School, Boston, MA, USA
| | - Walter J Paulus
- Department of Clinical Neurophysiology, University Medical Center, Georg-August University, Göttingen, Germany
| | - Janine Reis
- Department of Neurology, Albert Ludwigs University, Freiburg, Germany
| | - Edwin M Robertson
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK
| | | | - Marco Sandrini
- Department of Psychology, University of Roehampton, London, UK
| | - Heidi M Schambra
- Department of Rehabilitation and Regenerative Medicine, Columbia University, New York, NY, USA
| | - Eric M Wassermann
- Behavioral Neurology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Ulf Ziemann
- Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University, Tübingen, Germany
| | - Leonardo G Cohen
- Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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Ammann C, Spampinato D, Márquez-Ruiz J. Modulating Motor Learning through Transcranial Direct-Current Stimulation: An Integrative View. Front Psychol 2016; 7:1981. [PMID: 28066300 PMCID: PMC5179543 DOI: 10.3389/fpsyg.2016.01981] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 12/05/2016] [Indexed: 02/05/2023] Open
Abstract
Motor learning consists of the ability to improve motor actions through practice playing a major role in the acquisition of skills required for high-performance sports or motor function recovery after brain lesions. During the last decades, it has been reported that transcranial direct-current stimulation (tDCS), consisting in applying weak direct current through the scalp, is able of inducing polarity-specific changes in the excitability of cortical neurons. This low-cost, painless and well-tolerated portable technique has found a wide-spread use in the motor learning domain where it has been successfully applied to enhance motor learning in healthy individuals and for motor recovery after brain lesion as well as in pathological states associated to motor deficits. The main objective of this mini-review is to offer an integrative view about the potential use of tDCS for human motor learning modulation. Furthermore, we introduce the basic mechanisms underlying immediate and long-term effects associated to tDCS along with important considerations about its limitations and progression in recent years.
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Affiliation(s)
- Claudia Ammann
- Department of Physical Medicine and Rehabilitation, Johns Hopkins Medical Institution Baltimore, MD, USA
| | - Danny Spampinato
- Department of Physical Medicine and Rehabilitation, Johns Hopkins Medical Institution Baltimore, MD, USA
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Grimm F, Naros G, Gharabaghi A. Closed-Loop Task Difficulty Adaptation during Virtual Reality Reach-to-Grasp Training Assisted with an Exoskeleton for Stroke Rehabilitation. Front Neurosci 2016; 10:518. [PMID: 27895550 PMCID: PMC5108796 DOI: 10.3389/fnins.2016.00518] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 10/26/2016] [Indexed: 11/23/2022] Open
Abstract
Stroke patients with severe motor deficits of the upper extremity may practice rehabilitation exercises with the assistance of a multi-joint exoskeleton. Although this technology enables intensive task-oriented training, it may also lead to slacking when the assistance is too supportive. Preserving the engagement of the patients while providing “assistance-as-needed” during the exercises, therefore remains an ongoing challenge. We applied a commercially available seven degree-of-freedom arm exoskeleton to provide passive gravity compensation during task-oriented training in a virtual environment. During this 4-week pilot study, five severely affected chronic stroke patients performed reach-to-grasp exercises resembling activities of daily living. The subjects received virtual reality feedback from their three-dimensional movements. The level of difficulty for the exercise was adjusted by a performance-dependent real-time adaptation algorithm. The goal of this algorithm was the automated improvement of the range of motion. In the course of 20 training and feedback sessions, this unsupervised adaptive training concept led to a progressive increase of the virtual training space (p < 0.001) in accordance with the subjects' abilities. This learning curve was paralleled by a concurrent improvement of real world kinematic parameters, i.e., range of motion (p = 0.008), accuracy of movement (p = 0.01), and movement velocity (p < 0.001). Notably, these kinematic gains were paralleled by motor improvements such as increased elbow movement (p = 0.001), grip force (p < 0.001), and upper extremity Fugl-Meyer-Assessment score from 14.3 ± 5 to 16.9 ± 6.1 (p = 0.026). Combining gravity-compensating assistance with adaptive closed-loop feedback in virtual reality provides customized rehabilitation environments for severely affected stroke patients. This approach may facilitate motor learning by progressively challenging the subject in accordance with the individual capacity for functional restoration. It might be necessary to apply concurrent restorative interventions to translate these improvements into relevant functional gains of severely motor impaired patients in activities of daily living.
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Affiliation(s)
- Florian Grimm
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University of Tuebingen Tuebingen, Germany
| | - Georgios Naros
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University of Tuebingen Tuebingen, Germany
| | - Alireza Gharabaghi
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University of Tuebingen Tuebingen, Germany
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Grimm F, Walter A, Spüler M, Naros G, Rosenstiel W, Gharabaghi A. Hybrid Neuroprosthesis for the Upper Limb: Combining Brain-Controlled Neuromuscular Stimulation with a Multi-Joint Arm Exoskeleton. Front Neurosci 2016; 10:367. [PMID: 27555805 PMCID: PMC4977295 DOI: 10.3389/fnins.2016.00367] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 07/25/2016] [Indexed: 11/13/2022] Open
Abstract
Brain-machine interface-controlled (BMI) neurofeedback training aims to modulate cortical physiology and is applied during neurorehabilitation to increase the responsiveness of the brain to subsequent physiotherapy. In a parallel line of research, robotic exoskeletons are used in goal-oriented rehabilitation exercises for patients with severe motor impairment to extend their range of motion (ROM) and the intensity of training. Furthermore, neuromuscular electrical stimulation (NMES) is applied in neurologically impaired patients to restore muscle strength by closing the sensorimotor loop. In this proof-of-principle study, we explored an integrated approach for providing assistance as needed to amplify the task-related ROM and the movement-related brain modulation during rehabilitation exercises of severely impaired patients. For this purpose, we combined these three approaches (BMI, NMES, and exoskeleton) in an integrated neuroprosthesis and studied the feasibility of this device in seven severely affected chronic stroke patients who performed wrist flexion and extension exercises while receiving feedback via a virtual environment. They were assisted by a gravity-compensating, seven degree-of-freedom exoskeleton which was attached to the paretic arm. NMES was applied to the wrist extensor and flexor muscles during the exercises and was controlled by a hybrid BMI based on both sensorimotor cortical desynchronization (ERD) and electromyography (EMG) activity. The stimulation intensity was individualized for each targeted muscle and remained subthreshold, i.e., induced no overt support. The hybrid BMI controlled the stimulation significantly better than the offline analyzed ERD (p = 0.028) or EMG (p = 0.021) modality alone. Neuromuscular stimulation could be well integrated into the exoskeleton-based training and amplified both the task-related ROM (p = 0.009) and the movement-related brain modulation (p = 0.019). Combining a hybrid BMI with neuromuscular stimulation and antigravity assistance augments upper limb function and brain activity during rehabilitation exercises and may thus provide a novel restorative framework for severely affected stroke patients.
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Affiliation(s)
- Florian Grimm
- Division of Functional and Restorative Neurosurgery, Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen Tuebingen, Germany
| | - Armin Walter
- Department of Computer Engineering, Wilhelm Schickard Institute for Computer Science, Eberhard Karls University Tuebingen Tuebingen, Germany
| | - Martin Spüler
- Department of Computer Engineering, Wilhelm Schickard Institute for Computer Science, Eberhard Karls University Tuebingen Tuebingen, Germany
| | - Georgios Naros
- Division of Functional and Restorative Neurosurgery, Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen Tuebingen, Germany
| | - Wolfgang Rosenstiel
- Department of Computer Engineering, Wilhelm Schickard Institute for Computer Science, Eberhard Karls University Tuebingen Tuebingen, Germany
| | - Alireza Gharabaghi
- Division of Functional and Restorative Neurosurgery, Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen Tuebingen, Germany
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Grimm F, Gharabaghi A. Closed-Loop Neuroprosthesis for Reach-to-Grasp Assistance: Combining Adaptive Multi-channel Neuromuscular Stimulation with a Multi-joint Arm Exoskeleton. Front Neurosci 2016; 10:284. [PMID: 27445658 PMCID: PMC4917563 DOI: 10.3389/fnins.2016.00284] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 06/07/2016] [Indexed: 11/25/2022] Open
Abstract
Stroke patients with severe motor deficits cannot execute task-oriented rehabilitation exercises with their affected upper extremity. Advanced rehabilitation technology may support them in performing such reach-to-grasp movements. The challenge is, however, to provide assistance as needed, while maintaining the participants' commitment during the exercises. In this feasibility study, we introduced a closed-loop neuroprosthesis for reach-to-grasp assistance which combines adaptive multi-channel neuromuscular stimulation with a multi-joint arm exoskeleton. Eighteen severely affected chronic stroke patients were assisted by a gravity-compensating, seven-degree-of-freedom exoskeleton which was attached to the paretic arm for performing reach-to-grasp exercises resembling activities of daily living in a virtual environment. During the exercises, adaptive electrical stimulation was applied to seven different muscles of the upper extremity in a performance-dependent way to enhance the task-oriented movement trajectory. The stimulation intensity was individualized for each targeted muscle and remained subthreshold, i.e., induced no overt support. Closed-loop neuromuscular stimulation could be well integrated into the exoskeleton-based training, and increased the task-related range of motion (p = 0.0004) and movement velocity (p = 0.015), while preserving accuracy. The highest relative stimulation intensity was required to facilitate the grasping function. The facilitated range of motion correlated with the upper extremity Fugl-Meyer Assessment score of the patients (p = 0.028). Combining adaptive multi-channel neuromuscular stimulation with antigravity assistance amplifies the residual motor capabilities of severely affected stroke patients during rehabilitation exercises and may thus provide a customized training environment for patient-tailored support while preserving the participants' engagement.
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Affiliation(s)
- Florian Grimm
- Division of Functional and Restorative Neurosurgery, Department of Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen Tuebingen, Germany
| | - Alireza Gharabaghi
- Division of Functional and Restorative Neurosurgery, Department of Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen Tuebingen, Germany
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Grimm F, Naros G, Gharabaghi A. Compensation or Restoration: Closed-Loop Feedback of Movement Quality for Assisted Reach-to-Grasp Exercises with a Multi-Joint Arm Exoskeleton. Front Neurosci 2016; 10:280. [PMID: 27445655 PMCID: PMC4914560 DOI: 10.3389/fnins.2016.00280] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 06/06/2016] [Indexed: 11/13/2022] Open
Abstract
Assistive technology allows for intensive practice and kinematic measurements during rehabilitation exercises. More recent approaches attach a gravity-compensating multi-joint exoskeleton to the upper extremity to facilitate task-oriented training in three-dimensional space with virtual reality feedback. The movement quality, however, is mostly captured through end-point measures that lack information on proximal inter-joint coordination. This limits the differentiation between compensation strategies and genuine restoration both during the exercise and in the course of rehabilitation. We extended in this proof-of-concept study a commercially available seven degree-of-freedom arm exoskeleton by using the real-time sensor data to display a three-dimensional multi-joint visualization of the user's arm. Ten healthy subjects and three severely affected chronic stroke patients performed reach-to-grasp exercises resembling activities of daily living assisted by the attached exoskeleton and received closed-loop online feedback of the three-dimensional movement in virtual reality. Patients in this pilot study differed significantly with regard to motor performance (accuracy, temporal efficiency, range of motion) and movement quality (proximal inter-joint coordination) from the healthy control group. In the course of 20 training and feedback sessions over 4 weeks, these pathological measures improved significantly toward the reference parameters of healthy participants. It was moreover feasible to capture the evolution of movement pattern kinematics of the shoulder and elbow and to quantify the individual degree of natural movement restoration for each patient. The virtual reality visualization and closed-loop feedback of joint-specific movement kinematics makes it possible to detect compensation strategies and may provide a tool to achieve the rehabilitation goals in accordance with the individual capacity for genuine functional restoration; a proposal that warrants further investigation in controlled studies with a larger cohort of stroke patients.
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Affiliation(s)
- Florian Grimm
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen, Germany
| | - Georgios Naros
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen, Germany
| | - Alireza Gharabaghi
- Division of Functional and Restorative Neurosurgery, and Centre for Integrative Neuroscience, Eberhard Karls University Tuebingen, Germany
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Naros G, Naros I, Grimm F, Ziemann U, Gharabaghi A. Reinforcement learning of self-regulated sensorimotor β-oscillations improves motor performance. Neuroimage 2016; 134:142-152. [PMID: 27046109 DOI: 10.1016/j.neuroimage.2016.03.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 01/29/2016] [Accepted: 03/07/2016] [Indexed: 10/22/2022] Open
Abstract
Self-regulation of sensorimotor oscillations is currently researched in neurorehabilitation, e.g. for priming subsequent physiotherapy in stroke patients, and may be modulated by neurofeedback or transcranial brain stimulation. It has still to be demonstrated, however, whether and under which training conditions such brain self-regulation could also result in motor gains. Thirty-two right-handed, healthy subjects participated in a three-day intervention during which they performed 462 trials of kinesthetic motor-imagery while a brain-robot interface (BRI) turned event-related β-band desynchronization of the left sensorimotor cortex into the opening of the right hand by a robotic orthosis. Different training conditions were compared in a parallel-group design: (i) adaptive classifier thresholding and contingent feedback, (ii) adaptive classifier thresholding and non-contingent feedback, (iii) non-adaptive classifier thresholding and contingent feedback, and (iv) non-adaptive classifier thresholding and non-contingent feedback. We studied the task-related cortical physiology with electroencephalography and the behavioral performance in a subsequent isometric motor task. Contingent neurofeedback and adaptive classifier thresholding were critical for learning brain self-regulation which, in turn, led to behavioral gains after the intervention. The acquired skill for sustained sensorimotor β-desynchronization correlated significantly with subsequent motor improvement. Operant learning of brain self-regulation with a BRI may offer a therapeutic perspective for severely affected stroke patients lacking residual hand function.
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Affiliation(s)
- G Naros
- Division of Functional and Restorative Neurosurgery, University of Tuebingen, Germany.
| | - I Naros
- Division of Functional and Restorative Neurosurgery, University of Tuebingen, Germany; Centre for Integrative Neuroscience, University of Tuebingen, Germany
| | - F Grimm
- Division of Functional and Restorative Neurosurgery, University of Tuebingen, Germany; Centre for Integrative Neuroscience, University of Tuebingen, Germany
| | - U Ziemann
- Department of Neurology and Stroke, University of Tuebingen, Germany; Hertie Institute for Clinical Brain Research, University of Tuebingen, Germany
| | - A Gharabaghi
- Division of Functional and Restorative Neurosurgery, University of Tuebingen, Germany; Centre for Integrative Neuroscience, University of Tuebingen, Germany.
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